Protonation and Alkylation of a Dinuclear Nickel Thiolate Complex.

Abstract

Reaction of a dinuclear Ni thiolate complex featuring both terminal and bridging thiolate ligands with 1 equiv of an alkylating agent leads to the production of a dinuclear complex where one of the terminal thiolate ligands has reacted to form a thioether ligand. The product of one such reaction has been crystallographically characterized. This structure reveals that little change in the core structure of the complex occurs upon alkylation. Similarly, reaction of the dinuclear Ni complex with 1 equiv of H+ leads to the isolation of a dinuclear complex containing a thiol ligand. The structure of this complex is deduced from NMR and XAS spectroscopy. Again, little change in structure can be detected. Nonetheless, the redox properties of the complex are dramatically affected. Thus protonation provides one possible mechanism for modulating the redox potential of metalloenzymes containing Ni thiolate active sites without affecting the structure of the Ni site.