Transition metal complexes with sulfur ligands.: 134 -: Synthesis of the tetradentate thioether amine and thioether thiolate ligands 'tpS2(NH2)2' and 'tpS4'-H2 and some representative six-coordinate ruthenium and osmium complexes ['tpS2(NH2)2'=1,2-bis(2-aminophenylthio)phenylene, 'tpS42-'=1,2-bis(2-mercaptophenylthio)phenylene(2-)]

In search of a tetradentate thioether thiolate Ligand that is more stable toward reductive C-S bond cleavage than the parent ligand 'S-4'-H-2 ['S-4'-H-2 = 1,2-bis(2-mercaptophenylthio)ethane], the novel tris-phenylene ligand 'tpS4'-H-2 (3) ['tpS(4)'-H-2 = 1,2-bis (2-mercaptophenylthio)phenylene] was synthesized via the nitro and amine compounds 'tpS(2)(NO2)(2)' (1) and 'tpS(2)(NH2)(2)' (2). The coordination of 'tpS(4)'(2-) to ruthenium centers resulted in the formation of six-coordinate [Ru(L)(PR3)('tpS(4)')] complexes (R = Et, L = PEt3 4; R = Ph, L = PPh3 5, CO 6, DMSO 7). The X-ray structure analyses of 4 and 6 revealed that the thiolate donors occupy trans positions; consequently the 'tpS(4)'(2-) ligand coordinates in the same way as the 'S-4'(2-) ligand. The stability of the 'tpS(4)'(2-) ligand toward reductive C-S cleavage reactions was shown by the synthesis of [OS(PEt3)(2)(tPS(4)')] (8) In contrast to [Os(PEt3)(2)('S-4')], 8 is stable for unlimited periods of time. The X-ray structure analysis of [Ru(Cl)(2)(PPh3)('tpS(2)(NH2)(2)')] (9) demonstrates that the potentially tetradentate ligand 'tpS(2)(NH2)(2)' coordinates in 9 through three donors leaving one NH2 donor dangling.