σ-Organyl complexes of ruthenium and osmium supported by a mixed-donor ligand

Abstract

A series of vinyl, aryl, acetylide and silyl complexes [Ru(R)(κ²-MI)(CO)(PPh₃)₂] (R = CHCH₂, CHCHPh, CHCHC₆H₄CH₃-4, CHCH^tBu, CHCHCPh₂OH, C(CCPh)CHPh, C₆H₅, CCPh, SiMe₂OEt; MI = 1-methylimidazole-2-thiolate) were prepared from either [Ru(R)Cl(CO)(PPh₃)₂] or [Ru(R)Cl(CO)(BTD)(PPh₃)₂] (BTD = 2,1,3-benzothiadiazole) by reaction with the nitrogen–sulfur mixed-donor ligand, 1-methyl-2-mercaptoimidazole (HMI), in the presence of base. In the same manner, [Os(CHCHPh)(κ²-MI)(CO)(PPh₃)₂] was prepared from [Os(CHCHPh)(CO)Cl(BTD)(PPh₃)₂]. The in situ hydroruthenation of 1-ethynylcyclohexan-1-ol by [RuH(CO)Cl(BTD)(PPh₃)₂] and subsequent addition of the HMI ligand and excess sodium methoxide yielded the dehydrated 1,3-dienyl complex [Ru(CHCHC₆H₉)(κ²-MI)(CO)(PPh₃)₂]. Dehydration of the complex [Ru(CHCHCPh₂OH)(κ²-MI)(CO)(PPh₃)₂] with HBF₄ yielded the vinyl carbene [Ru(CHCHCPh₂)(κ²-MI)(CO)(PPh₃)₂]BF₄. The hydride complexes [MH(κ²-MI)(CO)(PPh₃)₂] (M = Ru, Os) were obtained from the reaction of HMI and KOH with [RuHCl(CO)(PPh₃)₃] and [OsHCl(CO)(BTD)(PPh₃)₂], respectively. Reaction of [Ru(CHCHC₆H₄CH₃-4)(κ²-MI)(CO)(PPh₃)₂] with excess HCCPh leads to isolation of the acetylide complex [Ru(CCPh)(κ²-MI)(CO)(PPh₃)₂], which is also accessible by direct reaction of [Ru(CCPh)Cl(CO)(BTD)(PPh₃)₂] with 1-methyl-2-mercaptoimidazole and NaOMe. The thiocarbonyl complex [Ru(CPhCHPh)Cl(CS)(PPh₃)₂] reacted with HMI and NaOMe without migration to yield [Ru(CPhCHPh)(κ²-MI)(CS)(PPh₃)₂], while treatment of [Ru(CHCHPh)Cl(CO)₂(PPh₃)₂] with HMI yielded the monodentate acyl product [Ru{η¹-C(O)CHCHPh}(κ²-MI)(CO)(PPh₃)₂]. The single-crystal X-ray structures of five complexes bearing vinyl, aryl, acetylide and dienyl functionality are reported.