Synthetic reactions and coordination modes of ruthenium complexes with tris(mercaptomethimazolyl)borate ligands

Interaction of the dimer [(η6-p-cymene)RuCl(μ-Cl)]2 or [Cp∗RuCl(μ-Cl)]2 with two equiv. of K[HB(timMe)3] at reflux gave anionic complex [(η6-p-cymene)Ru{κ3-S,S,S-HB(timMe)3}]Cl (1) or neutral complex [Cp∗Ru{κ3-S,S,S-HB(timMe)3}] (2), respectively, with terminally non-coordinated BH bond. Complexes 1 and 2 were further refluxed in CHCl3 to result in the quantitative formation of [(η6-p-cymene)Ru{κ3-S,S,S-ClB(timMe)3}]Cl (3) and [Cp∗Ru{κ3-S,S,S-ClB(timMe)3}] (4), respectively, with BCl bonds. Treatment of [RuHCl(CO)(PPh3)3] or [Ru(PPh3)3Cl2] with equal equiv. of K[HB(timMe)3] at reflux afforded the neutral complex [RuH(CO)(PPh3){κ3-S,S,H-HB(timMe)3}] (5) or [Ru(PPh3)2Cl{κ3-S,S,H-HB(timMe)3}] (6), respectively, with an agostic BH⋯Ru bond. Complex 6 was further treated with one equiv. of NatimMe in THF solution to result in formation of new complex [Ru(PPh3)(κ2-S,N-timMe){κ3-S,S,H-HB(timMe)3}] (7) with chelating [timMe]– moiety. All complexes were spectroscopically characterized, of which the structures of 1·1/4C6H14, 4·C6H14·3/4H2O, 5·1/2CH2Cl2, and 7·2CH2Cl2 have been established by X-ray crystallography.