Thiol-copper(I) and disulfide-dicopper(I) complex O2-reactivity leading to sulfonate-copper(II) complex or the formation of a cross-linked thioether-phenol product with phenol addition.

In order to better understand copper mediated oxidative chemistry via ligand-Cu(I)/O(2) reactivity employing S-donor ligands for copper, O(2)-reactivity studies of the copper(I) complexes (1 and 2, Chart 2) have been carried out with a tridentate N(2)S thiol ligand (1-(N-methyl-N-(2-(pyridin-2-yl)ethyl)amino)propane-2-thiol; L(SH)) or its oxidized disulfide form (L(SS)). Reactions of L(SH)Cu(I) (1) and L(SS)(Cu(I))(2)(X)(2) (2) with O(2) give approximately 90% and approximately 70% yields of L(SO3)Cu(II)(MeOH)(2) (3), respectively, where L(SO3) is S-oxygenated sulfonate; 3 was characterized by electrospray ionization (ESI) mass spectrometry and X-ray crystallography. Mimicking TyrCys galactose oxidase cofactor biogenesis, a new C-S bond is formed (within new thioether moiety L(SPhOH)) from cuprous complex (both 1 and 2) dioxygen reactivity in the presence of 2,4-tBu(2)-phenolate. In addition, the disulfide ligand (L(SS)) reacts with 2equiv. cupric ion salts and the phenolate to efficiently give the cross-linked product L(SPhOH) in high yield (>90%) under anaerobic conditions. Separately, complex [L(SPhO)Cu(II)(ClO(4))] (4), possessing the cross-linked L(SPhOH), was characterized by ESI mass spectrometry and X-ray crystallography.