Infrared and UV-VIS photodissociation spectroscopy. The IR and Vis spectra of mass-selected ions were measured with a helium tagging photodissociation method using the ISORI instrument. The ions were generated by the electrospray ionization, mass selected by a quadrupole, and transferred to a wire quadrupole trap operated at 3 K. The ions were trapped and cooled down using the helium buffer gas. The relaxed ions attached a helium atom. The helium complexes then served for the spectroscopic experiments. The complexes were irradiated with the OPO/OPA system from LaserVision pumped by Nd:YAG laser Surelite EX from Continuum (tuning range 700-4700 cm -1 , FWHM ~ 1.5 cm -1 , 10 ns pulse length) or with supercontinuum laser NKT Photonics SuperK Extreme (430-700 nm range using acusto-optic tunable filter SuperK Select). The spectra are constructed as (1 -Ni/Ni0), where Ni and Ni0 are numbers of helium complexes with and without laser irradiation. Electrochemistry. Cyclic voltammetry (CV) experiments were performed using a Metrohm potentiostat (Autolab PGSTAT204) at room temperature in a solution of 0.25 mM of the respective gold complex, 0.1 M of the supporting electrolyte (tertabutyl ammonium hexafluorophosphate) either in DMF or in DCM. Glassy carbon working electrode, Pt counter electrode and a double junction non-aqueous Ag/AgCl reference electrode filled with 2 M LiCl in ethanol as the inner electrolyte was used. Prior to the measurements the electrolyte was deoxygenated by argon bubbling, and during the measurement electrolyte was kept under the argon atmosphere. Reference electrode was calibrated against ferrocene redox couple before measurements. DFT calculations. All quantum chemical calculations were carried out using Gaussian 16, and Turbomole 7.5.1. programs. Density functional theory (DFT) has been mostly used throughout. A set of density functionals, including pure generalized-gradient approximation (GGA), meta-GGA and hybrids were employed: B3LYP, PBE, TPSS, and PBE0. Basis sets of triple-zeta quality -6-311+G**, and def2-TZVP(P) -used throughout are considered as sufficiently large to report the converged DFT values. For gold and iodine core Stuttgart-Dresden (SDD) pseudopotentials (ECP's) were used. The electronic excitation spectra were mostly calculated by employing time-dependent (TD-) DFT theory as implemented in Gaussian 16. For comparison, the ab initio CC2 and ADC2 calculations were performed using the Turbomole 7.5.1 code. The spin-orbit SO-ZORA excitations we obtained in the ADF 2021 program suite. The particular method used for computations is always denoted in the following by employing the standard notation: Method A/basis set A//method B/basis set B. This describes the level of theory at which the geometry was optimized (method B/basis set B) and the final single-point energy (method A/basis set A) calculated. Zero-point vibrational energy (and entropic and thermal contributions, if needed) were obtained employing the standard normal-mode analysis. Quantum Theory of Atoms in Molecules (QTAIM) and NBO analysis. To investigate chemical bonding and to determine the oxidation states of metal in the studied complexes, quantum theory of atoms in molecules, QTAIM, was employed. All QTAIM computations were performed by the AIMAll suite of programs. Natural bond orbital analysis used program NBO 7.0 linked to the Gaussian 16 code.