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66ef8f4d51558a15efbe2f75 | 10.26434/chemrxiv-2024-7b24p | Single-molecule detection of oligonucleotides using the fluorescent nucleobase analogue ABN | In this study, we investigate the properties of the fluorescent pyrimidine analogue ABN in duplex DNA oligonucleotides using ensemble measurements, time-resolved fluorescence, and single-molecule total internal reflection fluorescence (smTIRF) microscopy. As a free nucleoside, ABN exhibits ε442 nm = 20,000 M−1cm−1 and Φem = 0.39 in 1× PBS buffer at pH 7.4 and its high brightness is retained when base-paired and stacked in duplex DNA. The ABN nucleoside’s time-resolved fluorescence shows that it emits primarily from a thymine-like tautomeric form T1 that matches its ground state, but is photo-tautomerized to a cytosine-like form T2 that contributes ~ 20% to the emission intensity, with a shorter lifetime. In duplex DNA when base-paired with adenine, fluorescent emission is again dominated by T1, with ~ 20% of the intensity deriving from photo-induced double proton transfer to form a Watson–Crick-like base pair between T2 and the imino tautomer of adenine. When base-paired with guanine, ABN adopts predominantly the T2 tautomer form to enable Watson–Crick base pairing and this tautomer exhibits red-shifted absorption and blue-shifted emission; around 20% of ABN remains in the T1 tautomeric form and engages in a wobble base pair with G, contributing to the bulk fluorescent properties. The high brightness of ABN and its relatively long absorption and emission wavelengths position it uniquely among fluorescent nucleobase analogues (FBAs) for applications in single-molecule fluorescence. We immobilized ABN using strand hybridization and biotin pull-down on a PLL-PEG–streptavidin surface and imaged it using a 488 nm laser and an smTIRF microscope. The brightness and photostability of ABN in this context are enhanced by the use of the GO/CAT oxygen scavenging system and triplet depopulation using Trolox. Under these conditions, ABN-containing oligos are readily observed as bright spots with time traces of up to 9 seconds and single-step photobleaching. These results show that ABN is the first FBA to enable single-molecule fluorescence studies of oligonucleotides and requires only a conventional smTIRF configuration. | George Samaan; Andres Jimenez Salinas; Alexandra Bailie; Julian Grim; Julian Cizmic; Anita Jones; Young Kwang Lee; Byron Purse | Physical Chemistry; Biological and Medicinal Chemistry; Organic Chemistry; Bioorganic Chemistry; Biophysical Chemistry; Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-09-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66ef8f4d51558a15efbe2f75/original/single-molecule-detection-of-oligonucleotides-using-the-fluorescent-nucleobase-analogue-abn.pdf |
672c3dc5f9980725cf66c292 | 10.26434/chemrxiv-2024-b0cjw-v2 | Waste Polystyrene Upcycling via the Birch Reduction with Ball-Mill Grinding | Commodity polymer upcycling methods, which turn plastic waste into new functional polymers, represent an important approach to reducing the burden of plastic on the environment. Here, we report a Birch reduction that is compatible with polystyrene (PS), PS derivatives, and several types of waste PS using a 1 min ball-mill grinding method. In most cases, full conversion was achieved, yielding primarily the dearomatized skipped diene repeat unit (up to ca. 80%), with minimal cross-linking and without chain scission. For PS derivatives, high reduction performance was maintained, and reductive defunctionalization was observed for halogenated- and sulfonated-PS derivatives. Importantly, full conversion of waste PS samples was achieved on a gram scale without increasing the reaction time. The resulting reduced polymer could also be cross-linked via thiol-ene reactions, giving network materials with distinct properties from PS. This study represents an important step toward developing a sustainable upcycling method for PS waste plastics. | Gyeonghun Kim; Byeongyeol Park; Nayeon Kim; Ye-jin Hwang; Antonio Rizzo; Gregory I. Peterson | Polymer Science | CC BY NC ND 4.0 | CHEMRXIV | 2024-11-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/672c3dc5f9980725cf66c292/original/waste-polystyrene-upcycling-via-the-birch-reduction-with-ball-mill-grinding.pdf |
62fbbb74d34847396773efba | 10.26434/chemrxiv-2022-5v7rt | The characteristic curvature (Cc) definition and its use in assessing Cc for single ionic surfactants | The Hydrophilic-Lipophilic-Difference (HLD) is a set of empirical equations that correlate the formulation conditions at phase inversion (HLD=0). Based on partition studies for nonionic surfactants, the HLD can be interpreted as a normalized chemical potential difference between the surfactant dissolved in water and oil. The Net-Average Curvature (NAC) model extrapolates this interpretation into a curvature form that has been used to fit and predict the phase behavior of surfactant-oil-water (SOW) systems. The curvature interpretation of HLD led to the renaming of the HLD surfactant parameter, sigma (σ), as the characteristic curvature (Cc). This work addresses two concerns around this interpretation; first, for ionic surfactants, an HLD≠0 value for one surfactant might not mean the same for another (breaking the chemical potential interpretation), and second, the Cc interpretation has not been demonstrated. To this end, the net curvature (Hn) of six anionic and two cationic surfactants was evaluated (individually) from solubilization data at the characteristic condition of 25°C, no added cosolvent, in the presence of an oil mixture with equivalent alkane carbon number (EACN) of zero, and as a function of salinity. These studies showed that, indeed, the original HLD equation for ionic surfactant could not be interpreted as chemical potential or curvature because a salinity prefactor "bi" was missing. The revised equation, HLDbi = bi∙ln(S)-kbi∙EACN+Ccbi -aTbi∙(T-25°C), could now be interpreted as a curvature expression, and it was demonstrated that Cc could be obtained from curvature at characteristic conditions, only that the proper expression is Cc = Ccbi/bi. | Zhuotao Leng; Edgar Acosta | Physical Chemistry; Chemical Engineering and Industrial Chemistry; Thermodynamics (Chem. Eng.); Interfaces; Self-Assembly | CC BY NC ND 4.0 | CHEMRXIV | 2022-08-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62fbbb74d34847396773efba/original/the-characteristic-curvature-cc-definition-and-its-use-in-assessing-cc-for-single-ionic-surfactants.pdf |
60c75700ee301c2c31c7b47d | 10.26434/chemrxiv.14356154.v1 | Unlocking the Catalytic Hydrogenolysis of Chlorosilanes into Hydrosilanes with Superbases | The efficient synthesis of hydrosilanes by catalytic ydrogenolysis of chlorosilanes is described, using an Iridum (III) pincer catalyst. A careful selection of a nitrogen base (incl.
sterically hindered guanidines and phosphazenes) can unlock the preparation of
Me<sub>3</sub>SiH, Et<sub>3</sub>SiH and Me<sub>2</sub>SiHCl in high yield (up
to 98%), directly from their corresponding chlorosilanes. | Gabriel Durin; Jean-Claude Berthet; Emmanuel Nicolas; Thibault Cantat | Homogeneous Catalysis; Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2021-04-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75700ee301c2c31c7b47d/original/unlocking-the-catalytic-hydrogenolysis-of-chlorosilanes-into-hydrosilanes-with-superbases.pdf |
6655d574418a5379b07ac8ee | 10.26434/chemrxiv-2024-cqq2c | POTASSIUM HEXATITANATE FIBER FREE.
A NEW CLASS OF ALKALI TITANATES WITH TITANIUM OXIDATION NUMBER DIFFERENT FROM +4
| A new class of Titanates are presented with Titanium oxidation N° different from +4. The Titanates thus obtained presents a non-fibrous morphology. Ways of synthesis are reported. SEM pictures and fiber analysis showing an absolutely fiber free material. A new structure, unknown till now, is displayed, recovered through a dedicated software, through which a new formula has been calculated. An hypothesis of structure stabilization is proposed, confirmed by TGA and DSC. The new material has been tested in brake pads, confirming with good performances. | Mario Gerardo Terruzzi | Inorganic Chemistry; Crystallography – Inorganic | CC BY NC ND 4.0 | CHEMRXIV | 2024-05-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6655d574418a5379b07ac8ee/original/potassium-hexatitanate-fiber-free-a-new-class-of-alkali-titanates-with-titanium-oxidation-number-different-from-4.pdf |
666859ae12188379d8d95de6 | 10.26434/chemrxiv-2024-v19rz | Unraveling the impact of nuclear quantum effects on proton affinity using nuclear electronic orbital-density functional theory: A Comprehensive Benchmark Study | This work presents a benchmarking of the nuclear electronic orbital-method used for multicomponent density functional theory calculations (NEO-DFT). We check the influence of the different parameters necessary in the method at the example of predicting proton affinity values. Here, NEO-DFT accounts for nuclear quantum effects of the proton being transferred. We used a test set of 72 molecules for this benchmark and took experimental proton affinities as reference. Our investigation of exchange correlation functionals reveals that CAM-B3LYP demonstrates the best performance. In the framework of NEO-DFT, the interaction with the quantum nuclei is treated via electron-proton correlation functionals. Here, the epc17-2 gave a similar performance to the computationally more demanding epc19. Compared to DFT (treating nuclei classically), NEO DFT provides a better value for the proton affinities when electron-proton correlation functionals are used. With respect to the electronic basis sets, the def2-QZVP basis set provides the most accurate values compared to def2-TZVP or def2-SVP, albeit with increased computational demands. Additionally, the nuclear basis sets show negligible effects on proton affinity accuracy and lack any trend. Overall, this study underlines the performance of NEO-DFT as an efficient approach to treat nuclear quantum effects using the example of calculating proton affinity values. The findings give a guideline towards the choice of optimal parameter sets in NEO-DFT calculations in the future. | Raza Ullah Khan; Ralf Tonner-Zech | Theoretical and Computational Chemistry; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2024-06-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/666859ae12188379d8d95de6/original/unraveling-the-impact-of-nuclear-quantum-effects-on-proton-affinity-using-nuclear-electronic-orbital-density-functional-theory-a-comprehensive-benchmark-study.pdf |
652e3e9e8bab5d20558423f7 | 10.26434/chemrxiv-2023-5pg50-v2 | Tribological Behaviour of Aluminium-Copper-Cullet
Metal Composite | An Aluminium composite metal, Al-Cu-CP was fabricated from recycled raw materials. The composite was fabricated by means of stir casting method due to its simplicity and economic worth. The composite and the unreinforced Al were both analysed for chemical and mechanical properties. The Al-Cu-CP metal composite produced has shown appreciable level of wear resistance and corrosion resistance in artificial seawater (3.5 g/L NaCl) and allowed to stand for 96 h at room temperature. Different loads were considered for the wear resistance tests, 5 N, 10 N, 15 N and 20 N while 150 rpm, 250 rpm, 350 rpm and 450 rpm were the speeds selected for the adhesive wear resistance test. Improved properties were observed after heat treatment of the Al-Cu-CP metal composite. The heat treated composite was more resistant to corrosion than the untreated composite and it has been confirmed that the corrosion resistance of the materials under study has direct relationship with the immersion period. When the maximum load was applied to the three (3) sets of the samples (unreinforced, treated and treated composites), severe degrees of wear manifested on their various surfaces. Optical images from morphological analysis revealed that wear severity was highest on the surface of the unreinforced matrix, followed by the untreated metal composite and the heat-treated composite was found to be the least affected. Due to these enhanced properties of the Al-Cu-CP metal composite, it could be recommended where high strength with light density product is required such as automobile brake shoes and brake disc as a result of its upgraded mechanical properties. | Awwal Hussain Nuhu; SUZI Salwah Jikan; SALIZA Asman; NUR AZAM Badarulzaman; ABDULLAHI Tijjani; MUNIRA Khalid | Materials Science; Analytical Chemistry; Composites; Analytical Chemistry - General; Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2023-10-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/652e3e9e8bab5d20558423f7/original/tribological-behaviour-of-aluminium-copper-cullet-metal-composite.pdf |
65c93d6b66c13817296bf3fc | 10.26434/chemrxiv-2024-lj9jk | Substantial Oxygen Loss and Chemical Expansion in Lithium-Rich Layered Oxides at Moderate Delithiation | Delithiation of layered oxide electrodes triggers irreversible oxygen loss, one of the primary degradation modes in lithium-ion batteries. However, the delithiation-dependent mechanisms of oxygen loss remain poorly understood. Here, we investigate the oxygen nonstoichiometry in Li- and Mn-rich Li1.18-xNi0.21Mn0.53Co0.08O2-δ electrodes as a function of Li content by utilizing cycling protocols with long open-circuit voltage steps at varying states of charge. Surprisingly, we observe significant oxygen loss even at moderate delithiation, corresponding to 2.5, 4.0 and 7.6 mL O2 g-1 after resting at 135, 200, and 265 mAh g-1 (relative to the pristine material) for 100 h. Our observations suggest an intrinsic oxygen instability consistent with predictions of high equilibrium oxygen activity at intermediate potentials. From a mechanistic viewpoint, we show that cation disorder greatly lowers the oxygen vacancy formation energy by decreasing the coordination number of transition metals to certain oxygen ions. In addition, we observe a large chemical expansion coefficient with respect to oxygen nonstoichiometry, which is about three times greater than those of classical oxygen-deficient materials such as fluorite and perovskite oxides. Our work challenges the conventional wisdom that deep delithiation is a necessary condition for oxygen loss in layered oxide electrodes and highlights the importance of calendar aging for investigating oxygen stability. | Peter M. Csernica; Kit McColl; Grace M. Busse; Kipil Lim; Diego F. Rivera; David A. Shapiro; M. Saiful Islam; William C. Chueh | Theoretical and Computational Chemistry; Materials Science; Energy; Energy Storage | CC BY NC 4.0 | CHEMRXIV | 2024-02-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65c93d6b66c13817296bf3fc/original/substantial-oxygen-loss-and-chemical-expansion-in-lithium-rich-layered-oxides-at-moderate-delithiation.pdf |
61ebd6fa0716a8529e3823dc | 10.26434/chemrxiv-2022-nq9k0 | An Open Platform for Large Scale LC-MS-Based Metabolomics
| Metabolomics utilising liquid chromatography mass spectrometry (LC-MS) offers biomedical researchers a powerful means of assessing and comparing human phenotypes via measurement of the metabolome in biological samples. Platforms for LC-MS-based global profiling quantify hundreds or thousands of small molecule metabolites and/or lipids using combinations of distinct methods and analyses to develop broad coverage of the metabolome with high analytical sensitivity and specificity. However, the breadth of coverage provided by global profiling assays still outpaces efforts to characterise them by annotating profile signals with their respective metabolite identities. Fully realising the utility of metabolomics in biomedical research requires closing this gap by more accurately defining the finite metabolome coverage provided by common LC-MS-based global profiling methods. To date, method characterisation activities have progressed in the absence of broadly accepted standard LC methods as parallel efforts at building in-house libraries. While methodological diversity is a natural consequence of different design constraints and priorities observed across laboratories, it does tend to relegate in-house libraries to silos of information and investment that fail to advance the broader metabolomics community. Here, the National Phenome Centre’s established platform for LC-MS-based global profiling of small molecule metabolites and lipids is made open in its entirety. Complete and detailed protocols for reversed-phase and hydrophilic interaction liquid chromatography LC-MS methods are offered alongside discussion of the rationale for their design specifics. In addition to the formal protocols used routinely within the Centre, the reader is provided with notes for replication and adaptation of the methodology, as well as guidance on the preparation of biofluid samples to ensure their suitability for the analytical platform. The Centre’s accompanying open-source software for data extraction and pre-processing is also reviewed, and finally the method-specific identity of more than 700 small molecule and lipid species is disclosed. We hope that the substantial annotation information is useful to metabolomics practitioners of all experience levels and promotes the subsequent disclosure and constructive comparison (e.g. for validation and collective growth) of other in-house libraries and their associated methods. For interdisciplinary research teams looking to introduce LC-MS based metabolomics to their biomedical research programmes, we offer the open platform as a turnkey solution and welcome the growth in collective knowledge that may arise from its implementation in others’ hands. | Matthew Lewis; Elena Chekmeneva; Stephane Camuzeaux; Caroline Sands; Ada Yuen; Mark David; Ash Salam; Katie Chappell; Benjamin Cooper; Gordon Haggart; Lynn Maslen; María Gómez-Romero; Verena Horneffer-van der Sluis; Gonçalo Correia; Zoltan Takats | Analytical Chemistry; Analytical Chemistry - General; Mass Spectrometry; Separation Science | CC BY 4.0 | CHEMRXIV | 2022-02-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61ebd6fa0716a8529e3823dc/original/an-open-platform-for-large-scale-lc-ms-based-metabolomics.pdf |
60f7f7a41f990cb45aa3a6e9 | 10.26434/chemrxiv-2021-j48tn | Surfactant-assisted synthesis of titanium nanoMOFs for thin film fabrication | We use dodecanoic acid as a modulator to yield titanium MOF nanoparticles with good control of size and colloid stability and minimum impact to the properties of the framework to enable direct fabrication of crystalline, porous thin films | María Romero-Angel; Javier Castells-Gil; Víctor Rubio-Giménez; Rob Ameloot; Sergio Tatay; Carlos Martí-Gastaldo | Inorganic Chemistry; Coordination Chemistry (Inorg.); Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2021-07-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60f7f7a41f990cb45aa3a6e9/original/surfactant-assisted-synthesis-of-titanium-nano-mo-fs-for-thin-film-fabrication.pdf |
60c74c6a702a9b11b618b66d | 10.26434/chemrxiv.12478568.v1 | In Silico Screening of Some Antiviral Phytochemicals as Drug Leads Against Covid-19 | <p>Background: COVID-19 caused by SARS-CoV-2 in December 2019 has become a pandemic</p><p>hazard to the community health. It is a respiratory difficulty causing fever, dry cough, fatigue,</p><p>shortness of breath, muscle aches and some instances lead to pneumonia. Coronaviruses have</p><p>large viral RNA Genomes and are single-stranded positive-sense RNA viruses. The nsp10/nsp16</p><p>protein is an important target because it is essential for the virus to replicate, the papain-like</p><p>protease (Nsp3), the main protease (Nsp5), the primary RNA-dependent RNA polymerase</p><p>(Nsp12) are also attractive drug targets for this disease. The uses of phytochemicals as</p><p>therapeutic agents have been increasing in recent years. Some antiviral phytochemicals were</p><p>taken based on literature survey for this study.</p><p>Methods: ADME parameters and drug like nature of phytochemicals were screened using</p><p>SwissADME web tool. Three dimensional structures of targets are downloaded from Protein</p><p>Data Bank and docked with phytochemicals & control by using software FlexX.</p><p>Results: Morin shows significant results in ADME screening and Drug likeness prediction</p><p>studies, it shows stable bonding pattern with all four targets in compare to other phytochemicals</p><p>and control, shows least score in docking and forms maximum number of hydrogen bonds with</p><p>the active residues of the receptors.</p><p>Conclusion: Based on present observation of docking results, ADME parameters and drug like</p><p>nature, we suggest that morin may be a potent new drug candidate against Covid-19.</p><p>Keywords: COVID-19, coronavirus, drug target, phytochemicals, Drug likeness, ADME,</p><p>docking, morin</p> | Monjur Ahmed Laskar; Moriom Begam; Manabendra Dutta Choudhury | Bioinformatics and Computational Biology | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74c6a702a9b11b618b66d/original/in-silico-screening-of-some-antiviral-phytochemicals-as-drug-leads-against-covid-19.pdf |
64e80bbedd1a73847f739b97 | 10.26434/chemrxiv-2023-545gw | The Training of Machine Learning Potentials for Reactive Systems: A Colab Tutorial on Basic Models | In the last several years, there has been a surge in the development of machine learning potential (MLP) models for describing molecular systems. We are interested in a particular area of this field — the training of system-specific MLPs for reactive systems — with the goal of using these MLPs to accelerate free energy simulations of chemical and enzyme reactions. To help new members in our labs become familiar with the basic techniques, we have put together a self-guided Colab tutorial (https://cc-ats.github.io/mlp_tutorial/), which we expect to be also useful to other young researchers in the community. Our tutorial begins with the introduction of simple fitting neural network (FNN) and kernel-based (using Gaussian Process Regression, GPR) models by fitting the two-dimensional Müller-Brown potential. Subsequently, two simple descriptors are presented for extracting features of molecular systems: symmetry functions (including the ANI variant) and embedding neural networks (such as DeepPot-SE). Lastly, these features will be fed into FNN and GPR models to reproduce the energy/force of molecular configurations of the Claisen rearrangement. | Xiaoliang Pan ; Ryan Snyder ; Jia-Ning Wang; Chance Lander ; Carly Wickizer; Richard Van ; Andrew Chesney; Yuanfei Xue ; Yuezhi Mao ; Ye Mei ; Jingzhi Pu; Yihan Shao | Theoretical and Computational Chemistry; Machine Learning | CC BY NC ND 4.0 | CHEMRXIV | 2023-08-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64e80bbedd1a73847f739b97/original/the-training-of-machine-learning-potentials-for-reactive-systems-a-colab-tutorial-on-basic-models.pdf |
63cf3206bb08ed75511511aa | 10.26434/chemrxiv-2023-w6lkp | RAFT polymerization by the radical decarboxylation of carboxylic acids | The controlled grafting of polymers from small- and macro-molecular substrates is an essential process for many advanced polymer applications. This usually requires the pre-functionalization of substrates with an appropriate functional group, such as a RAFT agent or ATRP initiator, which requires additional synthetic steps. In this paper, we describe the direct grafting of RAFT polymers from carboxylate containing substrates via photochemical radical decarboxylation. This method utilizes the innate functional groups present in the substrates, and achieves efficient polymer initiation in a single step with excellent control of molecular weight and dispersity. | Meri Ayurini; Joel Francis Brolan Hooper | Polymer Science; Organic Polymers; Polymerization catalysts | CC BY NC ND 4.0 | CHEMRXIV | 2023-01-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63cf3206bb08ed75511511aa/original/raft-polymerization-by-the-radical-decarboxylation-of-carboxylic-acids.pdf |
660d577d418a5379b0fb07a9 | 10.26434/chemrxiv-2024-n6zhx | Nickel-Catalyzed Atroposelective Cross-Electrophile Coupling of Aryl Halides: A General and Practical Route to Diverse MOP-type Ligands | We report a highly cross- and atroposelective coupling between ortho-(chloro)arylphosphine oxides and ortho-(bromo)arylethers. This previously unknown asymmetric nickel-catalyzed reaction offers a direct route to highly enantioenriched axially chiral biaryl monophos-phine oxides that are difficult to access by other means. These products can be readily reduced to generate chiral MOP-type ligands bear-ing complex skeletal backbones. The utility of these chiral ligands in asymmetric catalysis is also demonstrated. | Raphael Kim; Lebogang Kgoadi; Jacob Hayes; Derek Rainboth; Catherine Mudd; Glenn Yap; Donald Watson | Organic Chemistry; Catalysis; Organometallic Chemistry; Organic Synthesis and Reactions; Catalysis; Ligands (Organomet.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-04-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/660d577d418a5379b0fb07a9/original/nickel-catalyzed-atroposelective-cross-electrophile-coupling-of-aryl-halides-a-general-and-practical-route-to-diverse-mop-type-ligands.pdf |
6780d1b56dde43c908f7bf05 | 10.26434/chemrxiv-2025-bn6l7 | Celite-Catalyzed Mechanochemical C-H Bond Trifluoromethylation and Pentafluoroethylation | The late-stage trifluoromethylation of C‒H bonds in (hetero)arenes is an important tool in the development of novel pharmaceuticals and agricultural chemicals, which typically relies on the use of electrophilic trifluoromethylating rea-gents in bulk solvent with or without a catalyst, while mechanochemical approaches rely on the use of piezoelectric materials. Herein, we describe a mechanochemical approach, in which celite, diatomaceous earth or biogenic sand activated through ball milling induce C‒H bond perfluoroalkylation of (hetero)arenes. To the best of our knowledge, this is the first reported reaction promoted by mechanoactivated Celite, along a number of Earth-abundant metal oxides and carbonates, including non-piezoelectric solids. This approach offers environmentally benign, Nature-inspired materials as efficient mechanoactivators and conceptually broadens the scope of mechanoactivated solids to the mate-rials previously deemed inert. | Thomas Hasiweder; Hoan Dinh; Dilip Pandey; Aleksandr Sorvanov; Julia Khusnutdinova | Inorganic Chemistry; Catalysis; Heterogeneous Catalysis; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6780d1b56dde43c908f7bf05/original/celite-catalyzed-mechanochemical-c-h-bond-trifluoromethylation-and-pentafluoroethylation.pdf |
653f257ea8b423585a8c242e | 10.26434/chemrxiv-2023-rsbjr | Natural Products Inspired [3 + 2] Cycloaddition Enables Efficient Syntheses of Lignans | Mimicking biosynthetic pathways of hongkonoids led to the development of a new Cu(Ⅰ)-catalyzed [3 + 2] cycloaddition of α-hydroxyketone and β-keto enol ethers, affording chiral tetrahydrofuran acetals in a highly diastereoselective manner and 100% atom economy. Computational studies on the mechanism disclosed a concerted but asynchronous Michael addition/aldol reaction. Of the same importance, this methodology provides a practical biomimetic approach for one-step construction of the dibenzylbutyrolactol lignan backbone starting from two phenyl propane derivatives, opening up a powerful new approach for lignan synthesis, which is showcased by succinct total syntheses of two biologically important aryltetralin-type lignans, β-apopicropodophyllin and cycloolivil. Given the mild and operationally simple conditions, the developed chemistry might have a promising prospect in potential industrial applications. | Dong-Yue Cai; Wei-Ming Shi; Zhao-Hui Jin; Zhi-Xiang Yu; Jin-Xin Zhao; Jian-Min Yue | Organic Chemistry; Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/653f257ea8b423585a8c242e/original/natural-products-inspired-3-2-cycloaddition-enables-efficient-syntheses-of-lignans.pdf |
610952b3d03b3d5d6404d4ae | 10.26434/chemrxiv-2022-93whb | Mechanism of Tubulin Oligomers and Single-Rings Disassembly Catastrophe | Cold tubulin dimers coexist with tubulin oligomers and single-rings. These structures are involved in microtubule assembly, however, their dynamics are poorly understood. Using state-of-the-art solution synchrotron time-resolved small-angle X-ray scattering we discovered a disassembly catastrophe (half-life of about 0.1 sec) of tubulin rings and oligomers upon dilution or addition of guanosine triphosphate. A slower disassembly (half-life of about 38 sec) was observed following a temperature increase.
Our analysis showed that the assembly and disassembly processes were consistent with an isodesmic mechanism, involving a sequence of reversible reactions at which dimers were rapidly added/removed one at a time, terminated by a two orders-of-magnitude slower ring-closing/opening step.
We revealed how assembly conditions varied the mass fraction of tubulin in each of the coexisting structures, the rate constants, and the standard Helmholtz free energies for closing a ring and for longitudinal dimer-dimer associations. | Asaf Shemesh; Avi Ginsburg; Raviv Dharan; Yael Levi-Kalisman; Israel Ringel; Uri Raviv | Physical Chemistry; Chemical Kinetics; Self-Assembly; Structure | CC BY NC ND 4.0 | CHEMRXIV | 2022-04-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/610952b3d03b3d5d6404d4ae/original/mechanism-of-tubulin-oligomers-and-single-rings-disassembly-catastrophe.pdf |
64676f42f2112b41e9ceba25 | 10.26434/chemrxiv-2023-5szvm | The Role of Inverted Ligand Field in the Electronic Structure and Reactivity of Octahedral Formal Platinum (IV) Complexes | Platinum complexes are ubiquitous in chemistry and largely used as catalysts or as precursors in drug chemistry, thus a deep knowledge of their electronic properties may help in planning new synthetic strategies or exploring new potential applications. Herein, the electronic structure of many octahedral platinum “IV” complexes is drastically revised especially when the metal is associated with electronegative elements such as halogens and chalcogens. The investigation revealed that in most of the cases the five d platinum orbitals are invariably full, thus the empty antibonding orbitals, usually localized on the metal, are mainly centered on the ligands, suggesting a questionable assignment of oxidation state IV. The analysis supports the occurrence of the Inverted Ligand Field theory in all cases with the only exceptions of the Pt-F and Pt-O bonding. The trends for the molecular complexes are mirrored also by the Density of States plots of extended structures featuring octahedral platinum moieties in association with chalcogens atoms. Based on the gathered information on the electronic structure of complexes and materials, the oxidative addition of a Se-Cl linkage to a square platinum complex to achieve an octahedral moiety has been revised in the framework of the Inverted Ligand Field. | Andrea Ienco; Francesco Ruffo; Gabriele Manca | Inorganic Chemistry; Bonding; Solid State Chemistry; Transition Metal Complexes (Inorg.) | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64676f42f2112b41e9ceba25/original/the-role-of-inverted-ligand-field-in-the-electronic-structure-and-reactivity-of-octahedral-formal-platinum-iv-complexes.pdf |
60c74a53ee301c5c2cc79c25 | 10.26434/chemrxiv.12180402.v1 | Protein Degradation Profile Reveals Dynamic Nature of 20S CP Small Molecule Stimulation | <p>Small molecules have recently been discovered to stimulate the 20S core particle (CP) of the proteasome to degrade proteins, such as a-synuclein. While these studies have focused on particular proteins that are known 20S CP substrates, it is currently unclear how many or what types of proteins may be affected by enhancing this degradation process. We present here a study that utilizes four 20S CP stimulators to determine how each can affect the degradation of proteins in a biochemical assay with purified proteins, an overexpressed GFP-fusion protein in cells, and the effects of stimulators using label-free quantitative proteomic analysis for a more broad understanding on their impact. The results of these studies highlight that the impact of small molecule stimulators of the 20S CP on protein degradation cannot be easily predicted. While 20S CP stimulators will likely increase the degradation of proteins that have significant disorder, such as a-synuclein and tau, we observed different impacts on the degradation of proteins less than 90% disordered. To gain greater insight into the cellular systems that may be affected by 20S CP stimulators, we analyzed the proteome of HEK-293T cells treated with two of our stimulators, AM-404 or miconazole. These results were then compared to cells treated with a proteasome inhibitor, bortezomib. Our results show that 20S CP stimulators affect a smaller number of proteins as compared to bortezomib. The proteomics analysis corroborates our biochemical and GFP-fusion protein results, confirming that the impact of a 20S CP stimulator on protein degradation is dependent on the stimulator. Taken together, this study reveals the dynamic nature of the 20S CP, as small molecule stimulators can have a variety of mechanisms of action to change protein degradation activity. Our studies show that 20S CP stimulation can lead to a decrease in protein levels, more so those proteins that are significantly disordered, and that small molecule stimulators can potentially be tailored to decrease certain protein types.</p> | Rachel
A. Coleman; Tiago Jose Paschoal Sobreira; Uma Aryal; Darci Trader | Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2020-04-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74a53ee301c5c2cc79c25/original/protein-degradation-profile-reveals-dynamic-nature-of-20s-cp-small-molecule-stimulation.pdf |
60c74ff19abda245b0f8d941 | 10.26434/chemrxiv.12964604.v1 | A Modular Toolkit to Fabricate Microfluidic Devices for 3D Cell Culture and Near Real-time Measurements | Microfluidic technology has tremendously facilitated the development of in vitro cell cultures and studies. Conventionally, microfluidic devices are fabricated with extensive facilities by well-trained researchers, which hinders the widespread adoption of the technology for broader applications. Enlightened by the fact that low-cost microbore tubing is a natural microfluidic channel, we developed a series of adaptors in a toolkit that can twine, connect, organize, and configure the tubing to produce functional microfluidic units. Three subsets of the toolkit were thoroughly developed: the tubing and scoring tools, the flow adaptors, and the 3D cell culture suite. To demonstrate the usefulness and versatility of the toolkit, we assembled a microfluidic device and successfully applied it for 3D macrophage cultures, flow-based stimulation, and automated near real-time quantitation with new knowledge generated. Overall, we present a new technology that allows simple, fast, and robust assembly of customizable and scalable microfluidic devices with minimal facilities, which is broadly applicable to research that needs or could be enhanced by microfluidics. | Giraso Kabandana; Adam Michael Ratajczak; Chengpeng Chen | Analytical Chemistry - General | CC BY NC ND 4.0 | CHEMRXIV | 2020-09-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74ff19abda245b0f8d941/original/a-modular-toolkit-to-fabricate-microfluidic-devices-for-3d-cell-culture-and-near-real-time-measurements.pdf |
66f27c9851558a15eff4036a | 10.26434/chemrxiv-2024-gnlt0 | High entropy alloys: assessing atomic-scale mixing and surface passivation with time-of-flight secondary ion mass spectrometry | High entropy alloys (HEAs) are alloys that consist of five or more principal elements in near-equiatomic proportions, that tend to form simple solid solutions during solidification owing to high mixing entropy. HEAs have been identified as promising candidates for various heterogeneous catalysis and electrocatalysis applications. This work illustrates the utility of time-of-flight secondary ion mass spectrometry (ToF-SIMS) in analyzing HEAs, offering detailed chemical information about the top layers of a sample. Ru-Pt-Pd-Ir-Rh based porous HEAs with different mixing characteristics were analyzed alongside seven simpler alloys. An automatic quantification process was developed to effectively deal with the large data sets obtained from ToF-SIMS spectra of HEAs, allowing for accurate and reliable data interpretation. The complex chemical fingerprint obtained from the alloys surface was translated into a matrix showing the individual isotopic mass distributions of each poly atomic chemical species. From this, we introduce two key metrics: the Cluster Ratio (CR) and the Oxide Ratio (OR), to quantify respectively the degree of atomic-level mixing and the surface oxidation. With such data processing framework in hands, ToF-SIMS becomes a highly effective tool for assessing the properties of HEAs. Our findings reveal that increasing elemental complexity (number of different elements in the alloy) enhances atomic mixing. Moreover, HEAs with enhanced atomic mixing are shown to be more resistant to surface oxidation. | Oscar F. Laurent; Maria Letizia De Marco; Marco Faustini; Cédric Boissière; Claude Poleunis; Arnaud Delcorte; Damien P. Debecker | Inorganic Chemistry; Analytical Chemistry; Analytical Chemistry - General; Spectroscopy (Anal. Chem.); Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2024-09-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66f27c9851558a15eff4036a/original/high-entropy-alloys-assessing-atomic-scale-mixing-and-surface-passivation-with-time-of-flight-secondary-ion-mass-spectrometry.pdf |
6142122e90051eea0ef4857c | 10.26434/chemrxiv-2021-qgnfh-v2 | Formation of Pharmaceutical Salts and Cocrystals via Vapour-Assisted Tumbling (VAT) – A Solvent Efficient Process with Potential Industrial Applications | Crystallisations on both the academic and industrial scale often use large volumes of solvent. In order decrease the environmental impact of such processes, new techniques must be discovered that increase the efficiency of the solvents used. Introduced here is a process that combines repurposed industry standard hardware and aspects of mechanochemistry to produce a technique we call “Vapour Assisted Tumbling” (VAT). Pharmaceutical and well-known cocrystals and salts were formed by tumbling the coformers in an atmosphere of vaporised solvent, in this study, methanol (MeOH). This was done inside a custom built analogue of an industrial rotary cone dryer (RCD). It was found that a desired solid form could be obtained as monitored by powder X-ray diffraction and differential scanning calorimetry. By repurposing industrial RCDs, it is feasible that solid forms can be crystallised with both minimal and reusable/recyclable solvent – drastically lowering the environmental impact of such transformations. | Alexander J. Stirk; Fabio E. S. Souza; Jenny Gerster; Fatemeh M. Mir; Avedis Karadeolian; Allan W. Rey | Chemical Engineering and Industrial Chemistry; Industrial Manufacturing; Pharmaceutical Industry; Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2021-09-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6142122e90051eea0ef4857c/original/formation-of-pharmaceutical-salts-and-cocrystals-via-vapour-assisted-tumbling-vat-a-solvent-efficient-process-with-potential-industrial-applications.pdf |
6260aa251033882bd5f4f314 | 10.26434/chemrxiv-2022-gtgzf | Making Cytometry of Reaction Rate Constant (CRRC) Applicable to Motile Cells | Cytometry of Reaction Rate Constant (CRRC) is a method for studying heterogeneity of cell populations with regards to activity of cellular reactions. It is based on time-lapse fluorescence microscopy which facilitates following reaction kinetics in individual cells. The current CRRC workflow utilizes a single fluorescence image to manually identify cell contours; these contours are then used to determine fluorescence intensity of individual cells in the entire time-stack of images. This workflow can only be used reliably if the cells maintain their positions during the time-lapse measurements; if the cells move, the results of a CRRC experiment will be inaccurate. The requirement of invariant cell positions during a prolonged imaging is impossible to satisfy for motile cells. Here we report on developing an advanced workflow that makes CRRC applicable to motile cells. The new workflow combines fluorescence microscopy with brightfield (BF) microscopy and utilizes automated processing and analysis of images. A BF image is taken right after every fluorescence image and used to determine cell contours. The contours are tracked through the time-stack of BF images to account for cell movement. A set of contours, which is unique for every image, is then used to determine fluorescence intensity of cells in the associated fluorescent image. Finally, time dependencies of intracellular fluorescence intensities are used to determine the rate constant and plot a kinetic histogram “number of cells vs rate constant”. The robustness of the new workflow to cell movement was confirmed experimentally by conducting a CRRC study of cross-membrane transport in motile cells. The new workflow makes CRRC applicable to a wide range of cell types and eliminates the influence of cell motility on the accuracy of results. | Robel Yosief; Giammarco Nebbioso; Vasilij Koshkin; Yumin Qiu; Chun Peng; Vadim Elisseev; Sergey Krylov | Analytical Chemistry; Chemoinformatics; Imaging; Microscopy | CC BY NC ND 4.0 | CHEMRXIV | 2022-04-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6260aa251033882bd5f4f314/original/making-cytometry-of-reaction-rate-constant-crrc-applicable-to-motile-cells.pdf |
64091d44cc600523a3e14c30 | 10.26434/chemrxiv-2022-t49dz-v2 | Simple and Convenient Mapping of Molecular Dynamics Mechanical Property Predictions for Strain Rate, Temperature, and Degree of Cure | It is well-known that all-atom molecular dynamics (MD) predictions of mechanical properties of thermoset resins suffer from multiple accuracy issues associated with their viscous nature. The nanosecond simulation times of MD simulations do not allow for the direct simulation of the molecular conformational relaxations that occur under laboratory time scales. This adversely affects the prediction of mechanical properties at realistic strain rates, intermediate degrees of cure, and elevated temperatures. An efficient method of correcting such MD predictions of elastic properties is proposed and demonstrated. The phenomenological approach is used to map the predictions of Young's modulus and Poisson's ratio for a DGEBF/DETDA epoxy system to the corresponding laboratory-based properties for intermediate degrees of cure and temperatures above and below the glass transition temperature. The approach uses characterization data from dynamical mechanical analysis temperature sweep experiments. The mathematical formulation and experimental characterization of the mapping are described, and the resulting corrections to the predicted elastic properties for various degrees of cure and temperatures are compared with the experiment. This mapping is particularly important to mitigate the strain-rate effect associated with MD predictions, as well as to accurately predict mechanical properties at elevated temperatures and intermediate degrees of cure to facilitate accurate and efficient composite material process modeling. | Sagar Patil; Aaron Krieg; Leif Odegard; Upendra Yadav; Julia King; Marianna Maiaru; Gregory Odegard | Theoretical and Computational Chemistry; Materials Science; Polymer Science; Polymerization (Polymers); Computational Chemistry and Modeling; Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2023-03-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64091d44cc600523a3e14c30/original/simple-and-convenient-mapping-of-molecular-dynamics-mechanical-property-predictions-for-strain-rate-temperature-and-degree-of-cure.pdf |
64b2ee2ab053dad33a4f3870 | 10.26434/chemrxiv-2023-7mzkw | Derivation of Morse Potential Function | The Morse potential is widely used in chemistry to describe interatomic interactions. However, there is no explicit derivation for this empirical potential from physically meaningful atomic quan- tities. We show that the Morse potential can be derived from a simple atomic screened charge model, which accounts for the shielded nuclear charge by the electron density and exponentially de- cays with distance. The bond dissociation energy of a diatomic molecule is obtained by combining the quantum mechanical covalent and classical electrostatic interactions. The revealed connec- tions between the parameters of the Morse potential, the Pauling bond order and electronegativity bridge the gap between the classical and quantum mechanical descriptions of chemical bonds. The proposed derivation and interpretation of the Morse potential in terms of atomic quantities such as electron-nuclear attraction energy and orbital exponents will be valuable in helping students to form a simple picture of chemical bond. | Amir Mirzanejad; Sergey Varganov | Theoretical and Computational Chemistry; Physical Chemistry; Chemical Education; Chemical Education - General; Computational Chemistry and Modeling; Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2023-07-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64b2ee2ab053dad33a4f3870/original/derivation-of-morse-potential-function.pdf |
661532a221291e5d1d74fbf3 | 10.26434/chemrxiv-2024-xv7db | Chemical composition, antileishmanial, and antifungal activi-ties of essential oils from Cinnamomum cassia bark, Schinus molle dried leaves and their blends | This study reports on the chemical composition and antileishmanial and anticandidal activities of essential oils (EOs) distilled from Schinus molle dried leaves (SM-EO), Cinnamomum cassia branch bark (CC-EO) and their blends against promastigote forms of Leishmania (Leishmania) ama-zonensis and nine Candida strains. Major constituents of SM-EO were spathulenol (26.93%), β-caryophyllene (19.90%), and caryophyllene oxide (12.69%), whereas cinnamaldehyde (60.11%), cinnamyl acetate (20.90%) and (E)-cis-2-methoxycinnamic acid (10.37%) were predominant in CC-EO. SM-EO (IC50 = 21.45 µg/mL) and CC-EO (IC50 = 23.27 µg/mL) displayed good activity against L. amazonensis. SM-EO and CC-EO also proved to be good or moderate activity against nine Can-dida strains, with Minimum Inhibitory Concentration (MIC) values ranging from 31.25 to 250 µg/mL. While the three SM-EO and CC-EO blends were not more active than the EOs tested in-dividually, they exhibited remarkably high antileishmanial activity, with IC50 values ranging between 3.12 and 7.04 µg/mL, which is very similar to the IC50 of amphotericin B (positive con-trol). These results show that SM-EO, CC-EO, and their blends may be considered to participate in the formulation of drugs with antileishmanial and antifungal activities. | Aternoskaires Silva; Cássia Fernandes; Daiane dos Santos; Maria Mazza; Jackson Silva; Lizandra Magalhães; Regina Pires; Mayker Miranda; Antônio Crotti | Biological and Medicinal Chemistry; Organic Chemistry; Agriculture and Food Chemistry; Natural Products; Drug Discovery and Drug Delivery Systems; Microbiology | CC BY NC ND 4.0 | CHEMRXIV | 2024-04-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/661532a221291e5d1d74fbf3/original/chemical-composition-antileishmanial-and-antifungal-activi-ties-of-essential-oils-from-cinnamomum-cassia-bark-schinus-molle-dried-leaves-and-their-blends.pdf |
60c745069abda2832df8c4bc | 10.26434/chemrxiv.9959132.v1 | Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores | Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br /> | Shuyuan Zheng; Taiping Hu; Xin Bin; Yunzhong Wang; Yuanping Yi; Yongming Zhang; Wang Zhang Yuan | Clusters; Physical and Chemical Processes; Physical and Chemical Properties | CC BY NC ND 4.0 | CHEMRXIV | 2019-10-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c745069abda2832df8c4bc/original/clustering-triggered-efficient-room-temperature-phosphorescence-from-nonconventional-luminophores.pdf |
663b6aee418a5379b0c2dd18 | 10.26434/chemrxiv-2024-hd62q | Versatile Deacylative Cross-coupling of Aromatic Ketones | Transition metal-catalyzed cross-couplings represent the most dependable techniques for linking aryl electrophiles with nucleophiles to synthesize a diverse array of valuable aromatic compounds. While aromatic ketones are crucial intermediates in the synthesis of aromatic compounds with numerous known methods for carbonyl transformations and aromatic ring modifications, few consider them as aryl electrophiles suitable for cross-coupling. This is primarily because forming new bonds with nucleophiles requires the cleavage of a strong C–C bond. Herein, we introduce a cross-coupling method that effectively utilizes aromatic ketones as versatile aryl electrophiles. The cornerstone of our strategy is the transformation of aromatic ketones into aromatic esters via sequential Claisen and regioselective retro-Claisen condensations. The resulting esters are then capable of undergoing reactions with various nucleophiles in a one-pot process. | Hikaru Nakahara; Ryota Isshiki; Masayuki Kubo; Keiichiro Iizumi; Kei Muto; Junichiro Yamaguchi | Organic Chemistry; Organic Compounds and Functional Groups; Organic Synthesis and Reactions | CC BY NC 4.0 | CHEMRXIV | 2024-05-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/663b6aee418a5379b0c2dd18/original/versatile-deacylative-cross-coupling-of-aromatic-ketones.pdf |
666be8dc01103d79c5311541 | 10.26434/chemrxiv-2024-4l3t8 | Iodine-Catalyzed Carbonyl-Alkyne Metathesis Reactions | The reaction between aldehydes or ketones and alkynes –the carbonyl-alkyne metathesis– constitutes a very useful strategy for the synthesis of ,-unsaturated carbonyls. We now demonstrate that iodine is a highly efficient catalyst for both the intra- and intermolecular metathesis reaction in very small concentrations (0.1–1 mol%). Our protocol outperforms other catalytic systems, is operationally very simple, cheap, metal-free, and tolerates a large variety of functional groups (e.g., –CN, –CO2Me, –Br, –OH) at very low catalyst loadings. We can furthermore show that iodine-catalyzed carbonyl-alkyne metatheses can be combined with other iodine-catalyzed reactions in one-pot procedures to afford larger and more complex molecular structures. Finally, our mechanistic studies indicate that the iodonium ion is the active catalyst under the reaction conditions. | Thiemo Arndt; Martin Breugst | Organic Chemistry; Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-06-14 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/666be8dc01103d79c5311541/original/iodine-catalyzed-carbonyl-alkyne-metathesis-reactions.pdf |
6785797c81d2151a02fb5500 | 10.26434/chemrxiv-2025-cjjxv | Photocatalysis Enables Chemodivergent Radical Polar Crossover: Ritter-Type Amidation vs Heck-Type Olefin Carbofunctionalizations | Enhancing the sp³-hybridized character of molecular scaffolds (the "Escape from Flatland" strategy) is a crucial target to in-crease the probability of finding new drugs or agrochemicals. In this regard, an ideal platform is provided by three-component alkene difunctionalization reactions, which enable the simultaneous introduction of two distinct, orthogonal functional groups into the C=C bond in a single step. Herein, we report a photoredox catalyzed Ritter-type carboamidation of electronically di-verse styrenes harnessing non-stabilized, nucleophilic primary radicals generated from readily-accessible carboxylic acid-derived redox active esters. Furthermore, it was found that Heck-type products were chemoselectively obtained by simply switching aryl olefin acceptors with 1,1-diarylolefins. In the context of photocatalytic chemodivergence, various trisubstituted alkenes were synthesized. Both Ritter-Type and Heck-type olefin carbofunctionalizations were scalable up to 4 mmol scale in batch and continuous flow. | Mattia Lepori; Cassie Pratley; Indrasish Dey; Veronika Roider; Joshua Philip Barham | Organic Chemistry; Catalysis; Photochemistry (Org.); Homogeneous Catalysis; Photocatalysis | CC BY 4.0 | CHEMRXIV | 2025-01-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6785797c81d2151a02fb5500/original/photocatalysis-enables-chemodivergent-radical-polar-crossover-ritter-type-amidation-vs-heck-type-olefin-carbofunctionalizations.pdf |
65c9eec29138d23161ec8dcc | 10.26434/chemrxiv-2023-fdjbl-v3 | Biofabrics from Sodium Alginate | This was a study meant to understand the properties and nature of
biofabrics made with the help of sodium alginate, which is an extract of
brown seaweed, sodium alginate as a substance is often used for baking
purposes. The research aimed at the making of biofabrics from many
different organic and inorganic materials like tea, beetroot, coffee, sugar,
water, colored water and even salt water. The study aims at
understanding and taking a step further at progressing the development
of sustainable fabrics. Our biofabrics showcase the potential to
significantly reduce the environmental impact associated with
conventional textile manufacturing. Its properties can be customized to
cater to a wide array of applications. | Mohammad Farhan; Syed Rahmathullah Hussaini; Affan Mohammed; Neelesh Gokuldas; Naresh Subramanian | Biological and Medicinal Chemistry; Biochemistry; Environmental biology | CC BY 4.0 | CHEMRXIV | 2025-03-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65c9eec29138d23161ec8dcc/original/biofabrics-from-sodium-alginate.pdf |
60c73f1b567dfeebe9ec3916 | 10.26434/chemrxiv.7240766.v1 | Plastic Embedded Gold Nanoparticles as 3D Printing Dichroic Nanocomposite Material | <div>
<div>
<div>
<div>
<p>The incorporation of dichroic nanoparticles in 3D printable plastic results in a dichroic
nanocomposite material that can be easily 3D printed. Gold nanoparticles that shows
dichroic properties have been embedded in polyvinylalcohol, a standard 3D printable plastic.
The nanocomposite shows dichroic properties and standard printability properties. </p>
</div>
</div>
</div>
</div> | Lars Kool; Anton Bunschoten; Aldrik Velders; Vittorio Saggiomo | Composites; Nanostructured Materials - Materials; Optical Materials; Nanostructured Materials - Nanoscience | CC BY NC ND 4.0 | CHEMRXIV | 2018-10-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73f1b567dfeebe9ec3916/original/plastic-embedded-gold-nanoparticles-as-3d-printing-dichroic-nanocomposite-material.pdf |
672ce759f9980725cf76412f | 10.26434/chemrxiv-2024-0x8b4 | Field-dependent relaxation profiles of biomolecular systems | The function of biomolecular systems, including biological macromolecules, often crucially depends on their dynamics. Nuclear Magnetic Resonance (NMR) is one of the most informative methods used to study biomolecules and their internal mobility, with atomic resolution, in near-physiological conditions. NMR relaxation profiles, obtained from the field dependence of the nuclear relaxation rates, in particular, offer the possibility to probe dynamic processes over a wide range of time scales. Relaxation profiles are routinely acquired using field-cycling relaxometers operating at a maximum field of the order of 1 T. These measurements however suffer from a lack of resolution. On the other hand, relaxation rates measured at high magnetic fields contain poor information on motions on timescales longer than few nanoseconds. The possibility to acquire relaxation profiles extended to low fields but with high resolution, obtained by shuttling the sample back and forth in the stray field of a high-field spectrometer, is expected to dramatically improve the potentialities of NMR relaxometry. Here, we review investigations of relaxometry in a wide range of biomolecular systems, such as proteins, phospholipids, or biological fluids. Although multiple models of motions have been developed to describe the relaxation rates and their field dependence, most experimental investigations rely on the model-free approach. A variety of relaxation profiles of both diamagnetic and paramagnetic biomolecular systems are here reviewed and analysed using point dipole-point dipole interaction models. | Adam Kubrak; Rajka Pejanovic; Kahinga Kamau; Danuta Kruk; Fabien Ferrage; Giacomo Parigi | Physical Chemistry | CC BY 4.0 | CHEMRXIV | 2024-11-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/672ce759f9980725cf76412f/original/field-dependent-relaxation-profiles-of-biomolecular-systems.pdf |
60c74f47337d6c4569e280f2 | 10.26434/chemrxiv.12886961.v1 | Step-Growth Polymerisation of Alkyl Acrylates via Concomitant Oxa-Michael and Transesterification Reactions | Herein we propose an auto-tandem catalytic approach towards the preparation of poly(ester-ether)s from simple alkyl acrylates and diols. By combining oxa-Michael addition with transesterification the preparation of hydroxy functionalised acrylate monomers can be avoided.<br /> | Karin Ratzenböck; David Pahovnik; Christian Slugovc | Organic Polymers; Polymerization (Polymers) | CC BY NC ND 4.0 | CHEMRXIV | 2020-09-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74f47337d6c4569e280f2/original/step-growth-polymerisation-of-alkyl-acrylates-via-concomitant-oxa-michael-and-transesterification-reactions.pdf |
67633ad6fa469535b903e303 | 10.26434/chemrxiv-2024-8dkh0 | Closed-Loop Navigation of a Kinetic Zone Diagram for Redox-Mediated Electrocatalysis Using Bayesian Optimization, a Digital Twin, and Automated Electrochemistry | Molecular electrocatalysis campaigns often require tuning multiple experimental parameters to obtain kinetically insightful electrochemical measurements, a prohibitively time-consuming task when performing comprehensive studies across multiple catalysts and substrates. In this work, we present an autonomous workflow that combines Bayesian optimization and automated electrochemistry to perform fully unsupervised cyclic voltammetry (CV) studies of molecular electrocatalysis. We developed CV descriptors that leveraged the conceptual framework of the EC’ kinetic zone diagram to enable efficient Bayesian optimization. The CV descriptor’s effect on optimization performance was evaluated using a digital twin of our autonomous experimental platform, quantifying the accuracy of obtained kinetic values against the known ground truth. We demonstrated our platform experimentally by performing autonomous studies of TEMPO-catalyzed ethanol and isopropanol electro-oxidation, demonstrating rapid identification of kinetically insightful conditions in 10 or less iterations through the closed-loop workflow. Overall, this work highlights the application of autonomous electrochemical platforms to accelerate mechanistic studies in molecular electrocatalysis and beyond. | Michael Pence; Gavin Hazen; Joaquín Rodríguez López | Catalysis; Analytical Chemistry; Energy; Electrochemical Analysis; High-throughput Screening; Electrocatalysis | CC BY 4.0 | CHEMRXIV | 2024-12-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67633ad6fa469535b903e303/original/closed-loop-navigation-of-a-kinetic-zone-diagram-for-redox-mediated-electrocatalysis-using-bayesian-optimization-a-digital-twin-and-automated-electrochemistry.pdf |
62d1922cfe12e3e43da3d624 | 10.26434/chemrxiv-2022-55czc | Enhanced Mechanical Stability and Scratch Resistance of Mesoporous Aluminosilicate Thin Films | Mesoporous coatings are widely used in industries such as optics, display technologies, photovoltaics, and bioengineering, due to their attractive properties such as high surface to volume ratio and excellent mass and electron transport characteristics. While structural parameters and material composition can be routinely tailored to the respective applications, improvements of their mechanical properties and robustness, essential for their long-term performance, remain a challenge. Herein, we provide a comprehensive study on the relationship between the degree of porosity, type of material processing and resulting mechanical properties for the use case of mesoporous aluminosilicate thin films that were co-assembled via a sacrificial block copolymer structure-directing agent. Several routes, including the introduction of chelating agents on the precursor solution, a two-step calcination process, and a variation over the aluminium content were explored with the objective of improving the scratch resistance and mechanical properties of the final mesoporous thin film. Pencil hardness tests were combined with atomic force microscopy analysis to investigate the macroscopic scratch resistance, i.e. plastic deformation. Ellipsometric porosimetry served to determine the elastic deformation of the nanoscopic architecture via measurement of the Young’s modulus. Our comparative investigation highlights the promising role of organic chelating agents to the sol-gel formulation to slow down the hydrolysis of the aluminium precursor, which facilitated improvements of the mechanical performance close to industrial standard. | Barry Reid; Ishaa Mane; Faizah Ahmed; Maximiliano Jara Fornerod; Máté Füredi; Alberto Alvarez-Fernandez; Stefan Guldin | Materials Science; Nanoscience; Coating Materials; Materials Processing; Thin Films; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-07-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62d1922cfe12e3e43da3d624/original/enhanced-mechanical-stability-and-scratch-resistance-of-mesoporous-aluminosilicate-thin-films.pdf |
61e2e6350121b94bb62d4ea6 | 10.26434/chemrxiv-2022-wr02f | Towards Identification of Protein-Protein Interaction Stabilizers via Inhibitory Peptide-Fragment Hybrids Using Templated Fragment Ligation | Using the hDMX/14-3-3 interaction, acylhydrazone-based ligand-directed fragment ligation was used to identify protein-protein interaction (PPI) inhibitory peptide-fragment hybrids. Separation of the peptide-fragment hybrids into the components yielded fragments that stabilized the hDMX/14-3-3 interaction. | Sonja Srdanovic; Zsofia Hegedus; Stuart Warriner; Wilson Andrew | Biological and Medicinal Chemistry; Organic Chemistry; Bioorganic Chemistry; Supramolecular Chemistry (Org.); Chemical Biology | CC BY 4.0 | CHEMRXIV | 2022-01-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61e2e6350121b94bb62d4ea6/original/towards-identification-of-protein-protein-interaction-stabilizers-via-inhibitory-peptide-fragment-hybrids-using-templated-fragment-ligation.pdf |
60c74535f96a00c2b2286b58 | 10.26434/chemrxiv.8678450.v2 | Direct Measurement of Charge Reversal on Lipid Bilayers using Heterodyne-Detected Second Harmonic Generation Spectroscopy | <div><div><div><p>We report the detection of charge reversal induced by the adsorption of a cationic polyelectrolyte, poly(allylamine) hydrochloride (PAH), to buried supported lipid bilayers (SLBs), used as idealized model biological membranes. Through the use of an α-quartz reference crystal, we quantify the total interfacial potential at the interface in absolute units, using HD-SHG as an optical voltmeter in which the traditional wire leads of a voltmeter have been replaced by photons. This quantification is made possible by isolating from other contributions to the total SHG response the phase-shifted potential-dependent third-order susceptibility. We detect the sign and magnitude of the surface potential and the point of charge reversal at buried interfaces without prior information or complementary data. Isolation of the second-order susceptibility contribution from the overall SHG response allows us to directly characterize the Stern and Diffuse Layers over single-component SLBs formed from three different zwitterionic lipids of different gel-to-fluid phase transition temperatures (Tms). We determine whether the surface potential changes with the physical phase state (gel, transitioning, or fluid) of the SLB and incorporate 20 percent of negatively charged lipids to the zwitterionic SLB to investigate how the surface potential and the</p><p>second-order nonlinear susceptibility chi(2) change with surface charge.</p></div></div></div> | HanByul Chang; Paul Ohno; Yangdongling Liu; Emilie Lozier; Naomi Dalchand; Franz Geiger | Biophysical Chemistry; Interfaces; Optics; Physical and Chemical Processes; Spectroscopy (Physical Chem.); Surface; Thermodynamics (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2019-10-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74535f96a00c2b2286b58/original/direct-measurement-of-charge-reversal-on-lipid-bilayers-using-heterodyne-detected-second-harmonic-generation-spectroscopy.pdf |
662f9ed321291e5d1d0460e5 | 10.26434/chemrxiv-2024-wh6tp | Identification of Dihydropyrazolo[1,5-a]pyrazin-4(5H)-ones as Cyclic Products of Beta-Amidomethyl Vinyl Sulfone Alphavirus Cysteine Protease Inhibitors | Optimized syntheses of (E)-5-(2-ethoxyphenyl)-N-(3-(methylsulfonyl)allyl)-1H-pyrazole-3-carboxamide (RA-0002034, 1), a promising antiviral covalent cysteine protease inhibitor lead, were developed. The syntheses avoid the contamination of 1 with the cyclic dihydropyrazolo[1,5-a]pyrazin-4(5H)-one 2, which formed by intramolecular aza-Michael reaction of the vinyl sulfone warhead under basic conditions and at pH 7.4 in phosphate buffer. 1 could be synthesized using either modified amide coupling conditions or through introduction of a MOM-protecting group and was stable as a TFA or HCl salt. Although acyclic 1 demonstrated poor pharmacokinetics with high in vivo clearance in mice, the cyclic 2 showed improved plasma exposure. The potential use of dihydropyrazolo[1,5-a]pyrazin-4(5H)-ones as prodrugs for the acyclic beta-amidomethyl-vinyl sulfone warhead was demonstrated by GSH capture experiments. | Anirban Ghoshal; Álvaro Magalhães; Kesatebrhan Asressu; Mohammad Hossain; Matthew Todd; Timothy Willson | Biological and Medicinal Chemistry; Drug Discovery and Drug Delivery Systems | CC BY 4.0 | CHEMRXIV | 2024-04-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/662f9ed321291e5d1d0460e5/original/identification-of-dihydropyrazolo-1-5-a-pyrazin-4-5h-ones-as-cyclic-products-of-beta-amidomethyl-vinyl-sulfone-alphavirus-cysteine-protease-inhibitors.pdf |
664f0bb7418a5379b0133a8e | 10.26434/chemrxiv-2024-s7dht | Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling | We report the synthesis of germanyl triazoles formed via a copper-catalysed azide-alkyne cycloaddition (CuAAC) of germanyl alkynes. The reaction is functional group tolerant and compatible with complex molecules. Installation of the Ge moeity enables further diversification of the triazole products, including chemoselective transition metal-catalysed cross-coupling reactions using bifunctional boryl/germyl species. | John Halford-McGuff; Thomas Richardson; Aidan McKay; Frederik Peschke; Glenn Burley; Allan Watson | Organic Chemistry; Catalysis; Organic Compounds and Functional Groups; Homogeneous Catalysis | CC BY 4.0 | CHEMRXIV | 2024-05-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/664f0bb7418a5379b0133a8e/original/germanyl-triazoles-as-a-platform-for-cu-aac-diversification-and-chemoselective-orthogonal-cross-coupling.pdf |
60c75c06469df42600f45992 | 10.26434/chemrxiv.6940379.v11 | The Master Key to the Problem of Reversible Chemical Hydrogen Storage is 12 kJ (mol H<sub>2</sub>)<sup>-1</sup> | <p>This article unveils on basis of the ideal gas law, the atomic conception of matter and classic equilibrium thermodynamics the ideal final regularity of reversible hydrogen mass transfer. This result allows to clarify problems of metal hydride chemistry which otherwise are impossible to understand e.g. why the substitution of 4 mol % Na by K in Ti-doped NaAlH<sub>4</sub> raises the reversible hydrogen capacity by 42 % at no substantial change to thermodynamic reaction parameters or how the dopants take effect in (Rb/K)-co-doped Mg(NH<sub>2</sub>)<sub>2</sub>/2LiH; both cases are discussed in this context. This ideal final regularity is a hitherto missed out superposition of physical chemistry fundamentals and defines the maximum specific energy at distinct conditions: directly for two-phase hydrogen storage methods and indirectly for electrochemical systems due to the normative role of hydrogen electrode potentials.</p> | Roland Hermann Pawelke | Alloys; Fuels - Materials; Hydrogen Storage Materials; Nanocatalysis - Catalysts & Materials; Solid State Chemistry; Theory - Inorganic; Energy Storage; Fuels - Energy Science; Fuel Cells; Physical and Chemical Processes; Physical and Chemical Properties; Thermodynamics (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2021-05-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75c06469df42600f45992/original/the-master-key-to-the-problem-of-reversible-chemical-hydrogen-storage-is-12-k-j-mol-h-sub-2-sub-sup-1-sup.pdf |
63e39d07a8f79476ca76df3d | 10.26434/chemrxiv-2023-f3dwd | Dual-modality hafnium oxide nanocrystals for computed tomography and fluorescence imaging of sentinel lymph nodes | In the surgical treatment of breast cancer the primary tumour is removed together with the so-called sentinel lymph nodes (SLNs), the lymph nodes that have the highest probability of being invaded by cancer cells. The current clinical standard to identify SLNs uses a combination of 99mTc labelled nanocolloids and blue dyes. This workflow comes with downsides such as inflexible procedures, exposure to radioactivity, allergic side-reactions and long-lasting skin discoloration. Here, we develop a dual-modality imaging probe as alternative to the current standard and demonstrate the in vivo detection of SLNs in mice using X-ray computed tomography and near-infrared fluorescence. We synthesize and stabilize hafnium oxide nanocrystals in physiological buffer and attach IRDye 800CW to the surface. The SLN is selectively detected via both imaging modalities 15-30 minutes post-injection of the probe. Moreover, a comparison between the probe and 99mTc nanocolloids reveals similar lymphatic drainage while utilizing faster, cheaper and more readily available imaging infrastructure, which could facilitate clinical integration. | Loren Deblock; Benedicte Descamps; Eline Goossens; Glenn Vergauwen; Jens Debacker; Philippe Tummers; Isabel Van Driessche; Klaartje De Buysser; Jonathan De Roo; Christian Vanhove | Biological and Medicinal Chemistry; Nanoscience; Nanostructured Materials - Nanoscience; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-02-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63e39d07a8f79476ca76df3d/original/dual-modality-hafnium-oxide-nanocrystals-for-computed-tomography-and-fluorescence-imaging-of-sentinel-lymph-nodes.pdf |
60c745c2842e652350db26b0 | 10.26434/chemrxiv.10255859.v1 | Trace Analysis of Heavy Metals (Cd, Pb, Hg) Using 3D Printed graphene/PLA Composite Electrodes | Here we investigate the use of 3D printed graphene/PLA electrodes for quantifying trace amounts of Hg, Pb, and Cd. We prepared cylindrical electrodes by sealing a 600 µm diameter graphene/PLA filament in a pipette tip filled with epoxy. We characterized the electrodes using scanning electron microscopy, Raman spectroscopy, and cyclic voltammetry in ferrocene methanol. The physical characterization showed a significant amount of disorder in the carbon structure and the electrochemical characterization showed quasi-reversible behavior without any electrode pretreatment. We then used unmodified graphene/PLA electrode to quantify Hg, and Pb and Cd in 0.01 M HCl and 0.1 M acetate buffer using square wave anodic stripping voltammetry. We were able to quantify Hg with a limit of detection (LOD) of 6.1 nM (1.2 ppb), but Pb and Cd did not present measurable peaks at concentrations below ~400 nM. We improved the LODs for Pb and Cd by depositing Bi microparticles on the graphene/PLA and, after optimization, achieved clear stripping peaks at the 20 nM level for both ions (4.1 and 2.2 ppb for Pb2+ and Cd2+, respectively). The results obtained for all three metals allowed quantification below the EPA action limits in drinking water. | John Walters; Shakir Ahmed; Irina Terrero Rodriguez; Glen O'Neil | Electrochemical Analysis | CC BY NC ND 4.0 | CHEMRXIV | 2019-11-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c745c2842e652350db26b0/original/trace-analysis-of-heavy-metals-cd-pb-hg-using-3d-printed-graphene-pla-composite-electrodes.pdf |
6629f0e1418a5379b0a8a9c5 | 10.26434/chemrxiv-2024-tcdgv | Oxygen Vacancy Controlled Hyperbolic Metamaterial based on Indium Tin Oxide (ITO) Nanotubes with Switchable Optical Properties | Nanostructured metamaterials can offer optical properties beyond what is achievable in conventional media, such as negative refraction or sub-wavelength imaging. Due to their structural anisotropy, the class of high aspect ratio metamaterials is of interest for the possibility of achieving hyperbolic behavior, i.e., materials with both metallic and dielectric optical response based on the excitation direction. Although widely investigated numerically, the fabrication of tailor-made metamaterials is very complex or often beyond range using current technology. For wire metamaterials composed of aligned metallic nanowires in a dielectric matrix, since the free carrier concentration in metals is fixed, light-matter interaction cannot be adjusted/ changed anymore after fabrication. Here, we introduce high aspect ratio metamaterial based on plasmonic ITO nanotubes with controllable hyperbolic response. The synthesis is achieved by a scalable template-based liquid-phase technique. Our tuning mechanism is based on controlling the carrier density in ITO via oxygen vacancy concentration. The process is reversible, the photonic features are activated by creating oxygen vacancies and can be switched off by filling them up again. Further, it is shown that the carrier concentration can also be controlled via a static electric field. Optical simulations support the experimental findings and highlight the parameters that determine the optical response of the metamaterial. | Thomas Herzog; Atefeh Habibpourmoghadam; Sonja Locmelis; Antonio Calà Lesina; Sebastian Polarz | Nanoscience; Nanostructured Materials - Nanoscience; Plasmonic and Photonic Structures and Devices; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-04-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6629f0e1418a5379b0a8a9c5/original/oxygen-vacancy-controlled-hyperbolic-metamaterial-based-on-indium-tin-oxide-ito-nanotubes-with-switchable-optical-properties.pdf |
6564ef0c29a13c4d47208248 | 10.26434/chemrxiv-2023-gq77g | Structure to Property: Machine Learning Methods for Predicting Electronic Properties of Crystals | We present a general-purpose machine learning model for predicting properties of crystals. Specifically, energy of formation, Fermi level energy, band gap, partial charges, and bulk modulus as well as spectral properties, including electronic and phonon densities of states are targeted. Thus, our model can be used to screen materials for specific properties. The model is based on atomic representations which enables it to effectively capture complex information about each atom and its surrounding environment in a crystal. The accuracy achieved for band gap values exceeds results previously published. By design, our model is not restricted to electronic properties discussed here but can be extended to fit diverse chemical databases. | Shokirbek Shermukhamedov; Dilorom Mamurjonova; Thana Maihom; Michael Probst | Theoretical and Computational Chemistry; Materials Science; Computational Chemistry and Modeling; Theory - Computational; Machine Learning; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2023-11-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6564ef0c29a13c4d47208248/original/structure-to-property-machine-learning-methods-for-predicting-electronic-properties-of-crystals.pdf |
67a0ebf881d2151a020cf8a9 | 10.26434/chemrxiv-2025-zwlnt | Photoluminescent rare-earth qubits embedded in a metal−organic framework as candidates for optical quantum memories | Optical quantum memories enable long-distance distribution of quantum information, which is critical for establishing global quantum internet. Rear-earth qubits are promising candidates for optical quantum memories because they can provide spin-optical interfaces with excellent spin coherence and optical properties. When doped into inorganic solids, they display relatively long excited-state lifetimes and in turn low storage efficiencies, which are difficult to optimize via material design. Metal−organic frameworks (MOFs) allow fine tuning of spin coherence and excited-state lifetimes through rational design of coordination environments, thereby offer alternative solid-state platforms to host rare-earth qubits. By incorporating Nd3+ and Yb3+ into an oxalate-based MOF, we develop frameworks that exhibit spin decoherence time exceeding 5 μs at 3.4 K, near-infrared and/or telecommunication-band photoluminescence, and excited-state lifetimes up to 150 μs. These materials hold the promise for optical quantum memories with long storage times and high storage efficiencies. Spin dynamic analysis reveals design principles to further improve coherence, which would promote the development of rare-earth MOFs for quantum information science. | Xiya Du; Lei Sun | Materials Science; Inorganic Chemistry; Coordination Chemistry (Inorg.); Lanthanides and Actinides; Spectroscopy (Inorg.); Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2025-02-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67a0ebf881d2151a020cf8a9/original/photoluminescent-rare-earth-qubits-embedded-in-a-metal-organic-framework-as-candidates-for-optical-quantum-memories.pdf |
619fdfcb836f6576287d7cbf | 10.26434/chemrxiv-2021-hd1ck | A Highly Fluorescent Dinuclear Aluminium Complex with Near-Unity Quantum Yield | The high natural abundance of aluminium makes the respective fluorophores attractive for
various optical applications, but photoluminescence quantum yields above 0.7 have yet not been
reported for solutions of aluminium complexes. In this contribution, a dinuclear aluminium(III)
complex featuring enhanced photoluminescence properties is described. Its facile one-pot synthesis
originates from a readily available precursor and trimethyl aluminium. In solution, the complex
exhibits an unprecedented photoluminescence quantum yield near unity (Φabsolute 1.0 ± 0.1) and an
excited-state lifetime of 2.3 ns. In the solid state, J-aggregation and aggregation-caused quenching
are noticed, but still quantum yields of 0.6 are observed. Embedding the complex in electrospun nonwoven
fabrics yields a highly fluorescent fleece possessing a quantum yield of 0.9 ± 0.04. | Flavio Luis Portwich; Yves Carstensen; Anindita Dasgupta; Stephan Kupfer; Ralf Wyrwa; Helmar Görls; Christian Eggeling; Benjamin Dietzek; Stephanie Gräfe; Maria Wächtler; Robert Kretschmer | Materials Science; Inorganic Chemistry; Organometallic Chemistry; Dyes and Chromophores; Main Group Chemistry (Inorg.); Spectroscopy (Inorg.) | CC BY NC ND 4.0 | CHEMRXIV | 2021-11-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/619fdfcb836f6576287d7cbf/original/a-highly-fluorescent-dinuclear-aluminium-complex-with-near-unity-quantum-yield.pdf |
6408d6bf6642bf8c8f30773d | 10.26434/chemrxiv-2023-330lz | Solvent effects on the chemo- and site-selectivity of transition metal-catalyzed heterogeneous nitrene transfer reactions: Alternatives to chlorinated solvents. | Transition metal-catalyzed, non-enzymatic nitrene transfer (NT) reactions that selectively transform C-H and C=C bonds to new C-N bonds represent a powerful strategy to streamline the preparation of valuable amine building blocks. Our group has been engaged in the development of silver-catalyzed NT reactions, where the nature of the ligand can be used to tune the chemo-, site- and enantioselectivity of the amination event in a predictable manner. However, the majority of solvents employed for these reactions are environmentally unfriendly and typically include dichloromethane, chloroform, 1,2-dichloroethane and benzene. In addition, the need for PhIO as the oxidant in our system gives heterogenous mixtures that have limited reaction throughput to date. In this work, a high-throughput experimentation (HTE) protocol for heterogeneous NT reaction mixtures is coupled with the American Chemical Society Pharmaceutical Roundtable (ACSPR) solvent tool to identify suitable replacements for chlorinated solvents and to better understand how the solvent affects chemo- and site-selectivity in NT. Silver catalysts were compared and contrasted other popular catalysts for NT using our HTE protocol, including dinuclear Rh and Fe/Mn phthalocyanine catalysts, to highlight key differences between these systems. Several unexpected solvents were identified that gave both high conversions and selectivities in diverse NT reactions, providing alternatives to traditional chlorinated solvents. We hope these insights will encourage the community to: (1) consider more diverse solvent selections when developing new synthetic methods, (2) employ solvent tools to identify favorable solvent characteristics/parameters and (3) consider SHE impacts in reaction design. | Robert Ward; Yun Hu; Noah Tu; Jennifer Schomaker | Organic Chemistry; Catalysis; Organic Compounds and Functional Groups; Organic Synthesis and Reactions; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-03-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6408d6bf6642bf8c8f30773d/original/solvent-effects-on-the-chemo-and-site-selectivity-of-transition-metal-catalyzed-heterogeneous-nitrene-transfer-reactions-alternatives-to-chlorinated-solvents.pdf |
655d462b6e0ec7777f6ea231 | 10.26434/chemrxiv-2023-7pn23 | Reviving the Absorbent Chemistry of Electrochemically Mediated Amine Regeneration for Improved Point Source Carbon Capture | Electrochemically mediated amine regeneration (EMAR) is emerging as a promising electrochemical approach for carbon capture from point sources. In this study, for the first time, the absorbent chemistry of the EMAR process was revived by considering criteria beyond metal-amine complexation. The systematic investigation focused on using secondary amines, which were previously overlooked in EMAR due to limited metal-amine interaction, despite their proven effectiveness in conventional carbon capture processes. The integration of secondary amines— monoethanolamine (MEA), aminomethyl propanol (AMP), and methyldiethanolamine (MDEA)—with the benchmark ethylenediamine (EDA) was thoroughly studied, evaluating their impact on absorption and desorption kinetics and capacities, and electrochemical performance. Among the blends, EDA+MDEA emerged as the top performer, particularly excelling in electrochemical aspects. The charge transfer resistance (RCT) of the deposition reaction, as the rate-limiting step, for the EDA+MDEA blend was reduced by 40% compared to pure EDA, and the heterogeneous electron transfer rate constant (k0) improved threefold. In the bench-scale assessments, the EDA+MDEA blend showed a notable decrease in desorption energetics to 37 kJ/molCO2, marking a 34% reduction compared to the 56 kJ/molCO2 required for pure EDA. This marks the lowest reported energetics for an EMAR process targeting point source carbon capture. This research paves the way for future systematic investigations of a wider range of amine blends for EMAR and eventually the process implementation at larger scales. | Ahmad Hassan; Abdelrahman Refaie; Prince Aleta; Mohsen Afshari; Elmira Kalantari; Yuanyuan Fang; MOHAMMAD (MIM) RAHIMI | Energy; Chemical Engineering and Industrial Chemistry; Fuels - Energy Science; Fuel Cells | CC BY NC 4.0 | CHEMRXIV | 2023-11-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/655d462b6e0ec7777f6ea231/original/reviving-the-absorbent-chemistry-of-electrochemically-mediated-amine-regeneration-for-improved-point-source-carbon-capture.pdf |
6763b51281d2151a022fb6a5 | 10.26434/chemrxiv-2023-296ch-v3 | AIMNet2: A Neural Network Potential to Meet your Neutral, Charged, Organic, and Elemental-Organic Needs | Machine learned interatomic potentials (MLIPs) are reshaping computational chemistry practices because of their ability to drastically exceed the accuracy-length/time scale tradeoff. Despite this attraction, the benefits of such efficiency are only impactful when an MLIP uniquely enables insight into a target system or is broadly transferable outside of the training dataset, where models achieving the latter are seldom reported. In this work, we present the 2nd generation of our atoms-in-molecules neural network potential (AIMNet2), which is applicable to species composed of up to 14 chemical elements in both neutral and charged states, making it a valuable method for modeling the majority of non-metallic compounds. Using an exhaustive dataset of 2 x 107 hybrid DFT level of theory quantum chemical calculations, AIMNet2 combines ML-parameterized short-range and physics-based long-range terms to attain generalizability that reaches from simple organics to diverse molecules with “exotic” element-organic bonding. We show that AIMNet2 outperforms semi-empirical GFN-xTB and is on par with reference density functional theory for interaction energy contributions, conformer search tasks, torsion rotation profiles, and molecular-to-macromolecular geometry optimization. Overall, the demonstrated chemical coverage and computational efficiency of AIMNet2 is a significant step toward providing access to MLIPs that avoid the crucial limitation of curating additional quantum chemical data and retraining with each new application. | Dylan Anstine; Roman Zubatyuk; Olexandr Isayev | Theoretical and Computational Chemistry; Organic Chemistry; Computational Chemistry and Modeling; Theory - Computational; Machine Learning | CC BY NC 4.0 | CHEMRXIV | 2024-12-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6763b51281d2151a022fb6a5/original/aim-net2-a-neural-network-potential-to-meet-your-neutral-charged-organic-and-elemental-organic-needs.pdf |
65e07f69e9ebbb4db98e0306 | 10.26434/chemrxiv-2024-h8q4c | Modelling microgel swelling: Influence of chain finite extensibility | Microgels exhibit the ability to undergo reversible swelling in response to shifts in environmental factors that include variations in temperature, concentration, and pH. While several models have been put forward to elucidate specific aspects of microgel swelling and its impact on bulk behavior, a consistent theoretical description that chains throughout the microscopic degrees of freedom with suspension properties and deepens into the full implications of swelling remains a challenge yet to be met.
In this work, we extend the mean-field swelling model of microgels from Denton and Tang (J. Chem. Phys. 145, 164901 (2016)) to include the finite extensibility of the polymer chains. The elastic contribution to swelling in the original work is formulated for Gaussian chains. By using the Langevin chain model, we modify this elastic contribution in order to account for finite extensibility effects, which become prominent for microgels containing highly charged polyelectrolytes and short polymer chains. We assess the performance of both elastic models, namely for Gaussian and Langevin chains, comparing against coarse-grained bead-spring simulations of ionic microgels with explicit electrostatic interactions. We examine the applicability scope of the models under variation of parameters such as ionization degree, microgel concentration and salt concentration. The models are also tested against experimental results. This work broadens the applicability of the microgel swelling model towards a more realistic description, which brings advantages when describing suspensions of nanogels and weak-polyelectrolyte micro/nanogels. | Mariano E. Brito; Christian Holm | Polymer Science; Drug delivery systems; Hydrogels; Polyelectrolytes - Polymers | CC BY 4.0 | CHEMRXIV | 2024-03-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65e07f69e9ebbb4db98e0306/original/modelling-microgel-swelling-influence-of-chain-finite-extensibility.pdf |
674ed9ff7be152b1d0c89283 | 10.26434/chemrxiv-2024-g9lh6 | Factors Affecting Thermal Stability of Vegetable Oil | The thermal degradation of vegetable oils presents considerable challenges for the food processing sector and public health. This paper explores the complexities of the thermal degradation of vegetable oil, highlighting the interdependent interactions among its various factors. The heterogeneity in oil composition and external factors such as temperature, frying time, and frying cycles, adds to the difficulty in understanding the degradation process. Research efforts have focused on internal factors like fatty acid composition and antioxidants and external factors such as heating temperature and time. Antioxidants from natural sources have shown promise in stabilizing vegetable oils, yet further research is needed to make them effective in elevated temperatures. Additionally, the role of metal surfaces in the degradation process remains underexplored, This review aims to summaries current knowledge and identify gaps for future research in improving vegetable oil stability and safety. The review is also relevant to the biodiesel application. | Sonia Randhawa; Tirtha Mukherjee | Agriculture and Food Chemistry; Food | CC BY 4.0 | CHEMRXIV | 2024-12-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/674ed9ff7be152b1d0c89283/original/factors-affecting-thermal-stability-of-vegetable-oil.pdf |
6495c06a4821a835f349dcc4 | 10.26434/chemrxiv-2023-3sj3d | Coupling microkinetics with continuum transport models to understand electrochemical CO2 reduction in flow reactors | We present a multiscale approach that couples ab-initio microkinetic simulations and two- dimensional (2D) continuum transport models to study electrochemical CO2 reduction to CO on Au electrodes in a flow reactor configuration. We find the key parameters including CO2 concentration, pH, the current density towards CO and the Tafel slopes to strongly depend on the applied poten- tial and position on the electrode. We find a rapid decrease in the CO2 concentration and current density towards CO as a function of electrode position. We further discuss two strategies to improve CO2 availability: increasing the shear/flow rate of CO2, and the introduction of a defect in between the electrode. In both cases, increased CO2 availability results in increased CO current density at the higher potentials. We find good agreement between a 1D continuum transport model with an effective boundary layer thickness corresponding to the shear rate used for the 2D simulations. Finally, we provide a phenomenological model that can be used instead of the microkinetic model to accelerate the multiscale simulations when extended to higher dimensions and more complicated reactor geometries. | Nitish Govindarajan; Tiras Lin; Thomas Roy; Christopher Hahn; Joel Varley | Catalysis; Electrocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-06-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6495c06a4821a835f349dcc4/original/coupling-microkinetics-with-continuum-transport-models-to-understand-electrochemical-co2-reduction-in-flow-reactors.pdf |
6584217966c1381729b724d2 | 10.26434/chemrxiv-2023-kwpqc | Diffuse basis functions for explicitly correlated calculations on the heavy p-block: aug-cc-pVnZ-PP-F12 sets for Ga–Kr, In–Xe, and Tl–Rn | New aug-cc-pVnZ-PP-F12 basis sets (n = D, T, Q) for the heavy p-block elements, Ga–Kr, In–Xe, and Tl–Rn, have been developed by augmenting the cc-pVnZ-PP-F12 sets with additional higher angular momentum diffuse functions. These basis sets have been optimized for use in explicitly correlated F12 calculations, and matching auxiliary basis sets for density fitting of conventional and F12 integrals have also been developed. The new sets have been validated with benchmark CCSD(T)-F12b calculations of electron affinities, where an accelerated convergence to the complete basis set limit is evident. The effect of the additional diffuse functions on electron affinities is shown to be comparable to the effect of correlating the outer-core d electrons. | Grant Hill | Theoretical and Computational Chemistry; Theory - Computational | CC BY 4.0 | CHEMRXIV | 2023-12-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6584217966c1381729b724d2/original/diffuse-basis-functions-for-explicitly-correlated-calculations-on-the-heavy-p-block-aug-cc-p-vn-z-pp-f12-sets-for-ga-kr-in-xe-and-tl-rn.pdf |
60c745fe337d6c7a0ce270a8 | 10.26434/chemrxiv.10312304.v1 | A Double-Dysprosocenium Single-Molecule Magnet Bound Together with Neutral Ligands | A dinuclear dysprosocenium dication has been synthesised that is bound
together by weak interactions between {Dy(Cp*)<sub>2</sub>}<sup>+</sup>
fragments and neutral NEt<sub>3</sub>AlMe<sub>3</sub> molecules. The axiality
of the Dy<sup>3+</sup> crystal fields are perturbed by these equatorial
interactions but a relatively large effective barrier to magnetisation reversal
of 860(60) cm<sup>–1</sup> and magnetic
hysteresis up to 15 K are observed. | Peter Evans; Daniel Reta; Conrad Goodwin; Fabrizio Ortu; Nicholas Chilton; David Mills | Coordination Chemistry (Inorg.); Lanthanides and Actinides; Organometallic Compounds; Theory - Inorganic; Transition Metal Complexes (Inorg.); Coordination Chemistry (Organomet.); Ligands (Organomet.); Theory - Organometallic; Transition Metal Complexes (Organomet.); Physical and Chemical Processes | CC BY NC ND 4.0 | CHEMRXIV | 2019-11-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c745fe337d6c7a0ce270a8/original/a-double-dysprosocenium-single-molecule-magnet-bound-together-with-neutral-ligands.pdf |
66a75d935101a2ffa87c17fc | 10.26434/chemrxiv-2024-1s1wc-v2 | Realization of extreme nonstoichiometry in gadolinium aluminate garnet phosphors by nonequilibrium synthesis | Rare-earth aluminates with the cubic garnet structure are an important class of optical materials with a range of technological applications. When synthesized as ceramics or single crystals, these materials do not tolerate large deviations from ideal RE3Al5O12 stoichiometry, and their luminescence properties are typically controlled by dopant selection. Here, we use glass crystallization as a nonequilibrium synthesis route to a new family of highly nonstoichiometric gadolinium aluminate garnet (GAG) phosphor hosts Gd3+xAl5-xO12 with 0 ≤ x ≤ 0.60. In these materials, excess Gd3+ is accommodated on the octahedrally-coordinated Al3+ sublattice of the garnet structure. The most extreme composition Gd3.6Al4.4O12 has 30% of these Al3+ sites substituted by Gd3+, but retains the cubic garnet structure type despite the vast size contrast between the two cations. The accessible nonstoichiometry range for GAG extends far beyond that of nonstoichiometric YAGs (Y3+xAl5-xO12, 0 ≤ x ≤ 0.4), enabled by a broader glass-forming domain in the Gd2O3 – Al2O3 system. We investigate three model phosphor systems based on nonstoichiometric GAG, and determine the crystallographic distributions of the dopant ions where possible, to evaluate the response of upconversion and photoluminescence to extreme nonstoichiometry. In particular, upconversion from the small rare-earth activator Tm3+ is found to be sensitive to nonstoichiometry in GAG. These results demonstrate that highly nonstoichiometric garnet aluminates are not limited to small rare-earth hosts such as YAG and should be realizable across the full 4f series, highlighting the potential for color tuning of new upconversion phosphors by control of host stoichiometry and opening new opportunities for development of different garnet-based optical and magnetic materials. | Xue Fang; Victor Castaing; Ana Becerro; Weiwei Cao; Emmanuel Veron; Didier Zanghi; Matthew Dyer; Cécile Genevois; Mathieu Allix; Michael Pitcher | Inorganic Chemistry; Solid State Chemistry; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2024-07-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66a75d935101a2ffa87c17fc/original/realization-of-extreme-nonstoichiometry-in-gadolinium-aluminate-garnet-phosphors-by-nonequilibrium-synthesis.pdf |
61a8eec17ce0561e3d8649da | 10.26434/chemrxiv-2021-13zcn | Monitoring electrode/electrolyte interfaces of Li-ion batteries under working conditions: A surface-enhanced Raman spectroscopic study on LiCoO2 composite cathodes | Lithium-ion batteries are commonly used for electrical energy storage in portable devices and are promising systems for large-scale energy storage. However, their application is still limited due to electrode degradation and stability issues. To enhance the fundamental understanding of electrode degradation we report on the Raman spectroscopic characterization of LiCoO2 cathode materials of working Li-ion batteries. To facilitate the spectroscopic analysis of the SEI (solid electrolyte interface) we apply surface-enhanced Raman spectroscopy by using Au nanoparticles coated with a thin SiO2 layer (Au@SiO2). We observe a surface-enhanced Raman signal of Li2CO3 at 1090 cm-1 during electrochemical cycling as an intermediate. Its formation/decomposition highlights the role of Li2CO3 as a component of the SEI on LiCoO2 composite cathodes. Our results demonstrate the potential of Raman spectroscopy to monitor electrode/electrolyte interfaces of lithium-ion batteries under working conditions thus allowing relations between electrochemical performance and structural changes to be established. | Marcel Heber; Christian Hess | Energy; Energy Storage | CC BY NC ND 4.0 | CHEMRXIV | 2021-12-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61a8eec17ce0561e3d8649da/original/monitoring-electrode-electrolyte-interfaces-of-li-ion-batteries-under-working-conditions-a-surface-enhanced-raman-spectroscopic-study-on-li-co-o2-composite-cathodes.pdf |
66f4a427cec5d6c14236b4db | 10.26434/chemrxiv-2024-37wks | Symmetry is the key to the design of reticular frameworks | De novo prediction of reticular framework structures is a challenging task for chemists and materials scientists. Herein, a computational workflow that predicts a list of possible reticular frameworks based on only the connectivity and symmetry of node and linker building blocks is presented. This list is ranked based on the occurrence of topologies in known structures, thus providing a manageable number of structures that can be optimized using density functional theory, and inform future experiments. This workflow is broadly applicable, correctly predicts known reticular materials, and furthermore identifies heretofore unknown phases for some systems. This workflow is available online at https://rationaldesign.pythonanywhere.com/ | Andrea Darù; John Anderson; Davide Proserpio; Laura Gagliardi | Theoretical and Computational Chemistry; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-09-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66f4a427cec5d6c14236b4db/original/symmetry-is-the-key-to-the-design-of-reticular-frameworks.pdf |
6374669fbe365e58ee20fef5 | 10.26434/chemrxiv-2022-5xfgw | On-the-Fly Nonadiabatic Dynamics of Caffeic
Acid Sunscreen Compound
| As a widely-used sunscreen compound, the caffeic acid (CA) shows the strong UV absorption, while the photoinduced reaction mechanisms behind its photoprotection ability are not fully understood. We try to investigate the photoinduced internal conversion dynamics of CA in order to explore the photoprotectiodn mechanism. The most stable CA isomer is selected to examine its nonadiabatic dynamics using the on-the-fly surface hopping simulations at the semi-empirical level of electronic-structure theory. The dynamics starting from different electronic states are simulated to explore the dependence of the photoinduced reaction channels on the excitation wavelengths. Several S1/S0 conical intersections, driven by the H-atom detachments and the ring deformations, have been found to be responsible for the nonadiabatic decay of the CA. The simulation results show that the branching ratio towards these intersections are modified by the light with different excitation energies. This provides the valuable information for the understanding of the photoprotection mechanism of the CA compound. | Xu Kang; Yifei Zhu; Juanjuan Zhang; Chao Xu; Zhenggang Lan | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Theory - Computational; Photochemistry (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2022-11-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6374669fbe365e58ee20fef5/original/on-the-fly-nonadiabatic-dynamics-of-caffeic-acid-sunscreen-compound.pdf |
67dad407fa469535b9cf151a | 10.26434/chemrxiv-2025-p93rp-v2 | Life Cycle Based Risk and Opportunity Mapping: A systematic collaborative procedure to integrate environmental and health aspects in early innovation as possible pre-screening to the safe and sustainable by design assessments | In this article we introduce a method to be used for life cycle-based assessment in early innovation to fill the gap of tools for assessing emerging technologies. The approach is intended to support innovation processes for clean technology. Thus, it needs to facilitate a dialogue and encourage innovators to share uncertain information. Such information could potentially hamper the development process if conclusions are drawn based on concepts before scale-up. For the required flexibility and transparency, we propose a series of direct exchanges and preliminary evaluations. The Chemicals Strategy for Sustainability, outlined to implement the European Green Deal, calls for the transition towards use of safe and sustainable chemicals, hence the Joint Research Center (JRC) published a framework for Safe and Sustainable by Design (SSbD) chemicals and materials. Among the key features of the framework is the application for early-stage developments of innovations, during which the outcome can be influenced, and parameters are not fully decided. The method proposed in this publication, life cycle-based risk and opportunity mapping (LCBROM), may be used both prior an SSbD assessment to facilitate its scoping process, as well as during an SSbD procedure. An LCBROM intends to bring together knowledge and requirements from different stakeholders in an innovation process and has been applied in four case studies within the area of clean technology. By applying the method we have realized that i) opportunity mapping is key for good involvement of the innovation owner but can only be performed if there is a suitable benchmark technology as reference or the consequences of inaction can be defined, ii) Several methods exist that in theory could be applied for assessing emerging technologies, although none seems to be commonly used, and iii) LCBROM has the potential to fulfill four criteria that we see as crucial for tools intended for assessing innovations at low TRL. A major benefit of the mapping approach is the increased transparency and communication between technology developer, problem owner and assessment experts. Such communication guides the process and allows for understanding of each other’s questions and feedback. LCBROM will be further improved and tested in the EU funded research programme BioSusTex. | Therese Kärnman; Steffen Schellenberger; Marie Gottfridsson; Maja Halling; Kristin Johansson; Tomas Rydberg; Jutta Hildenbrand | Materials Science; Earth, Space, and Environmental Chemistry; Chemical Engineering and Industrial Chemistry; Environmental Science | CC BY NC 4.0 | CHEMRXIV | 2025-03-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67dad407fa469535b9cf151a/original/life-cycle-based-risk-and-opportunity-mapping-a-systematic-collaborative-procedure-to-integrate-environmental-and-health-aspects-in-early-innovation-as-possible-pre-screening-to-the-safe-and-sustainable-by-design-assessments.pdf |
64ad6c3e9ea64cc167d4cf08 | 10.26434/chemrxiv-2023-91mfg | Morphology of Organic/Inorganic Aerosol with Varying Seed Particle Water Content | The morphology of mixed organic/inorganic particles can strongly influence the physicochemical properties of aerosols but remains relatively less examined in particle formation studies. The morphologies of inorganic seed particles grown with either alpha-pinene or limonene secondary organic aerosol (SOA) generated in a flow tube reactor were found to depend on initial seed particle water content. Effloresced and deliquesced ammonium sulfate seed particles were generated at low relative humidity (<15% RH, dry) and high relative humidity (~60% RH, wet) and were also coated with secondary organic material under low growth and high growth conditions. Particles were dried and analyzed using SMPS and TEM for diameter and substrate-induced diameter changes and for the prevalence of phase separation for organic-coated particles. Effloresced inorganic seed particle diameters generally increased after impaction, whereas deliquesced inorganic seed particles had smaller differences in diameter, although they appeared morphologically similar to the effloresced seed particles. Differences in the changes to diameter for deliquesced seed particles suggest crystal restructuring with RH cycling. SOA-coated particles showed negative diameter changes for low organic growth, although wet-seeded organic particles changed by larger magnitudes compared to dry-seeded organic particles. High organic growth gave wide ranging diameter percent differences for both dry- and wet-seeded samples. Wet-seeded particles with organic coatings occasionally showed a textured morphology unseen in the coated particles with dry seeds. Using a flow tube reactor with a combination of spectrometry and microscopy techniques allows for insights into the dependence of aerosol particle morphology on formation parameters for two seed conditions and two secondary organic precursors. | Emma Tackman; Devon Higgins; Murray Johnston; Miriam Freedman | Physical Chemistry; Analytical Chemistry; Earth, Space, and Environmental Chemistry; Atmospheric Chemistry; Microscopy; Surface | CC BY NC ND 4.0 | CHEMRXIV | 2023-07-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64ad6c3e9ea64cc167d4cf08/original/morphology-of-organic-inorganic-aerosol-with-varying-seed-particle-water-content.pdf |
60c749914c89190390ad30d7 | 10.26434/chemrxiv.12083202.v1 | Factorial Design of Experiments for Optimization of Photocatalytic Degradation of Tartrazine by Zinc Oxide (ZnO) Nanorods with Different Aspect Ratios | The photocatalytic degradation of the azo dye
tartrazine using zinc oxide (ZnO) as photocatalyst under ultraviolet light was
investigated using a 2<sup>4</sup> factorial design. The variables studied were
the aspect ratio of ZnO nanorods, the ZnO load, the initial pH of tartrazine
solution, and the H<sub>2</sub>O<sub>2</sub> volume. These variables were
studied aiming to maximize the tartrazine removal efficiency and the pseudo-1<sup>st</sup>-order
rate constant of the removal process. The ZnO aspect ratio was tuned by varying
the Lewis base during the synthesis, hexamethylenetetramine (HMTA) was used to
prepare ZnO with low aspect ratio (ZnO_LowAR), and NaOH was used to prepare ZnO
with high aspect ratio (ZnO_HighAR). The microstructural characterizations
indicated that ZnO_LowAR and ZnO_HighAR nanorods have similar structural,
textural and optical properties. The only exception was the dimensions of the
nanorods obtained, which could result in differences in the facets exposed on
each type of nanorod surface. The factorial design revealed that ZnO aspect
ratio, the initial pH of tartrazine solution, and the H<sub>2</sub>O<sub>2</sub>
volume all have primary significant effects, whereas the ZnO load is not
significant neither in the tartrazine removal efficiency nor in the pseudo-1<sup>st</sup>-order
rate constant. Statistical models considering the coefficients of the
significant interactions were obtained, leading to reasonable predicted results
in comparison to the results experimentally obtained. The conditions leading to
highest removal efficiency (~92%) and pseudo-1<sup>st</sup>-order rate constant
(3.81 x 10<sup>-2</sup> min<sup>-1</sup>) were carried out with ZnO_HighAR,
initial pH 7, and without H<sub>2</sub>O<sub>2</sub>, which outperformed the
TiO<sub>2</sub> P-25 under the same conditions. | Andrew Skinner; Anthony DiBernardo; Arvid Masud; Nirupam Aich; Alexandre Pinto | Wastes; Nanocatalysis - Catalysts & Materials; Chemical Kinetics | CC BY NC ND 4.0 | CHEMRXIV | 2020-04-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c749914c89190390ad30d7/original/factorial-design-of-experiments-for-optimization-of-photocatalytic-degradation-of-tartrazine-by-zinc-oxide-zn-o-nanorods-with-different-aspect-ratios.pdf |
60c74b61f96a00a28d2875cd | 10.26434/chemrxiv.12319067.v1 | Designing New Metal Chalcogenide Nanoclusters Through Atom-by-Atom Substitution | <p>Here, we
report the first study focused on atom-by-atom substitution of Fe and Ni to the
core of a well-defined cobalt sulfide superatom ligated with
triethylphosphine,[Co<sub>5</sub>MS<sub>8</sub>(PEt<sub>3</sub>)<sub>6</sub>]<sup>+</sup>
(M=Fe, Ni). Electrospray ionization mass spectrometry confirms the substitution
of 1-6 Fe atoms with the single Fe-substituted cluster being the dominant
species. The Fe-substituted clusters oxidize in solution to generate dicationic
species. In contrast, only a single Ni-substituted cluster is observed, which
remains stable as a singly charged species. Collision-induced dissociation
experiments indicate the reduced stability of the [Co<sub>5</sub>FeS<sub>8</sub>(PEt<sub>3</sub>)]<sup>+</sup>
towards ligand loss in comparison with the unsubstituted and Ni-substituted
counterparts. Density functional theory calculations provide insights into the
effect of metal atom substitution on the electronic structures of the clusters.
Our results indicate that Fe and Ni have a different impact on the electronic structure,
optical and magnetic properties, as well as ligand-core interaction of [Co<sub>6</sub>S<sub>8</sub>(PEt<sub>3</sub>)<sub>6</sub>].
This study extends the atom-by-atom substitution strategy to the metal
chalcogenide superatoms providing a direct path toward designing novel
atomically precise core-tailored superatoms.</p> | Habib Gholipour-Ranjbar; Hong Fang; Jintong Guan; D`Angelo Peters; Audra Seifert; Puru Jena; Julia Laskin | Nanostructured Materials - Materials; Nanostructured Materials - Nanoscience | CC BY NC ND 4.0 | CHEMRXIV | 2020-05-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74b61f96a00a28d2875cd/original/designing-new-metal-chalcogenide-nanoclusters-through-atom-by-atom-substitution.pdf |
66b4ca2b5101a2ffa88da673 | 10.26434/chemrxiv-2024-bvww6 | Massive Assessment of the Geometries of Atmospheric Molecular Clusters | Atmospheric molecular clusters are important for the formation of new aerosol particles in the air. However, current experimental techniques are not able to yield direct insight into the cluster geometries. This implies that to date there is limited information about how accurately the applied computational methods depict the cluster structures. Here we massively benchmark the molecular geometries of atmospheric molecular clusters. We initially assess how well different DF-MP2 approaches reproduce the geometries of 45 dimer clusters obtained at a high DF-CCSD(T)-F12b/cc-pVDZ-F12 level of theory. Based on the results we find that the DF-MP2/aug-cc-pVQZ level of theory best resembles the DF-CCSD(T)-F12b/cc-pVDZ-F12 reference level. We subsequently optimize 1283 acid–base cluster structures (up to tetramers) at the DF-MP2/aug-cc- pVQZ level of theory and assess how more approximate methods reproduce the geometries. Out of the tested semi-empirical methods, we find that the newly parameterized atmospheric molecular cluster extended tight binding method (AMC-xTB) is most re- liable for locating the correct lowest energy configuration and yield the lowest RMSD compared to the reference level. In addition, we find that the DFT-3c methods show similar performance as the usually employed ωB97X-D/6-31++G(d,p) level of theory at a potentially reduced computational cost. This suggests that these methods could prove valuable for large-scale screenings of cluster structures in the future. | Andreas Buchgraitz Jensen; Jonas Elm | Theoretical and Computational Chemistry; Physical Chemistry; Earth, Space, and Environmental Chemistry; Computational Chemistry and Modeling; Theory - Computational; Clusters | CC BY 4.0 | CHEMRXIV | 2024-08-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66b4ca2b5101a2ffa88da673/original/massive-assessment-of-the-geometries-of-atmospheric-molecular-clusters.pdf |
67cdf76bfa469535b9a2e461 | 10.26434/chemrxiv-2025-9mbf9 | Colloidal Crystallization of Virus-Like Particles with Polycations | Virus-like particles (VLPs) are protein nanocages capable of encapsulating or attaching guest molecules. Unlike viruses, they do not replicate in cells, making them promising candidates for advanced biomaterial design, particularly for biomedical applications such as drug delivery. However, the mechanisms governing VLP self-assembly into highly ordered suprastructures with enhanced functionality remain largely unexplored. This study investigates the development of pH-responsive biomaterials using the icosahedral Acinetobacter phage coat protein AP205 VLP with a diameter of around 28 nm. Small-angle X-ray scattering, dynamic light scattering, and zeta-potential measurements reveal that AP205 self-assembles with the polycation poly[2-(methacryloyloxy)ethyl] trimethylammonium chloride into highly ordered suprastructures. The structural organization is strongly influenced by composition, pH, and ionic strength. The findings provide insight into the directional interactions governing VLP self-assembly, enabling the design of tunable VLP-based biomaterials. | Bettina Tran; Tim Keys; Milad Radiom; Stefan Salentinig | Physical Chemistry; Biophysical Chemistry; Self-Assembly; Structure; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2025-03-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67cdf76bfa469535b9a2e461/original/colloidal-crystallization-of-virus-like-particles-with-polycations.pdf |
6613494121291e5d1d56ccbb | 10.26434/chemrxiv-2024-jnc6h-v3 | Total Synthesis of Eutyscoparol A and Violaceoid C | The first total synthesis of eutyscoparol A and total synthesis of violaceoid C via violaceoid A, have been accomplished including the improved total syntheses of violaceoid A and violaceoid B. This synthetic method, which employed the desymmetrization of a symmetric diol, enabled divergent access to other violaceoids, eutyscoparols, and their derivatives. | Takatsugu Murata; Takuto Iwayama; Teppei Kuboki; Shotaro Taguchi; Shou Tsugawa; Takumi Yoshida; Hisazumi Tsutsui; Ayana Shimauchi; Yukiho Kosaka; Isamu Shiina | Organic Chemistry | CC BY NC 4.0 | CHEMRXIV | 2024-04-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6613494121291e5d1d56ccbb/original/total-synthesis-of-eutyscoparol-a-and-violaceoid-c.pdf |
66802d7e5101a2ffa8de2342 | 10.26434/chemrxiv-2024-q8h1q | Atomistics-consistent continuum models and pore-collapse-generated hotspot temperatures in energetic crystals I: beta-1,3,5,7-tetranitro-1,3,5,7-tetrazocane (beta-HMX) | Hotspot formation due to pore collapse is a key mechanism for initiating detonation of shocked energetic materials. Energy localization at and around the pore collapse site leads to high-temperature hotspots, initiating chemical reactions. Because chemical reaction rates depend sensitively on temperature, predictive continuum models need to get the pore-collapse dynamics and resulting hotspot temperatures right; this imposes stringent demands on the fidelity of thermophysical model forms and parameters, and on the numerical methods employed to perform high-resolution meso-scale calculations. Here, continuum material models for beta-HMX are examined in the context of nanoscale shock-induced pore collapse, treating predictions from molecular dynamics (MD) simulations as ground truth. Using MD-consistent material properties, we show that the currently available strength models for HMX fail to correctly capture pore collapse and hotspot temperatures. Insights from MD are then employed to advance a Modified Johnson-Cook (M-JC) strength model form that captures aspects of shear strain and strain-rate dependency not represented by the standard JC form, but which are shown to be critical for accurately describing the nanoscale physics of shock-induced localization in HMX. The study culminates in a fully MD-determined strength model for beta-HMX that produces continuum pore-collapse results well aligned in all aspects with those predicted by MD, including pore-collapse mechanism and rate, shear-band formation in the collapse zone, and temperature, strain, and stress fields in the hotspot zone and surrounding material. The resulting MD-informed/MD-determined M-JC model should improve the fidelity of simulations to predict the detonation initiation of HMX-based energetic materials in microstructure-aware multi-scale frameworks. | Yen Thi Nguyen; Chukwudubem Okafor; Puhan Zhao; Oishik Sen; Catalin R. Picu; Tommy Sewell; H. S. Udaykumar | Physical Chemistry; Materials Science; Physical and Chemical Processes | CC BY NC ND 4.0 | CHEMRXIV | 2024-07-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66802d7e5101a2ffa8de2342/original/atomistics-consistent-continuum-models-and-pore-collapse-generated-hotspot-temperatures-in-energetic-crystals-i-beta-1-3-5-7-tetranitro-1-3-5-7-tetrazocane-beta-hmx.pdf |
641e504791074bccd03d91ea | 10.26434/chemrxiv-2023-2h4jm | Stable and efficient Ir nanoshells for oxygen reduction and evolution reactions | We report the characterization and applications of core-shell Cu-Ir nanocatalysts for fuel cells. Core-shell Cu-Ir particles with tunable thickness of Ir can be oxidized to remove the Cu core and obtain Ir shells. The thickness of the Ir shells determines the stability and optimization of the precious metals. We showed with in situ scanning transmission electron microscopy the remarkable stability of the Ir shells at elevated temperatures under oxidative and reductive environments. In situ microscopy and in situ X-ray absorption spectroscopy showed that traces of remaining copper could be detected in the Ir shells. Electrochemical measurements for oxygen reduction reaction and oxygen evolution reactions show promising activity and stability compared to a commercial catalyst. Thin Ir shells, with high surface area per gram of Ir, were more active but less stable than thicker shells. In contrast, thicker Ir shells were more stable and had excellent electrochemical properties in both aqueous and alkaline environments. Hence, Ir nanoshells appear as promising candidates to reduce the cost of catalysis while improving chemical performance in fuel cells. | Alexandre C. Foucher; Daniel J. Rosen; Shengsong Yang; Dario Ferreira Sanchez; Ilia I. Sadykov; Daniel Grolimund; Anatoly I. Frenkel; Christopher B. Murray; Eric A. Stach | Materials Science; Catalysis; Nanoscience; Alloys; Nanocatalysis - Catalysts & Materials; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-03-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/641e504791074bccd03d91ea/original/stable-and-efficient-ir-nanoshells-for-oxygen-reduction-and-evolution-reactions.pdf |
670eb007cec5d6c1423eea6d | 10.26434/chemrxiv-2024-29hgx | Electrocatalytic Ammonia Oxidation by Pyridyl Substituted Ferrocenes | Ammonia (NH3) is a promising carbon-free fuel when prepared from sustainable resources. First-row transition metal electrocatalysts for ammonia oxidation are an enabling technology for sustainable energy production. We describe electrocatalytic ammonia oxidation using robust molecular complexes based on Earth-abundant iron. Electrochemical studies of ferrocenes with covalently attached pyridine arms reveal facile ammonia oxidation in DMSO (2.4 M NH3) with modest overpotentials (770 - 820 mV) and turnover frequencies (125 - 560 h-1). Experimental and compu-tational studies indicate that the pendant pyridyl base serves as an H-bond acceptor with an N-H bond of ammonia that transfers a proton to the pyridine following oxidation by the attached ferrocenium moiety in a proton-coupled electron transfer (PCET) step. This generates an amidyl (•NH2) radical stabilized via H-bonding to a pendant pyri-dinium moiety that rapidly dimerizes to hydrazine (H2NNH2), which is easily oxidized to nitrogen (N2) at the glassy carbon working electrode. This report identifies a general strategy to oxidize ammonia via H-bonding to a base (B:), thereby activating [B…H-NH2] towards PCET by a proximal oxidant to form [BH…NH2]+/• radical cations, which are sus-ceptible to dimerization to form easily oxidized hydrazine. | Md Estak Ahmed; Richard Staples; Thomas Cundari; Timothy Warren | Inorganic Chemistry; Catalysis; Kinetics and Mechanism - Inorganic Reactions; Small Molecule Activation (Inorg.); Electrocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-10-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/670eb007cec5d6c1423eea6d/original/electrocatalytic-ammonia-oxidation-by-pyridyl-substituted-ferrocenes.pdf |
60c742f4ee301c79b4c78f27 | 10.26434/chemrxiv.8866295.v1 | Pan-Specific and Partially Selective Dye-Labeled Peptidic Inhibitors of the Polycomb Paralog Proteins | <div><div><div><p>Epigenetic regulation of gene expression is in part controlled by post-translational modifications on histone proteins. Histone methylation is a key epigenetic mark that controls gene transcription and repression. There are five human polycomb paralog proteins (Cbx2/4/6/7/8) which use their chromodomains to recognize trimethylated lysine 27 on Histone 3 (H3K27me3). Recognition of the methyllysine side chain is achieved through multiple cation-pi interactions within an ‘aromatic cage’ motif. Despite high structural similarity within the chromodomains of this protein family, they each have unique functional roles and are linked to different cancers. Selective inhibition of different CBX proteins is highly desirable for both fundamental studies and potential therapeutic applications. We will report on a series of peptidic inhibitors that selectively target certain polycomb paralogs. We have identified peptidic scaffolds with sub-micromolar potency, and will report examples that are pan-specific and that are partially selective for individual members within the family. The data presented include extensive new synthesis with characterization by LC, Mass Spectrometry, and NMR. The binding interactions are measured by fluorescence polarization, molecular dynamics simulations, and protein microarray assays. These results highlight important structure-activity relationships that allow for selectivity to be achieved through interactions outside of the methyllysine binding aromatic cage motif.</p></div></div></div> | Natalia Milosevich; James McFarlane; Michael Gignac; Janessa Li; Tyler Brown; Chelsea Wilson; Lindsay Devorkin; Caitlin Croft; Rebecca Hof; Irina Paci; Julian Lum; Fraser Hof | Bioorganic Chemistry; Biochemistry; Drug Discovery and Drug Delivery Systems | CC BY NC ND 4.0 | CHEMRXIV | 1970-01-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c742f4ee301c79b4c78f27/original/pan-specific-and-partially-selective-dye-labeled-peptidic-inhibitors-of-the-polycomb-paralog-proteins.pdf |
66dbcf8951558a15ef499a79 | 10.26434/chemrxiv-2024-snzf8 | Progress Towards Stable Organic Solar Cells | Organic solar cells (OSCs) are suitable candidates for next-generation renewable energy sources due to their low cost of production and flexibility. Their power conversion efficiency has improved significantly to about 20% in both single- and multi-junction devices due to the tremendous work in optimising the synthesis of novel active-layer materials while improving device fabrication. Despite a few reports predicting a 20-year lifetime for OSC devices, their stability currently lags behind their commercialisation. This review discusses the issues that impair OSC stability and how to mitigate them. While emphasising the importance of the International Summit on Organic Photovoltaic Stability (ISOS) protocols, an overview of recent advancements in OSC power conversion efficiency (PCE) and lifetime is provided. A comprehensive list of experimental techniques for studying OSC degradation mechanisms is also extensively discussed, weighing the advantages and disadvantages of different methods. In addition, the review emphasises the importance of essential and cost-effective equipment to encourage impactful contributions especially from resource-limited laboratories, to foster a more inclusive and globally collaborative research landscape, ensuring that diverse scientific perspectives contribute to advancing the field. Finally, fundamental challenges to developing high-performance and stable OSCs are discussed along with general recommendations for improving the stability of OSCs. | Newayemedhin Tegegne; Leonato Nchinda; Tjaart Krüger | Materials Science; Polymer Science; Energy; Organic Polymers; Photovoltaics | CC BY NC ND 4.0 | CHEMRXIV | 2024-09-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66dbcf8951558a15ef499a79/original/progress-towards-stable-organic-solar-cells.pdf |
677d980f6dde43c908a7a55e | 10.26434/chemrxiv-2024-gf7qp-v2 | Coordination environments of platinum single atom catalysts from NMR fingerprints | Single atom catalysts (SACs) have revolutionized the field of catalysis achieving an unprecedented level of control and metal utilization for solid materials, approaching what is expected with molecular catalysts.1-3 Establishing structure-activity relationships for their wide-ranging applications requires precise elucidation of the metal coordination environment, which remains a grand challenge.1,2 While electron microscopy reveals atomic dispersion, only average coordination environments can be deduced from state-of-the-art spectroscopic methods used in heterogeneous catalysis. Here, we establish 195Pt solid-state nuclear magnetic resonance (NMR) spectroscopy as a powerful methodology to acquire NMR signatures across a series of Pt-SACs dispersed on carbon based supports. Monte-Carlo simulations allow the conversion of NMR signatures into SAC fingerprints that describe local coordination environments with molecular precision and enable to quantitatively assess Pt-site distribution and homogeneity. This methodology can track the influence of synthetic parameters, e.g., specific protocols, synthetic steps and type of supports, on Pt-SAC structures, to guide the reproducible development of SACs with targeted structures; it also enables to monitor the change of coordination environment of SACs upon reaction. Such development provides a blueprint for the quantitative assessment of larger SAC families containing other NMR-active isotopes. | Jonas Koppe; Alexander V. Yakimov; Domenico Gioffrè; Marc-Eduard Usteri; Thomas Vosegaard; Guido Pintacuda; Anne Lesage; Andrew J. Pell; Sharon Mitchell; Javier Pérez-Ramírez; Christophe Copéret | Physical Chemistry; Materials Science; Catalysis; Heterogeneous Catalysis; Spectroscopy (Physical Chem.); Surface | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/677d980f6dde43c908a7a55e/original/coordination-environments-of-platinum-single-atom-catalysts-from-nmr-fingerprints.pdf |
66ece39751558a15ef861781 | 10.26434/chemrxiv-2024-pw0pg-v2 | A Practical, Large Scale Preparation of Ni(tmeda)(o-tol)Cl | A convenient, inexpensive synthesis of the previously reported and well-defined complex Ni(tmeda)(o-tol)Cl is described. This protocol enables rapid and safe access to Ni(tmeda)(o-tol)Cl, obviating the use of the hazardous reagent AlMe3 or the air-sensitive Ni(COD)2. Ni(tmeda)(o-tol) is prepared, from the commercially available and easily synthesized precursor, Ni(acac)2 at room temperature and the product can be isolated at gram scale in air via simple filtration. We expect this simple method to be attractive to chemical industry and academia given the types of solvents, reaction temperature and reagents used. | Scott Stewart; Morgan John; Daven Foster; Stephen Moggach; George Koutsantonis; Reto Dorta | Organometallic Chemistry; Catalysis; Reaction (Organomet.); Transition Metal Complexes (Organomet.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-09-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66ece39751558a15ef861781/original/a-practical-large-scale-preparation-of-ni-tmeda-o-tol-cl.pdf |
60f69064393cc9882f4db6bf | 10.26434/chemrxiv-2021-60k1r | Insights from an information thermodynamics analysis of a synthetic molecular
motor | Information is a physical quantity, the realisation of which transformed the physics of measurement and communication in the latter half of the 20th Century. However, the relationship and flow between information, energy and mechanics in chemical systems and mechanisms remains largely unexplored. Here we analyze a minimalist experimental example of an autonomous artificial chemically-driven molecular motor - a molecular information ratchet - in terms of information
thermodynamics, a framework that quantitatively relates information to other thermodynamic parameters. This treatment reveals how directional motion is generated by free energy transfer from the chemical to the mechanical processes involving the motor. We find that the free
energy transfer consists of two distinct contributions that can be considered as “energy flow” and “information flow”. We identify the efficiency with which the chemical fuel powers the free energy transfer and show that this is a useful quantity with which to compare and evaluate
mechanisms of, and guide designs for, molecular machines. The study provides a thermodynamic level of understanding of molecular motors that is general, complements previous analyses based on kinetics, and has practical implications for designing and improving synthetic molecular machines, regardless of the particular type of machine or chemical structure. In particular, the study confirms that, in line with kinetic analysis, power strokes do not affect the directionality of chemically-driven molecular machines. However, we also find that under some conditions power
strokes can modulate the molecular motor current (how fast the components rotate), efficiency with respect to how free energy is dissipated, and the number of fuel molecules consumed per cycle. This may help explain the role of such conformational changes in biomolecular machine mechanisms and illustrates the interplay between energy and information in chemical systems. | Shuntaro Amano; Massimiliano Esposito; Elisabeth Kreidt; David A. Leigh; Emanuele Penocchio; Benjamin M. W. Roberts | Physical Chemistry; Nanoscience; Nanodevices; Statistical Mechanics; Thermodynamics (Physical Chem.) | CC BY 4.0 | CHEMRXIV | 2021-07-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60f69064393cc9882f4db6bf/original/insights-from-an-information-thermodynamics-analysis-of-a-synthetic-molecular-motor.pdf |
65709467cf8b3c3cd7ea940f | 10.26434/chemrxiv-2023-h8h99 | Transient intermediate in the formation of an amorphous metal–organic framework | Amorphous metal–organic frameworks are rarely formed via direct synthesis. Our limited understanding of their atomic assembly in solution prevents full exploitation of the unique functionalities that their structural complexity can impart. Here, we use in-situ synchrotron X-ray absorption spectroscopy with sub-second time resolution to probe the formation of the amorphous Fe-BTC framework. Using a combination of spectral fingerprinting, linear combination analysis, and principal component analysis coupled with kinetic analyses, we reveal a multi- stage formation mechanism that, crucially, proceeds via the generation of a transient intermediate species. | Adam Sapnik; Michael Thorne; Celia Castillo-Blas; Luke Keenan; Timothy Johnson; Thomas Bennett | Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-12-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65709467cf8b3c3cd7ea940f/original/transient-intermediate-in-the-formation-of-an-amorphous-metal-organic-framework.pdf |
60c741a7ee301c8890c78cdc | 10.26434/chemrxiv.8081156.v1 | Mechanoenzymatic Breakdown of Chitinous Material to N-Acetylglucosamine: The Benefits of a Solvent-Free Environment | We
report an innovative and efficient mechanoenzymatic method to hydrolyze
chitin to N-acetylglucosamine monomer using chitinase under the
recently developed RAging methodology, i.e. a combination of
mechanochemical ball milling activation and accelerated aging repeated
over many cycles, in the absence of bulk solvent. Our result show that
the activity of chitinases increases several times by switching from
traditional solvent-based conditions of enzymatic catalysis to
solvent-free RAging, which operates on moist solid substrates.
Importantly, RAging is also highly efficient for the production of
N-actylglucosamine directly from shrimp and crab shell biomass without
any other processing, except for a gentle wash with aqueous acetic acid.<br /> | J. P. Daniel Therien; Fabien Hammerer; Tomislav Friscic; Karine Auclair | Bioorganic Chemistry; Natural Products; Biopolymers; Cellulosic materials; Biocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2019-05-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c741a7ee301c8890c78cdc/original/mechanoenzymatic-breakdown-of-chitinous-material-to-n-acetylglucosamine-the-benefits-of-a-solvent-free-environment.pdf |
60c747240f50db0bf639654f | 10.26434/chemrxiv.11536263.v1 | Folding of the Transmembrane 25-Residues Influenza A M2 and Ala-25 Peptides | <p>The correct balance between
hydrophobic London dispersion (LD) and peptide hydrogen bonding interactions
must be attained for proteins to fold correctly. To investigate these important
contributors we sought a comparison of the influenza A transmembrane M2 protein (M2TM) 25-residues monomer and
the 25-Ala (Ala<sub>25</sub>)
peptide, used as reference since alanine is the only amino acid forming a
standard peptide helix which is stabilized by the backbone peptide hydrogen bonding interactions. Folding molecular dynamics (MD) simulations were performed ing the AMBER99SB-STAR-ILDN force field
in trifluoroethanol (TFE) as a
membrane mimetic, to study the α-helical stability of M2TM and Ala<sub>25</sub>
peptides. It was shown that M2TM
peptide did not form a single stable α-helix compared to Ala<sub>25</sub>. Instead
appears to be dynamic in nature and quickly inter-converts between an ensemble
of various folded helical structures having the highest thermal stability to
the N-terminal compared to Ala<sub>25</sub>. Circular dichroism (CD) experiments confirm
the stability of the α-helical M2TM. DFT
calculations results revealed an extra stabilization for the folding of M2TM from
b-strand to the α-helix compared to Ala<sub>25</sub>, due to forces that can't be
described from a force field. On a technical level, calculations using D95(d,p)
single point at a ONIOM (6-31G,3-21G) minimized geometry, in which the backbone
is calculated with 6-31G and alkyl side chains with 3-21G, produced an energy
differential for M2TM comparable with full D95(d,p). Natural bond orbital (NBO)
and quantum theory of atoms in molecules (QTAIM)
calculations were applied to investigate the relative contribution of N-H∙∙∙O as
compared to C-H∙∙∙O hydrogen bonding interactions in the M2TM which included 17
lipophilic residues; 26 CH∙∙∙O interactions were identified, as compared to 22
NH∙∙∙O H-bonds. The calculations suggested that CH∙∙∙O hydrogen bonds, although
individually weaker, have a cumulative effect that cannot be ignored and may contribute
as much as half of the total interaction energy when compared to NH∙∙∙O to the
stabilization of the folded α-helix in M2TM compared to Ala<sub>25</sub>.</p> | Ioannis Stylianakis; Steve Scheiner; Isaiah Arkin; Nikolas Glykos; Antonios Kolocouris | Biochemistry; Bioinformatics and Computational Biology; Biophysics | CC BY NC ND 4.0 | CHEMRXIV | 2020-01-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c747240f50db0bf639654f/original/folding-of-the-transmembrane-25-residues-influenza-a-m2-and-ala-25-peptides.pdf |
60c7577cf96a007f5a288c95 | 10.26434/chemrxiv.14356517.v1 | Platinum Interdigitated Electrode Arrays for Reagent-Free Detection of Copper | <p>Water is a precious resource that is under threat from a number
of pressures, including release of toxic compounds that can have damaging
effect on ecology and human health. The current methods of water quality
monitoring are based on sample collection and analysis at dedicated
laboratories. This can provide an incomplete picture of the status of the water
body as pollution events can be missed. Recently, electrochemical based methods
have attracted a lot of attention for environmental sensing owing to their
versatility, sensitivity and compatible integration with cost effective, smart
and portable readout systems. In the present work, we report on the fabrication
and characterization of platinum interdigitated microband electrodes arrays,
and their application for trace detection of copper. Using square wave voltammetry
after acidification with mineral acids, a limit of detection of 0.8 μg/L was
achieved. Copper detection was also under taken on river water samples and
compared with standard analytical techniques. The possibility of controlling
the pH at the surface of the sensors – thereby avoiding the necessity to add
mineral acids – was investigated. By applying potentials driving the water
splitting reaction at one comb on the sensors electrode (the protonator), it
was possible to lower the pH in the vicinity of the sensing electrode.
Detection of standard copper solutions down to 5 μg/L using this technique is
reported. This reagent free method of
detection opens the way for autonomous, in situ monitoring of pollutants in
water bodies.</p> | Robert Daly; Tarun Narayan; Alan O'Riordan; Pierre Lovera | Electrochemical Analysis | CC BY NC ND 4.0 | CHEMRXIV | 2021-04-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7577cf96a007f5a288c95/original/platinum-interdigitated-electrode-arrays-for-reagent-free-detection-of-copper.pdf |
6189098c8ac7a24d446c6944 | 10.26434/chemrxiv-2021-9sjjh-v2 | Influence of the first coordination of uranyl on its luminescence properties: study of uranyl binitrate with N,N-dialkyl amide DEHiBA and water | Uranyl binitrate complexes have a particular interest in the nuclear industry, especially in the reprocessing of spent nuclear fuel. The modified PUREX extraction process is designed to extract U(VI) in the form of UO2(NO3)2(L)2 as it has been confirmed by EXAFS, XRD and TRLFS measurements. In this study, the L ligands are two molecules of N,N-di-(ethyl- 2-hexyl)isobutyramide (DEHiBA) monoamide used to bind uranyl in its first coordination sphere. DEHiBA ligands can coordinate uranyl in either trans- or cis-positions with respect to the nitrate ligands and these two conformers may co-exist in solution. In order to use luminescence spectroscopy as a speciation technique, it is important to determine whether or not these conformers can be discriminated by their spectroscopic properties. To answer this question, the spectra of trans- and cis-UO2(NO3)2(DEiBA)2 conformers were modeled with ab initio methods and compared to the experimental time-resolved luminescence spectra on the UO2(NO3)2(DEHiBA)2 systems. Moreover, the hydrated uranyl binitrate UO2(NO3)2(H2O)2 complexes in the same trans and cis configurations were modeled to quantify the impact of organic DEHiBA on the luminescence properties. | Hanna Oher; Geoffroy Ferru; Laurent Couston; Laurence Berthon; Dominique Guillaumont; Florent Réal; Thomas Vercouter; Valérie Vallet | Inorganic Chemistry; Lanthanides and Actinides; Spectroscopy (Inorg.); Theory - Inorganic | CC BY NC 4.0 | CHEMRXIV | 2021-12-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6189098c8ac7a24d446c6944/original/influence-of-the-first-coordination-of-uranyl-on-its-luminescence-properties-study-of-uranyl-binitrate-with-n-n-dialkyl-amide-de-hi-ba-and-water.pdf |
668f297cc9c6a5c07aeb654b | 10.26434/chemrxiv-2024-jfb21 | Modulating Phononic Landscapes: The Role of Silicon Ion Bombardment in Tailoring
Si/Si+Ge and SiO2/SiO2+Ge Superlattices for Advanced Neutron Superreflector
Applications | This study examines the impact of silicon ion bombardment on the phononic properties
of Si/Si+Ge and SiO2/SiO2+Ge superlattices to enhance neutron superreflector
technology. Using precise ion implantation and Fourier Transform Infrared
Spectroscopy, we observed alterations in transverse and longitudinal optical phonon
modes. The Si/Si+Ge system showed significant redshifts and intensity changes, while
SiO2/SiO2+Ge exhibited increased lattice disorder and peak broadening. These
findings underscore ion bombardment's potential to optimize phononic landscapes for
improved nuclear reactor safety and efficiency through advanced phonon engineering. | Clyde Varner II; Jonathan Lassiter; Satilmis Budak | Physical Chemistry; Physical and Chemical Properties | CC BY NC ND 4.0 | CHEMRXIV | 2024-07-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/668f297cc9c6a5c07aeb654b/original/modulating-phononic-landscapes-the-role-of-silicon-ion-bombardment-in-tailoring-si-si-ge-and-si-o2-si-o2-ge-superlattices-for-advanced-neutron-superreflector-applications.pdf |
60c73d929abda2790ef8b726 | 10.26434/chemrxiv.5924140.v1 | Effect of Ethanol Treatment on Lycopene Extraction yield | In order to extract
lycopene more effectively, this experiment focused on the optimization of
ethanol pretreatment method to study the effects of ethanol treatment on the
extraction rate of lycopene and its antioxidant activity. The test results show
that 2 times ethanol treatment is very effective for improving lycopene yield.
The optimum conditions of ethanol treatment are temperature 50 ℃,
treatment time 1 time 2h, 2 times 2h, solid to liquid ratio is 1:12. The lycopene
yield can be reached 20mg / 100g above. | Nam Kyong-il; KIM rak-chon; Kang chang-hyok; Lee song-nam; Ryom sok-hun | Natural Products; Food | CC BY NC ND 4.0 | CHEMRXIV | 1970-01-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73d929abda2790ef8b726/original/effect-of-ethanol-treatment-on-lycopene-extraction-yield.pdf |
63ac67c104902a8403128c4c | 10.26434/chemrxiv-2022-qb667 | Optimization of the Synthesis of Chloro Dodecachloro Boron Subphthalocyanine. | During this study, we analyze different methodologies to synthesize previously reported chloro dodecachloro boron subphthalocyanine (Cl-Cl12BsubPc). As we attempt to replicate the previously reported method, we were unable to successfully achieve the yield and purity that was reported, and this negative outcome was confirmed via running many times. This led us to explore different pathways to produce Cl-Cl12BsubPc, for first example, utilizing AlCl3 in axial halide exchange from Br-Cl12BsubPc to Cl-Cl12BsubPc. However, due to inability to track reaction progression during the reaction and only partial conversion, other pathways were considered. Ultimate conclusion was that we were able to synthesize Cl-Cl12BsubPc using BCl3 in p-xylene, where we achieve an improved yield of 69%, with a purity of 93%. Using TGA, to also note, we postulate a reason for the decreased thermal stability of Cl-Cl12BsubPc during train sublimation, and therefore if sublimation was done at higher temperature it results in lower purification yields. | Kacper Wojtkiewicz; Adam Tetreault; Timothy Bender | Chemical Engineering and Industrial Chemistry; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-12-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63ac67c104902a8403128c4c/original/optimization-of-the-synthesis-of-chloro-dodecachloro-boron-subphthalocyanine.pdf |
6654bdef91aefa6ce1215516 | 10.26434/chemrxiv-2024-v3qww | Large Property Models: A New Generative Paradigm for Molecules | Generative models for the inverse design of molecules with particular properties have been heavily hyped but have yet to demonstrate significant gains over machine learning augmented expert intuition. A major challenge of such models is their limited accuracy in predicting molecules with targeted properties in the data scarce regime, which is the regime typical of the prized outliers that inverse models are hoped to discover. For example, activity data for a drug target or stability data for a material may only number in the tens to hundreds of samples, which is insufficient to learn an accurate and reasonably general property-to-structure inverse mapping from scratch. We’ve hypothesized that the property to structure mapping becomes unique when a sufficient number of properties are supplied to the models during training. This hypothesis has several important corollaries if true. It would imply that data scarce properties can be completely determined by a set of more accessible molecular properties. It would also imply that a generative model trained on multiple properties would exhibit an accuracy phase transition after achieving a sufficient size—a process analogous to what has been observed in the context of large language models. To interrogate these behaviors, we have built the first transformers trained on the property to molecular graph task, which we dub “large property models” (LPMs). A key ingredient is supplementing these models during training with relatively basic but abundant chemical property data. The motivation for the large property model paradigm, the model architectures, and case studies are presented here for review and discussion at the upcoming Faraday Discussion on “Data-driven discovery in the chemical sciences”. | Tianfan Jin; Veerupaksh Singla; Hsuan-Hao Hsu; Brett Savoie | Theoretical and Computational Chemistry; Physical Chemistry; Organic Chemistry; Machine Learning; Artificial Intelligence | CC BY NC ND 4.0 | CHEMRXIV | 2024-05-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6654bdef91aefa6ce1215516/original/large-property-models-a-new-generative-paradigm-for-molecules.pdf |
634f3fe61df6889162959ce3 | 10.26434/chemrxiv-2022-knpb0 | Development and Applications of the Density-based Theory of Chemical Reactivity | Density functional theory well-recognized by its accuracy and efficiency has become the workhorse for modeling the electronic structure of molecules and extended materials in the past decades. Nevertheless, how to establish a density-based conceptual framework to appreciate bonding, stability, function, reactivity, and other physiochemical properties is still an unaccomplished task. In this Perspective, we at first overview the four pathways currently available in the literature to tackle the matter, including orbital-free density functional theory, conceptual density functional theory, direct use of density associated quantities, and information-theoretic approach. Then, we highlight several recent advances of employing these approaches to harvest new understandings for chemical concepts such as covalent bonding, noncovalent interactions, cooperation, frustration, homochirality, chirality hierarchy, electrophilicity, nucleophilicity, regioselectivity, and stereoselectivity. Finally, we provide a few hints for the future development of this relatively uncharted territory. Opportunities are abundant, and they are all ours for the taking. | Shubin Liu; Chunying Rong; Dongbo Zhao; Xin He | Theoretical and Computational Chemistry; Theory - Computational | CC BY 4.0 | CHEMRXIV | 2022-10-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/634f3fe61df6889162959ce3/original/development-and-applications-of-the-density-based-theory-of-chemical-reactivity.pdf |
6696c809c9c6a5c07a76a5f7 | 10.26434/chemrxiv-2024-18n19 | Point Sensor Network Detects Short Releases Under Favorable Wind Conditions | In this study, we apply a recursive Bayesian state updater algorithm to assimilate meteorological data with point-sensor measurements of methane concentrations to infer timeseries of methane emission rates at three operating oil and gas facilities. These calculations are performed over a timeframe with known numerous short (~ 30 minute) controlled releases, allowing for "ground truth'' data to compare our emission estimates against. The highly-varying and unknown operational emissions pose challenges in analyzing quantification results when trying to determine whether there is evidence in the emission estimates of a given controlled release. Ultimately, we find that despite the non-ideal conditions at these sites (poor sensor placement and the presence of large obstructions that the quantification model does not account for) that the site-level emission estimates show evidence for 31 out of the 60 controlled releases and that the majority of nondetections were due to the wind simply not pointing from the source to any sensor in the network during a short release event. | David Ball; Ali Lashgari; Umair Ismail; Noah Metzger; Nathan Eichenlaub | Energy; Earth, Space, and Environmental Chemistry; Atmospheric Chemistry; Environmental Science | CC BY NC 4.0 | CHEMRXIV | 2024-07-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6696c809c9c6a5c07a76a5f7/original/point-sensor-network-detects-short-releases-under-favorable-wind-conditions.pdf |
613cc926abeb632e50cfcb45 | 10.26434/chemrxiv-2021-tnfcq | Superphanes: Facile and Efficient Preparation, Functionalization and Unique Properties | Superphanes, compounds in which the two benzene rings clamped parallel on top of each other by six bridges, have garnered considerable interest due to their aesthetically pleasing structures and unique chemical physical properties. However, until now progress in the research of superphane chemistry and beyond has been seriously hampered by their poor availability. Herein, we report the facile and scalable synthesis of a collection of superphanes with structural diversity and their unique photophysical properties, as well as their unusual host–guest behavior. Initially, a set of dodecaimino–containing super-phanes 7a–7e are obtained via dynamic self–assembly of a hexakis–amine and a series of readily derived aromatic dialde-hyde in one pot. The resulting superphanes are found capable of being reduced with NaBH4 to their corresponding second-ary–amine versions 3a–3e. Subsequently, superphane 3c bearing 12 amine–NHs was further subject to post–functionalization with various functional groups, e.g., ethyl, allyl, propargyl and but–2–yn–1–yl. Unprecedentedly, the sec-ondary amine–based superphanes 3a–3e were observed to exhibit genuine fluorescence both in solution and in the solid state while the imine–based superphanes 7a–7e were found to highly emissive only in solid state with fluorescent quantum yields of 3.5 ~ 17.1. Finally, fully protonated 3a was exemplified to encapsulate a 2Cl–·H2O cluster both in the solid state and in solution. With the easy and versatile synthesis, modification, as well as unique photophysical and host–guest properties, we believe that this study will break the bottleneck in superphane chemistry and open the door to a novel class of supramo-lecular hosts and advanced functional materials on the basis of superphanes. | Aimin Li; Yuanchu Liu; Wei Zhou; Yunqi Jiang; Qing He | Organic Chemistry; Organic Compounds and Functional Groups; Supramolecular Chemistry (Org.); Materials Chemistry; Crystallography – Organic | CC BY NC ND 4.0 | CHEMRXIV | 2021-09-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/613cc926abeb632e50cfcb45/original/superphanes-facile-and-efficient-preparation-functionalization-and-unique-properties.pdf |
628645b96b12b65d93777cd1 | 10.26434/chemrxiv-2022-ldmbm | Metal Complexes as Antifungals?
–
From a Crowd-Sourced Compound Library to First In Vivo Experiments
| There are currently fewer than ten antifungal drugs in clinical development, but new fungal strains, which are resistant to most current antifungals are spreading rapidly across the world. To prevent a second resistance crisis, new classes of antifungal drugs are urgently needed. Metal complexes have proven to be promising candidates for novel antibiotics, but so far, few compounds have been explored for their potential application as antifungal agents. In this work we report the evaluation of 1039 metal-containing compounds that were screened by the Community for Open Antimicrobial Drug Discovery (CO-ADD). We show that 20.9% of all metal compounds tested have antimicrobial activity against two representative Candida and Cryptococcus strains, compared with only 1.1% of the >300,000 purely organic molecules tested through CO-ADD. We identified 90 metal compounds (8.7%) that show antifungal activity while not displaying any cytotoxicity against mammalian cell lines or haemolytic properties at similar concentrations. The structures of 21 metal complexes which display high antifungal activity (MIC ≤ 1.25 µM) are discussed and evaluated further against a broad panel of yeasts. Most of these have not been evaluated for antifungal activity. Eleven of these metal complexes were tested for toxicity in the Galleria mellonella moth larvae model, revealing that only one compound showed signs of toxicity at the highest injected concentration. Lastly, we demonstrated that the organo-Pt(II) cyclooctadiene complex Pt1 significantly reduces fungal load in an in vivo G. mellonella infection model. These findings showcase that the structural and chemical diversity of metal-based compounds can be an invaluable tool in the development of new drugs against infectious diseases. | Angelo Frei; Alysha G. Elliott; Alex Kan; Hue Dinh; Stefan Braese; Alice E. Bruce; Mitchell R. Bruce; Feng Chen; Dhirgam Humaidy; Nicole Jung; A. Paden King; Peter G. Lye; Hanna K. Maliszewska; Ahmed M. Mansour; Dimitris Matiadis; María Paz Muñoz; Tsung-Yu Pai; Shyam Pokhrel; Peter J. Sadler; Marina Sagnou; Michelle Taylor; Justin J. Wilson; Dean Woods; Johannes Zuegg; Wieland Meyer; Amy K. Cain; Matthew A. Cooper; Mark A. T. Blaskovich | Inorganic Chemistry; Organometallic Chemistry; Bioinorganic Chemistry; Transition Metal Complexes (Inorg.); Bioorganometallic Chemistry | CC BY 4.0 | CHEMRXIV | 2022-05-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/628645b96b12b65d93777cd1/original/metal-complexes-as-antifungals-from-a-crowd-sourced-compound-library-to-first-in-vivo-experiments.pdf |
60c749c4bdbb898665a39237 | 10.26434/chemrxiv.8869460.v3 | Exact Generalized Kohn-Sham Theory for Hybrid Functionals | Hybrid functionals have proven to be of immense practical value in density functional theory calculations. While they are often thought to be a heuristic construct, it has been established that this is in fact not the case. Here, we present a rigorous and formally exact analysis of generalized Kohn-Sham (GKS) density functional theory of hybrid functionals, in which exact remainder exchange-correlation potentials combine with a fraction of Fock exchange to produce the correct ground state density. First, we extend formal GKS theory by proving a generalized adiabatic connection theorem. We then use this extension to derive two different definitions for a rigorous distinction between multiplicative exchange and correlation components - one new and one previously postulated. We examine their density-scaling behavior and discuss their similarities and differences. We then present a new algorithm for obtaining exact GKS potentials by inversion of accurate reference electron densities and employ this algorithm to obtain exact potentials for simple atoms and ions. We establish that an equivalent description of the many-electron problem is indeed obtained with any arbitrary global fraction of Fock exchange and we rationalize the Fock-fraction dependence of the computed remainder exchange-correlation potentials in terms of the new formal theory. Finally, we use the exact theoretical framework and numerical results to shed light on the exchange-correlation potential used in approximate hybrid functional calculations and to assess the consequences of different choices of fractional exchange.<br /><br /> | Rachel Garrick; Amir Natan; Tim Gould; Leeor Kronik | Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2020-03-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c749c4bdbb898665a39237/original/exact-generalized-kohn-sham-theory-for-hybrid-functionals.pdf |
673e3b457be152b1d0f4253c | 10.26434/chemrxiv-2024-mwgqr | Perturbation of Nanoplastics on Biomembranes: Molecular Insights from Neutron Scattering | Plastic waste is now pervasive in the environment, breaking down into microplastics and nanoplastics under many environmental conditions. These particles have been found in various ecosystems and even in human tissues, raising significant environmental and health concerns. In this study, we investigated the interaction of polystyrene nanoplastics, with and without surface modifications, on biomembrane structures using contrast-matching small-angle neutron scattering and neutron spin echo spectroscopy. The neutron contrast matching enabled selective study of biomembranes in the presence of nanoplastics. Two model membranes were employed: a simple zwitterionic bilayer (i.e., dimyristoylphosphatidylcholine [DMPC]) and an Escherichia coli lipid extract as a bacterial membrane model. The results show profound membrane disruptions, including thinning, vesicle fragmentation, lipid monolayer formation, and inter-vesicle aggregation, with the most severe effects observed in DMPC membranes. Notably, E. coli membranes exhibited greater resilience, suggesting that biological membranes with diverse lipid compositions may mitigate some nanoplastic particle–induced damage. These findings highlight the potential risks posed by environmental nanoplastic particles to biological membranes, with insights for molecular-level interactions and the environmental toxicity of nanoplastics. This work provides a foundation for future studies into nanoplastic–biomembrane interactions and their broader implications for health and environment. | Shuo Qian; Honghai Zhang; Wellington Leite; Andrew Whitten; Piotr Zolnierczuk; Qiu Zhang | Physical Chemistry; Nanoscience; Earth, Space, and Environmental Chemistry; Environmental Science; Wastes; Biophysical Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-11-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/673e3b457be152b1d0f4253c/original/perturbation-of-nanoplastics-on-biomembranes-molecular-insights-from-neutron-scattering.pdf |
60c74574ee301cd6c5c792f1 | 10.26434/chemrxiv.10025789.v1 | Voltage Imaging with a NIR-Absorbing Phosphine Oxide Rhodamine Voltage Reporter | Near infrared (NIR) fluorophores may hold the key for
non-invasive optical imaging of deep structures in intact organisms with high
spatial and temporal resolution. Yet, developing fluorescent dyes that emit and
absorb light at wavelengths greater than 700 nm and that respond to biochemical
and biophysical events in living systems remains an outstanding challenge.
Here, we report the design, synthesis, and application of NIR-absorbing and
-emitting, sulfonated, phosphine-oxide (po) rhodamines for voltage imaging in
thick tissue from the central nervous system. We find po-rhodamine based
voltage reporters, or poRhoVRs, display NIR excitation and emission profiles at
greater than 700 nm, show best-in class voltage sensitivity (up to 43% ΔF/F per
100 mV in HEK cells), and can be combined with existing optical sensors, like
Ca<sup>2+</sup>-sensitive fluorescent proteins (GCaMP), and actuators, like
light-activated opsins ChannelRhodopsin-2 (ChR2). Simultaneous voltage and Ca<sup>2+</sup>
imaging reveals differences in activity dynamics in rat hippocampal neurons,
and pairing poRhoVR with blue-light based ChR2 affords all-optical
electrophysiology. In <i>ex vivo</i> retinas
isolated from a mouse model of retinal degeneration, poRhoVR, together with
GCaMP-based Ca<sup>2+</sup> imaging and traditional multi-electrode array (MEA)
recording, can provide a comprehensive physiological activity profile of
neuronal activity. Taken together, these experiments establish that poRhoVR
will open new horizons in optical interrogation of cellular and neuronal
physiology in intact systems. | Monica Gonzalez; Alison Walker; Kevin Cao; Julia Lazzari-Dean; Nick Settineri; Eui Ju Kong; Richard Kramer; Evan Miller | Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2019-10-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74574ee301cd6c5c792f1/original/voltage-imaging-with-a-nir-absorbing-phosphine-oxide-rhodamine-voltage-reporter.pdf |
646e59e54f8b1884b737be5f | 10.26434/chemrxiv-2023-v0ght | High performance graphene-based pseudo-ductile composites | High-performance fibre reinforced polymer (FRP) composites offer excellent specific strength and stiffness when compared to high-density metallic materials. However, their inherent brittleness leads to sudden and catastrophic failure without sufficient pre-warning, rendering them unsuitable for many applications. To address this limitation, we present a novel approach using graphene-based glass-carbon FRP hybrid composites that exhibit excellent pseudo-ductile properties. Our technique involves coating glass and carbon fibre balanced plain woven fabrics with graphene-based materials using a facile and scalable pad-dry-cure coating technique, followed by reinforcement with an epoxy matrix via vacuum-assisted resin infusion (VARI). Our tensile and flexural tests demonstrate the exceptional pseudo-ductile behaviour of these hybrid composites, with no visible changes in damage initiation after the initial failure of carbon fibre. By enabling the manufacture of high-performance pseudo-ductile composites at scale using a low-cost manufacturing method, our graphene-based glass-carbon hybrid FRP composites have significant potential for next-generation applications. | Mohammad Hamidul Islam; Shaila Afroj; Nazmul Karim | Materials Science; Carbon-based Materials; Composites | CC BY 4.0 | CHEMRXIV | 2023-05-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/646e59e54f8b1884b737be5f/original/high-performance-graphene-based-pseudo-ductile-composites.pdf |
66747f3f5101a2ffa8186ada | 10.26434/chemrxiv-2024-7q00c | Excited State Electronic Structure of Dimethyl Disulfide Involved in Photodissociation at ∼200 nm | Dimethyl disulfide (DMDS), one of the smallest organic molecules with an S-S bond, serves as a model system for understanding photofragmentation in polypeptides and pro- teins. Prior studies of DMDS photodissociation excited at ∼266 nm and ∼248 nm have elucidated the mechanisms of S-S and C-S bond cleavage, which involve the lowest excited electronic states S1 and S2. Far less is known about the dissociation mechanisms and elec- tronic structure of relevant excited states of DMDS excited at ∼200 nm. Herein we present calculations of the electronic structure and properties of excited states S1-S6 accessed when DMDS is excited at ∼200 nm. Our analysis includes a comparison of theoretical and ex- perimental UV spectra, as well as theoretically predicted one-dimensional cuts through the singlet and triplet potential energy surfaces along the S-S and C-S bond dissociation coordinates. Finally, we present calculations of spin-orbit coupling constants at the Franck- Condon geometry to assess the likelihood of ultrafast intersystem crossing. We show that choosing an accurate yet computationally efficient electronic structure method for calcu- lating the S0-S6 potential energy surfaces along relevant dissociation coordinates is chal- lenging due to excited states with doubly excited character and/or mixed Rydberg-valence character. Our findings demonstrate that the extended multi-state complete active space second-order perturbation theory (XMS-CASPT2) balances this computational efficiency and accuracy, as it captures both the Rydberg character of states in the Franck-Condon region and multiconfigurational character toward the bond-dissociation limits. We com- pare the performance of XMS-CASPT2 to a new variant of equation of motion coupled cluster theory with single, double, and perturbative triple corrections, EOM-CCSD(T)(a)*, finding that EOM-CCSD(T)(a)* significantly improves the treatment of doubly excited states compared to EOM-CCSD, but struggles to quantitatively capture asymptotic ener- gies along bond dissociation coordinates for these states. | Varun Rishi; Neil Cole-Filipiak; Krupa Ramasesha; Laura McCaslin | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Theory - Computational; Photochemistry (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-06-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66747f3f5101a2ffa8186ada/original/excited-state-electronic-structure-of-dimethyl-disulfide-involved-in-photodissociation-at-200-nm.pdf |
6793a14e81d2151a02c5a15a | 10.26434/chemrxiv-2025-h00mw | Chemical Research Odyssey: From High School Foundations to University Frontiers | Practicing research in high school is fundamental to training future university students, developing critical thinking skills, and understanding societal issues in a broader context. However, such training is rarely incorporated into upper secondary education. For the past 10 years, we have developed a research programme tailored for high school students, enabling them to build colorimetric sensors for analytes of societal importance using the simple strategy of indicator displacement assay (IDA). Our work has not only been published, including in international journals, but has also garnered awards and recognition at the fall meeting of the Swiss Chemical Society (SCS), benefiting both our students and among our students and the broader scientific community. We have presented our research findings annually at the SCS. Furthermore, we have extended our concept to universities, using the knowledge gained at high school level to initiate a PhD thesis with a student in the field of sensing. This demonstrates that, on a larger scale, this visionary program should be further developed in high schools and supported by institutions to promote excellence in science and chemistry. We therefore hope that this article will resonate with the scientific community. | Thibaud Rossel | Chemical Education | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6793a14e81d2151a02c5a15a/original/chemical-research-odyssey-from-high-school-foundations-to-university-frontiers.pdf |
60c7474a842e659799db295c | 10.26434/chemrxiv.10280849.v2 | Fragment-Based Design of Mycobacterium Tuberculosis InhA Inhibitors | <p>Tuberculosis (TB) remains a leading cause of mortality amongst infectious diseases worldwide. InhA, an enoyl ACP-reductase, has been the focus of numerous drug discovery efforts as this is the target of the first line pro-drug isoniazid. However, with resistance to this drug becoming more common the aim has been to find new clinical candidates that directly inhibit this enzyme and that do not require activation by the catalase peroxidase KatG, thus circumventing the majority of the resistance mechanisms. In this work, the screening and validation of a fragment library is described and development of the fragment hits using a fragment growing strategy was employed which led to the development InhA inhibitors with affinities of up to 250 nM.</p> | Mohamad Sabbah; Vitor Mendes; Robert G. Vistal; David M. G. Dias; Monika Záhorszká; Katarina Mikušová; Jana Korduláková; Anthony Coyne; Tom. L. Blundell; Chris Abell | Biochemistry; Drug Discovery and Drug Delivery Systems | CC BY NC ND 4.0 | CHEMRXIV | 2020-01-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7474a842e659799db295c/original/fragment-based-design-of-mycobacterium-tuberculosis-inh-a-inhibitors.pdf |
60c7546ff96a000e61288669 | 10.26434/chemrxiv.13661081.v1 | Outstanding Nobility Observed in Cu5 Clusters Reveals the Key Role of Collective Quantum Effects | Subnanometer-sized metal clusters often feature a molecule-like electronic structure, which makes their physical and chemical properties significantly different from those of nanoparticles and bulk material. Considering potential applications, there is a major concern about their thermal stability and susceptibility towards oxidation. Cu clusters of only 5 atoms (Cu<sub>5</sub> clusters) are first synthesized in high concentration using a new-generation wet chemical method. Next, it is shown that, contrary to what is currently assumed, Cu<sub>5</sub> clusters display nobility, beyond resistance to irreversible oxidation, at a broad range of temperatures and oxygen pressures. The outstanding nobility arises from an unusual reversible oxidation which is observed by <i>in situ</i> X-ray Absorption Spectroscopy and X-ray Photoelectron Spectroscopy on Cu<sub>5</sub> clusters deposited onto highly oriented pyrolitic graphite at different oxygen pressures and up to 773 K. This atypical property is explained by a theoretical approach combining different state-of-the-art first principles theories. It reveals the essential role of collective quantum effects in the physical mechanism responsible for the nobility of Cu<sub>5</sub> clusters, encompassing a structural ‘breathing’ through concerted Cu–Cu elongations/contractions upon O<sub>2</sub> uptake/release, and collective charge transfer as well. A predictive phase diagram of their reversible oxidation states is also delivered, agreeing with the experimental observations. The collective quantum effects responsible of the observed nobility are expected to be general in subnanometer-sized metal clusters, pushing this new generation of materials to an upper level. | David Buceta; Shahana Huseyinova; Miguel Cuerva; Héctor Lozano; Lisandro J. Giovanetti; José M. Ramallo-López; Patricia López-Caballero; Alexandre Zanchet; Alexander O. Mitrushchenkov; Andreas W. Hauser; Giampaolo Barone; Cristián Huck-Iriart; Carlos Escudero; Juan Carlos Hernández-Garrido; José Calvino; Miguel Lopez-Haro; Maria Pilar de Lara-Castells; Felix G. Requejo; M. Arturo López-Quintela | Catalysts; Nanocatalysis - Catalysts & Materials; Computational Chemistry and Modeling; Theory - Computational; Nanocatalysis - Reactions & Mechanisms; Clusters; Physical and Chemical Processes; Quantum Mechanics; Structure; Thermodynamics (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2021-02-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7546ff96a000e61288669/original/outstanding-nobility-observed-in-cu5-clusters-reveals-the-key-role-of-collective-quantum-effects.pdf |
6788aeef6dde43c908c7aab5 | 10.26434/chemrxiv-2025-jr7qk | Enantioselective domino carbopalladation/Csp3-Pd capture using carbenes generated from N-tosylhydrazones: Access to chiral 3,3-disubstituted oxindoles bearing chiral quaternary carbon center
| N-tosylhydrazones have become convenient synthons in organic synthesis ever since their inception as diazo precursors. Yet, enantioselective processes involving N-tosylhydrazones are quite rare and challenging. In our continuing efforts in maneuvering Pd carbenes to synthesize complex heterocycles, we have developed a domino process for intercepting the enantioenriched alkyl-Pd species in a Mizoroki-Heck cascade. In this enantioselective domino process, N-alkyl acrylamides undergo a regiospecific 5-exo-trig cyclization to form an alkyl palladium species at a chiral quaternary carbon center that lacks a facile β-hydrogen. The alkyl palladium species formed is then trapped via carbene generated from bench-stable N-tosylhydrazones. The method constructs a chiral quaternary carbon center and provides direct access to chiral 3,3-disubstituted oxindoles with yields up to 91% and enantioselectivity >99% with tolerance for diverse functional groups. Mechanistic investigations revealed that a cationic Heck cascade is involved. The structure of the active catalytic species has been studied by HRMS analysis and linear relationship plot between the % ee of the catalyst and % ee of the product. Based on these experimental insights, computational studies of the catalytic cycle have been done to study the energetics of the steps involved. Further, the stereochemical outcome of the reaction has been justified by comparing the free energies of the diastereomeric transition states involved in the enantio-determining step. The constructed alkene handle next to the chiral center enhances the utility of this methodology. Apart from ease of functionalization, the proximity of the chiral center to the alkene, facilitates efficient transfer of chirality during transformations. This highlights the utility of the synthesized 3,3-disubstituted oxindoles as valuable chiral synthons. This has been demonstrated via a handful of synthetic transformations of the model oxindole and formal synthesis of five natural products, namely (+)-esermethole,
(+)-physostigmine, (+)-deoxyseroline, (+)-phenserine and (+)-physovenine, which are a couple of steps apart in synthesis according to reported procedures.
| Vysakh Venugopalan Nair; Esackraj Karthikraja ; Venkatesan Subramanian; Sekar Govindasamy | Organic Chemistry; Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6788aeef6dde43c908c7aab5/original/enantioselective-domino-carbopalladation-csp3-pd-capture-using-carbenes-generated-from-n-tosylhydrazones-access-to-chiral-3-3-disubstituted-oxindoles-bearing-chiral-quaternary-carbon-center.pdf |
6513090bade1178b24299014 | 10.26434/chemrxiv-2023-hr255 | Palladium K-edge XAS studies on Controlled Ligand Systems | X-ray absorption spectroscopy (XAS) is widely used across life and physical sciences to identify the electronics and structure surrounding a specific element. XAS is less often used for characterization of organometallic compounds, especially for sensitive and highly reactive species. In this study, we used solid- and solution-phase XAS to compare a series of related 25 palladium complexes in controlled lig-and environments. The compounds include palladium centers in the formal I, II, III, and IV oxidation states, supported by tridentate and tetradentate macrocyclic ligands, and different halide and methyl lig-and combinations. Based on the analysis of the K-edge energies, it was observed that these energies in-crease not only upon oxidation of the metal center, but also upon increasing the denticity of the ligand framework, substituting sigma-donating methyl groups with chlorides, and increasing the charge of the overall metal complex by replacing charged ligands with neutral ligands. Subsequently, these trends were applied to characterize compounds whose oxidation states were otherwise unconfirmed. | Liviu Mirica; Luke Westawker; Julia R. Khusnutdinova; Rachel Wallick | Inorganic Chemistry; Coordination Chemistry (Inorg.); Organometallic Compounds | CC BY NC ND 4.0 | CHEMRXIV | 2023-09-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6513090bade1178b24299014/original/palladium-k-edge-xas-studies-on-controlled-ligand-systems.pdf |
60c75458f96a00be7028863e | 10.26434/chemrxiv.13649816.v1 | Ionic Liquid Facilitated Melting of the Metal-Organic Framework ZIF-8 | <div>Hybrid glasses from melt-quenched metal-organic frameworks (MOFs) have
been emerging as a new class of materials, which combine the functional
properties of crystalline MOFs with the processability of glasses.
However, only a handful of the vast variety of crystalline MOFs have
been identified as being meltable. Porosity and metal-linker interaction
strength have both been identified as crucial parameters in the
trade-off between thermal decomposition of the organic linker and, more
desirably, melting. For example, the inability of the prototypical
zeolitic imidazolate framework (ZIF) ZIF-8 to melt, is ascribed to the
instability of the organic linker upon dissociation from the metal
center. Here, we demonstrate that the incorporation of an ionic liquid
(IL) into the porous interior of ZIF-8 provides a means to reduce its
melting temperature to below its thermal decomposition temperature (Tm
< Td). Experimental evidence shows that the Tm of ZIF-8 obtained by
IL infiltration is around 381 °C, and that the glass forming ability
(Tg/Tm) of such melts is above 0.9, i.e. higher than those previously
reported for other meltable MOFs. Our structural studies show that the
prevention of decomposition, and successful melting, is due to the IL
interactions stabilizing the rapidly dissociating ZIF-8 linkers upon
heating. This understanding may act as a general guide for extending the
range of meltable MOF materials and, hence, the chemical and structural
variety of MOF-derived glasses.</div> | Vahid Nozari; Courtney Calahoo; Joshua M. Tuffnell; David
A. Keen; Thomas Bennett; Lothar Wondraczek | Hybrid Organic-Inorganic Materials; Nanostructured Materials - Materials; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2021-01-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75458f96a00be7028863e/original/ionic-liquid-facilitated-melting-of-the-metal-organic-framework-zif-8.pdf |
659efae09138d23161a12efd | 10.26434/chemrxiv-2024-02bj5 | Graphene Derived from Municipal Solid Waste | Landfilling has long been the most common method of disposal for municipal solid waste (MSW). However, many countries seek to implement different methods of MSW treatment due to the high global warming potential associated with landfilling. Other methods such as recycling and incineration are either limited to only a fraction of generated MSW or still produce large greenhouse gas emissions, thereby providing an unsustainable disposal method. Here, we report the production of graphene from treated MSW, which includes treated wood waste, using flash Joule heating. Results indicate an 81-89% reduction in global warming potential compared to traditional disposal methods at a net cost of -$304 per tonne of MSW, presuming the graphene is sold at just 5% of its current market value to offset the cost of the flash Joule heating process. | Karla Silva; Kevin Wyss; Carolyn Teng; Yi Cheng; Lucas Eddy; James Tour | Materials Science; Earth, Space, and Environmental Chemistry; Carbon-based Materials; Materials Processing; Environmental Science; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-01-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/659efae09138d23161a12efd/original/graphene-derived-from-municipal-solid-waste.pdf |
6426f61a16782ec9e622d124 | 10.26434/chemrxiv-2023-q1tmf-v2 | Two modes of fusogenic action for influenza virus fusion peptide | The entry of influenza virus into the host cell requires fusion of its lipid envelope with the host membrane. It is catalysed by viral hemagglutinin protein, whose fragments called fusion peptides become inserted into the target bilayer and initiate its merging with the viral membrane. Isolated fusion peptides are already capable of inducing lipid mixing between liposomes. Years of studies indicate that upon membrane binding they form bend helical structure whose degree of opening fluctuates between tightly closed hairpin and an extended boomerang. The actual way in which they initiate fusion remains elusive. In this work we employ atomistic simulations of wild type and fusion inactive W14A mutant of influenza fusion peptides confined between two closely apposed lipid bilayers. We characterise peptide induced membrane perturbation and determine the potential of mean force for the formation of the first fusion intermediate, an interbilayer lipid bridge called stalk. Our results demonstrate two routes through which the peptides can lower free energy barrier towards fusion. The first one assumes peptides capability to adopt transmembrane configuration which subsequently promotes the creation of a stalk-hole complex. The second involves surface bound peptide configuration and proceeds owing to its ability to stabilise stalk by fitting into the region of extreme negative membrane curvature resulting from its formation. In both cases, the active peptide conformation corresponds to tight helical hairpin, whereas extended boomerang geometry appears to be unable to provide favourable thermodynamic effect. The latter observation offers plausible explanation for long known inactivity of boomerang-stabilising W14A mutation. | Michal Michalski; Piotr Setny | Theoretical and Computational Chemistry; Biological and Medicinal Chemistry; Bioinformatics and Computational Biology; Biophysics; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2023-04-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6426f61a16782ec9e622d124/original/two-modes-of-fusogenic-action-for-influenza-virus-fusion-peptide.pdf |
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