Ruthenium complexes with dihydridobis(N-methyl-2-mercaptoimidazolyl)borate ligands

Treatment of [Ru(PPh3)3Cl2] with two equiv. of K[H2B(timMe)2] (timMe = N-methyl-2-mercaptoimidazol-1-yl) in tetrahydrofran (THF) at room temperature afforded a neutral complex [Ru(PPh3){κ3-H,S,S′-H2B(timMe)2}{κ2-S,S′-H2B(timMe)2}] (1), while reaction of the similar reactants in THF at reflux gave a cationic complex [Ru(PPh3){κ3-H,S,S′-H2B(timMe)2}(η1-S-HtimMe)2}]Cl (2) during which the fragmentation of the ligand [H2B(timMe)2]− occurred due to higher temperature. Treatment of [Ru(DMSO)4Cl2] with two equiv. of K[H2B(timMe)2] in THF solution at room temperature resulted in formation of a neutral complex [Ru{κ3-H,S,S′-H2B(timMe)2}2] (3) with a [RuS4H2] core. The crystal structures of complexes 1–3 have been determined by single-crystal X-ray diffraction, establishing the configuration and the B–H⋯Ru bonding mode of the ligands. The ruthenium atom in each of the above complexes adopts a pseudo-octahedral geometry with a three-center, two-electron B–H⋯Ru interaction. Spectroscopic and electrochemical properties of all complexes are also reported.