Transition Metal Complexes with Sulfur Ligands. 136.1 Enforced Trans Coordination of Thiolate Donors in Electron Rich Iron, Ruthenium, and Nickel [M(L)(pyN2H2S2)] and [M(L)(pyS4)] Complexes (L = CO, PPh3, DMSO) (pyN2H2S22- = 2,6-Bis(2-mercaptophenylamino)dimethylpyridine(2−); pyS42- = 2,6-Bis(2-mercaptophenylthio)dimethylpyridine(2−))

Abstract

In the course of a systematic study of transition metal complexes exhibiting three properties, electron rich metal centers, core structures with trans thiolate donors, and the capability to bind nitrogenase related small molecules, the pentadentate ligands pyN2H2S2-H2 (=2,6-bis(2-mercaptophenylamino)dimethylpyridine) and pyS4-H2 (=2,6-bis(2-mercaptophenylthio)dimethylpyridine) have been synthesized. Alkylation of 2(3H)-benzothiazolone by 2,6-bis[(tosyloxy)methyl]pyridine and subsequent alkaline hydrolysis yielded pyN2H2S2-H2 (3). Template alkylation of [Ni(S2C6H4)2]2- (6) by 2,6-bis[(tosyloxy)methyl]pyridine gave [Ni(pyS4)]2 (7) whose acidic hydrolysis yielded pyS4-H2·HCl (9). The reaction of Fe(II) salts with pyN2H2S22- gave [Fe(pyN2H2S2)] (10). Five-coordinate 10 is paramagnetic (μeff (293 K) = 5.34 μB), has a trigonal bipyramidal structure, and coordinates CO to give diamagnetic [Fe(CO)(pyN2H2S2)] (11). Although the ν(CO) of 11 (1928 cm-1 (KBr)) indicates electron rich Fe centers and strong Fe−CO bonds...