Nucleophilicity of zinc-bound thiolates

The nucleophilicity of biomimetic zinc-thiolate complexes against methyl iodide has been studied. The activation barrier has been computed with the B3LYP functional. The reactivity depends on the global charge, the nature of the ligand set and the presence of hydrogen bonds. This shows that the understanding of zinc site nucleophilicity can not be achieved by the knowledge of the atom donor set for zinc only, as currently done in the literature. Moreover, we show that sulfur proton affinity and activation barrier are directly proportional, thus providing a good nucleophilicity index for zinc-bound thiolate.