Oxidation of Silver Cyanide Ag(CN)2 by the OH Radical: From Ab Initio Calculation to Molecular Simulation and to Experiment

by Céline Léonard, Frédéric Le Quéré, Daniel Adjei, Sergey A. Denisov, Mehran Mostafavi and Pierre Archirel

J. Phys. Chem. A 2020, 124, 51, 10787–10798; doi.org/10.1021/acs.jpca.0c08038

We investigate the oxidation of silver cyanide  in water by the OH radical in order to compare this complex with the free cation Ag+ and to measure the influence of the ligands. High-level ab initio calculations of the model species  enable the calibration of molecular simulations and the prediction of the oxidized species:  and its absorption spectrum, with an intense band at 292 nm and a weaker one at 390 nm. Pulse radiolysis measurements of the oxidation of  by the OH radical in water yields a transient species with a broad, intense band at 290 nm and a weaker band at 410 nm at short times after the pulse and a blue shift of the spectrum at longer times. The prediction of the simulations, that the oxidized complex  is formed, is confirmed by thermochemistry. Our calculations also suggest that the formation of the OH-adduct is possible only in very basic solution and that the blue shift observed at long times after the pulse is due to disproportionation of the oxidized complex. We also perform molecular simulations of the oxidation of free Ag+ cations by the OH radical. The results are compared to that of the literature and to the results obtained with the  complex.

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