Increasing the Reactivity of Vaska’s Compound. Oxidative Addition of Chlorobenzene at Ambient Temperature

Silylium ion-like reagents, R3Siδ+(carboraneδ−), are successful where silver salts fail in abstracting chloride ion from IrCl(CO)(PPh3)2 in arene solvents. Replacement of chloride by a very weakly coordinating carborane anion such as CHB11H5Cl6− promotes unusually facile oxidative addition of chlorobenzene, giving the coordinatively unsaturated IrCl(CO)(C6H5)(PPh3)2]+ cation. Other arene solvents promote disproportionation with loss of a phosphine ligand to give labile Ir(I) cations of the type [Ir(arene)(CO)(PPh3)]+, having three latent vacant coordination sites.