Reduction of gold(III) to gold(I) by dialkyl sulphides. Evidence for an atom-transfer redox process

A spectroscopic and electrochemical investigation of the oxidation pathway of glycyl-d,l-methionine and its N-acetyl derivative induced by gold(III)

“…operative in the oxidation of organic sulfides with bromine, resulting in the corresponding sulfoxides [43,44]. Furthermore, the same reaction mechanism was suggested by Natile et al in the kinetic study of the reduction gold(III) to gold(I) by dialkyl sulfides in aqueous methanol solution [32]. The formations of products 1 and 2 are evident in the 1 H NMR spectrum from the chemical shifts of the resonances at 2.89 and 2.79 ppm, due to the methyl protons of the methionine residue (Fig.…”

“…Au(III) is very short-lived in the presence of different biomolecules because it can rapidly oxidize them, thereby being reduced to Au(I). It has been known for some time that Au(III) can oxidize thiols to disulfides [28,29], cleave the disulfide bond of cystine to give the sulfonic acid [28][29][30][31], oxidize dialkyl sulfides to sulfoxide [32], the sulfur atom of the amino acid methionine stereospecifically to methioninesulfoxide [33][34][35][36][37], and can desulfonate thioamides [38]. The structural consequences of these reactions can play an important role in the toxic side effects of gold-based drugs.…”

Cellular trafficking, accumulation and DNA platination of a series of cisplatin-based dicarboxylato Pt(IV) prodrugs

“…Although apoMets7 and apoMnk1 contain methionine or cysteine residues, which have good coordinating ability towards platinum, they are unable to react with 1 nor they are able to reduce Pt(IV) to Pt(II) complexes, while such a reduction takes place readily with isoelectronic Au(III) complexes [38,39]. Therefore, the interaction with model proteins was repeated in the presence of GSH and AA, the biomolecules usually employed to test the reduction of Pt(IV) prodrugs to Pt(II) species [17,32,40].…”

Substitution versus redox reactions of gold(iii) complexes with l-cysteine, l-methionine and glutathione

“…2), for which equilibrium constants have been determined previously. 23 Some representative plots for k obsd = f[Nu], obtained for the substitution step, are shown in Fig. 3 and Fig.…”