Novel nucleophilic reactivity of disulfido ligands coordinated parallel to M-M (M = Rh, Ir) bonds

Reaction of trans-[(MCp*)(2)(mu-CH2)(2)Cl-2] (M = Rh, Ir; Cp* = eta(5)-C5Me5) with Li2S2 afforded the disulfido complexes [(MCp*)(2)(mu-CH2)(2)(mu-S-2-S:S')] which were easily oxidized by 02 to give the oxygenated complexes [(MCP*)(2)(mu-CH2)(2)(mu-SSO2-S:S')]. Although [(RhCP*)(2)(mu-CH2)(2)(mu-S-2-S:S')] gave a complicated mixture when reacted with CH2Cl2 or CHCl3, [(IrCP*)(2)(mu-CH2)(2)(mu-S-2-S:S')] reacted with both CH2Cl2 and CHCl3 to give the dithioformato complex [(IrCP*)(2)(mu-CH2)(2)(mu-S2CH-S:S')]Cl and the cyclotetrasulfido complex [{(IrCp*)(2)(mu-CH2)(2)}(2)(mu-S-4-S:S':S":S'")]Cl-2. The oxygenated complexes [(RhCP*)(2)(mu-CH2)(2)(mu-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.