Principles of formation of catalytic systems for oxidation of aliphatic thiols based on d-element complexes

Abstract

Mechanism of catalytic selective oxidation of aliphatic thiols RSH into disulfides R₂S₂ has been suggested basing on quantum-chemical DFT simulation (M06/Def2-TZVP) of coordination compounds of d-elements and using the principle of complementarity. The active center of the catalytic system is a binuclear fragment {M(m-OH)₂M′}ⁿ⁺ formed due to hydrolysis of the starting mononuclear d-element compound. The catalysts based on Pd(II) and Pt(II) binuclear active centers are spatially similar throughout the process. The chief interrelated functions of the binuclear catalysts are spatial approaching of two thiolate anions RS^– in the inner sphere of the bridged coordination compound required for the disulfide (–S–S–) cross-linking and providing for two-electron redox transfer during the transformation of these anions into disulfide (СH₃)₂S₂.