Rhodium(I) carbonyl complexes of triphenylphosphine chalcogenides and their catalytic activity

Rhodium(I) carbonyl complexes [Rh(CO)2ClL] where L = Ph3PO, Ph3PS and Ph3PSe, were synthesized and characterized by elemental analysis, i.r. and by 1H-, 13C- and 31P-n.m.r. spectroscopy. The vBD;(CO) band frequencies in the complexes follow the order: Ph3PO > Ph3PS > Ph3PSe, in keeping with the hard/soft nature of the interactions. The complexes undergo oxidative additions with electrophiles such as MeI, PhCH2Cl and I2 to give, e.g. [Rh(CO)(COMe)ClIL] which react with PPh3 to give trans-[Rh(CO)Cl(PPh3)2]. The catalytic activity of the [Rh(CO)2ClL] complexes in carbonylation of MeOH is higher than that of the well-known [Rh(CO)2I2]− species.