Redox-Innocent Metal-Assisted Cleavage of S–S Bond in a Disulfide-Containing Ligand

Charlène Esmieu (1) , Maylis Orio (2) , Laurent Le Pape (1) , Colette Lebrun (3, 4) , Jacques Pécaut (3, 4) , Stéphane Ménage (1) , Stéphane Torelli (1)

1 LCBM - UMR 5249 - Laboratoire de Chimie et Biologie des Métaux
2 ISM2 - Institut des Sciences Moléculaires de Marseille
3 SCIB - UMR E3 - Service de Chimie Inorganique et Biologique
4 RICC - Reconnaissance Ionique et Chimie de Coordination

Due to their redox capabilities, thiols have an important role in biological oxidative/reductive processes through the formation of disulfides or their oxidation to into sulfenic, sulfinic, or sulfonic derivatives being also relevant for specific enzyme activities. The mechanisms of these biological pathways often involve metal ion(s). In this case, deciphering metal-assisted transformation of the S–S bond is of primary interest. This report details the reactivity of the disulfide-containing 2,6-bis[(bis(pyridylmethyl)amino)methyl]-4-methylmercaptophenyldisulfide (LMe(BPA)S–S) ligand with Cu(II) using different experimental conditions (anaerobic, H2O-only, H2O/O2, or O2-only). Crystallographic snapshots show the formation of tetranuclear disulfide, dinuclear sulfinate, and sulfonate complexes. Mechanistic investigations using Zn(II) as control indicate a non-metal-redox-assisted process in all cases. When present, water acts as nucleophile and attacks at the S–S bond. Under anhydrous conditions, a different pathway involving a direct O2 attack at the disulfide is proposed.

Domaines: Chimie inorganique; Chimie de coordination

Charlène Esmieu, Maylis Orio, Laurent Le Pape, Colette Lebrun, Jacques Pécaut, et al.. Redox-Innocent Metal-Assisted Cleavage of S–S Bond in a Disulfide-Containing Ligand. Inorganic Chemistry, 2016, 55 (12), pp.6208-6217. ⟨10.1021/acs.inorgchem.6b00819⟩. ⟨hal-01344145⟩