Oxidative addition of water to novel Ir(I) complexes stabilized by dimethyl sulfoxide ligands.

The oxidative addition of water to novel Ir(I) DMSO complexes is described. IrCl(DMSO)3 (1) is synthesized in 90% yield when treating a toluene slurry of [Ir2Cl2(COE)4] (COE = cyclooctene) with excess DMSO. Its dimer, [Ir2Cl2(DMSO)4] (2) is obtained in 95% yield starting from 1. The cationic complex [Ir(DMSO)4]PF6 (6) is prepared in situ from [Ir(COE)2(O=CMe2)2]PF6 (5). These complexes add water at room temperature, giving rise to the oxidative addition products syn-[(DMSO)2HIr(mu-OH)2(mu-Cl)IrH(DMSO)2] [IrCl2(DMSO)2] (3) and anti-[(DMSO)2(DMSO)HIr(mu-OH)2IrH(DMSO)2(DMSO)](PF6)2 (7), respectively. Reductive elimination in pyridine leads to quantitative isolation of mixed Ir(I) DMSO-pyridine complexes IrCl(py)(DMSO)2 (4) and [Ir(py)2(DMSO)2]PF6 (8), respectively. Compounds 1, 3, and 7 have been characterized by X-ray crystallography. 3 and 7 show dimeric structures with the hydroxo ligands bridging the iridium atoms and in 7 both O- and S-bonded DMSO ligands are present.