Metal–metal complexes with iridium–gold, iridium–copper, and rhodium–copper bonds

Abstract

Metal–metal bonded complexes of the type [Cl₂(CO)(PPh₃)₂Ir–AuPPh₃], [Cl₂(CO)M(PPh₃)₂Ir–Cu(PPh₃)], [Cl₂(CO)(PPh₃)₂Rh–Cu(PPh₃)] obtained by reaction of Rh^I and Ir^I carbonyl derivatives of the type [Cl(CO)M(PPh₃)₂] with PPh₃AuCl and PPh₃CuCl in benzene or acetone are reported. Reactions of these complexes in benzene or dichloromethane with (i) Cl₂, HCl, ICl, IBr (X–Y type), (ii) 1,2-bis(diphenylphosphino)ethane, 2,2′-bipyridyl (L–L type), carbon monoxide, and (iii) tetracyanoethylene, p-toluenesulphonyl chloride have been examined. The first type of reactants brings about cleavage of the metal–metal bond leading to the Ir^III and Rh^III derivatives [Cl₂Y(CO)(PPh₃)₂M^III]. The second type leads to reductive elimination resulting in the Ir^I and Rh^I complexes of the type trans-[M^I(PPh₃)₂(CO)Cl]. With the third type of reactant cleavage of the metal–metal bond occurs to give some well known 6-co-ordinate complexes.