Synthesis, crystalline and molecular structure of palladium(II) binuclear complex with cysteine

Effect of metal nature (Ni, Pd, Pt) on the catalytic oxidation of aliphatic thiols: Quantum-chemical DFT modeling of separate steps of the catalytic cycle

“…(2c)Taking into account the solvent effect (water) this value decreased to 1.73 eV.The scheme of the catalytic cycle similar to the earlier considered[1] for coordination compounds of Pd(II) assumes the destruction of the species [(en)(OH)· Ni(μ-SCH 3 ) 2 (μ-ОН)Ni(en)] 2+ with the formation of the hydroxo-bridged dimer [(en)Ni(μ-OH) 2 Ni(en)] 2+ and dimethyl disulfide CH 3 SSCH 3 by reaction (3с). [(en)(OH)Ni(μ-SCH 3 ) 2 (μ-ОН)Ni(en)] 2+ ↔ [(en)Ni(μ-OH) 2 Ni(en)] 2+ + (СH 3 ) 2 S 2 .…”

“…The decrease in both the rigidity of the binuclear core Ni(μ-OH) 2 Ni favorable for reaction (1с) and the softness of the core Pt(μ-SR) 2 Pt promoting the rupture of the Pt-S bridge bonds in reaction (3b) can be favored by terminal ligands with optimal combination of the donoracceptor properties for the given catalytic cycle. In [1], the effectiveness of the catalytic action of ultramicro amounts of the studied binuclear palladium compounds on the process of oxidation of a biologically important endogenic thiol, glutathione, was experimentally proved. The present work opens a prospect for the search of effective nickel and platinum catalysts of selective oxidation of biologically active thiols.…”

“…At the same time, six-coordinate polyhedra with d 2 sp 3 -hybrid orbitals of the metal belong to complex compounds of Pd(IV). Thus, as in [1], in the complex cation [(NH 3 ) 2 (OH) 2 · M IV (μ-SCH 3 ) 2 M II (NH 3 ) 2 ] 2+ we assign to the sixcoordinate metal ion the state Pt(IV), and to the tetracoordinate metal ion, Pt(II).…”

“…Earlier we have shown that one of the most probable functions of the metal in catalytic oxidation of aliphatic thiols RSH to disulfides RSSR' is the formation of coordination compounds with thiolate ions RSwith their subsequent oxidation and destruction of the coordination polyhedron [1]. For the modeling of the process of oxidation of thiolate ions we considered the catalytic cycle with participation of the hydroxo-bridged complex of Pd(II) with terminal 2,2'-dipyridyl (dipy) ligands, [Pd 2 (μ-OH) 2 (dipy) 2 ] 2+ , for which the following reactions were suggested as the principal processes:…”