Synthesis and characterization of some novel ruthenium(II) complexes containing thiolate ligands

Reactions of the ruthenium complexes [RuH(CO)Cl(PPh3)3] and [RuCl2(PPh3)3] with hetero-difunctional S,N-donor ligands 2-mercapto-5-methyl-1,3,5-thiadiazole (HL1), 2-mercapto-4-methyl-5-thiazoleacetic acid (HL2), and 2-mercaptobenzothiazole (HL3) have been investigated. Neutral complexes [RuCl(CO)(PPh3)2(HL1)] (1), [RuCl(CO)(PPh3)2(HL2)] (2), [RuCl(CO)(PPh3)2(HL3)] (3), [Ru(PPh3)2(HL1)2] (4), [RuCl(PPh3)3(HL2)] (5), and [RuCl(PPh3)3(HL3)] (6) imparting κ2-S,N-bonded ligands have been isolated from these reactions. Complexes 1 and 4 reacted with diphenyl-2-pyridylphosphine (PPh2Py) to give neutral κ1-P bonded complexes [RuCl(CO)(κ1-P-PPh2Py)2(HL1)] (7), and [Ru(κ1-P-PPh2Py)2(HL1)2] (8). Complexes 1–8 have been characterized by analytical, spectral (IR, NMR, and electronic absorption) and electrochemical studies. Molecular structures of 1, 2, 4, and 7 have been determined crystallographically. Crystal structure determination revealed coordination of the mercapto-thiadiazole ligands (HL1–HL3) to ruthenium as κ2-N,S-thiolates and presence of rare intermolecular S–S weak bonding interaction in complex 1.