Zinc Thiolate Complexes of (N,N,S)‐Tridentate Ligands for the Modeling of Thiolate Alkylating Enzymes

Zinc thiolate complexes of three tridentate (N,N,S) ligands were prepared as models for the structure and function of thiolate alkylating zinc enzymes. N ‐(2‐Mercaptoisobutyl)(2‐pyridin‐2‐yl‐methyl)amine ( L 1 ) forms isobutylthiolate‐bridged dinuclear complexes with ZnN 2 S 3 coordination. N ‐(2‐Mercaptoisobutyl)(2‐pyridin‐2‐yl‐ethyl)amine ( L 2 ) yields isobutylthiolate‐bridged dinuclear complexes in which the pyridine donor is not coordinated to zinc, resulting in a ZnNS 3 coordination. Only N ‐(2‐mercaptoisobutyl)(2‐pyridin‐2‐yl‐ethyl)methylamine ( L 3 ) forms the desired mononuclear complexes with ZnN 2 S 2 coordination. The latter react with the alkylating agents CH 3 I and PO(OCH 3 ) 3 in a two‐step process. In the first step the isobutylthiolate function is methylated and its position in the ligand sphere of zinc is taken by I – or OPO(OCH 3 ) 2 – , respectively, and in the second step the additional thiolate ligand is methylated and replaced by a second iodide or dimethyl phosphate anion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)