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66c473dbf3f4b052906b9663 | 10.26434/chemrxiv-2024-4fj46 | Amine Carboxyborane: A Versatile Ligated Boryl Radical Precursor | Amine carboxyborane has been demonstrated as a novel precursor for amine-ligated boryl radicals. The anion of amine carboxyborane was effectively oxidized using a 5CzBN photocatalyst under blue LED light, with subsequent decarboxylation facilitating the generation of ligated boryl radicals. This process enabled an efficient halogen atom transfer (XAT) with alkyl bromides, resulting in Giese addition products with various electron-deficient double bonds. Moreover, direct addition of several boryl radicals was also possible using ligated carboxyboranes. | Changhee Park; Seyun Gi; Seongkyeong Yoon; Seong Jung Kwon; Sunggi Lee | Organic Chemistry; Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-08-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66c473dbf3f4b052906b9663/original/amine-carboxyborane-a-versatile-ligated-boryl-radical-precursor.pdf |
635c2030ac45c701409c6d82 | 10.26434/chemrxiv-2022-9xx75 | Atom-in-SMILES tokenization | Tokenization is an important preprocessing step in natural language processing that may have a significant influence on prediction quality. In this study we show that the conventional SMILES tokenization itself is at fault, resulting in tokens that fail to reflect the true nature of molecules.
To address this we propose atom-in-SMILES approach, resolving the ambiguities in the genericness of SMILES tokens. Our findings in multiple translation tasks suggest that proper tokenization has a great impact on the prediction quality. Considering the prediction accuracy and token degeneration comparisons, atom-in-SMILES appears as an effective method to draw higher quality SMILES sequences out of AI-based chemical models than other tokenization schemes. We investigate the token degeneration, highlight its pernicious influence on prediction quality, quantify the token-level repetitions, and include generated examples for qualitative analysis. We believe that atom-in-SMILES tokenization can readily be utilized by the community at large, providing chemically accurate, tailor-made tokens for molecular prediction models. | Umit Volkan Ucak; Islambek Ashyrmamatov; Juyong Lee | Theoretical and Computational Chemistry; Machine Learning; Artificial Intelligence; Chemoinformatics - Computational Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-10-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/635c2030ac45c701409c6d82/original/atom-in-smiles-tokenization.pdf |
633bd00aba8a6d9b70672877 | 10.26434/chemrxiv-2022-d0s34 | Surface Sites and Ligation of Amine-capped CdSe Nanocrystals | The conversion of colloidal nanocrystals (NCs) into various applications is usually facilitated by
designing and controlling their surface properties. A key strategy for tailoring surface properties is to
modulate surface ligands. Amines, as L-type ligands, have been universally introduced into various
surface modifications, promoting NCs synthesis, processing and performances. However, a full
understanding of the nature of the amine-capped NCs surface has yet to be established, due to several
challenges, such as the presence of various surface, subsurface and bulk sites along with the presence
of surface dynamic. In this work, we addressed the issue on CdSe NCs, looking at both NC surface
sites and the ligation of amine based on the combination of 113Cd, 77Se and 15N NMR spectroscopy,
respectively. In particular, dynamic nuclear polarization (DNP) enhanced 113Cd and 77Se NMR
allowed acquisition of high quality 1D spectra, thus enabling the identification of bulk and surface
sites on different facets. Amines terminated sites on both Se-rich facets and nonpolar facets were
resolved by 113Cd 2D NMR spectroscopy, augmented with density function theory (DFT) calculations.
In addition to directly bonding to surface sites, amines interaction through hydrogen-bonding with
absorbed water and carboxylate surface ligands were further revealed by 15N NMR. The insight into
the complexity of amine-capped CdSe NCs surface and the characterization methodology developed
in this work is an important step towards rational design, assessing surface modification as well as
improving the processing of colloidal NCs towards their exploitation in various applications. | Weicheng Cao; Alexander Yakimov; Xudong Qian; Jiongzhao Li; Xiaogang Peng; Xueqian Kong; Christophe Copéret | Theoretical and Computational Chemistry; Physical Chemistry; Inorganic Chemistry; Computational Chemistry and Modeling; Spectroscopy (Physical Chem.); Surface | CC BY NC 4.0 | CHEMRXIV | 2022-10-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/633bd00aba8a6d9b70672877/original/surface-sites-and-ligation-of-amine-capped-cd-se-nanocrystals.pdf |
60c74e6a9abda25b17f8d64f | 10.26434/chemrxiv.12086766.v2 | Computational Study of the Stereoselectivity Profiles of the Diels-Alder Cycloaddition Reactions of Cyclopentadiene and Butadiene with Cyclopropenes | The <i>endo</i>
and <i>exo</i> stereoselectivities of the
Diels-Alder (DA) cycloaddition reactions of 3,3-disubstituted cyclopropenes
with butadiene and cyclopentadiene, the latter for the first time, were
investigated by means of density functional and quantum chemical calculations
for a comparison. To establish distinction between the selectivites, activation
free energies were systematically estimated in the gas phase and also in
solvents. The differential activation free energies clearly predict exclusive <i>endo</i> configuration of the products formed
from the reaction of the unsubstituted cyclopropene with butadiene and
cyclopentadiene. However, the results were found to be markedly different for
the substituted cyclopropenes from available experimental selectivities. It was
also discovered that butadiene and cyclopentadiene are markedly different in
their respective stereospecific product yields, nevertheless the difference between
the two was only a methylene group. The failure of the differential activation
free energy approach to predict the experimental stereoselectivities of the DA
reactions of several perhalocyclopropenes with cyclopentadiene is probably due
to yet insufficient development of the various theoretical models dealing with the
<i>endo</i> and <i>exo</i> DA preferences. | Veejendra Yadav | Physical Organic Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2020-07-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74e6a9abda25b17f8d64f/original/computational-study-of-the-stereoselectivity-profiles-of-the-diels-alder-cycloaddition-reactions-of-cyclopentadiene-and-butadiene-with-cyclopropenes.pdf |
60c73f1a469df43b35f429eb | 10.26434/chemrxiv.7230986.v1 | Spin-Forbidden Channels in Reactions of Unsaturated Hydrocarbons with O(3P) | Electronic structure of four prototypical Cvetanovic diradicals, species derived by addition of O(3P) to unsaturated compounds, is investigated by high-level electronic structure calculations and kinetics modeling. The main focus of this study is on the electronic factors controlling the rate of inter-system crossing (ISC), minimal energy crossing points (MECPs) and spin-orbit couplings (SOCs). The calculations illuminate significant differences in the electronic structure of ethylene- and acetylene-derived compounds and a relatively minor effect due to methylation. The computed MECPs heights and SOCs reveal different mechanisms of ISC in ethylene- and acetylene-derived species, thus explaining variations in the observed branching ratios between singlet and triplet products and a puzzling effect of the methyl substitution. In the ethylene- and propylene-derived species, the MECP is very low and the rate is controlled by the SOC variations, whereas in the acetylene- and propyne-derived species the MECP is high and the changes in the ISC rate due to methyl substitutions are driven by the variations in MECP heights. | Pavel Pokhilko; Robin Shannon; David Glowacki; Hai Wang; Anna I. Krylov | Computational Chemistry and Modeling; Chemical Kinetics; Quantum Mechanics | CC BY 4.0 | CHEMRXIV | 2018-10-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73f1a469df43b35f429eb/original/spin-forbidden-channels-in-reactions-of-unsaturated-hydrocarbons-with-o-3p.pdf |
667553c5c9c6a5c07a05cf5c | 10.26434/chemrxiv-2024-94vbg-v2 | Exact Factorization of the Photon-Electron-Nuclear Wavefunction: Formulation and Coupled-Trajectory Dynamics | We employ the exact-factorization formalism to study the coupled dynamics of photons, electrons, and nuclei at the quantum mechanical level, proposing illustrative examples of model situations of nonadiabatic dynamics and spontaneous emission of electron-nuclear systems in the regime of strong light-matter coupling. We make a particular choice of factorization for such a multi-component system, where the full wavefunction is factored as a conditional electronic amplitude and a marginal photon-nuclear amplitude. Then, we apply the coupled-trajectory mixed quantum-classical (CTMQC) algorithm to perform trajectory-based simulations, by treating photonic and nuclear degrees of freedom on equal footing in terms of classical-like trajectories. The analysis of the time-dependent potentials of the theory along with the assessment of the performance of CTMQC allow us to point out some limitations of the current ap- proximations used in CTMQC. On the other hand, comparing CTMQC with other trajectory-based algorithms, namely multi-trajectory Ehrenfest and Tully surface hopping, demonstrates the better quality of CTMQC predictions. | Eduarda Sangiogo Gil; David Lauvergnat; Federica Agostini | Theoretical and Computational Chemistry; Physical Chemistry | CC BY 4.0 | CHEMRXIV | 2024-06-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/667553c5c9c6a5c07a05cf5c/original/exact-factorization-of-the-photon-electron-nuclear-wavefunction-formulation-and-coupled-trajectory-dynamics.pdf |
6405156237e01856dc34e3ca | 10.26434/chemrxiv-2023-32hnp | Engineering flat and dispersive bands in 2D layered COFs via interlayer stacking and donor-acceptor strategy | Covalent organic frameworks (COFs) are an emergent class of two-dimensional (2D) crystalline organic materials that exhibit unique electronic, optical, and transport properties. In this study, we employ density functional theory (DFT) and the multiparticle Holstein formalism (MHF) to investigate the electronic structure and two-dimensional coherence of polarons in donor-acceptor COFs as a function of interlayer stacking arrangement. We show that simple modifications in the interlayer stacking arrangement have a profound impact on the transport properties, which can range from metallic behavior with vanishing band gap to highly localized states having completely flat bands. The extent of charge delocalization is found to be sensitive to the type of stacking arrangement and the precise arrangement of the donor and acceptor fragments within the COF structure. The results from the DFT calculations are consistent with MHF-based simulations, demonstrating that stacking-induced interlayer interac- tions facilitate better in-plane charge delocalization. As a consequence, we find that interlayer interactions help circumvent defect-induced trap states to enhance overall charge delocalization. Based on these analyses, we conclude that interlayer stacking can be exploited to guide the design of new 2D layered COF structures with potential applications in organic electronics. | Yuanhui Pan; Ching-Hwa Ho; Francesco Paesani; Raja Ghosh | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Physical and Chemical Properties; Quasiparticles and Excitations; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-03-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6405156237e01856dc34e3ca/original/engineering-flat-and-dispersive-bands-in-2d-layered-co-fs-via-interlayer-stacking-and-donor-acceptor-strategy.pdf |
652cf24ebda59ceb9aae0c70 | 10.26434/chemrxiv-2023-gpkcs | Investigating the catalytic efficiency of supported NHC-Ag(I) com-plexes in Borono-Minisci reaction | N-heterocyclic carbenes (NHCs) have been utilized as ligands of metal complexes to catalyze C–C, C–H, C–O, and C–N bond formation reactions. Herein, we present the development of novel supported NHC-Ag(I) complexes as catalysts for Borono-Minisci reactions. Kinetic and cyclic voltammetric studies have evidenced how the structure of both the ligand and complex influence the Ag(I)/Ag(II) redox potential and the reaction efficiency providing a complementary tactic to homo-geneous approaches. | Giada Moroni; Elena Bombonato; Samuele Bonafè; Alessandro Di Michele; Sara Presenti; Sara Guarienti; Massimo Marcaccio; Roccaldo Sardella; Paolo Ronchi; Antimo Gioiello | Catalysis; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/652cf24ebda59ceb9aae0c70/original/investigating-the-catalytic-efficiency-of-supported-nhc-ag-i-com-plexes-in-borono-minisci-reaction.pdf |
65c63ddf66c13817294a4902 | 10.26434/chemrxiv-2023-zdh13-v5 | Accurate Electronic and Optical Properties of Organic Doublet Radicals Using Machine Learned Range-Separated Functionals | Luminescent organic semiconducting doublet-spin radicals are unique and emergent optical materials because their fluorescent quantum yields (Φfl) are not compromised by the spin-flipping intersystem crossing (ISC) into a dark high-spin state. The multiconfigurational nature of these radicals challenges their electronic structure calculations in the framework of single-reference density functional theory
(DFT) and introduces room for method improvement. In the present study, we extended our earlier development of ML-ωPBE [J. Phys. Chem. Lett., 2021, 12, 9516], a range-separated hybrid (RSH) exchange–correlation (XC) functional constructed using the stacked ensemble machine learning (SEML) algorithm, from closed-shell organic semiconducting molecules to doublet-spin organic semiconducting radicals. We assessed its performance for a new test set of 64 doublet-spin radicals from five categories while placing all previously compiled 3,926 closed-shell molecules in the new training set. Interestingly,
ML-ωPBE agrees with the first-principles OT-ωPBE functional regarding the prediction of the molecule-dependent range-separation parameter (ω), with a small mean absolute error (MAE) of 0.0197 bohr−1 but saves the computational cost by 2.46 orders of magnitude. This result demonstrates an outstanding domain adaptation capacity of ML-ωPBE for diverse organic semiconducting species. To further assess the predictive power of ML-ωPBE in experimental observables, we also applied it to evaluate absorption and fluorescence energies (Eabs and Efl), using linear-response time-dependent DFT (TDDFT) and compared its behavior with nine popular XC functionals. For
most radicals, ML-ωPBE reproduces experimental measurements of Eabs and Efl with small MAEs of 0.299 and 0.254 eV, only marginally different from OT-ωPBE. Our work illustrates a successful extension of the SEML framework from closed-shell molecules to doublet-spin radicals and will open the venue for calculating optical properties for organic semiconductors using single-reference TDDFT. | Cheng-Wei Ju; Yili Shen; Ethan French; Jun Yi; Hongshan Bi; Aaron Tian; Zhou Lin | Theoretical and Computational Chemistry; Physical Chemistry; Machine Learning; Chemoinformatics - Computational Chemistry; Quantum Mechanics; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-02-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65c63ddf66c13817294a4902/original/accurate-electronic-and-optical-properties-of-organic-doublet-radicals-using-machine-learned-range-separated-functionals.pdf |
65c4de3866c138172937a0a9 | 10.26434/chemrxiv-2024-j0wmd | Sulfur(VI) Fluoride Exchange Chemistry in Solid-Phase Synthesis of Compound Arrays: Discovery of Histone Deacetylase Inhibitors | Multistep synthesis performed on solid support is a powerful means to generate small molecule libraries for the discovery of chemical probes to dissect biological mechanisms as well as for drug discovery. Therefore, expansion of the collection of robust chemical transformations amenable to solid-phase synthesis is desirable for achieving chemically diverse libraries for biological testing. Here we show that sulfur(VI) fluoride ex-change (SuFEx) chemistry, exemplified by pairing phenols with aryl fluorosulfates, can be used for solid-phase synthesis of biologically active compounds. As a case study, we designed and synthesized a library of 84 hy-droxamic acid containing small molecules, providing a rich source of inhibitors with diverse selectivity pro-files across the human histone deacetylase enzyme family, which is a validated drug target. Among other dis-coveries, we identified a scaffold that furnished inhibitors of HDAC11 with exquisite selectivity in vitro and a selective inhibitor of HDAC6 that was shown to bind this target enzyme selectively over HDAC8 in cells, using cellular thermal shift assays (CETSA). Our results encourage the further use of SuFEx chemistry for the syn-thesis of diverse small molecule libraries, provides insight for future design of selective HDAC inhibitors, and show that CETSA can be applied for evaluation of cellular target engagement of HDAC inhibitors. | Tobias N. Hansen; Daniela Dankova; Michael Bæk; Linda Grlas; Christian Adam Olsen | Biological and Medicinal Chemistry; Organic Chemistry; Combinatorial Chemistry; Organic Synthesis and Reactions; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2024-02-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65c4de3866c138172937a0a9/original/sulfur-vi-fluoride-exchange-chemistry-in-solid-phase-synthesis-of-compound-arrays-discovery-of-histone-deacetylase-inhibitors.pdf |
60c74cf7842e65de01db33ae | 10.26434/chemrxiv.12567746.v1 | Indoor Exposure to Commonly Used Disinfectants During the COVID-19 Pandemic | Staying safe during <a></a><a>the COVID-19 pandemic</a>
requires frequent disinfecting of the indoor environment. Quaternary ammonium
compounds (QACs or “quats”) are the major class of chemicals widely used as disinfectants
in consumer products. While disinfection is necessary for a safe environment
during the pandemic, the increased use of QACs is concerning as exposure to
these compounds has been associated with adverse effects on reproductive and
respiratory systems. We have determined the occurrence and distribution of 19
QACs in 46 residential dust collected before and during the outbreak of
COVID-19. All QACs were detected in more than 90% of the samples at concentrations
ranging from 1.95 to 531 μg/g (median 58.9 μg/g). Higher QAC concentrations
were found in dust collected before the COVID-19 pandemic and in homes with higher
disinfecting frequencies (<i>p </i>< 0.05). In addition, 7 products most
frequently used in these homes were analyzed, and QACs were detected at
concentrations reaching up to 16,600 mg/L.
The QAC profiles in dust and in products were similar, suggesting that these
products can be a significant source of QACs. Our findings indicate that the
indoor exposure to QACs is widespread, raising concerns about increased
exposure to these chemicals during the ongoing pandemic. | Guomao Zheng; Gabriel Filippelli; Amina Salamova | Environmental Science | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74cf7842e65de01db33ae/original/indoor-exposure-to-commonly-used-disinfectants-during-the-covid-19-pandemic.pdf |
60c74726f96a006589286e8d | 10.26434/chemrxiv.11541927.v1 | Stereoelectronic Effects Impact Glycan Recognition | Recognition of distinct glycans is central to biology, and lectins mediate this function. Lectin glycan preferences are usually centered on specific monosaccharides. In contrast, human intelectin-1 (hItln-1, also known as Omentin-1) is a soluble lectin that binds a range of microbial sugars, including β-Dgalactofuranose (β-Galf), D-glycerol 1-phosphate, D-glycero-D-talo-oct-2-ulosonic acid (KO), and 3- deoxy-D-manno-oct-2-ulosonic acid (KDO). Though these saccharides differ dramatically in structure, they share a common feature—an exocyclic vicinal diol. How and whether such a small fragment is sufficient for recognition was unclear. We tested several glycans with this epitope and found that L-glycero-α-Dmanno- heptose and D-glycero-α-D-manno-heptose possess the critical diol motif yet bind weakly. To better understand hItln-1 recognition, we determined the structure of the hItln-1·KO complex using X-ray crystallography, and our 1.59-Å resolution structure enabled unambiguous assignment of the bound KO conformation. This carbohydrate conformation was present in >97% of the KDO/KO structures in the Protein Data Bank. Bioinformatic analysis revealed that KO and KDO adopt a common conformation, while heptoses prefer different conformers. The preferred conformers of KO and KDO favor hItln-1 engagement, but those of the heptoses do not. Natural bond orbital (NBO) calculations suggest these observed conformations, including the side chain orientations, are stabilized by not only steric but also stereoelectronic effects. Thus, our data highlight a role for stereoelectronic effects in dictating the specificity of glycan recognition by proteins. Finally, our finding that hItln-1 avoids binding prevalent glycans with a terminal 1,2 diol (e.g., NeuAc, and L-glycero-α-D-manno-heptose) suggests the lectin has evolved to recognize distinct bacterial species. | Caitlin
M. McMahon; Christine R. Isabella; Ian W. Windsor; Paul Kosma; R. T. Raines; Laura Kiessling | Biochemistry; Biophysics; Chemical Biology; Microbiology | CC BY NC ND 4.0 | CHEMRXIV | 2020-01-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74726f96a006589286e8d/original/stereoelectronic-effects-impact-glycan-recognition.pdf |
60c7595c702a9b96b518ceaf | 10.26434/chemrxiv.14681061.v1 | Transition Metal Free Sandmeyer-Type Reductive Disulfuration of Anilines | A transition metal/ligand free disulfuration of anilines with disulfur transfer reagents (dithiosulfonate or tetrasulfide) is reported herein. The reaction, which can be considered as a reductive disulfuration variation of the classic Sandmeyer reaction, is performed under mild conditions and exhibits broad scope across aniline substrate and disulfur transfer reagent classes. The gram-scale synthesis of disulfides is successfully achieved through this method, rendering the approach highly valuable.
<br /> | Shiqi Chen; Si Cao; Chaoyang Liu; Baoxu Wang; Xiaorui Ren; Hang Huang; Xi Wang | Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2021-05-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7595c702a9b96b518ceaf/original/transition-metal-free-sandmeyer-type-reductive-disulfuration-of-anilines.pdf |
60c757b10f50db54263982f7 | 10.26434/chemrxiv.14449668.v1 | Isodesmic C–H Functionalization: Carboxyl-Assisted Remote meta- and ortho-C–H Iodination of Arenes via Shuttle Catalysis | Isodesmic C–H
functionalization reactions are extremely rare. Herein
we report the first Pd(II)-catalyzed isodesmic C–H iodination of arenes using
2-nitrophenyl iodides as the mild iodinating reagents. Unusual C–I reductive
elimination occurred in preference to
competing C–C coupling in this reaction. Assisted by aliphatic carboxyl
directing groups, a range of hydrocinnamic acids and related arenes could be
selectively iodinated at either <i>meta</i>- or <i>ortho</i>-positions of the
phenyl ring. Remote diastereoselective C–H activation was also promising. This
method may open up a new way to iodinate challenging substrates. | Shangda Li; Chunhui Zhang; Lei Fu; Hang Wang; Lei Cai; Xiaoxi Chen; Xinchao Wang; Gang Li | Organic Synthesis and Reactions; Homogeneous Catalysis; Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2021-04-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c757b10f50db54263982f7/original/isodesmic-c-h-functionalization-carboxyl-assisted-remote-meta-and-ortho-c-h-iodination-of-arenes-via-shuttle-catalysis.pdf |
63393258114b7ea829251b3f | 10.26434/chemrxiv-2022-b8j51 | Electrochemical Carbon Dioxide Capture and Concentration | Electrochemical carbon capture and concentration (eCCC) offers a promising alternative to thermochemical processes as it circumvents the limitations of temperature-driven capture and release. This review will begin by discussing the history of eCCC, describing early work in the field and the motivation for pursuing such a process. We will then transition towards discussing more recent approaches, with a heavier emphasis on methods that employ redox mediators to facilitate CO2 capture and release. These methods rely more on optimization through chemical design and include pH-mediated systems, electrochemically-mediated amine regeneration, and direct capture with redox-active molecules. For each approach, we provide a general overview of the system, discuss redox mediator chemistries that have been studied in literature, and highlight requirements for future generations of redox mediators. We also describe previous demonstrations of each method and current cell/system designs that have been used at the lab-scale. To conclude, we summarize achievements in the field, current challenges, and opportunities for improving these technologies. Overall, this review is a comprehensive survey of the eCCC field and evaluates the chemical, theoretical, and electrochemical engineering aspects of this approach. We hope this work can be used to assist the community in the development of modern economical eCCC technologies that can be utilized in large-scale CCS processes. | Alessandra Zito; Lauren Clarke; Jeffrey Barlow; Daniel Bim; Zisheng Zhang; Katelyn Ripley; Clarabella Li; Amanda Kummeth; McLain Leonard; Anastassia Alexandrova; Fikile Brushett; Jenny Yang | Inorganic Chemistry; Energy; Chemical Engineering and Industrial Chemistry; Electrochemistry; Thermodynamics (Chem. Eng.) | CC BY NC ND 4.0 | CHEMRXIV | 2022-10-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63393258114b7ea829251b3f/original/electrochemical-carbon-dioxide-capture-and-concentration.pdf |
60c74354702a9b750518a5b6 | 10.26434/chemrxiv.9067979.v1 | Solubility of Polar and Non-Polar Aromatic Molecules in Subcritical Water: The Role of the Dielectric Constant | Liquid water at temperatures above the boiling point and high pressures, also known as pressurized hot water, or subcritical water (SBCW), is an effective solvent for both polar and non-polar organic solutes. This is often associated to the decrease of water's dielectric constant at high temperatures, apparently allowing water to behave like an organic solvent. The decrease of the solubility at high pressures, in turn, is explained by a mild increase of the dielectric constant of water. Nevertheless, the relationship between the dielectric constant of water, hydration, and the solubility of polar and non-polar molecules in SBCW, remains poorly understood. Here, we study through molecular dynamics, the hydration thermodynamic parameters and the solubility of non-polar and polar aromatic model systems, for which a solubility increase in SBCW is observed. We show that the temperature dependence of the hydration free energy of the model non-polar solutes is nonmonotonic, exhibiting a solute size independent maximum at ~475 K, above which hydration becomes entropically favorable and enthalpically unfavorable. The monotonic increase of the solubility, separated here in hydration and vaporization or sublimation components of the pure liquid or solid solute, respectively, is, in turn, related to the temperature increase of the latter, and only to a minor extent with the decrease of the hydration free energy above ~475 K, via the hydration entropy. A solubility increase or decrease is also found at high pressures for different solutes, explained by the relative magnitude of the hydration and the vaporization or sublimation components of the solubility. For the model solid polar system studied, the hydration free energy increases monotonically with the temperature, instead, and the solubility increase is caused by the decrease of the sublimation component of the solubility. Thus, despite of the observed increase of the hydration free energy with pressure, related to the entropic component decrease, our results indicate that the dielectric constant plays no significant role on the solubility increase of non-polar and polar solutes in SBCW, opposite to the dielectric constant picture. The structure of water next to the solutes is also investigated and a structural enhancement at room temperature is observed, resulting in significantly stronger pair interactions between a water molecule and its third and fourth nearest water neighbors. This structural and energetic enhancement nearly vanishes, however, at high temperatures, contributing to a positive hydration entropy. <br /> | Nuno Galamba; Alexandre Paiva; Susana Barreiros; Pedro Simões | Physical and Chemical Processes; Physical and Chemical Properties; Solution Chemistry; Statistical Mechanics; Thermodynamics (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2019-07-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74354702a9b750518a5b6/original/solubility-of-polar-and-non-polar-aromatic-molecules-in-subcritical-water-the-role-of-the-dielectric-constant.pdf |
650fb8fdb927619fe7b3a705 | 10.26434/chemrxiv-2023-p8lfk | Determining times to detection for large methane release events using continuously operating methane sensing systems at simulated oil and gas production sites | Methane release events with large instantaneous emission rates are significant sources of emissions in multiple oil and gas production regions. Large release events detections are generally based on short duration observations, such as observations from aircraft or satellites. To be included in annual emissions reporting, instantaneous emission rate observations must be coupled with an estimate of event duration. Continuously operating, fixed point methane monitoring systems provide a mechanism for narrowly constraining event durations, however even continuously operating monitoring systems do not detect releases from all emission sources at all times. A method for using continuous monitoring system data to evaluate time to event detection was developed and demonstrated using data from a monitoring network operating in the Permian Basin of west Texas. Time to detection for events depends on meteorological conditions, the number and precision of the sensors, the criteria used in defining a detection and the positioning of the sensors relative to emission sources. For the case study in the Permian Basin, the presence of a single monitoring system per site enabled a time to detection of large release events that averaged less than half a day, and the methodology for determining bounds on event duration is applicable to a wide range of locations and types of sites. | Qining Chen; Yosuke Kimura; David Allen | Earth, Space, and Environmental Chemistry; Environmental Science | CC BY NC ND 4.0 | CHEMRXIV | 2023-09-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/650fb8fdb927619fe7b3a705/original/determining-times-to-detection-for-large-methane-release-events-using-continuously-operating-methane-sensing-systems-at-simulated-oil-and-gas-production-sites.pdf |
66281adb91aefa6ce13c833c | 10.26434/chemrxiv-2024-7hz4h | Controlling structure and morphology of MoS2 via sulfur precursor for optimized pseudocapacitive lithium intercalation hosts | Molybdenum disulfide (MoS2)-based electrode materials can exhibit a pseudocapacitive charge storage mechanism induced by nanosized dimension of the crystalline domains. This effect is achievable through hydrothermal synthesis of MoS2, which often yields different properties of the final material, thereby affecting its electrochemical lithium intercalation behavior. In this study, we investigate how the use of different sulfide precursors, specifically thiourea (TU), thioacetamide (TAA), and L-cysteine (LC), during the hydrothermal synthesis of MoS2, affects its physicochemical, and consequently, electrochemical properties. The three materials obtained exhibit distinct morphologies, ranging from micron-sized architectures (MoS2 TU), to nanosized flakes (MoS2 TAA and LC), which influence their available specific surface area and tortuosity. Consequently, the choice of hydrothermal synthesis parameters allows to control the resulting electrochemical signature. The individual charge storage properties are analyzed by operando X-ray diffraction, dilatometry, and 3D Bode analysis, revealing a correlation between the morphology, porosity, and the electrochemical intercalation behavior of the obtained electrode materials. The results demonstrate a facile strategy to control MoS2 structure and related functionality by choice of hydrothermal synthesis precursors. | Maciej Tobis; Mennatalla Elmanzalawy; Jaehoon Choi; Elżbieta Frąckowiak; Simon Fleischmann | Physical Chemistry; Inorganic Chemistry; Energy; Electrochemistry; Solid State Chemistry; Energy Storage | CC BY 4.0 | CHEMRXIV | 2024-04-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66281adb91aefa6ce13c833c/original/controlling-structure-and-morphology-of-mo-s2-via-sulfur-precursor-for-optimized-pseudocapacitive-lithium-intercalation-hosts.pdf |
65289f668bab5d20553d8a32 | 10.26434/chemrxiv-2023-qlgqq | Application of Taylor Vortex Flow Reactor Enabling Precise Control of Nucleation in Reactive Crystallization | A system that requires slurry handling such as reactive crystallization is not usually compatible with continuous flow synthesis due to the risk of clogging. Here we suggest the use of a Taylor vortex flow reactor to achieve the robust process for imination with reactive crystallization under continuous flow conditions. A Taylor vortex flow reactor realizes high shear stress and mixing efficiency, which accelerate the timing for nucleation of target imines and enable precise control of nucleation in reactive crystallization. A Taylor vortex flow reactor also mitigates the risk of adhesion to the flow reactor and clogging in reactive crystallization. | Masahiro Hosoya; Atsushi Manaka; Takahiro Kawajiri; Takafumi Ohara | Organic Chemistry; Chemical Engineering and Industrial Chemistry; Organic Synthesis and Reactions; Process Chemistry; Process Control | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65289f668bab5d20553d8a32/original/application-of-taylor-vortex-flow-reactor-enabling-precise-control-of-nucleation-in-reactive-crystallization.pdf |
60c758d9f96a0068bf288ee4 | 10.26434/chemrxiv.14594562.v1 | Control of Nucleophile Chemoselectivity in Cyanobactin YcaO Heterocyclases PatD and TruD | <div><div><div><p>YcaO proteins are ubiquitous in living organisms, where they perform crucial post-translational modifications of peptides and proteins. They are used extensively in biotechnology in companies and academic settings around the world. They also underlie some of the most important natural products in pharmaceutical development, such as thiopeptides (thiostrepton, etc.). Here, we solve one of the major outstanding mysteries behind YcaO proteins: how they exert precision selectivity of the nucleophile. The resulting findings have major implications in understanding the >30,000 YcaO proteins currently in sequencing databases and will be used widely for precision synthetic biology applications.</p></div></div></div> | Wenjia Gu; Yiwu Zheng; Taras Pogorelov; Satish K. Nair; Eric W. Schmidt | Biochemistry; Bioengineering and Biotechnology | CC BY NC ND 4.0 | CHEMRXIV | 2021-05-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c758d9f96a0068bf288ee4/original/control-of-nucleophile-chemoselectivity-in-cyanobactin-yca-o-heterocyclases-pat-d-and-tru-d.pdf |
61ae03ea535d63a8b1916089 | 10.26434/chemrxiv-2021-dmjz0 | Phosphinate MOF formed from tetratopic ligands as proton conductive materials | Metal organic frameworks (MOFs) are attracting attention as potential proton conductors. There are two main advantages of MOFs in this application: the possibility of rational design and tuning of the properties, and clear conduction pathways given by their crystalline structure. We hereby present two new MOF structures, ICR-10 and ICR-11, based on tetratopic phosphinate ligands. The structures of both MOFs were determined by 3D electron diffraction. They both crystallize in the P-3 space group and contain arrays of parallel linear pores lined with hydrophilic non-coordinated phosphinate groups. This, together with the adsorbed water molecules, facilitates proton transfer via the Grotthuss mechanism, leading to the proton conductivity up to 4.26∙10-4 S cm-1 for ICR-11. | Matouš Kloda; Tomáš Plecháček; Soňa Ondrušová; Petr Brázda; Petr Chalupský; Jan Rohlíček; Jan Demel; Jan Hynek | Inorganic Chemistry; Energy; Coordination Chemistry (Inorg.); Ligands (Inorg.); Materials Chemistry; Crystallography – Inorganic | CC BY NC ND 4.0 | CHEMRXIV | 2021-12-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61ae03ea535d63a8b1916089/original/phosphinate-mof-formed-from-tetratopic-ligands-as-proton-conductive-materials.pdf |
60d5cefb461f56c2f248c02e | 10.26434/chemrxiv-2021-b2m52 | Spiro-based thermally activated delayed fluorescence emitters with reduced non-radiative decay for high quantum efficiency, low roll-off, light-emitting diodes | Herein, we report the use of spiro-configured fluorene-xanthene scaffolds as a novel, promising and effective strategy in thermally activated delayed fluorescence (TADF) emitter design to attain high photoluminescence quantum yields (PL), short delayed luminescence lifetime, high external quantum efficiency (EQE) and minimum efficiency roll-off characteristics in organic light-emitting diodes (OLEDs). The optoelectronic and electroluminescence properties of SFX-, spiro-(fluorene-9,9’-xanthene), based emitters (SFX-PO-DPA, SFX-PO-DPA-Me and SFX-PO-DPA-OMe) were investigated both theoretically and experimentally. All three emitters exhibited sky blue to green emission enabled by a Herzberg-Teller mechanism in the excited state. They possess short excited state delayed lifetimes (<10 s), high photoluminescence quantum yields (PL ~70%) and small singlet-triplet splitting energies (EST < 0.10 eV) in the doped films in an mCP host matrix. The OLEDs showed some of the highest EQEs using spiro-containing emitters where maximum external quantum efficiencies (EQEmax) of 11% and 16% were obtained for devices using SFX-PO-DPA and SFX-PO-DPA-OMe, respectively. Further, a record EQEmax of 23% for a spiro-based emitter coupled with a small efficiency roll off (19% at 100 cd m-2) was attained with SFX-PO-DPA-Me. | Nidhi Sharma; Michal Maciejczyk; David Hall; Wenbo Li; Vincent Liegeois; David Beljonne; Yoann Olivier; Neil Robertson; Ifor Samuel; Eli Zysman-Colman | Physical Chemistry; Organic Chemistry; Organic Compounds and Functional Groups; Optics; Spectroscopy (Physical Chem.); Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2021-06-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60d5cefb461f56c2f248c02e/original/spiro-based-thermally-activated-delayed-fluorescence-emitters-with-reduced-non-radiative-decay-for-high-quantum-efficiency-low-roll-off-light-emitting-diodes.pdf |
660fefde21291e5d1d250446 | 10.26434/chemrxiv-2024-mvww4 | A sustainable CVD approach for ZrN as potential catalyst for nitrogen reduction reaction | In pursuit of developing alternatives for the highly polluting Haber-Bosch process for ammonia synthesis, the electrocatalytic nitrogen reduction reaction (NRR) on transition metal nitrides such as zirconium mononitride (ZrN) has been identified as potential pathway for ammonia synthesis. In particular, specific facets of ZrN have been theoretically described as a potentially active and selective for the NRR. Major obstacles that need to be overcome include the synthesis of tailored catalyst materials that can activate the inert dinitrogen bond while suppressing the hydrogen evolution reaction (HER) and not being degraded during electrocatalysis. To tackle these challenges, a comprehensive understanding of the influence of the catalyst’s structure, composition, and morphology on the NRR activity is required. This motivates the use of metalorganic chemical vapor deposition (MOCVD) as the materials synthesis route, as it enables catalyst nanoengineering by tailoring the process parameters. Herein, we report the fabrication of oriented and facetted crystalline ZrN thin films employing a single source precursor (SSP) MOCVD approach on silicon and glassy carbon (GC) substrates. First principles density functional theory (DFT) simulations elucidated the preferred decomposition pathway of the SSP, while ab initio molecular dynamics simulations show that ZrN at room temperature undergoes surface oxidation with ambient O2, yielding a Zr-O-N film, which is consistent with compositional analysis from Rutherford backscattering spectrometry (RBS) in combination with nuclear reaction analysis (NRA) and X-ray photoelectron spectroscopy (XPS) depth profiling. Proof-of-principle NRR experiments of ZrN/GC hint towards a possible activity for the electrochemical NRR in sulfuric acid electrolyte. | Jean-Pierre Glauber; Julian Lorenz; Ji Liu; Bjorn Muller; Sebastian Bragulla; Aleksander Kostka; Detlef Rogalla; Michael Wark; Michael Nolan; Corinna Harms; Anjana Devi | Theoretical and Computational Chemistry; Catalysis; Computational Chemistry and Modeling; Electrocatalysis; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2024-04-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/660fefde21291e5d1d250446/original/a-sustainable-cvd-approach-for-zr-n-as-potential-catalyst-for-nitrogen-reduction-reaction.pdf |
60c7541b337d6cce24e289b0 | 10.26434/chemrxiv.13613678.v1 | Highly Accurate Many-Body Potentials for Simulations of N2O5 in Water: Benchmarks, Development, and Validation | <div><div><div><p>Dinitrogen pentoxide (N2O5) is an important intermediate in the atmospheric chemistry of nitrogen oxides. Although there has been much research, the processes that govern the physical interactions between N2O5 and water are still not fully understood at a molecular level. Gaining quantitative insight from computer simulations requires going beyond the accuracy of classical force fields, while accessing length scales and time scales that are out of reach for high-level quantum chemical approaches. To this end we present the development of MB-nrg many-body potential energy functions for simulations of N2O5 in water. This MB-nrg model is based on electronic structure calculations at the coupled cluster level of theory and is compatible with the successful MB-pol model for water. It provides a physically correct description of long-range many-body interactions in combination with an explicit representation of up to three-body short-range interactions in terms of multidimensional permutationally invariant polynomials. In order to further investigate the importance of the underlying interactions in the model, a TTM-nrg model was also devised. TTM- nrg is a more simplistic representation that contains only two-body short-range interactions represented through Born-Mayer functions. In this work an active learning approach was employed to efficiently build representative training sets of monomer, dimer and trimer structures, and benchmarks are presented to determine the accuracy of our new models in comparison to a range of density functional theory methods. By assessing binding curves, distortion energies of N2O5, and interaction energies in clusters of N2O5 and water, we evaluate the importance of two-body and three-body short-range potentials. The results demonstrate that our MB-nrg model has high accuracy with respect to the coupled cluster reference, outperforms current density functional theory models, and thus enables highly accurate simulations of N2O5 in aqueous environments.</p></div></div></div> | Vinicius Cruzeiro; Eleftherios Lambros; Marc Riera; Ronak Roy; Francesco Paesani; Andreas Goetz | Computational Chemistry and Modeling; Theory - Computational; Machine Learning; Clusters | CC BY NC ND 4.0 | CHEMRXIV | 2021-01-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7541b337d6cce24e289b0/original/highly-accurate-many-body-potentials-for-simulations-of-n2o5-in-water-benchmarks-development-and-validation.pdf |
67ab714e81d2151a02fa2c3d | 10.26434/chemrxiv-2025-wg75c | Towards automated physics-based absolute drug residence time predictions | The residence time (τ) of a drug bound to a receptor target is increasingly recognized as a key property to control during ligand-optimization campaigns and provides a useful dimension for modulating compound profiles in addition to binding affinity. For this reason, many computational approaches have been developed to predict this quantity. Several methods employ an empirical correlation between the residence time and the measured simulation time for a ligand to escape the binding pocket during biased molecular dynamics (MD), while others rely on more formal approaches that require a substantially larger computational effort and/or setup times often impractical in a fast-paced drug-discovery setting. Here we propose a new scheme to calculate absolute residence times by using two enhanced sampling approaches, consisting of an exploration phase followed by an exploitation phase that estimates the residence time: Random Acceleration Molecular Dynamics (RAMD) to harvest plausible egress pathways, and then Infrequent Metadynamics (iMetaD) to estimate residence time. This protocol caters to drug discovery programs, where a key aspect is the compromise between accuracy, throughput, and ease of use. We benchmark this approach by computing residence times for a congeneric series of ligands binding to several diverse drug targets and show that we can achieve good accuracy (RMSE of 1.22 and R2 of 0.80 in log10(τ)) without manually tuning the enhanced sampling parameters. | Zachary Smith; Davide Branduardi; Dmitry Lupyan; Giulia D'Arrigo; Pratyush Tiwary; Lingle Wang; Goran Krilov | Theoretical and Computational Chemistry; Computational Chemistry and Modeling | CC BY 4.0 | CHEMRXIV | 2025-02-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67ab714e81d2151a02fa2c3d/original/towards-automated-physics-based-absolute-drug-residence-time-predictions.pdf |
6777055481d2151a02b2444e | 10.26434/chemrxiv-2025-5w2fc | Interrogation of the Intermolecular Forces that Drive Bulk Properties of Molecular Crystals with Terahertz Spectroscopy and Density Functional Theory | Identifying and characterizing intermolecular forces in the condensed phase is crucial for understanding both micro- and macroscopic properties of solids; ranging from solid-state reactivity to thermal expansion. Insight into these interactions enables a holistic comprehension of bulk properties, and thus understanding them has direct implications for supramolecular design. However, even modest changes to intermolecular interactions can create unpredictable changes to solid-state structures and dynamics. For example, copper(II) acetylacetonate (Cu(C5}H7O2)2) and copper(II) hexafluoroacetylacetonate (Cu(C5HF6O2)2) exhibit similar molecular conformations, yet differences between the methyl and trifluoromethyl groups produce distinct sets of intermolecular forces in the condensed phase. Ultimately, these differences produce unique molecular arrangements in the solid state, with corresponding differences in material properties between the two crystals. In this work, terahertz spectroscopy is used to measure low-frequency vibrational dynamics, which, by extension, provide detailed insight into the underlying intermolecular forces that exist in each system. The experimental data is coupled to theoretical quantum mechanical simulations to precisely quantify the interplay between various energetic effects, and these results highlight the delicate balance that is struck between electronic and dispersive interactions that underpin the structural and related differences between the two systems. | William Stoll; Peter Banks; Steven Dannenberg; Rory Waterman; Luca Catalano; Michael Ruggiero | Physical Chemistry; Materials Science; Physical and Chemical Properties; Spectroscopy (Physical Chem.); Materials Chemistry; Crystallography | CC BY NC 4.0 | CHEMRXIV | 2025-01-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6777055481d2151a02b2444e/original/interrogation-of-the-intermolecular-forces-that-drive-bulk-properties-of-molecular-crystals-with-terahertz-spectroscopy-and-density-functional-theory.pdf |
67d87945fa469535b98db09f | 10.26434/chemrxiv-2025-fvq6k | Insights into Electrolyte Reactivity at the Li Metal Surface from Density Functional Theory | Understanding interfacial reactivity and electrolyte degradation is critical for designing functional solid electrolyte interphase (SEI) layers in lithium-ion batteries (LIBs). This work employs density functional theory (DFT) calculations to model the adsorption and degradation mechanisms of two common electrolyte solvents—ethylene carbonate (EC) and propylene carbonate (PC)—and two widely used additive molecules — vinylene carbonate (VC) and fluoroethylene carbonate (FEC)—on the Li metal anode surface. Our findings reveal that solvent molecules exhibit stronger adsorption on the Li metal surface compared to additive molecules. Nudged elastic band calculations are employed to study two distinct C–O bond dissociation pathways, providing insights into the preferred degradation mechanisms and the resulting early-stage SEI products. EC and PC predominantly decompose to form Li2CO3 and C2H4, whereas FEC and VC follow alternate ring-opening pathways that yield intermediates prone to polymerization or further decomposition into CO and CO2. To validate our computational approach, we benchmarked three DFT functionals (r2SCAN, rVV10, and PBE) against hybrid functionals (HSE06 and PBE0). Among them, r2SCAN achieved the closest agreement with hybrid-level results, while rVV10 notably underestimated activation barriers. We also examined charge transfer using two different partitioning schemes, finding the Bader scheme more reliable than the Lowdin scheme, which significantly underpredicted charge transfer. These results provide a detailed mechanistic understanding of electrolyte degradation at the Li metal surface, offering valuable insights for the design of stable SEI layers in LIBs. | Garvit Agarwal; Casey N. Brock; Rishabh D. Guha; Karun K. Rao; James M. Stevenson; Subodh C. Tiwari; Alexandr Fonari; Leif D. Jacobson; H. Shaun Kwak; Mathew D. Halls | Theoretical and Computational Chemistry; Energy; Computational Chemistry and Modeling; Theory - Computational; Energy Storage; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2025-03-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67d87945fa469535b98db09f/original/insights-into-electrolyte-reactivity-at-the-li-metal-surface-from-density-functional-theory.pdf |
60c750fdbb8c1aa63c3dbbe0 | 10.26434/chemrxiv.13107566.v1 | New n-type Zintl Phases for Thermoelectrics: Discovery, Structural Characterization and Band Engineering of the Compounds A2CdP2 (A = Sr, Ba, Eu) | Zintl phases, owing to their complex crystal structures and intricate chemical bonding, have recently been recognized as promising candidates for thermoelectric (TE) applications. Band engineering, including band convergence has been shown to be an effective way to enhance the thermoelectric performance of such materials. In this work, a series of emerging TE materials, the isostructural Zintl phases with the general formula <i>A</i><sub>2</sub>CdP<sub>2</sub> (<i>A</i> = Sr, Ba, Eu) are presented for the first time. Their structures, established from single-crystal X-ray diffraction methods, show them to crystallize with the orthorhombic Yb<sub>2</sub>CdSb<sub>2</sub> structure type, with first-principles calculations on phase stability confirming that Ba<sub>2</sub>CdP<sub>2</sub> and Sr<sub>2</sub>CdP<sub>2</sub> are thermodynamically stable. Computationally, it was found that both Ba<sub>2</sub>CdP<sub>2</sub> and Sr<sub>2</sub>CdP<sub>2</sub> have the potential to exhibit high <i>n</i>-type TE performance (0.6 and 0.7 relative to the <i>n</i>-type PbTe, a reference TE material). To optimize the TE performance, band engineering strategies, including isovalent substitution and cation mutations, were investigated. From the band engineering of Ba<sub>2</sub>CdP<sub>2</sub> via isovalent substitution of Sr on a single Ba site, leading to the quaternary composition SrBaCdP<sub>2</sub>, it can be suggested that increasing the conduction band valley degeneracy is an effective way to improve the <i>n</i>-type TE performance by three-fold. Moreover, first-principles defect calculations reveal that both Ba<sub>2</sub>CdP<sub>2</sub> and SrBaCdP<sub>2</sub> are <i>n</i>-type dopable, adding these compounds to a small list of rare <i>n</i>-type dopable Zintl phases. The band engineering strategies used in this work are equally applicable to other TE materials, either for optimization of existing TE materials or designing new materials with desired properties. | Adam Balvanz; Jiaxing Qu; Sviatoslav Baranets; Elif Ertekin; Prashun Gorai; Svilen Bobev | Solid State Chemistry; Theory - Inorganic; Computational Chemistry and Modeling; Theory - Computational; Piezoelectricity and Thermoelectricity; Materials Chemistry; Crystallography – Inorganic | CC BY NC ND 4.0 | CHEMRXIV | 2020-10-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c750fdbb8c1aa63c3dbbe0/original/new-n-type-zintl-phases-for-thermoelectrics-discovery-structural-characterization-and-band-engineering-of-the-compounds-a2cd-p2-a-sr-ba-eu.pdf |
6523c80b45aaa5fdbb98225e | 10.26434/chemrxiv-2023-7cfwq-v2 | FRET-sensing of multivalent protein binding at the interface of targeted biomimetic microparticles functionalized with tunable fluorescent lipids | Cell adhesion is a fundamental phenomenon for cell communication and regulation. Adhesion sites are triggered by the binding of single ligand-receptor pairs that will initiate the formation of clusters of receptors. To study cell adhesion in live cells with microscopy techniques, there is a need of fluorescent particles targeted towards membrane receptors with a signal sensitive to the binding and movement of receptors and ligands at the interface. We propose new biomimetic fluorescent lipid microparticles for membrane receptor targeting and sensing. The particles are functionalized with tailor-made fluorescent lipids targeted towards lectins or biotin membrane receptor and can be specifically recognized and internalized by cells as evidenced by their phagocytosis in primary murine bone-marrow derived macrophages. By using a FRET pair of fluorescent mannolipids, it was possible to detect the presence of concanavalin A in solution by energy transfer showing that the particles can sense receptor binding at the interface and the associated movement of the ligands at the site of adhesion. Our results demonstrate that this biosensing platform can be specifically internalized by phagocytes, effectively mimicking a bacteria, and reveal short-range interactions of surface receptors via FRET. | Sophie Michelis; Chiara Pompili; Florence Niedergang; Jacques Fattaccioli; Blaise Dumat; Jean-Maurice Mallet | Biological and Medicinal Chemistry; Biophysics; Chemical Biology; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6523c80b45aaa5fdbb98225e/original/fret-sensing-of-multivalent-protein-binding-at-the-interface-of-targeted-biomimetic-microparticles-functionalized-with-tunable-fluorescent-lipids.pdf |
61c0d8db75c572df9ef27263 | 10.26434/chemrxiv-2021-6h2b7 | Substituent Control of σ-interference Effects in the
Transmission of Saturated Molecules | The single-molecule conductance of saturated molecules can potentially be fully
suppressed by destructive quantum interference in their σ-system. However, only few molecules
with σ-interference have been identified and the structure-property relationship remains to be
elucidated. Here, we explore the role of substituents in modulating the electronic transmission of
saturated molecules. In functionalized bicyclo[2.2.2]octanes, the transmission is suppressed by σ-
interference when fluorine substituents are applied. For bicyclo[2.2.2]octasilane and -
octagermanes the transmission is suppressed when carbon-based substituents are used, and such
molecules are likely to be highly insulating. For the carbon-based substituents we find a strong
correlation between the appropriate Hammett constants and the transmission. The substituent
effect enables systematic optimization of the insulating properties of saturated molecular cores. | Marc H. Garner; Mads Koerstz; Jan H. Jensen; Gemma C. Solomon | Theoretical and Computational Chemistry | CC BY 4.0 | CHEMRXIV | 2021-12-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61c0d8db75c572df9ef27263/original/substituent-control-of-interference-effects-in-the-transmission-of-saturated-molecules.pdf |
61ce22cb7284d0e2d4fdea81 | 10.26434/chemrxiv-2022-vn66h | Towards a Density-Based Description of Chemical Bonds and Noncovalent Interactions with Pauli Energy | Chemical bonds and noncovalent interactions are extraordinarily important concepts in chemistry and beyond. Using density-based quantities to describe them has a long history in the literature, yet none can satisfactorily describe the entire spectrum of interactions from strong chemical bonds to weak van der Waals forces. In this work, employing Pauli energy as the theoretical foundation, we fill in that knowledge gap. Our results show that the newly established density-based index can describe single and multiple covalent bonds, ionic bonds, metallic bonds, and different kinds of noncovalent interactions, all with unique and readily identifiable signature shapes. Two new descriptors, NBI (nonbonding and bonding identification) index and USI (ultra-strong interaction) index, have been introduced in this work. Together with NCI (noncovalent interaction) and SCI (strong covalent interaction) indexes already available in the literature, a density-based description of both chemical bonds and noncovalent interactions is accomplished. | Shubin Liu; Shujing Zhong; Xin He; Siyuan Liu; Bin Wang; Tian Lu; Chunying Rong | Theoretical and Computational Chemistry; Theory - Computational | CC BY NC 4.0 | CHEMRXIV | 2022-01-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61ce22cb7284d0e2d4fdea81/original/towards-a-density-based-description-of-chemical-bonds-and-noncovalent-interactions-with-pauli-energy.pdf |
62851e76f053df523f204845 | 10.26434/chemrxiv-2022-3ppq1 | Spontaneous Seed Formation During Electrodeposition Drives Epitaxial Growth of Metastable Bismuth Selenide Microcrystals | Materials with metastable phases can exhibit vastly different properties from their thermodynamically favored counterparts. Methods to synthesize metastable phases without the need for high-temperature or high-pressure conditions would facilitate their widespread use. We report on the electrochemical growth of microcrystals of bismuth selenide, Bi2Se3, in the metastable orthorhombic phase at room temperature in aqueous solution. Rather than direct epitaxy with the growth substrate, the spontaneous formation of a seed layer containing nanocrystals of cubic BiSe enforces the metastable phase. We first used single-crystal silicon substrates with a range of resistivities and different orientations to identify the conditions needed to produce the metastable phase. When the applied potential during electrochemical growth is positive of the reduction potential of Bi3+, an initial, Bi-rich seed layer forms. Electron microscopy imaging and diffraction reveal that the seed layer consists of nanocrystals of cubic BiSe embedded within an amorphous matrix of Bi and Se. Using density-functional theory calculations, we show that epitaxial matching between cubic BiSe and orthorhombic Bi2Se3 can help stabilize the metastable orthorhombic phase over the thermodynamically stable rhombohedral phase. The spontaneous formation of the seed layer enables us to grow orthorhombic Bi2Se3 on a variety of substrates including single-crystal silicon with different orientations, polycrystalline fluorine-doped tin oxide, and polycrystalline gold. The ability to stabilize the metastable phase through room-temperature electrodeposition in aqueous solution without requiring a single-crystal substrate, broadens the range of applications for this semiconductor in optoelectronic and electrochemical devices. | Jiang Luo; Guodong Ren; Brandon Campbell; Dongyan Zhang; Tengfei Cao; Rohan Mishra; Bryce Sadtler | Nanoscience; Nanostructured Materials - Nanoscience; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-05-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62851e76f053df523f204845/original/spontaneous-seed-formation-during-electrodeposition-drives-epitaxial-growth-of-metastable-bismuth-selenide-microcrystals.pdf |
60c73e13ee301c74e2c78685 | 10.26434/chemrxiv.5732976.v3 | Surfactant Impurities Can Explain the Jones-Ray Effect | <div>
<p>
</p><div>
<div>
<div>
<p>The surface tension of dilute salt water is a fundamental property that is crucial to understanding the complexity of many aqueous phase processes. Small ions are known
to be repelled from the air-water surface leading to an increase in the surface tension
in accordance with the Gibbs adsorption isotherm. The Jones-Ray effect refers to
the observation that at extremely low salt concentration the surface tension decreases
in apparent contradiction with thermodynamics. Determining the mechanism that
is responsible for this Jones-Ray effect is important for theoretically predicting the
distribution of ions near surfaces. Here we show that this surface tension decrease
can be explained by surfactant impurities in water that create a substantial negative
electrostatic potential at the air-water interface. This potential strongly attracts positive cations in water to the interface lowering the surface tension and thus explaining
the signature of the Jones-Ray effect. At higher salt concentrations, this electrostatic
potential is screened by the added salt reducing the magnitude of this effect. The
effect of surface curvature on this behavior is also examined and the implications
for unexplained bubble phenomena is discussed. This work suggests that the purity
standards for water may be inadequate and that the interactions between ions with
background impurities are important to incorporate into our understanding of the
driving forces that give rise to the speciation of ions at interfaces. </p>
</div>
</div>
</div>
</div> | Timothy Duignan; Marcel Baer; Christopher Mundy | Interfaces; Physical and Chemical Properties; Surface; Thermodynamics (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2018-02-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73e13ee301c74e2c78685/original/surfactant-impurities-can-explain-the-jones-ray-effect.pdf |
646647baf2112b41e9c31cf4 | 10.26434/chemrxiv-2023-qgr9n-v2 | Room temperature reduction of nitrogen oxide on iron Metal-Organic Frameworks | Air pollution is an epochal concern, particularly in urban areas, and is linked to combustion
processes 1
. The emission of nitrogen oxides (NOx) constitutes a critical environmental
problem, and it can affect severely human health2,3,4
. At ambient temperature and pressure
NOx decomposition is thermodynamically favoured; however, this process is kinetically
inhibited, owing to a high activation energy5,6
. To date, no reported catalysts have had the
required properties to lower the activation energy of this process without the help of coreacting agents and high temperatures7,8,9
. Here, we show that NO conversion to molecular
nitrogen can be achieved at room temperature in the presence of O2 and H2O vapour, and in
the absence of any further reducing agent, using iron-based Metal-Organic Frameworks
(MOFs). Further, we demonstrate that MOFs work similarly to enzymes, but are stable in
environments unfriendly to living matter. These findings open large perspectives on the
solution of stringent problems in chemistry, such as the removal of pollutants or the activation
of highly stable molecules.<br /> | Marco Daturi; Vanessa BLASIN-AUBE; Ji Wong Yoon; Philippe Bazin; Alexandre Vimont; Jong-San Chang; Young Kyu Hwang; You-Kyong Seo; Seunghun Jang; Hyunju Chang; Stefan Wuttke; Patricia Horcajada; Masaaki Haneda; Christian Serre | Catalysis; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/646647baf2112b41e9c31cf4/original/room-temperature-reduction-of-nitrogen-oxide-on-iron-metal-organic-frameworks.pdf |
65f3249ae9ebbb4db9b380dd | 10.26434/chemrxiv-2023-fk7kf-v2 | Molecular set representation learning | Computational representation of molecules can take many forms, including graphs, string-encodings of graphs, binary vectors, or learned embeddings in the form of real-valued vectors. These representations are then used in downstream classification and regression tasks using a wide range of machine-learning models. However, existing models come with limitations, such as the requirement for clearly defined chemical bonds, which often do not represent the true underlying nature of a molecule. Here, we propose a framework for molecular machine learning tasks based on set representation learning. We show that learning on sets of atomic invariants alone reaches the performance of state-of-the-art graph-based models on the most-used chemical benchmark data sets and that introducing a set representation layer into graph neural networks can surpass the performance of established methods in the domains of chemistry, biology, and material science. We introduce specialised set representation-based neural network architectures for reaction yield and protein-ligand binding affinity prediction. Overall, we show that the technique we denote molecular set representation learning is both an alternative and an extension to graph neural network architectures for machine learning tasks on molecules, molecule complexes, and chemical reactions. | Maria Boulougouri; Pierre Vandergheynst; Daniel Probst | Theoretical and Computational Chemistry; Biological and Medicinal Chemistry; Materials Science; Computational Chemistry and Modeling; Artificial Intelligence; Chemoinformatics - Computational Chemistry | CC BY 4.0 | CHEMRXIV | 2024-03-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65f3249ae9ebbb4db9b380dd/original/molecular-set-representation-learning.pdf |
65262c788bab5d205516e39f | 10.26434/chemrxiv-2023-2ffdr | Direct Heterocycle C–H Alkenylation via Dual Catalysis Using a Palladacycle Precatalyst: Multifactor Optimization and Scope Exploration Enabled by High-Throughput Experimentation
| One of the major challenges in developing catalytic methods for C–C bond formation is the identification of generally applicable reaction conditions, particularly if multiple substrate structural classes are involved. Pd-catalyzed direct arylation reactions are powerful transformations that enable direct functionalization of C–H bonds; however, the corresponding direct alkenylation reactions, using vinyl (pseudo)halide electrophiles, are less well developed. Inspired by process development efforts toward GSK3368715, an investigational active pharmaceutical ingredient, we report that a Pd(II) palladacycle derived from tri-¬tert-butylphosphine and Pd(OAc)2 is an effective single-component precatalyst for a variety of direct alkenylation reactions. High-throughput experimentation identified optimal solvent/base combinations for a variety of HetAr–H substrate classes undergoing C–H activation without the need for co-catalysts or stoichiometric silver bases (e.g. Ag2CO3). We propose this reaction proceeds via a dual cooperative catalytic mechanism, where in situ generated Pd(0) supports a canonical Pd(0)/(II) cross-coupling cycle, and the palladacycle effects C–H activation via CMD in a redox-neutral cycle. In all, 192 substrate combinations were tested, with a hit-rate of approx. 40% and 24 isolated examples. Importantly, this method was applied to prepare a key intermediate in the synthesis of GSK3368715 on multigram scale. | Nahiane Pipaon-Fernandez; Odhran Cruise; Sarah Easton; Justin Kaplan; John Woodard; Damian Hruszkewycz; David Leitch | Organic Chemistry; Catalysis; Combinatorial Chemistry; Organic Synthesis and Reactions; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65262c788bab5d205516e39f/original/direct-heterocycle-c-h-alkenylation-via-dual-catalysis-using-a-palladacycle-precatalyst-multifactor-optimization-and-scope-exploration-enabled-by-high-throughput-experimentation.pdf |
60c7401fee301c796ac789e7 | 10.26434/chemrxiv.7613213.v1 | Probing Cellular Outcomes Using Heterobivalent Constructs | <div>
<div>
<div>
<p>Conjugation techniques are central to improving
intracellular delivery of bioactive small molecules. However, tracking
and assessing the overall biological outcome of these constructs
remains poorly understood. We addressed this issue by having
developed a focused library of heterobivalent constructs based on
Rho kinase inhibitors to probe various scenarios. By comparing
induction of a phenotype of interest vs. cell viability vs. cellular uptake,
we demonstrate that such conjugates indeed lead to divergent cellular
outcomes.
</p>
</div>
</div>
</div> | Rohit Bhadoria; Kefeng Ping; Christer Lohk; Ivar Järving; Pavel Starkov | Bioorganic Chemistry; Organic Synthesis and Reactions; Cell and Molecular Biology; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2019-01-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7401fee301c796ac789e7/original/probing-cellular-outcomes-using-heterobivalent-constructs.pdf |
642db15b0784a63aee971f33 | 10.26434/chemrxiv-2023-2lgv9-v2 | Models of Polaron Transport in Inorganic and Hybrid Organic-Inorganic Titanium Oxides | Polarons are a type of localized excess charge in materials and often form in transition metal oxides. The large effective mass and confined nature of polarons make them of fundamental interest for photochemical and electrochemical reactions. The most studied polaronic system is rutile TiO2 where electron addition results in small polaron formation through the reduction of Ti(IV) d0 to Ti(III) d1 centers. Using this model system, we perform a systematic analysis of the potential energy surface based on semi-classical Marcus theory parameterized from the first-principles potential energy landscape. We show that F-doped TiO2 only binds polaron weakly with effective dielectric screening after the second nearest neighbor. To tailor the polaron transport, we compare TiO2 to two metal-organic frameworks: MIL-125 and ACM-1. The choice of ligands and connectivity of the TiO6 octahedra largely vary the shape of the diabatic potential energy surface and the polaron mobility. Our models are applicable to other polaronic materials. | Kazuki Morita; Matthias Golomb; Miguel Rivera; Aron Walsh | Theoretical and Computational Chemistry; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2023-04-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/642db15b0784a63aee971f33/original/models-of-polaron-transport-in-inorganic-and-hybrid-organic-inorganic-titanium-oxides.pdf |
63fd63de897b18336f39f813 | 10.26434/chemrxiv-2023-2mrsw | Spin-Polarized Radicals with Extremely Long Spin-Lattice Relaxation Time at Room Temperature in a Metal-Organic Framework | The generation of spin polarization is key in quantum information science and dynamical nuclear polarization. Polarized electron spins with long spin-lattice relaxation times (T1) at room temperature are important for these applications, but have been difficult to achieve. We report the realization of spin-polarized radicals with extremely long T1 at room temperature in a metal-organic framework (MOF) in which azaacene chromophores are densely integrated. Persistent radicals are generated in the MOF by charge separation after photoexcitation. Spin polarization of triplet generated by photoexcitation are successfully transferred to the persistent radicals. Pulse ESR measurements reveal that the T1 of the polarized radical in the MOF is as long as 274 s at room temperature. The achievement of extremely long spin polarization in MOFs with nanopores accessible to guest molecules will be an important cornerstone for future highly sensitive quantum sensing and efficient dynamic nuclear polarization. | Kana Orihashi; Akio Yamauchi; Saiya Fujiwara; Mizue Asada; Toshikazu Nakamura; Joseph Ka-Ho Hui; Nobuo Kimizuka; Kenichiro Tateishi; Tomohiro Uesaka; Nobuhiro Yanai | Physical Chemistry; Photochemistry (Physical Chem.); Physical and Chemical Properties; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-02-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63fd63de897b18336f39f813/original/spin-polarized-radicals-with-extremely-long-spin-lattice-relaxation-time-at-room-temperature-in-a-metal-organic-framework.pdf |
6568e8835bc9fcb5c9c15142 | 10.26434/chemrxiv-2023-9g0d5 | Overriding Innate Decomposition Temperatures of an Avibactam
Prodrug Precursor using Data Science-Guided Synthesis | Statistical analysis is used to correlate the thermal decomposition temperature of diverse leaving groups of an avibactam
prodrug precursor. SMILES strings and Mordred calculated parameters were leveraged to provide a time-efficient workflow
for model development. The resulting models were deployed to predict a novel analog with a higher onset temperature,
allowing for an overall safer reagent and proof of concept for the workflow. Interperetation of the descriptors featured in
the models and subsequent DFT analysis uncovered univariate trends providing a deeper understanding of the
decomposition pathway. Finally, this workflow enabled the development of a predictive model correlating energy output of
the precursor analogs for a more comprehensive assessment. | Jacob Werth; Michael Butler; Jenson Verghese; Nga Do; Lacey Samp; Remzi Duzguner; Michele Buetti-Weekly | Theoretical and Computational Chemistry; Organic Chemistry | CC BY NC 4.0 | CHEMRXIV | 2023-12-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6568e8835bc9fcb5c9c15142/original/overriding-innate-decomposition-temperatures-of-an-avibactam-prodrug-precursor-using-data-science-guided-synthesis.pdf |
62c530cb08a0f953525d285b | 10.26434/chemrxiv-2022-rs2m8 | Gaussian Processes for the Analysis of Electrochemical Impedance Spectroscopy Data: Prediction, Filtering, and Active Learning | Electrochemical impedance spectroscopy (EIS) is a widespread characterization technique used to study electrochemical systems. However, several shortcomings still limit the application of this technique. First, EIS data is intrinsically noisy, hindering spectra regression and prediction at unknown frequencies. Second, many physicochemical properties, such as the polarization resistance, are determined through non-unique equivalent circuits. Third, probed frequencies are usually log-spaced with a fixed number of points per decade, which is not necessarily optimal. This article illustrates how Gaussian processes (GPs) can overcome these three issues by showing that GPs can successfully filter EIS data and be used to determine the polarization resistance as a stochastic variable. Lastly, a GP-based, active-learning framework is developed to select EIS frequencies optimally for quick and accurate measurements. | Baptiste Py; Adeleke Maradesa; Francesco Ciucci | Energy; Chemical Engineering and Industrial Chemistry; Energy Storage; Photovoltaics; Power | CC BY 4.0 | CHEMRXIV | 2022-07-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62c530cb08a0f953525d285b/original/gaussian-processes-for-the-analysis-of-electrochemical-impedance-spectroscopy-data-prediction-filtering-and-active-learning.pdf |
6628f0e891aefa6ce14c72b6 | 10.26434/chemrxiv-2024-3jvf5 | Transition Behaviors of Isostructural sql-Topological Hydrogen-Bonded Frameworks Composed of Naphthalene, Quinoxaline, and Pyrazinopyrazine Derivatives | A series of isostructural reticular framework materials with systematic differences on chemical structures allows us to disclose correlations between specific structural factors and properties, providing insights for designing novel porous frameworks. However, even slight differences in the molecular structure often lead to non-isostructural polymorphic frameworks particularly in the case of hydrogen-bonded organic frameworks (HOFs) because the structures of HOFs are based on a subtle balance of reversible interactions. In this study, we found that three simple analogues of tetracarboxylic acids with naphthalene, quinoxaline, and pyrazinopyrazine cores (NT, QX, and PP, respectively) yield isostructural solvated HOFs (NT-1, QX-1, and PP-1, respectively), where hydrogen-bonded sql-networked sheets are slip-stacked with closely similar manners, and that these HOFs undergo structural transformations in different ways by guest solvent removal. Comparison of the crystal structures of the HOFs before and after the transformation revealed that intermolecular interactions of the core significantly affected on rearrangements of hydrogen bonds after the transformation. The results suggest the potential to control the properties and functions of isostructural HOFs by elemental doping. | Haruka Kubo; Shunsuke Konishi; Ryusei Oketani; Takashi Hayashi; Ichiro Hisaki | Organic Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-04-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6628f0e891aefa6ce14c72b6/original/transition-behaviors-of-isostructural-sql-topological-hydrogen-bonded-frameworks-composed-of-naphthalene-quinoxaline-and-pyrazinopyrazine-derivatives.pdf |
62b1ecd01672a233784716d9 | 10.26434/chemrxiv-2022-7cvbc-v2 | Limits of the quantum cognition hypothesis: 31P singlet order lifetimes of pyrophosphate from experiment and simulation | A proposal of quantum cognition advances the hypothesis that quantum entanglement between 31P nuclei could serve as a means of information storage in the brain. Testing this hypothesis requires an understanding of how long-lived these quantum effects may be. We used NMR spectroscopy and molecular dynamics simulations to study the mechanisms that limit these quantum processes in 18O-enriched molecules of pyrophosphate, the simplest biomolecule that can sustain quantum-entangled 31P nuclear spin singlet states. We confirmed that chemical shift anisotropy limits the singlet magnetization order lifetimes in high magnetic fields, and we discovered that rapid rotation of the phosphate groups limits the lifetime in low magnetic fields. These findings represent an important starting point in studying whether quantum cognition can be a true biological phenomenon. | David Korenchan; Jiaqi Lu; Mohamed Sabba; Laurynas Dagys; Lynda Brown; Malcolm Levitt ; Alexej Jerschow | Physical Chemistry; Biophysical Chemistry; Quantum Mechanics; Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2022-06-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62b1ecd01672a233784716d9/original/limits-of-the-quantum-cognition-hypothesis-31p-singlet-order-lifetimes-of-pyrophosphate-from-experiment-and-simulation.pdf |
65380c89c3693ca9930816d9 | 10.26434/chemrxiv-2023-m3shw-v2 | Vitamin B12–Photocatalyzed Cyclopropanation of Electron-Deficient Alkenes using Dichloromethane as the Methylene Source | The cyclopropyl group is of great importance in medicinal chemistry, as it can be leveraged to influence a range of pharmaceutical properties in drug molecules. This report describes a Vitamin B12-photocatalyzed approach for the cyclopropanation of Michael acceptors using CH2Cl2 as the methylene source. The reaction proceeds in good to excellent yields under mild conditions, has excellent functional group compatibility, and is highly regioselective. The scope could also be extended to the preparation of D2-cyclopropyl and methyl-substituted cyclopropyl adducts starting from CD2Cl2 and 1,1-dichloroethane, respectively. | John Hayford Teye-Kau; Mayokun Ayodele; Spencer Pitre | Organic Chemistry; Catalysis; Organic Synthesis and Reactions; Homogeneous Catalysis; Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65380c89c3693ca9930816d9/original/vitamin-b12-photocatalyzed-cyclopropanation-of-electron-deficient-alkenes-using-dichloromethane-as-the-methylene-source.pdf |
66a0ef56c9c6a5c07ac21e6e | 10.26434/chemrxiv-2024-fz42r-v2 | Variable-Area Sensor Permits Near-Continuous Multi-Point Measurements of Aqueous Biological and Chemical Analytes | The timely detection of aqueous analytes is critical to decision-makers in agriculture, industry, and munici-palities. However, nearly all water sensor systems rely on single-point measurements, often taken at an instantaneous point in time and in one location, which can limit their ability to detect analytes passing through the water matrix at other locations or times. In this work, we present the concept of employing a mass-manufactured nanotextured diffraction surface as a variable-area sensor system capable of provid-ing spectrophotometric information on aqueous analytes across multiple locations over time. We show that by placing the nanotextured surface of the sensor system under or behind a water matrix, the water can be scanned by simply changing the location or angle of the light source and detector. We demonstrate the detection and quantification of a variety of aqueous analytes, including visible and ultraviolet (UV)-absorbing dyes, dust particles, and microalgae species at accuracies similar to commercial spectropho-tometers. A machine learning algorithm was used to lower the limit of detection of methylene blue from 5 µg/mL to 3 µg/mL and automate the classification of three distinct analyte types. These results demonstrate that using a mass-produced, textured surface as a sensor can offer benefits in water sensing capabilities, facilitating widely deployable aqueous analyte monitoring in a variety of applications. | Liza White; Jordan Miner; Luke McKinney; Lindsay Pierce; Anna Folley; Ariel Larrabee; Lea Scrapchansky; Wyatt Fessler; Manisha Choudhary; Manoj Kamalanathan; Ramin Pouria; Saman Zare; Emma Perry; Sheila Edalatpour; Onur Apul; Caitlin Howell | Analytical Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-07-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66a0ef56c9c6a5c07ac21e6e/original/variable-area-sensor-permits-near-continuous-multi-point-measurements-of-aqueous-biological-and-chemical-analytes.pdf |
65e9863c9138d23161e9df4b | 10.26434/chemrxiv-2024-14r7s | Electronic Strong Coupling Modifies the Ground-state Intermolecular Interactions in Chlorin Thin Films | The electronic strong coupling (ESC) of a molecular transition with cavity modes can result in modified excited state photophysics compared to its uncoupled counterparts. Often, such changes are attributed to kinetics effects, overlooking the possible modifications to ground-state intermolecular interactions. The spin-coated films of Chlorin e6 trimethyl ester (Ce6T) provide a platform for studying the role of ESC in dictating photophysics and intermolecular interactions. The preorganization of Ce6T molecules in thin films facilitates intermolecular excitonic interaction, leading to an intense excimer-like emission upon photoexcitation. Interestingly, the ESC of the Ce6T Q-band results in modified luminescence characteristics, where the polaritonic emission dominates over the excimer-like emission. Remarkably, our steady-state, time-resolved emission and the excitation spectral analysis reveal that ESC suppresses the ground-state intermolecular excitonic interactions that otherwise exist in the preorganized Ce6T thin films. These findings will provide valuable insights into the fundamentals of quantum light-matter interactions and coherent energy transport processes. | Subha Biswas; Mainak Mondal; Gokul Chandrasekharan; Akshay Singh; Anoop Thomas | Physical Chemistry; Photochemistry (Physical Chem.); Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-03-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65e9863c9138d23161e9df4b/original/electronic-strong-coupling-modifies-the-ground-state-intermolecular-interactions-in-chlorin-thin-films.pdf |
67a8c6a46dde43c9082efc46 | 10.26434/chemrxiv-2025-5c6j0 | Ab Initio Insights into CO2, H2O and N2 Adsorption on BN-Doped Polymeric C60 Monolayers | This study utilizes density functional theory (DFT) to explore the structural stability, electronic properties, adsorption behaviour, optical characteristics, and hydrogen evolution reaction (HER) activity of BN-doped quasi-tetragonal packed (qTP) C60 polymeric nanosheets. Adsorption studies indicate a significantly higher affinity of H2O molecules compared to CO2 and N2 upon BN doping, highlighting the crucial role of humidity in modulating gas-sensing responses. This aligns with the limited atomic-scale understanding of water interactions on novel, nonmetallic 2D interfaces. Bader charge transfer analysis and adsorption energy calculations further validate the enhanced adsorption of H2O (+0.056 e), inducing notable band gap modifications ranging from 0.5 to 1.2 eV. Optical studies reveal improved light absorption in the visible spectrum, demonstrating the material’s potential for optoelectronic and photocatalytic applications. HER activity assessments indicate that BN doping reduces the overpotential for hydrogen evolution, enhancing the catalytic efficiency. Collectively, BN-doped qTP C60 nanosheets exhibit superior gas selectivity, improved optical properties, and improved catalytic performance, making them promising candidates for greenhouse gas capture, humidity sensing, and sustainable energy applications. | VIVEK YADAV | Theoretical and Computational Chemistry | CC BY 4.0 | CHEMRXIV | 2025-03-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67a8c6a46dde43c9082efc46/original/ab-initio-insights-into-co2-h2o-and-n2-adsorption-on-bn-doped-polymeric-c60-monolayers.pdf |
60d1f057b361526998014abe | 10.26434/chemrxiv-2021-jv6lv | Using automated serendipity to discover how trace water promotes and inhibits lead halide perovskite crystal formation | We use a data-driven approach to discover the influence of trace amounts of water on perovskite crystal formation. Statistical analysis of 8,470 inverse-temperature crystallization lead iodide perovskite synthesis reactions, performed over 20 months using a robotic system, revealed discrepancies between the empirical crystal formation rate in experiments conducted under different ambient relative humidity conditions. We used the robotic system to conduct 1,296 controlled interventional experiments in which small amounts of water were deliberately introduced to the reactions. Addition of trace amounts of water promotes crystal formation for 4-methoxyphenylammonium lead iodide and iso-propylammonium lead iodide and inhibits crystal formation for dimethylammonium lead iodide and acetamidinium lead iodide. We also performed thin-film syntheses of these four materials and determined the grain size distributions using scanning electron microscopy. Addition of water results in smaller grain sizes for dimethylammonium and larger grain sizes for isopropylammonium, consistent with earlier or delayed nucleation, respectively. | Philip Nega; Zhi Li; Victor Ghosh; Janak Thapa; Shijing Sun; Noor Titan Putri Hartono; Mansoor Ani Najeeb Nellikkal; Alexander J. Norquist; Tonio Buonassisi; Emory M. Chan; Joshua Schrier | Materials Science; Energy; Hybrid Organic-Inorganic Materials; Materials Processing; Thin Films; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2021-06-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60d1f057b361526998014abe/original/using-automated-serendipity-to-discover-how-trace-water-promotes-and-inhibits-lead-halide-perovskite-crystal-formation.pdf |
60c75275bdbb8942f9a3a28b | 10.26434/chemrxiv.13298984.v1 | Charge Transfer Excitation and Asymmetric Energy Transfer at the Interface of Pentacene-Perfluoropentacene Heterostacks | The formation pathways of CT-excitons at the model crystalline donor-acceptor interface of pentacene-perfluoropentacene (PEN-PFP) is studied by a combination of advanced experimental and theoretical techniques. More specifically, we compare the one-photon photoluminescence excitation (PLE) and absorption spectra of three different PEN-PFP heterostructures with different molecular alignment at the interface at cryogenic temperatures. <br /><div></div> | Anna-Katharina Hansmann; Robin C. Döring; Andre Rinn; Steffen M. Giesen; Melanie Fey; Tobias Breuer; Robert Berger; Gregor Witte; Sangam Chatterjee | Photovoltaics | CC BY NC ND 4.0 | CHEMRXIV | 2020-12-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75275bdbb8942f9a3a28b/original/charge-transfer-excitation-and-asymmetric-energy-transfer-at-the-interface-of-pentacene-perfluoropentacene-heterostacks.pdf |
678fb44c81d2151a021eda2d | 10.26434/chemrxiv-2025-1p0xw | Impact of geochemistry on wettability and electrical properties of kerogen and organic-rich mudrocks | The distribution of fluids in the pore space significantly affects the borehole electrical measurements such as resistivity logs, multiphase fluid flow and hydrocarbon recovery. Wettability is therefore an important factor impacting the water production and low resistivity pays in organic-rich mudrocks. Development of reliable models for hydrocarbon-in-place and water saturation estimation requires knowledge about wettability of mudrocks and the factors affecting it. A significant fraction of mudrock is composed of kerogen – insoluble organic matter in mudrocks – and therefore the properties of kerogen can considerably affect the mudrock properties.
Studying rock physics and interfacial properties of kerogen remains an area of active research. Kerogen is often considered as hydrocarbon-wet in reservoir characterization. Despite this, wettability of kerogen is not fully understood and quantified. Assumptions made about the wettability of kerogen affects interpretation of borehole geophysical measurements such as electromagnetic measurements. It is therefore important to quantify wettability of kerogen as a function of relevant factors. For instance, the chemical structure and composition can vary as a function of kerogen type, which affects its surface properties such as wettability. In addition, processes such as thermal maturation induce changes in the chemical composition and structure. Thermal maturation decreases oxygen and hydrogen content and increases aromaticity. Oxygen containing function groups are also altered during thermal maturity. Moreover, changes in temperature and pressure also alter surface properties and affect the wettability of kerogen. However, the impact of different functional groups present in kerogen and reservoir temperature and pressure on kerogen wettability are yet to be quantified through a fundamental study.
Molecular simulation studies can be used to understand the kerogen wettability for a wide range of chemical position of kerogen. In a previous work, molecular dynamics simulation was used to quantify wettability of kerogen. However, simplified kerogen structures were used which does not capture the heterogeneity and complexity of the kerogen structure. Moreover, there have been no studies which consider the impact of functional groups such as carboxyl and hydroxyl groups, and the impact of temperature and pressure conditions on the wettability of kerogen. There has been no previous experimental study to reliably determine wettability of pure kerogen, because of the challenges associated with kerogen isolation and with determining wettability of powders.
I propose to use a combination of experimental and molecular simulation-based approaches to understand wettability of kerogen. First, the impact of composition and thermal maturity of kerogen on wettability of organic-rich mudrock will be studied using experimental and molecular simulation methods. The impact of reservoir temperature and pressure conditions on kerogwn wettability would be quantified using molecular dynamics simulations. The methods proposed in the thesis will help in improving the understanding of wettability of organic-rich mudrocks. The sensitivity of wettability of kerogen on the electrical resistivity measurements of organic-rich mudrock will be quantified using a combination of experimental methods and numerical simulation. This study could also provide insight into water production issues in shale and will potentially improve formation evaluation and the understanding of fluid flow mechanisms in organic-rich mudrocks.
| Archana Jagadisan | Earth, Space, and Environmental Chemistry; Chemical Engineering and Industrial Chemistry | CC BY 4.0 | CHEMRXIV | 2025-01-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/678fb44c81d2151a021eda2d/original/impact-of-geochemistry-on-wettability-and-electrical-properties-of-kerogen-and-organic-rich-mudrocks.pdf |
60c74d05567dfefcbdec529a | 10.26434/chemrxiv.12452849.v2 | Cocrystal Prediction by Artificial Neural Networks | <div>A significant amount of attention has been given to the design and synthesis of cocrystals by both industry and academia because of its potential to change a molecule’s physicochemical properties. This paper reports on the application of a data-driven cocrystal prediction method, based on two types of artificial neural network models and cocrystal data present in the Cambridge Structural Database. The models accept pairs of coformers and predict whether a cocrystal is likely to form.</div> | Jan-Joris Devogelaer; Hugo Meekes; Paul Tinnemans; Elias Vlieg; Rene de Gelder | Solid State Chemistry; Machine Learning; Crystallography | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74d05567dfefcbdec529a/original/cocrystal-prediction-by-artificial-neural-networks.pdf |
659d4d00e9ebbb4db9c41839 | 10.26434/chemrxiv-2024-pxrdm | Inter-subunit Energy Transfer Processes in a Minimal Plant Photosystem II Supercomplex | Photosystem II (PSII) is an integral part of the photosynthesis machinery, in which several light-harvesting complexes rely on inter-complex excitonic energy transfer (EET) processes to channel energy to the reaction center. In this paper, we report on the direct observation of the inter-complex EET in a small PSII supercomplex from plants, containing the trimeric light-harvesting complex II (LHCII), the monomeric light-harvesting complex CP26 and the monomeric PSII core complex. Using two-dimensional electronic spectroscopy, we measure an average inter-complex EET time scale of 60±5 ps for excitations from the LHCII-CP26 peripheral antenna to the PSII core. The 2D electronic spectra also reveal that the transfer time scale is nearly constant over the excitation spectrum of 600-700 nm. Structure-based calculations reveal the contribution of each antenna complex to the measured inter-complex EET time. These results provide a step in elucidating the full inter-complex energy transfer network, which allows us to understand the efficiency and robustness of the PSII machinery | Hoang Long Nguyen; Thanh Nhut Do; Kai Zhong; Parveen Akhtar; Thomas Jansen; Jasper Knoester; Stefano Caffarri; Petar Lambrev; Howe-Siang Tan | Physical Chemistry; Biophysical Chemistry; Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-01-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/659d4d00e9ebbb4db9c41839/original/inter-subunit-energy-transfer-processes-in-a-minimal-plant-photosystem-ii-supercomplex.pdf |
656a962829a13c4d477a31ec | 10.26434/chemrxiv-2023-8qlmv | Prebiotic Access to Enantioenriched Amino Acids via Peptide-Mediated Transamination Reactions | The kinetic resolution of racemic amino acids mediated by dipeptides and pyridoxal provides a prebiotically plausible route to enantioenriched proteinogenic amino acids. The enzymatic transamination cycles that are key to modern biochemical formation of enantiopure amino acids may have evolved from this half of the reversible reaction couple. Kinetic resolution of racemic precursors emerges as a general route to enantioenrichment under prebiotic conditions. | Jinhan Yu; Andrea daru; Min Deng; Donna Blackmond | Organic Chemistry; Physical Organic Chemistry; Stereochemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-12-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/656a962829a13c4d477a31ec/original/prebiotic-access-to-enantioenriched-amino-acids-via-peptide-mediated-transamination-reactions.pdf |
62b047fc1fdc345809408b66 | 10.26434/chemrxiv-2022-cgnf5 | Using genetic algorithms to systematically improve the synthesis conditions of Al-PMOF | The synthesis of metal-organic frameworks (MOFs) is often complex and the desired structure is not always obtained. In this work, we report a methodology that uses a joint machine learning and experimental approach to obtain the optimal synthesis of a MOF. A synthetic conditions finder was used to derive the experimental protocols and a microwave based high-throughput robotic platform was used for the synthesis of Al-PMOF ([H2TCPP[AlOH]2(DMF3(H2O)2)]). Al-PMOF was previously synthesized using a hydrothermal reaction, which gave a low throughput yield due to its relatively long reaction time (16 hours). In this work, we carried out a systematic search for the optimal reaction conditions using a microwave assisted reaction synthesis. For this search we used a genetic algorithm and we show that already in the 2nd generation we obtained conditions that give excellent crystallinity and yield close to 80% in much shorter reaction time (50 minutes). In addition, by analysing the failed and partly successful experiments, we could identify the most important experimental variables that determine the crystallinity and yield. | Nency P. Domingues; Seyed Mohamad Moosavi; Leopold Talirz; Christopher P. Ireland; Fatmah Mish Ebrahim; Berend Smit | Theoretical and Computational Chemistry; Materials Science; Nanostructured Materials - Materials; Machine Learning | CC BY 4.0 | CHEMRXIV | 2022-06-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62b047fc1fdc345809408b66/original/using-genetic-algorithms-to-systematically-improve-the-synthesis-conditions-of-al-pmof.pdf |
66cfe09620ac769e5f29b4c9 | 10.26434/chemrxiv-2024-1hvg3-v2 | Electrochemical Phase Interconversion Enables Homogeneous-Heterogeneous Bifunctionality in Pd-Catalyzed Vinyl Acetate Synthesis | Current mechanistic paradigms in catalysis generally hold that a catalytic cycle is carried out by either a homogeneous or heterogeneous active species. Herein, we show that a prominent industrial process, palladium-catalyzed vinyl acetate synthesis, proceeds via interconversion of heterogeneous Pd(0) and homogeneous Pd(II) during catalysis, with each species playing a complementary role. Using electrochemical probes, we find that heterogeneous nanoparticulate Pd(0) serves as an active oxygen reduction electrocatalyst to furnish the high driving force required for corrosion to form homogeneous Pd(II), which then catalyzes selective ethylene acetoxylation with re-formation of heterogeneous Pd(0). Inhibiting the corrosion of Pd(0) to Pd(II) by galvanic protection results in reversible poisoning of catalysis, highlighting the essential role of phase conversion in this catalytic cycle. These results challenge the tacit assumption that catalysis proceeds via either homogeneous or heterogeneous modes, and instead highlights how dynamic phase interconversion can serve to harness and couple complementary reactivity across molecular and material active sites. | Deiaa M. Harraz; Kunal Lodaya; Bryan Y. Tang; Yogesh Surendranath | Inorganic Chemistry; Catalysis; Electrocatalysis; Heterogeneous Catalysis; Nanocatalysis - Reactions & Mechanisms | CC BY NC ND 4.0 | CHEMRXIV | 2024-08-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66cfe09620ac769e5f29b4c9/original/electrochemical-phase-interconversion-enables-homogeneous-heterogeneous-bifunctionality-in-pd-catalyzed-vinyl-acetate-synthesis.pdf |
64ff047e99918fe537c17df6 | 10.26434/chemrxiv-2023-mhb04 | Potent activity of Metal-Organic Framework nanoparticles loaded by hydrophobic natural products via one-pot synthetic method against pancreatic cancers | Metal-organic frameworks (MOFs) have been recently proposed as a new nanoscale drug delivery vector posing significant surface area and tunable chemo physical properties. The main procedure of encapsulation of anticancer drugs into the MOFs are post synthetic methods (PSM), however that is time/energy consuming and often not be reproducible in large scale. Further, PSM method would not be applicable without coating due to the burst drug release. Herein, we report a new strategy of incorporating of hydrophobic natural drugs into zirconium terephthalate MOF UiO-66 via one-pot synthetic route. The drugs are added by one-pot solvothermal method and uniformly distributed throughout the MOFs surfaces. Potency of formulation showed a 7-fold increase compared to PSM MOFs against 3D cultured pancreatic cancers and can be applicable for other hydrophobic drugs. | Arivn Eskandari; Yang Wang; Ross Stewart Forgan | Inorganic Chemistry; Nanoscience; Nanostructured Materials - Nanoscience; Supramolecular Chemistry (Inorg.); Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2023-09-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64ff047e99918fe537c17df6/original/potent-activity-of-metal-organic-framework-nanoparticles-loaded-by-hydrophobic-natural-products-via-one-pot-synthetic-method-against-pancreatic-cancers.pdf |
643becea1d262d40ea93f9ad | 10.26434/chemrxiv-2023-t000n | High pressure-driven batch distillation optimal control for methyl acetate-methanol separation | The pressure-swing distillation process with high-pressurized batch columns (HHP), with and or without a recycling stream, for separating methyl acetate-methanol is studied from the aspect of optimal control. The results show that even though not heat integrated, the process using HHP benefits in productivity. Based on the maximum recovery, the dynamic controllability without any kind of heat integration is researched. The proposed process, however, has the economic potential of both capital and energy by internal heat integration, ie. connecting the reboiler of the lower high-pressurized column to the condenser of the higher high-pressurized column. In the future, even more azeotropes, both minimum and/or maximum boilers, should be investigated in order to establish a “heuristic guidance” for HHP design and industrial usage. | Marija Stojkovic | Chemical Engineering and Industrial Chemistry; Chemical Education; Industrial Manufacturing; Pharmaceutical Industry; Process Control | CC BY NC ND 4.0 | CHEMRXIV | 2023-04-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/643becea1d262d40ea93f9ad/original/high-pressure-driven-batch-distillation-optimal-control-for-methyl-acetate-methanol-separation.pdf |
60c75842bdbb89145ba3ad40 | 10.26434/chemrxiv.14529483.v1 | Aggregation-Induced Radical of Donor-Acceptor Organic Semiconductors | <p></p><p>Narrow bandgap
donor-acceptor organic semiconductors are generally
considered to show closed-shell singlet ground state and their radicals are
reported as impurities, polarons, charge transfer state monoradical or defects.
<a>Herein,
we reported the open-shell singlet diradical electronic ground state of two
diketopyrrolopyrrole-based compounds Flu-TDPP and
DTP-TDPP</a> via the combination of variable temperature
NMR, variable temperature electron spin spectroscopy (ESR), superconducting
quantum interference device magnetometry, and theoretical calculations. It is
observed that the
quinoid-diradical character is significantly enhanced in aggregation state because of the limitation of
intramolecular rotation. Consequently, we propose a mechanism of
aggregation-induced radical to understand the driving force of the open-shell
diradical formation of DTP-TDPP based on the ESR spectroscopy
test in different proportions of mixed solvents. Our results demonstrate
the thermally-excited triplet state for donor-acceptor organic semiconductors, providing a novel view to
comprehend the intrinsic chemical structure of donor-acceptor organic semiconductors, as
well as the potential electronic transition process between ground state and
excited state.<br /></p><br /><p></p> | Zhongxin Chen; Yuan Li; Weiya Zhu; zejun wang; Wenqiang Li; Miao Zeng; fei huang; LI YUAN | Organic Synthesis and Reactions; Aggregates and Assemblies; Photovoltaics | CC BY NC ND 4.0 | CHEMRXIV | 2021-05-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75842bdbb89145ba3ad40/original/aggregation-induced-radical-of-donor-acceptor-organic-semiconductors.pdf |
61dc6d9aa16050219b9c2850 | 10.26434/chemrxiv-2022-lj6br | Synthesis and Columnar Organization of Partially Fluorinated Dehydrobenz[18]annulenes | Two diamond-shaped and partially fluorinated dehydrobenz[18]annulene macrocycles have been synthesized through a one-pot synthesis relying on fourfold Sonogashira coupling. Single crystal structures of the prepared macrocycles show continuous columnar stacks of these molecules that are mediated by the fluoroarene–alkyne, arene–alkyne, fluoroarene–fluoroarene, and alkyne–alkyne [π···π] interactions instead of the expected fluoroarene–arene [π···π] interaction. | Sumitra Karki; Lucas J. Karas; Xiqu Wang; Judy I. Wu; Ognjen Š. Miljanić | Organic Chemistry; Supramolecular Chemistry (Org.); Crystallography – Organic | CC BY 4.0 | CHEMRXIV | 2022-01-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61dc6d9aa16050219b9c2850/original/synthesis-and-columnar-organization-of-partially-fluorinated-dehydrobenz-18-annulenes.pdf |
60c74795469df471e3f43848 | 10.26434/chemrxiv.11739819.v1 | Probing the Birth and Dynamics of Hydrated Electrons at the Gold/Liquid Water Interface via a Novel Optoelectronic Approach | <p>The hydrated electron has fundamental and practical significance in radiation and radical chemistry, catalysis and radiobiology. While its bulk properties have been extensively studied, its behavior at buried solid/liquid interfaces is still unclear due to the lack of effective tools to characterize this short-lived species in between two condensed matter layers. In this study, we develop a novel optoelectronic technique for the characterization of the birth and structural evolution of solvated electrons at the metal/liquid interface with a femtosecond time resolution. We thus recorded for the first time their transient spectra (in a photon energy range from 0.31 to 1.85 eV) <i>in situ</i><i> </i>with a time resolution of 50 fs. The transient species show state-dependent optical transition behaviors from being isotropic in the hot state to perpendicular to the surface in the trapped and solvated states. The technique will enable a better understanding of hot electron-driven reactions at electrochemical interfaces.</p> | François Lapointe; Martin Wolf; Kramer Campen; Yujin Tong | Electrochemistry - Mechanisms, Theory & Study; Interfaces; Optics; Photochemistry (Physical Chem.); Physical and Chemical Processes; Physical and Chemical Properties; Spectroscopy (Physical Chem.); Structure; Surface | CC BY NC ND 4.0 | CHEMRXIV | 2020-01-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74795469df471e3f43848/original/probing-the-birth-and-dynamics-of-hydrated-electrons-at-the-gold-liquid-water-interface-via-a-novel-optoelectronic-approach.pdf |
66ee2a0b51558a15ef9eee0c | 10.26434/chemrxiv-2024-1w3tm | Singlets-Driven Photoredox Catalysts: Transforming Noncatalytic Red Fluorophores to Efficient Catalysts | Red-light absorbing photoredox catalysts offer potential advantages for large-scale reactions, expanding the range of usable substrates and facilitating bio-orthogonal applications. While many red-light absorbing/emitting fluorophores have been developed recently, functional red-light absorbing photoredox catalysts are scarce. Many photoredox catalysts rely on long-lived triplet excited states (triplets), which can efficiently engage in single electron transfer (SET) reactions with substrates. However, triplets of π-conjugated molecules are often significantly lower in energy than photogenerated singlet excited states (singlets). Combined with the inherent low energy of red light, this could limit the reductive/oxidative powers. Here, we introduce a series of sustainable heavy atom–free photoredox catalysts based on red-light absorbing dibenzo-fused BODIPY. The catalysts consist of two covalently linked units: a dibenzo-fused BODIPY fluorophore and an electron donor, arranged orthogonally. Excitation of the dibenzoBODIPY unit induces charge separation (CS) from the donor to the dibenzoBODIPY unit, forming a radical pair (RP) state. Unlike the regular BODIPY counterparts, these catalysts do not form triplets. Instead, SET occurs from the high-energy singlet-born RP states, preventing energy loss and effectively utilizing the low-energy red light. The proximity of donor molecules allows efficient charge separation despite the CS being uphill in energy. The molecules demonstrate efficient catalysis of Atom Transfer Radical Addition (ATRA) reaction, yielding products with high yields ranging from 70% to 90%, while the molecule without a donor group does not exhibit catalytic activity. The mechanistic studies by transient absorption and electron paramagnetic resonance (EPR) spectroscopy methods support the proposed mechanism. The study presents a new molecular design strategy for converting noncatalytic fluorophores to efficient photoredox catalysts operating in the red spectral region. | Sara Abuhadba; Charlotte Fuqua; Anthony Maltese; Caroline Schwinn; Neo Lin; Angela Chen; Rilee Martzloff; Tatiana Esipova; Tomoyasu Mani | Physical Chemistry; Organic Chemistry; Catalysis; Physical Organic Chemistry; Photocatalysis; Photochemistry (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-10-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66ee2a0b51558a15ef9eee0c/original/singlets-driven-photoredox-catalysts-transforming-noncatalytic-red-fluorophores-to-efficient-catalysts.pdf |
66de51d112ff75c3a1cf9037 | 10.26434/chemrxiv-2024-f5kkq-v2 | Molecular Association and Reactivity of the Pyridine Dimer Cation | A recent experimental report has identified the formation of C–N hemi-bonded pyridine dimer cation following vacuum ultraviolet near-threshold photoionization [J. Phys. Chem. Lett. 2021, 12, 4936–4943]. Herein, the dynamics and consequent reactivity of the pyridine dimer cation was investigated employing Born-Oppenheimer Molecular Dynamics (BOMD) simulations. A anti-parallel π-stacked pyridine dimer in the neutral ground state is transformed to a non-covalently interacting C–H∙∙∙N hydrogen-bonded structure which can lead to proton transfer in the cationic state. Additionally, C–N and N–N bonded adducts were formed in the cationic state. Further, metastable C–H∙∙∙H–C bonded cationic was observed, which rearranges to N–N bonded adduct. In contrast to the experimental observation, migration of the proton to the α position was not observed in the C–N bonded adduct owing to a high barrier of about 2 eV. The observed trends in the molecular association, proton transfer and the formation of C–N and N–N bonded adducts is a consequence of roaming dynamics of one pyridine moiety over the other in the cationic state. | Amol Tagad; G Naresh Patwari | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Clusters | CC BY NC ND 4.0 | CHEMRXIV | 2024-09-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66de51d112ff75c3a1cf9037/original/molecular-association-and-reactivity-of-the-pyridine-dimer-cation.pdf |
648ff7c9e64f843f41ffdc56 | 10.26434/chemrxiv-2023-n0sp5 | Unravelling the Super-Reductive State of Iridium Photoredox Catalysts | Harnessing the excited state of reduced species has long posed a challenge in the field of photocatalysis. This study presents the isolation and characterization of 1-electron reduced iridium complexes commonly employed in photoredox catalysis. Stochiometric reactions unveiled an unprecedented super-reductant ability for the isolated complexes under light irradiation, reaching potentials below 3 V vs SCE. Notably, the reduced iridium complex can also be electrochemically generated in situ with analogous super-reductant ability, enabling electro(photo)catalysis. Experimental and computational studies reveal that photoreactivity rises from intrinsic excitation of the reduced (bpy●‒)* ligand within the iridium complex, while the metal center acts as a spectator. Corroborating this finding, the organic salt Li+bpy●‒ exhibited equivalent super-reducing reactivity under photochemical conditions. Our findings shed light on the access to the super-reductant states of iridium photoredox catalysts and other metalated bipyridines, opening new opportunities for electro(photo) synthetic methodologies. | Julio Lloret-Fillol; David Pascual; Sergio Fernandez; Suyun Sun; Geyla C. Dubed Bandomo; Vlad Martin-Diaconescu; Mattia Vettori; Jingjing Meng; Noufal Kandoth; Jordi Benet-Buchholz; Fabio Juliá; Julia Pérez-Prieto | Catalysis; Homogeneous Catalysis; Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-06-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/648ff7c9e64f843f41ffdc56/original/unravelling-the-super-reductive-state-of-iridium-photoredox-catalysts.pdf |
60c73d1a337d6cbab0e260eb | 10.26434/chemrxiv.14718183.v2 | Ender3 3D Printer Kit Transformed into Open, Programmable Syringe Pump Set | Ender 3 syringe pumps is an open source and open hardware device for converting an Ender 3 kit to a set of 3 syringe pumps. Almost everything needed for the build is the Ender 3 kit, even all the screws and the tools needed for the assembly. The only parts which needed to be bought are three 5x5 shaft couplers and M5 lead screw. | Sander Baas; Vittorio Saggiomo | Fluid Mechanics | CC BY 4.0 | CHEMRXIV | 2021-06-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73d1a337d6cbab0e260eb/original/ender3-3d-printer-kit-transformed-into-open-programmable-syringe-pump-set.pdf |
636ca0e88e0d35ca48152cd3 | 10.26434/chemrxiv-2022-9pcpz | Estimating the Number of Molecules in Molecular Junctions
Merely Based on the Low Bias Tunneling Conductance at
Variable Temperature | Temperature ($T$) dependent conductance $G = G(T)$ data measured in molecular junctions are routinely taken as evidence for a two-step hopping mechanism. The present paper emphasizes that this is not necessarily the case. A curve of $\ln G$ versus $1/T$ decreasing almost linearly (Arrhenius-like regime) and eventually switching to a nearly horizontal plateau (Sommerfeld regime), or possessing a slope gradually decreasing with increasing $1/T$ is fully compatible with a single-step tunneling mechanism. The results for the dependence of $G$ on $T$ presented include both analytical exact and accurate approximate formulas and numerical simulations. To be specific, we analyze in detail data available for molecular junctions based on ferrocene (Fc). As a particularly important finding, we show how the present analytic formulas for $G=G(T)$ can be utilized to compute the ratio $f = A_{\mbox{\small eff}} / A_n$ between the effective and nominal areas of large area Fc-based junctions with an EGaIn top electrode. Our estimate $f\approx 0.6 \times 10^{-4}$ is comparable with previously reported values for related large area molecular junctions. | Ioan Baldea | Theoretical and Computational Chemistry; Materials Science; Nanoscience; Nanodevices; Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2022-11-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/636ca0e88e0d35ca48152cd3/original/estimating-the-number-of-molecules-in-molecular-junctions-merely-based-on-the-low-bias-tunneling-conductance-at-variable-temperature.pdf |
66a960555101a2ffa8a29c52 | 10.26434/chemrxiv-2024-59vs5 | Diastereoselective Dearomative 1,3-Dipolar Cycloaddition of
Bicyclobutanes with Pyridinium Ylides: A Modular Approach to Multisubstituted Azabicyclo[3.1.1]heptanes | We describe a formal 1,3-dipolar cycloaddition between bicyclobutanes and pyridinium ylides to form azabicycloheptanes via diastereoselective pyridine dearomatization. Microscale highthroughput experimentation led to identification of conditions affording high yield and stereoselectivity without the need for catalysis. These reactions proceed using as-received reagents and solvents under ambient atmosphere. The resulting ring-fused azabicyclo[3.1.1]heptanes have diverse synthetic handles for further transformations, making them potentially valuable scaffolds for the design of Csp3-rich drug candidates. We also demonstrate a diastereoselective photochemical skeletal rearrangement to give a 1,1,3,3-tetrasubstitued cyclobutane. | Kushal Dhake; Kyla Woelk; Liam Krueckl; Faith Alberts; James Mutter; Matthew Pohl; Gilian Thomas; Muskan Sharma; Jaelyn Bjornerud-Brown; Nahiane Pipaon Fernandez; Nathan Schley; David Leitch | Biological and Medicinal Chemistry; Organic Chemistry; Organic Compounds and Functional Groups; Organic Synthesis and Reactions; Stereochemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-08-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66a960555101a2ffa8a29c52/original/diastereoselective-dearomative-1-3-dipolar-cycloaddition-of-bicyclobutanes-with-pyridinium-ylides-a-modular-approach-to-multisubstituted-azabicyclo-3-1-1-heptanes.pdf |
645ab613fb40f6b3ee4ec554 | 10.26434/chemrxiv-2023-vd2d2 | Do Nanodisc Assembly Conditions Affect Natural Lipid Uptake? | Lipids play critical roles in modulating membrane protein structure, interactions, and activity. Nanodiscs provide a tunable membrane mimetic that can model these endogenous protein-lipid interactions in a nanoscale lipid bilayer. However, most studies of membrane proteins with nanodiscs use simple synthetic lipids that lack the head group and fatty acyl diversity of natural extracts. Prior research has successfully used natural lipid extracts in nanodiscs that more accurately mimic natural environments, but it is not clear how nanodisc assembly may bias the incorporated lipid profiles. Here, we applied lipidomics to investigate how nanodisc assembly conditions affect the profile of natural lipids in nanodiscs. Specifically, we tested the effects of assembly temperature, nanodisc size, and lipidome extract complexity. Globally, our analysis demonstrates that the lipids profiles are largely unaffected by nanodisc assembly conditions. However, a few notable changes emerged within individual lipids and lipid classes, such as a differential incorporation of cardiolipin and phosphatidylglycerol lipids from the E. coli polar lipid extract at different temperatures. Conversely, some classes of brain lipids were affected by nanodisc size at higher temperatures. Collectively, these data enable the application of nano-discs to study protein-lipid interactions in complex lipid environments. | Melanie Odenkirk; Guozhi Zhang; Michael Marty | Biological and Medicinal Chemistry; Analytical Chemistry; Biochemical Analysis; Mass Spectrometry; Bioengineering and Biotechnology | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/645ab613fb40f6b3ee4ec554/original/do-nanodisc-assembly-conditions-affect-natural-lipid-uptake.pdf |
6640095621291e5d1d09e2a0 | 10.26434/chemrxiv-2024-pl3t1 | Fragment correlation mass spectrometry: determining the structures of biopolymers in a complex mixture without isolating individual components | Fragment correlation mass spectrometry correlates ion pairs generated from the same fragmentation pathway, achieved by covariance mapping of tandem mass spectra generated with an unmodified linear ion trap without pre-separation. We enable identification of different precursors at different charge states in a complex mixture from a large isolation window, empowering a new analytical approach for data-independent acquisition. The method resolves and matches isobaric fragments, internal ions, and disulfide bond fragments. | Yangjie Li; Guy L Cavet; Richard N Zare; Taran Driver | Analytical Chemistry; Mass Spectrometry | CC BY NC 4.0 | CHEMRXIV | 2024-05-14 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6640095621291e5d1d09e2a0/original/fragment-correlation-mass-spectrometry-determining-the-structures-of-biopolymers-in-a-complex-mixture-without-isolating-individual-components.pdf |
64d9345769bfb8925ae0809f | 10.26434/chemrxiv-2023-rg3rn | A water-promoted Mars-van-Krevelen reaction dominates low-temperature CO oxidation over Au-Fe2O3, but not over Au-TiO2 | We provide experimental evidence that is inconsistent with often proposed Langmuir-Hinshelwood (LH) mechanistic hypotheses for water-promoted CO oxidation over Au-Fe2O3. Passing CO and H2O, but no O2, over Au-γ-Fe2O3 at 25 oC, we observe significant CO2 production, inconsistent with LH mechanistic hypotheses. Experiments with H218O further show that previous LH mechanistic proposals cannot account for water-promoted CO oxidation over Au-γ-Fe2O3. Guided by density functional theory, we instead postulate a water-promoted Mars-van-Krevelen (w-MvK) reaction. Our proposed w-MvK mechanism is consistent both with observed CO2 production in absence of O2, and with CO oxidation in presence of H218O and 16O2. In contrast, for Au-TiO2, our data is consistent with previous LH mechanistic hypotheses. | Alexander Holm; Bernadette Davies; Sara Boscolo Bibi; Felix Santiago Moncada Arias; Joakim Halldin-Stenlid; Laurynas Paskevicius; Vincent Claman; Adam Slabon; Cheuk-Wai Tai; Egon Campos dos-Santos; Sergey Koroidov | Catalysis; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-08-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64d9345769bfb8925ae0809f/original/a-water-promoted-mars-van-krevelen-reaction-dominates-low-temperature-co-oxidation-over-au-fe2o3-but-not-over-au-ti-o2.pdf |
6797eec26dde43c9089da6b5 | 10.26434/chemrxiv-2025-77gn3 | Catalyst-Free Polyhydroxyurethane Covalent Adaptable Network Exhibiting Full Cross-Link Density Recovery after Reprocessing: Facilitation by Synthesis with Sterically Hindered Secondary Amines
| Polyhydroxyurethane (PHU) covalent adaptable networks (CANs) made from primary multifunctional amines require catalysts for reprocessing by compression molding at moderate temperatures and within time frames that minimize undesired side reactions. We developed a catalyst-free PHU CAN using a sterically hindered secondary diamine. Our choice of 4,4'-trimethylene dipiperidine (TmPiP) was informed by small-molecule studies showing that hydroxyurethane (HU) could be produced at high fractional conversion by reacting propylene carbonate (PC), a five-membered cyclic carbonate, with not only primary amines but also with piperidine, a sterically hindered secondary amine. In contrast, the synthesis of HU from PC with other secondary amines led to much lower fractional conversion. Our studies also revealed a higher catalyst-free bond exchange rate at 140 degrees C in the piperidine-based HU than in primary amine-based HU, suggesting that piperidine-based PHU networks may allow for easier reprocessing. Our catalyst-free TmPiP-based PHU network and hexamethylenediamine (HMDA, a primary amine)-based PHU network had rubbery plateau tensile moduli of 1.0 MPa, indicating substantial cross-link density. However, the TmPiP-based PHU network exhibited four times faster stress relaxation at 160 degrees C. Using compression molding at 160 degrees C for 1.0 h, we could reprocess the catalyst-free TmPiP-based PHU network into consolidated films but not the catalyst-free HMDA-based PHU network. The catalyst-free TmPiP-based PHU CAN was reprocessable multiple times with full recovery of cross-link density and tensile properties. Thus, with well-designed molecular structure, inherent PHU chemistry can lead to catalyst-free PHU CANs with robust reprocessability. | Yen-Wen Huang; John Torkelson | Polymer Science; Organic Polymers; Polymerization (Polymers); Polymerization kinetics | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6797eec26dde43c9089da6b5/original/catalyst-free-polyhydroxyurethane-covalent-adaptable-network-exhibiting-full-cross-link-density-recovery-after-reprocessing-facilitation-by-synthesis-with-sterically-hindered-secondary-amines.pdf |
60c756ceee301c25bbc7b42d | 10.26434/chemrxiv.14331320.v1 | The Effects of Protein Charge Patterning on Complex Coacervation | The complex coacervation of proteins with other macromolecules has applications in protein encapsulation and delivery and for determining the function of cellular coacervates. Theoretical or empirical predictions for protein coacervates would enable the design of these coacervates with tunable and predictable structure-function relationships; unfortunately, no such theories exist. To help establish predictive models, the impact of protein-specific parameters on complex coacervation were probed in this study. The complex coacervation of sequence-specific, polypeptide-tagged, GFP variants and a strong synthetic polyelectrolyte was used to evaluate the effects of protein charge patterning on phase behavior. Phase portraits for the protein coacervates demonstrated that charge patterning dictates the protein’s binodal phase boundary. Protein concentrations over 100 mg mL<sup>-1</sup> were achieved in the coacervate phase, with concentrations dependent on the polypeptide sequence. In addition to shifting the binodal phase boundary, polypeptide charge patterning provided entropic advantages over isotropically patterned proteins. Together, these results show that modest changes of only a few amino acids alter the coacervation thermodynamics and can be used to tune the phase behavior of polypeptides or proteins of interest. | Nicholas Zervoudis; Allie Obermeyer | Biopolymers; Polyelectrolytes - Polymers | CC BY NC ND 4.0 | CHEMRXIV | 2021-03-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c756ceee301c25bbc7b42d/original/the-effects-of-protein-charge-patterning-on-complex-coacervation.pdf |
634551331037d6a0f53f4bf5 | 10.26434/chemrxiv-2022-4vj37 | Ligand-Assisted Gold-Catalyzed Efficient Alkynylative
Cyclization with Terminal Alkynes Using H2O2 as Oxidant | The gold-catalyzed cyclization-functionalization is a powerful approach to
construct high-value organic molecules. However, current strategies mainly rely on
expensive external oxidants or pre-functionalized substrates, which exhibit low atom
economy and high costs. Considering the current increasing demand for environmentally
friendly and atomically efficient processes, the development of greener and more efficient
synthetic strategies becomes more valuable and attractive. To circumvent these
drawbacks, we developed a green gold-catalyzed cyclization-functionalization strategy
using hydrogen peroxide as oxidant. A direct construction of 3-alkynylbenzofurans from
terminal alkynes was possible by this gold-catalyzed process. Green and inexpensive
oxidants, simple gold catalysts, mild reaction conditions, high atom economy, remarkable
selectivity, wide substrate scope, broad functional group compatibility and a facile
gram-scale synthesis make this alkynylative cyclization method practical for many forms
of cyclization reactions. In contrast to prior methods neither pre-functionalized alkynes nor
expensive external oxidants are needed. | A. Stephen K. Hashmi; Hongwei Shi; Martin C. Dietl; Philipp M. Stein; Matthias Rudolph; Tao Wang; Jun Li; Petra Krämer; Frank Rominger | Organic Chemistry; Catalysis; Organic Synthesis and Reactions; Homogeneous Catalysis; Redox Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2022-10-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/634551331037d6a0f53f4bf5/original/ligand-assisted-gold-catalyzed-efficient-alkynylative-cyclization-with-terminal-alkynes-using-h2o2-as-oxidant.pdf |
60c742d5567dfe8613ec3fa8 | 10.26434/chemrxiv.8792171.v1 | Vapour-Phase Deposition of Oriented Copper Dicarboxylate Metal-Organic Framework Thin Films | Copper dicarboxylate metal-organic framework films are deposited via chemical vapour deposition. Uniform films of CuBDC and CuCDC with an out-of-plane orientation and accessible porosity are obtained from the reaction of Cu and CuO with vaporised dicarboxylic acid linkers. | Timothée Stassin; Sabina Rodríguez-Hermida; Benedikt Schrode; Alexander John Cruz; Francesco Carraro; Dmitry Kravchenko; Vincent Creemers; Ivo Stassen; Tom Hauffman; Dirk De Vos; Paolo Falcaro; Roland Resel; Rob Ameloot | Hybrid Organic-Inorganic Materials; Thin Films; Physical and Chemical Processes | CC BY NC 4.0 | CHEMRXIV | 2019-07-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c742d5567dfe8613ec3fa8/original/vapour-phase-deposition-of-oriented-copper-dicarboxylate-metal-organic-framework-thin-films.pdf |
624ea1cd5ab8df6c8d8cc8b3 | 10.26434/chemrxiv-2022-2rr6h | Widespread Occurrence of Non-Extractable Fluorine in Artificial Turfs from Stockholm, Sweden | Per- and polyfluoroalkyl substances (PFAS) are frequently used in the production of rubber and plastic, but little is known about the identity, concentration, or prevalence of PFAS in these products. In this study, a representative sample of plastic- and rubber-containing artificial turf (AT) fields from Stockholm, Sweden, were subjected to total fluorine (TF), extractable organic fluorine (EOF) and target PFAS analysis. TF was observed in all 51 AT samples (range: 16-313, 12-310, and 24-661 µg F/g in backing, filling, and blades, respectively), while EOF and target PFAS occurred in <42% of all samples (<200 and <1 ng F/g, respectively). A subset of samples extracted with water confirmed the absence of fluoride. Moreover, application of the total oxidizable precursor assay revealed negligible perfluoroalkyl acid (PFAA) formation across all three sample types, indicating that the fluorinated substance(s) in AT are not low molecular weight PFAA-precursors. Collectively, these results point towards polymeric organofluorine (e.g. fluoroelastomer, polytetrafluoroethylene, polyvinylidene fluoride), consistent with patent literature. The combination of poor extractability and recalcitrance towards advanced oxidation suggests that the fluorine in AT does not pose an imminent risk to users. However, concerns remain surrounding the production and end-of-life of ATs, as well as the contribution of filling to environmental microplastic contamination. | Mélanie Lauria; Ayman Naim; Merle Plassmann; Jenny Fäldt; Roxana Sühring; Jonathan Benskin | Materials Science; Analytical Chemistry; Earth, Space, and Environmental Chemistry; Environmental Science; Environmental Analysis; Mass Spectrometry | CC BY NC ND 4.0 | CHEMRXIV | 2022-04-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/624ea1cd5ab8df6c8d8cc8b3/original/widespread-occurrence-of-non-extractable-fluorine-in-artificial-turfs-from-stockholm-sweden.pdf |
60c745a3bdbb89c5bda38a77 | 10.26434/chemrxiv.10046276.v1 | First-Principles and Thermodynamics Comparison of Compositionally-Tuned Delafossites: Cation Release from the (001) Surface of Complex Metal Oxides | <p>
Nanoscale complex metal oxides have transformed how technology is
used around the world. A
ubiquitous example is the class of electroreactive cathodes used in
Li-ion batteries, found in
portable electronics and electric cars. Lack of recyling
infrasructure and financial
drivers contribute to improper disposal, and ultimate introduction of these materials into
the environment. Outside of sealed operational conditions, it has been demonstrated
that complex metal oxides can transform in the environment, and cause negative
biological impact through leaching of cations into aqueous phases.
Using a combined DFT +
Thermodynamics analysis, insights into the mechanism and driving forces of cation
release can be studied at the molecular-level. Here, we describe
design principles that can
be drawn from previous collaborative research on complex metal oxide dissoltuion of
the Li(Ni<sub>y</sub>Mn<sub>z</sub>Co<sub>1−y−z</sub>)O2 family of materials, and go on to
posit ternary complex
metal oxides in the delafossite structure type with controlled
release behavior. Using
equistoichiometric formulations, we use DFT + Thermodynamics to model cation
release. The trends are discussed in terms of lattice stability,
solution chemistry/solubility limits, and electronic/magnetic properties. Inercalation voltages are calculated and
discussed as a predictive metric for potential functionality of the model materials.</p> | Joseph W. Bennett; Diamond Jones; Blake G. Hudson; Joshua Melendez-Rivera; Robert Hamers; Sara E. Mason | Theory - Computational | CC BY 4.0 | CHEMRXIV | 2019-11-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c745a3bdbb89c5bda38a77/original/first-principles-and-thermodynamics-comparison-of-compositionally-tuned-delafossites-cation-release-from-the-001-surface-of-complex-metal-oxides.pdf |
678153fe81d2151a029c7da8 | 10.26434/chemrxiv-2025-1qlft | Noise Removal Tool for Compressible and Incompressible Flows Using a Physics-Informed Neural Network | Noise removal from data or sensors is a crucial challenge in experimental studies, where traditional techniques such as filters and smoothers are commonly employed. However, these methods often lack a physics-based foundation, requiring either domain expertise or an extensive trial-and-error process to achieve satisfactory outcomes. Moreover, their performance deteriorates as noise levels increase, often leading to significant distortion of the original signal or derived quantity based on the signal. Physics-informed neural networks (PINNs) provide an innovative solution by integrating physical laws and governing equations into the machine learning framework. This study investigates the potential of PINNs to enhance noise removal compared to conventional numerical methods. Specifically, we assess the performance of numerical methods both with and without filtering alongside PINNs in the context of transport equations. We have studied the effectiveness of the above-mentioned techniques on synthetically generated subsonic and supersonic flows from numerical simulation. The results reveal that PINNs can effectively reconstruct pressure information from noisy velocity data, a task that traditional numerical methods do not perform adequately on noisy high Reynolds number cases. This finding highlights the superior capability of PINNs in addressing noise-related challenges in signal processing, particularly under high-noise conditions and high Reynolds number cases. | Jishnu Chandran; Ishwariya R; Jisha C R; Ashish Garg; Arun Govind Neelan | Chemical Engineering and Industrial Chemistry; Fluid Mechanics | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/678153fe81d2151a029c7da8/original/noise-removal-tool-for-compressible-and-incompressible-flows-using-a-physics-informed-neural-network.pdf |
60c75413bb8c1a73943dc187 | 10.26434/chemrxiv.13606556.v1 | Ab Initio Prediction of High-Temperature Magnetic Relaxation Rates in Single-Molecule Magnets | <p>Organometallic molecules based on [Dy(Cp<sup>R</sup>)<sub>2</sub>]<sup>+</sup> cations have emerged as clear front-runners in the search for high-temperature single-molecule magnets. However, despite a growing family of structurally-similar molecules, these molecules show significant variations in their magnetic properties, demonstrating the importance of understanding magneto-structural relationships towards developing more efficient design strategies. Here we refine our <i>ab initio</i> spin dynamics methodology and show that it is capable of quantitative prediction of relative relaxation rates in the Orbach region. Applying it to all reported [Dy(Cp<sup>R</sup>)<sub>2</sub>]<sup>+</sup> cations allows us to tease out differences in their relaxation dynamics, highlighting that the main discriminant is the magnitude of the crystal field splitting. We subsequently employ the method to predict relaxation rates for a series of hypothetical organometallic sandwich compounds, revealing an upper limit to the effective barrier to magnetic relaxation of around 2200 K, which has been reached. However, we show that further improvements to single-molecule magnets can be made by moving vibrational modes off-resonance with electronic excitations.</p> | Daniel Reta; Jon G. C. Kragskow; Nicholas Chilton | Coordination Chemistry (Inorg.); Lanthanides and Actinides; Magnetism; Theory - Inorganic; Computational Chemistry and Modeling; Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2021-01-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75413bb8c1a73943dc187/original/ab-initio-prediction-of-high-temperature-magnetic-relaxation-rates-in-single-molecule-magnets.pdf |
66fa449051558a15ef8fc9eb | 10.26434/chemrxiv-2024-mgq6l | Electrochemical and Spectro-Microscopic Analyses of Charge Accumulation and Ion Migration in Dry Processed Perovskite Solar Cells under Electrical Biasing | We study the influence of the electrical biasing on the modification of the chemical composition and the electrical performance of perovskite solar cells (PSCs) by coupling Electrochemical impedance spectroscopy (EIS) and scanning transmission X-ray microscopy (STXM) techniques. EIS reveals the formation of charge accumulation at the interfaces and changes in resistive and capacitive properties. STXM study on PSCs after applying strong electric field for a long biasing time indicates the break-down of methylammonium (MA+) cation promoting iodide ions to migrate and create defects at the interface. This complementary EIS and STXM study allows to suggest a degradation mechanism that includes the migration of iodide ions that leads to interface defects and subsequent degradation of solar cell performance. In addition, we study the evolution of the performance of PSCs under air. We observe an increased hysteresis index on current-voltage curves and fill factor reduction of the perovskite solar cells with ageing in air. EIS measurements show the formation of a capacitive layer resulting from accumulation of iodide ions through modification of the mobile ion concentration and ion mobility. | Haeyeon Jun; Denis Tondelier; Bernard Geffroy; Ileana Florea; Jean‐Eric Bouree; Pilar Lopez-Varo; Philip Schulz; Yvan Bonnassieux; Sufal Swaraj | Nanoscience; Energy; Nanostructured Materials - Nanoscience; Photovoltaics; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-10-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66fa449051558a15ef8fc9eb/original/electrochemical-and-spectro-microscopic-analyses-of-charge-accumulation-and-ion-migration-in-dry-processed-perovskite-solar-cells-under-electrical-biasing.pdf |
60c747c1842e6508b2db2a15 | 10.26434/chemrxiv.11559819.v2 | Toward an Understanding of Electronic Excitation Energies Beyond the Molecular Orbital Picture | <pre><div><div><div><p>Tuning the energies of molecular excited states is a central research theme in modern chemistry with high relevance for optoelectronic applications and chemical synthesis. Whereas frontier orbitals have proven to be an intuitive and simple model in many cases, they can only provide a very rough approximation of the underlying wavefunctions. The purpose of this Perspective is to explore how our qualitative understanding of electronic excitation processes can be promoted beyond the molecular orbital picture by exploiting methods and insights from modern quantum chemistry. For this purpose, the physics of a correlated electron-hole pair is analysed in detail to show the origin of exchange repulsion and a dynamic Coulomb attraction, which determine its energy aside from the orbital energies. Furthermore, we identify and discuss the two additional effects of secondary orbital relaxation and de-excitations. Rules for reconstructing these four contributions from general excited-state computations are presented and their use is exem- plified in three case studies concerned with the relative ordering of the singlet and triplet ππ∗ and nπ∗ states of uracil, the large energetic differences between the first singlet and triplet states of the polyacenes, and the assignment of plasmonic states in octatetraene. Finally, we lay out some general ideas for how the knowledge gained could ultimately lead to new design principles for tuning molecular excitation energies as well as for diagnosing possible shortcomings of commonly used electronic structure methods.</p></div></div></div></pre> | Patrick Kimber; Felix Plasser | Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2020-01-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c747c1842e6508b2db2a15/original/toward-an-understanding-of-electronic-excitation-energies-beyond-the-molecular-orbital-picture.pdf |
652eaca3bda59ceb9ac66f0c | 10.26434/chemrxiv-2023-n4ds3 | [2.2]Paracyclophane-based coumarins: effective organophotocatalysts for light-induced desulfonylation processes | Herein, we demonstrate for the first time that coumarins derived from [2.2]paracyclophane (pCp) can act as effective organophotocatalysts and promote the reductive cleavage of sulfonamides under light-irradiation. In the presence of these original compounds, photodesulfonylation reactions occur under mild conditions at low catalyst loadings in the presence of Hantzsch ester. Theoretical and experimental investigations are described, which elucidate the reaction mechanism and the nature of the active species involved in the photocatalytic process. This proof-of-concept study paves the way for further application of pCps in the field of photocatalysis. | Jules Brom; Antoine Maruani; Serge Turcaud; Sonia Lajnef; Fabienne Peyrot; Laurent Micouin; Erica Benedetti | Organic Chemistry; Catalysis; Photochemistry (Org.); Homogeneous Catalysis; Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/652eaca3bda59ceb9ac66f0c/original/2-2-paracyclophane-based-coumarins-effective-organophotocatalysts-for-light-induced-desulfonylation-processes.pdf |
60c73f9f9abda22a79f8bb39 | 10.26434/chemrxiv.7458719.v1 | The Influence of Nitrogen Position on Charge Carrier Mobility in Enantiopure Aza[6]helicene Crystals | <p>The properties of an organic semiconductor are dependent on both the chemical structure of the molecule involved, and how it is arranged in the solid-state. It is challenging to extract the influence of each individual factor, as small changes in the molecular structure often dramatically change the crystal packing and hence solid-state structure. Here, we use calculations to explore the influence of the nitrogen position on the charge mobility of a chiral organic molecule when the crystal packing is kept constant. The transfer integrals for a series of enantiopure aza[6]helicene crystals sharing the same packing were analysed in order to identify the best supramolecular motifs to promote charge carrier mobility. The regioisomers considered differ only in the positioning of the nitrogen atom in the aromatic scaffold. The simulations showed that even this small change in the chemical structure has a strong effect on the charge transport in the crystal, leading to differences in charge mobility of up to one order of magnitude. Some aza[6]helicene isomers that were packed interlocked with each other showed high HOMO-HOMO integrals (up to 70 meV), whilst molecules arranged with translational symmetry generally afforded the highest LUMO-LUMO integrals (40 - 70 meV). As many of the results are not intuitively obvious, a computational approach provides additional insight into the design of new semiconducting organic materials.</p> | Francesco Salerno; Beth Rice; Julia A. Schmidt; Matthew J. Fuchter; Jenny Nelson; Kim Jelfs | Supramolecular Chemistry (Org.); Computational Chemistry and Modeling; Physical and Chemical Properties | CC BY NC ND 4.0 | CHEMRXIV | 2018-12-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73f9f9abda22a79f8bb39/original/the-influence-of-nitrogen-position-on-charge-carrier-mobility-in-enantiopure-aza-6-helicene-crystals.pdf |
65f3101d66c1381729fba57e | 10.26434/chemrxiv-2024-3m9ff | Molecular Switching by Proton-Coupled Electron Transport Drives Giant Negative Differential Resistance | To develop new types of dynamic molecular devices with atomic-scale control over electronic function, new types of molecular switches are needed with time-dependent switching probabilities. We report such a molecular switch based on proton-coupled electron transfer (PCET) reaction with giant hysteric negative differential resistance (NDR) with peak-to-valley ratios of 120 ± 6.6 and memory on/off ratios of (2.4 ± 0.6) * 103. The switching dynamics probabilities are modulated by bias voltage sweep rate and can also be controlled by pH and relative humidity, confirmed by kinetic isotope effect measurements. The demonstrated dynamical and environment-specific modulation of giant NDR and memory effects provide new opportunities for bioelectronics and artificial neural networks. | Qian Zhang; Yulong Wang; Cameron Nickle; Ziyu Zhang; Andrea Leoncini; Dong-Chen Qi; Kai Sotthewes; Alessandro Borrini; Harold J. W. Zandvliet; Enrique del Barco; Damien Thompson; Christian A. Nijhuis | Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-03-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65f3101d66c1381729fba57e/original/molecular-switching-by-proton-coupled-electron-transport-drives-giant-negative-differential-resistance.pdf |
60c746be4c891954a4ad2bba | 10.26434/chemrxiv.11385774.v1 | Ring-Opening Carbonyl-Olefin Metathesis of Norbornenes | <div>
<p>A computational and experimental study of the
hydrazine-catalyzed ring-opening carbonyl-olefin metathesis of norbornenes is
described. Detailed theoretical investigation of the energetic landscape for
the full reaction pathway with six different hydrazines revealed several
crucial aspects for the design of next-generation hydrazine catalysts. This
study indicated that a [2.2.2]-bicyclic hydrazine should offer substantially
increased reactivity versus the previously reported [2.2.1]-hydrazine due to a
lowered activation barrier for the rate-determining cycloreversion step, a
prediction which was verified experimentally. Optimized conditions for both
cycloaddition and cycloreversion steps were identified, and a brief substrate
scope study for each was conducted. A complication for catalysis was found to
be the slow hydrolysis of the ring-opened hydrazonium intermediates, which were
shown to suffer from a competitive and irreversible cycloaddition with a second
equivalent of norbornene. This problem was overcome by the strategic
incorporation of a bridgehead methyl group on the norbornene ring, leading to
the first demonstrated catalytic carbonyl-olefin metathesis of norbornene
rings.</p>
</div> | Janis Jermaks; Phong K. Quach; Zara M. Seibel; Julien Pomarole; Tristan Lambert | Organocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2019-12-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c746be4c891954a4ad2bba/original/ring-opening-carbonyl-olefin-metathesis-of-norbornenes.pdf |
60e7f14c9ab06e66064ccfbe | 10.26434/chemrxiv-2021-56f12 | From Photoredox Catalysis to the Direct Excitation of
EthynylBenziodoXolones: Accessing Alkynylated Quaternary
Carbons from Alcohols via Oxalates | EthynylBenziodoXolones (EBXs) are commonly used as radical traps in photocatalytic alkynylations. Herein, we report their application in two complementary deoxygenation strategies allowing the synthesis of valuable alkynylated all-carbon quaternary centers from tertiary alcohols via stable oxalate salts. Our first approach involves a photocatalytic process using 4CzIPN as an organic dye to promote oxidative degradation of the oxalate and EBXs to trap the formed radical. In our second approach, we demonstrate the direct photoexcitation of an EBX, which then acts as both oxidant and radical trap, alleviating the need for a photocatalyst in several EBX-mediated alkynylation processes. | Stephanie G. E. Amos; Diana Cavalli; Franck Le Vaillant; Jerome Waser | Organic Chemistry; Catalysis; Organic Synthesis and Reactions; Photochemistry (Org.); Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2021-07-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60e7f14c9ab06e66064ccfbe/original/from-photoredox-catalysis-to-the-direct-excitation-of-ethynyl-benziodo-xolones-accessing-alkynylated-quaternary-carbons-from-alcohols-via-oxalates.pdf |
6159c30aaef99c70b40b0eda | 10.26434/chemrxiv-2021-p28qd | Designing Highly Luminescent Molecular Aggregates via Bottom-Up Nanoscale Engineering | Coupling of excitations between organic fluorophores in J-aggregates leads to coherent delocalization of excitons across multiple molecules, resulting in materials with high extinction coefficients, long-range exciton transport, and, in particular, short radiative lifetimes. Despite these favorable optical properties, uses of J-aggregates as high-speed light sources have been hindered by their low photoluminescence quantum yields. Here, we take a bottom-up approach to design a novel J-aggregate system with a large extinction coefficient, a high quantum yield and a short lifetime. To achieve this goal, we first select a J-aggregating cyanine chromophore and reduce its nonradiative pathways by rigidifying the backbone of the cyanine dye. The resulting conformationally-restrained cyanine dye exhibits strong absorbance at 530 nm and fluorescence at 550 nm with 90% quantum yield and 2.3 ns lifetime. We develop optimal conditions for the self-assembly of highly emissive J-aggregates. Cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS) reveal micron-scale extended structures with 2D sheet-like morphology, indicating long-range structural order. These novel J-aggregates have a strong red-shifted absorption at 600 nm, resonant fluorescence with no Stokes shift, 50% quantum yield, and 220 ps lifetime at room temperature. We further stabilize these aggregates in a glassy sugar matrix and study their excitonic behavior using temperature-dependent absorption and fluorescence spectroscopy. These temperature- dependent studies confirm J-type excitonic coupling and superradiance. Our results have implications for the development of a new generation of organic fluorophores that combine high speed, high quantum yield and solution processing.
| Ulugbek Barotov; Megan Klein; Lili Wang; Moungi Bawendi | Physical Chemistry; Nanoscience; Nanostructured Materials - Nanoscience; Self-Assembly; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2021-10-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6159c30aaef99c70b40b0eda/original/designing-highly-luminescent-molecular-aggregates-via-bottom-up-nanoscale-engineering.pdf |
655753bb2c3c11ed7194bfca | 10.26434/chemrxiv-2023-7n4mg | Lattice oxygen evolution in rutile Ru(1−x)Ni(x)O2 electrocatalysts | Efficient predictive tools for oxygen evolution reaction (OER) activity assessment are vital for rational design of anodes for green hydrogen production. Reaction mechanism prediction represents an important pre-requisite for such catalyst design. Even then, lattice oxygen evolution remains understudied and without reliable prediction methods. We propose a computational screening approach using density functional theory to evaluate the lattice oxygen evolution tendency in candidate surfaces. The method is based on a systematic assessment of the adsorption energies of oxygen evolution intermediates on model active sites with varying local structure. The power of the model is shown on model rutile (110) oriented surfaces of a) RuO2, b) Ru(1−x)Ni(x)O2 and c) Ru(1−x)Ti(x)O2. The model predicts a) no lattice exchange, b) lattice exchange at elevated electrode potentials and c) minor lattice exchange at elevated electrode potentials and high titanium content. While in the case of a) and b) the predictions provide sufficiently accurate agreement with experimental data, c) experimentally deviates from the above prediction by expressing a high tendency to evolve lattice oxygen at high titanium content (x = 0.20). This discrepancy can likely be attributed to the presence of structural defects in the prepared material, which are hard to accurately model with the applied methodology. | Adrian Frandsen; Kateřina Minhová; Jan Rossmeisl; Petr Krtil | Physical Chemistry; Catalysis; Electrocatalysis; Electrochemistry - Mechanisms, Theory & Study; Surface | CC BY 4.0 | CHEMRXIV | 2023-11-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/655753bb2c3c11ed7194bfca/original/lattice-oxygen-evolution-in-rutile-ru-1-x-ni-x-o2-electrocatalysts.pdf |
6532bba62431cc1dac2c86ec | 10.26434/chemrxiv-2023-hqbz5-v2 | Detection, quantification, and isomer differentiation of per- and polyfluoroalkyl substances (PFAS) using MALDI-TOF with trapped ion mobility | Per- and polyfluoroalkyl substances (PFAS) are a class of organic compounds that have attracted global attention for their persistence in the environment, exposure to biological organisms, and their adverse health effects. There is an urgent need to develop analytical methodologies for characterization of PFAS in various sample matrices. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) represents a chromatography-free MS method that performs laser-based ionization and in situ analysis on samples. In the present study, we present PFAS analysis by MALDI-time-of-flight MS with trapped ion mobility (TIMS), which provides an additional dimension of gas phase separation based on the size-to-charge ratios. MALDI matrix composition and key instrument parameters were optimized to produce different ranges of calibration curves. Parts per billion range of calibration curves were achieved for a list of legacy and alternative perfluorosulfonic acids (PFSAs) and perfluorocarboxylic acids (PFCAs), while ion mobility spectrum filtering enabled parts per trillion (ppt) range of calibration curves for PFSAs. We also successfully demonstrated the separation of three perfluorooctanesulfonic acid (PFOS) structural isomers in the gas phase using TIMS. Our results demonstrated the new development of utilizing MALDI-TOF-MS coupled with TIMS for fast, quantitative, and sensitive analysis of PFAS, paving ways to future high-throughput and in situ analysis of PFAS such as MS imaging applications. | Aidan Reynolds; Abby Smith; Tian (Autumn) Qiu | Analytical Chemistry; Environmental Analysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6532bba62431cc1dac2c86ec/original/detection-quantification-and-isomer-differentiation-of-per-and-polyfluoroalkyl-substances-pfas-using-maldi-tof-with-trapped-ion-mobility.pdf |
6644eb9a418a5379b05f3743 | 10.26434/chemrxiv-2024-3j2r1 | Ruthenium-catalyzed deformylative C–C activation and carbene insertion towards diversity-oriented synthesis of unsymmetrical biaryldiols and heterobiaryl amino alcohols | While 1,1-biaryl diols and amino alcohols are privileged scaffolds, their streamlined catalytic synthesis with unsymmetrical substitution patterns remains a daunting challenge. Herein, we describe the first ruthenium(II)-catalyzed synthesis of un-symmetrical 1,1-biaryl-2,2-diols via a deformylative coupling of ortho-hydroxy aromatic aldehydes with diverse cyclic di-azo compounds. The protocol is operationally simple, scalable, and involves intriguing C–C bond activation and carbene insertion cascade to produce a range of diversely functionalized biaryl diols in very high to excellent yields and regioselectivity. The methodology is also suitable to access heterobiaryl amino alcohols bearing indole motif, applicable in challenging two-fold C–C activation leading to valuable tetrahydroxy bis-biaryls, and retains efficacy in the site-selective modification of pharmaceutical agents. DFT studies have also been conducted to illustrate the intricacy of this catalytic cycle. | Chandan Kumar Giri; Tejender Singh; Sudeshna Mondal; Soumya Ghosh; Mahiuddin Baidya | Organic Chemistry; Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-05-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6644eb9a418a5379b05f3743/original/ruthenium-catalyzed-deformylative-c-c-activation-and-carbene-insertion-towards-diversity-oriented-synthesis-of-unsymmetrical-biaryldiols-and-heterobiaryl-amino-alcohols.pdf |
60c7479c9abda2cc47f8c967 | 10.26434/chemrxiv.11456118.v2 | Photochemically-Mediated Nickel-Catalyzed Synthesis of N-(Hetero)aryl Sulfamides | A general method for the <i>N</i>-arylation of sulfamides with aryl bromides is described. The protocol leverates a dual-catalytic system of nickel and a photoexcitable iridium complex and proceeds at room temperature under visible light irradiation. Using these tactics, aryl boronic esters and aryl chlorides can be carried through the reaction untouched. Thereby, this method complements known Buchwald-Hartwig coupling methods for N-arylation of sulfamides. | R. Thomas Simons; Georgia Scott; Anastasia Gant Kanegusuku; Jennifer Roizen | Homogeneous Catalysis; Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2020-01-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7479c9abda2cc47f8c967/original/photochemically-mediated-nickel-catalyzed-synthesis-of-n-hetero-aryl-sulfamides.pdf |
65241204bda59ceb9a2e5fda | 10.26434/chemrxiv-2023-h618h | First dehydrogenation of ethanol catalyzed by a single atom of d-block metals | The initial dehydrogenation of ethanol is important in the development of sustainable and practical energy processes. Transition metals, especially the less expensive and more abundant 3d metals, are appealing as catalysts for ethanol dehydrogenation. As a single atom adsorbed to ethanol, these metals are likely to have enhanced selectivity and activity, in addition to maximized utilization efficiency. Density functional theory calculations were performed with Gaussian16 to investigate these ideas using both the B3PW91 and PBEPBE functional. The presented work explores the use of 18 different single metal atoms as catalysts in the first dehydrogenation of ethanol. All of the 3d metals, as well as eight 4d and 5d metals, were investigated as catalysts for this reaction. Three ethanol dehydrogenation pathways were studied for each metal catalyst: α-H, β-H, and o-H cleavage. Analysis of the energies of each reaction allowed for a determination of the dehydrogenation pathway most favored by each metal catalyst, and ultimately yielded a top catalyst for each dehydrogenation pathway. Based on the results of these calculations, the best predicted catalyst for o-H cleavage was scandium, for β-H and α-H cleavage was platinum. However, differences in the B3PW91 and PBEPBE results suggest that β-H cleavage could also be favored for Pt, and that another possible top catalyst for β-H cleavage could be Pd. This work will serve as a benchmark for heterogeneous catalysis of the ethanol dehydrogenation reaction. | Kaitlyn Wiegand; Ruitao Wu; Peshala Jayamaha; Delaney Collazo; Lichang Wang | Theoretical and Computational Chemistry; Physical Chemistry; Catalysis; Computational Chemistry and Modeling; Heterogeneous Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-10-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65241204bda59ceb9a2e5fda/original/first-dehydrogenation-of-ethanol-catalyzed-by-a-single-atom-of-d-block-metals.pdf |
60c7542d567dfef824ec602a | 10.26434/chemrxiv.13621529.v1 | Enhancing the Electrocatalytic Activity and Stability of Prussian Blue Analogues Through the Introduction of Au Nanoparticles in a Core@shell Heterostructure | Prussian blue analogues (PBAs) have shown to be useful as earth-abundant electrocatalysts for the Oxygen Evolution Reaction (OER) in acidic, neutral and alkaline media. Still, further improvements can be achieved by increasing their electrical conductivity. In this work, we have obtained and fully characterized a variety of monodisperse core@shell hybrid nanoparticles of Au@PBA (PBA of NiIIFeII and CoIIFeII) with different shell sizes. Their electrocatalytical activity is evaluated by studying the OER, which is compared to the pristine PBA and other Au-PBA heterostructures. It was observed that the introduction in a core@shell of 5-10 % of Au in weight leads to an increment in the electroactive mass able to be reduced or oxidized and thus, to a higher number of sites capable to take part in the OER. This larger amount of electroactive sites leads to a significant decrease in the onset potential (a reduction of the onset potential up to 100 mV and an increase up to 420 % of the current density recorded at an overpotential of 350 mV), while the Tafel slope remains unchanged, suggesting that Au reduces the limiting potential of the catalyst with no variation in the reaction kinetics. These effects are not experimented in the other Au-PBA nanostructures mainly due to the lower contact between both compounds and the oxidation of Au. Hence, an Au core activates the PBA shell and increases the conductivity of the resulting hybrid while the PBA shell prevents Au oxidation. These improvements come from the strong synergistic effect existing in the core@shell structure and evidence the importance of the chemical design for preparing PBA-based nanostructures displaying better electrocatalytic performances and higher electrochemical stabilities. | Roger Sanchis-Gual; Toribio F. Otero; Marc Coronado-Puchau; Eugenio Coronado | Core-Shell Materials; Nanocatalysis - Catalysts & Materials | CC BY NC ND 4.0 | CHEMRXIV | 2021-01-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7542d567dfef824ec602a/original/enhancing-the-electrocatalytic-activity-and-stability-of-prussian-blue-analogues-through-the-introduction-of-au-nanoparticles-in-a-core-shell-heterostructure.pdf |
66b61a8801103d79c55cc246 | 10.26434/chemrxiv-2024-sxjwr | Atomically Precise Au24Pt(thiolate)12(ditholate)3 Nanoclusters with Excellent Electrocatalytic Hydrogen Evolution Reactivity | [Au24Pt(C6)18]0 (C6 = 1-hexanethiolate) is twice as active as commercial Pt nanoparticles in promoting the electrocata-lytic hydrogen evolution reaction (HER), thereby attracting attention as new HER catalysts with well-controlled geo-metric structures. In this study, we succeeded in synthesizing two new Au–Pt alloy nanoclusters, namely [Au24Pt(TBBT)12(TDT)3]0 (TBBT = 4-tert-butylbenzenethiolate; TDT = thiodithiolate) and [Au24Pt(TBBT)12(PDT)3]0 (PDT = 1,3-propanedithiolate), by exchanging all the ligands of [Au24Pt(PET)18]0 (PET = 2-phenylethanethiolate) with mono- or di-thiolates. Although [Au24Pt(TBBT)12(TDT)3]0 was synthesized serendipitously, a similar cluster, [Au24Pt(TBBT)12(PDT)3]0, was subsequently obtained by selecting the appropriate reaction conditions and optimal combination of thiolate and dithiolate ligands. Single crystal X-ray diffraction analyses revealed that the lengths and orientations of –Au(I)–SR–Au(I)– staples in [Au24Pt(TBBT)12(TDT)3]0 and [Au24Pt(TBBT)12(PDT)3]0 were different from those in [Au24Pt(C6)18]0, [Au24Pt(PET)18]0, and [Au24Pt(TBBT)18]0, and these subtle differences were reflected in the geometric and electronic structures as well as the HER activities of [Au24Pt(TBBT)12(TDT)3]0 and [Au24Pt(TBBT)12(PDT)3]0. Accordingly, the HER activities of products [Au24Pt(TBBT)12(TDT)3]0 and [Au24Pt(TBBT)12(PDT)3]0 were, respectively, 3.5 and 4.9 times higher than those of [Au24Pt(C6)18]0 and [Au24Pt(TBBT)18]0. | Miyu Sera; Sakiat Hossain; Sara Yoshikawa; Kana Takemae; Ayaka Ikeda; Tomoya Tanaka; Taiga Tanaka; Yoshiki Niihori; Tokuhisa Kawawaki; Yuichi Negishi | Catalysis; Nanoscience; Nanostructured Materials - Nanoscience; Electrocatalysis; Homogeneous Catalysis; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2024-08-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66b61a8801103d79c55cc246/original/atomically-precise-au24pt-thiolate-12-ditholate-3-nanoclusters-with-excellent-electrocatalytic-hydrogen-evolution-reactivity.pdf |
60c75415f96a0085032885b1 | 10.26434/chemrxiv.13550579.v1 | High-Performance Non-doped Blue OLEDs based on Efficiently Triplet-Triplet Upconversion and Aggregation-induced Emission | Triplet-triplet
upconversion (TTU), where two low-energy triplet excitons are converted to one
higher energy singlet exciton, is excellent approach to break through the
theoretical limit of the pure fluorescent organic light-emitting diodes (OLEDs)
by 5%. To data, however, the reported emitters with high emission
efficiency and efficiently TTU in film state are rare. Herein, we design the blue
aggregation-induced emission luminogens (AIEgens) and investigate their
upconversion efficiency. TPA-An-mPhCz can not only achieve high emission
efficiency in the film state, but also show high upconversion efficiency of close
to 50% even though the calculated energy level of the triplet excitons (T<sub>2</sub>) is lower
than 2T<sub>1</sub>. A possible upconversion mechanism is proposed according to
the transient electroluminescence spectra and theoretical calculation. This strategy
may provide a new platform for the construction of highly efficient non-doped blue
OLEDs based on TTU and AIEgens. | Pengbo Han; Chengwei Lin; Kaojin Wang; Yanping Qiu; Haozhong Wu; Dongge Ma; Anjun Qin; Ben Zhong Tang | Dyes and Chromophores | CC BY NC ND 4.0 | CHEMRXIV | 2021-01-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75415f96a0085032885b1/original/high-performance-non-doped-blue-ole-ds-based-on-efficiently-triplet-triplet-upconversion-and-aggregation-induced-emission.pdf |
67d9752a6dde43c9084633d0 | 10.26434/chemrxiv-2025-cz860-v2 | The natural redox cofactor PQQ enables photocatalytic radical cyclizations | Photoenzymatic catalysis facilitates stereoselective new-to-nature chemistry under mild conditions. In addition to the rational design of artificial photoenzymes, naturally occurring redox enzymes have been repurposed for this approach. Most prominently, flavin-containing cofactors can promote photoredox catalysis in the chiral protein environment, with several examples of enantioselective C–C bond forming reactions reported in recent years. Here, we add another class of natural enzymes, which utilize the pyrroloquinoline quinone (PQQ) cofactor, to the toolbox of photobiocatalysis. Although structurally distinct from flavin, PQQ exhibits mechanistic similarities, as it also absorbs visible light and is capable of single-electron transfer. First, we established the trimethyl ester PQQMe3 as a stand-alone photoredox catalyst in pure organic solvent. Upon excitation, PQQMe3 enables the redox-neutral radical cyclization of an N-(bromoalkyl)-substituted indole. We then tested a panel of PQQ-dependent sugar and alcohol dehydrogenases for photoenzymatic catalysis in aqueous buffer, focusing on a redox-neutral radical reaction to form oxindoles. Under optimized reaction conditions, we obtained 69% yield and an 82:18 enantiomeric ratio. Our work thus demonstrates that PQQ enzymes are capable of stereoselective photoredox catalysis. Future enzyme engineering efforts based on computational modelling and directed evolution will fully unlock their synthetic potential. | Srishti Ballabh Bahukhandi; Andreas Sebastian Klein; Ghulam Mustafa; Maria Weyh; Alexandra Walter; Erling Thyrhaug; Jürgen Hauer; Golo Storch; Cathleen Zeymer | Catalysis; Biocatalysis; Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2025-03-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67d9752a6dde43c9084633d0/original/the-natural-redox-cofactor-pqq-enables-photocatalytic-radical-cyclizations.pdf |
60c74fc2842e65a562db38e9 | 10.26434/chemrxiv.12921455.v1 | Specific Impulse and Absolute Chemical Hardness | <p>The present work is dedicated to show that there
are relationships between the absolute chemical hardness (η) of monopropellants
and their specific impulse (I<sub>s</sub>). A total of sixteen monopropellants
have been modelled and the absolute hardness obtained by quantum chemical
calculations. The following equation was obtained: I<sub>s</sub> =
17.562 η + 125.551, providing specific impulse results in very good agreement
with reference values. </p>
<p> </p> | George Santos Marinho; Robson de Farias | Theory - Inorganic | CC BY NC ND 4.0 | CHEMRXIV | 2020-09-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74fc2842e65a562db38e9/original/specific-impulse-and-absolute-chemical-hardness.pdf |
6707c28f12ff75c3a10c3f5c | 10.26434/chemrxiv-2024-45v17 | Citrus IntegroPectin: a multifunctional bioactive phytocomplex with large therapeutic potential | Pectin is a bioactive polysaccharide widely investigated for its therapeutic properties as well as in tissue engineering and regenerative medicine for its gelling behavior, wound healing ability and high biocompatibility. First isolated in 2019 via hydrodynamic cavitation carried out in water only of the by-product of the industrial process of manufacturing orange juice, IntegroPectin is a new pectin-based phytocomplex rich in citrus flavonoids and terpenes whose low-methoxyl pectin backbone is enriched in RG-I rhamnogalacturonan regions. Antioxidant, anti-inflammatory, cardioprotective, neuroprotective, mitoprotective, antimicrobial and anticancer properties comprise the multitarget biological activity demonstrated so far investigating lemon, grapefruit, and mandarin IntegroPectin in both in vitro and in vivo studies. Research achievements in the first five years following its discovery highlight the large potential of citrus IntegroPectin as therapeutic and preventive agent. A critical perspective towards production and practical uptake of this new phytocomplex for the treatment and prevention of numerous ailments concludes the review. | Rosaria Ciriminna; Valentina Di Liberto; Chiara Valenza; Giovanna Li Petri; Giuseppe Angellotti; Lorenzo Albanese; Francesco Meneguzzo; Mario Pagliaro | Biological and Medicinal Chemistry; Biochemistry; Bioengineering and Biotechnology; Drug Discovery and Drug Delivery Systems | CC BY NC 4.0 | CHEMRXIV | 2024-10-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6707c28f12ff75c3a10c3f5c/original/citrus-integro-pectin-a-multifunctional-bioactive-phytocomplex-with-large-therapeutic-potential.pdf |
61e419daeab6ef2b05e31e8d | 10.26434/chemrxiv-2022-d673f | Regulating Internal Electric Field by Breaking Symmetry in Polymeric Photocatalysts for Visible-Light-Driven Disinfection | The inefficient charge separation and transport (CST) process has been a major obstacle that limits the catalytic activity of polymeric photocatalysts. Here we propose a symmetry-breaking strategy to regulate the internal electric field (IEF) in crystalline polymers for enhanced CST and photocatalytic efficiency. As a proof of concept, two crystalline linear copolymers, p-phenylenediamine/m-phthalaldehyde (PDA-MAH) and p-phenylenediamine/p-phthalaldehyde (PDA-PAH), were synthesized. By breaking the lattice symmetry, we observed robust IEF in the non-centrosymmetric PDA-MAH, as compared to the centrosymmetric PDA-PAH. Such strong IEF was extended throughout the catalyst bulk to accelerate the CST process in PDA-MAH, resulting in a photocatalytic disinfection performance under visible light irradiation that surpassed the best of the previously reported polymeric photocatalysts. This work presents a promising paradigm for tailoring polymeric semiconductors with efficient CST process. | Dawei Zhang; Xiangrong Li; Yukun Yan; Zihao Rei Gao; Hanwen Wang; Jinsong Zhang; Jun Xiao | Catalysis; Polymer Science; Organic Polymers; Photocatalysis; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2022-01-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61e419daeab6ef2b05e31e8d/original/regulating-internal-electric-field-by-breaking-symmetry-in-polymeric-photocatalysts-for-visible-light-driven-disinfection.pdf |
60f061452b9101114e72e899 | 10.26434/chemrxiv-2021-j9stg | Membrane fusion mediated by non-covalent binding of re-engineered cholera toxin assemblies to glycolipids | Membrane fusion is essential for the transport of macromolecules and viruses across membranes. While glycan-binding proteins (lectins) often initiate cellular adhesion, subsequent fusion events require additional protein machinery. No mechanism for membrane fusion arising from simply a protein binding to membrane glycolipids has been described thus far. Herein we report that a biotinylated protein derived from cholera toxin, becomes a fusogenic lectin upon crosslinking with streptavidin. This novel reengineered protein brings about hemifusion and fusion of vesicles as demonstrated by mixing of fluorescently labelled lipids between vesicles as well as content mixing of liposomes filled with fluorescently labelled dextran. Exclusion of the complex at vesicle-vesicle interfaces could also be observed indicating the formation of hemifusion diaphragms. We propose that negative membrane curvature, caused by binding of the cholera toxin to the membrane surface, induces formation of a fusion stalk as a result of high bending energies building up between multiple inverted membrane dimples aligned on opposing membranes at the vesicle-vesicle interface. Discovery of this fusogenic lectin complex demonstrates that new emergent properties can arise from simple changes in protein architecture and provides insights towards new mechanisms of lipid-driven fusion | Sarah Wehrum; Daniel J Williamson; Lina Siukstaite; Thomas R Branson; Taras Sych; Josef Madl; Gemma C Wildsmith; Wenyue Dai; James F Ross; Maren Thomsen; Michael E Webb; Winfried Römer; W Bruce Turnbull | Biological and Medicinal Chemistry; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2021-07-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60f061452b9101114e72e899/original/membrane-fusion-mediated-by-non-covalent-binding-of-re-engineered-cholera-toxin-assemblies-to-glycolipids.pdf |
60c73fdfbdbb8927b2a380ba | 10.26434/chemrxiv.7208531.v2 | Assessment of Constant-Potential Implicit Solvation Calculations of Electrochemical Energy Barriers for H2 evolution on Pt | Theoretical estimation of the activation energy of electrochemical reactions is of critical importance but remains challenging. In this work, we address the usage of an implicit solvation model for describing hydrogen evolution reaction steps on Pt(111) and Pt(110), and compare with the `extrapolation' approach as well as single-crystal measurements. We find that both methods yield qualitatively similar results, which are in fair agreement with the experimental data. Care should be taken, however, in addressing spurious electrostatic interactions between periodically repeated slabs in the VASPsol implementation. Considering the lower computational cost and higher flexibility of the implicit solvation approach, we expect this method to become a valuable tool in electrocatalysis.<br /> | Maxime Van den Bossche; Egill Skúlason; Christoph Rose-Petruck; Hannes Jonsson | Computational Chemistry and Modeling; Electrocatalysis; Electrochemistry - Mechanisms, Theory & Study | CC BY NC ND 4.0 | CHEMRXIV | 2018-12-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73fdfbdbb8927b2a380ba/original/assessment-of-constant-potential-implicit-solvation-calculations-of-electrochemical-energy-barriers-for-h2-evolution-on-pt.pdf |
60c74ec3702a9b71a318ba5f | 10.26434/chemrxiv.12798143.v1 | Automated Liquid-Level Monitoring and Control using Computer Vision | Chemists spend an inordinate amount of time performing low-level tasks based on visual observation. Camera-enabled laboratory
equipment in conversation with computer vision algorithms can be used to automate many of these processes, thereby freeing up valuable
time and resources. We developed a generalizable computer-vision based system capable of monitoring and controlling liquid-level across
a variety of chemistry applications. This paper reports on the system’s motivation, architecture, and successful deployment in three
experimental use cases which require continous stirring: continuous preferential crystallization (CPC), slurry filtration, and solvent swap
distillation | Tara Zepel; Veronica Lai; Lars P.
E. Yunker; Jason E. Hein | Physical Organic Chemistry; Process Chemistry; Analytical Chemistry - General; Process Control; Reaction Engineering | CC BY NC 4.0 | CHEMRXIV | 2020-08-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74ec3702a9b71a318ba5f/original/automated-liquid-level-monitoring-and-control-using-computer-vision.pdf |
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