Synthesis of diiridium complexes containing bridging thiolate and thioether ligands [(η5-C5Me5)Ir(μ-SR) (μ-MeSR) -Ir(η5-C5Me5)] [OSO2CF3] (R-Pri, cyclohexyl) and their reactivities toward CO and H2

Article abstract of DOI:10.1016/s0020-1693(97)05709-5

Treatment of [Cp*Ir(μ-SR)₂IrCp*] (Cp* = η⁵-C₅Me₅, R = Prⁱ, Cy; Cy = cyclohexyl) with MeOTf (OTf=OSO₂CF₃) afforded the thiolate- and thioether-bridged diiridium complexes [Cp*Ir(μ-SR) (μ-MeSR) IrCp*] [OTf] (3). Upon heating a THF solution of 3a (R = Prⁱ) under N₂, dissociation of the bridging MeSPrⁱ ligand took place and a coordinatively unsaturated complex [Cp*Ir(μ-SPrⁱ)IrCp*] [OTf] (4) was isolated in an analytically pure form, and characterized spectroscopically. When 3a was treated analogously under CO, a diiridium carbonyl complex [Cp*Ir(CO) (μ-SPrⁱ) IrCp* (CO)] [OTf] (5) was obtained in 53percent yield together with 4 (39percent yield). On the other hand, reactions of 3 with H₂ under similar conditions resulted in the formation of diiridium complexes bridged by two hydride and one thiolate ligands [Cp*Ir(μ-H)₂(μ-SR)IrCp*] [OTf] (6) in high yields. The structure of 6 was determined by X-ray analysis using a single crystal of [Cp*Ir(μ-H)₂(μ-SCy)IrCp*] [BPh₄] derived from 6b (R=Cy).