Novel Nucleophilic Reactivity of Disulfido Ligands Coordinated Parallel to M−M (M = Rh, Ir) Bonds

Reaction of trans-[(MCp*)2(μ-CH2)2Cl2] (M = Rh, Ir; Cp* = η5-C5Me5) with Li2S2 afforded the disulfido complexes [(MCp*)2(μ-CH2)2(μ-S2-S:S‘)] which were easily oxidized by O2 to give the oxygenated complexes [(MCp*)2(μ-CH2)2(μ-SSO2-S:S‘)]. Although [(RhCp*)2(μ-CH2)2(μ-S2-S:S‘)] gave a complicated mixture when reacted with CH2Cl2 or CHCl3, [(IrCp*)2(μ-CH2)2(μ-S2-S:S‘)] reacted with both CH2Cl2 and CHCl3 to give the dithioformato complex [(IrCp*)2(μ-CH2)2(μ-S2CH-S:S‘)]Cl and the cyclotetrasulfido complex [{(IrCp*)2(μ-CH2)2}2(μ-S4-S:S‘:S‘‘:S‘‘‘)]Cl2. The oxygenated complexes [(RhCp*)2(μ-CH2)2(μ-SSO2-S:S‘)] reacted with hydrocarbyl halides to afford bridging hydrocarbyl thiolato complexes accompanied by the generation of SO2 gas. These complexes have been characterized by NMR spectroscopy, ESI-MS, and X-ray diffraction.