Synthesis and characterization of new pentamethylcyclopentadienyl iridium hydride complexes

Pentamethylcyclopentadienyl iridium dihydride complexes [Cp*Ir(H)2(PR3)]; (PR3 = PPh2Me, PTA) were prepared by reaction of [Cp*IrCl2(PPh2Me)] and [Cp*IrCl2(PTA)], respectively, with an excess of sodium bis(2-methoxyethoxy)aluminium hydride (Red-Al). Protonation of the dihydride [Cp*Ir(H)2(PPh2Me)] with HBF4·Et2O at low temperature gave the classical trihydride complex [Cp*Ir(H)3(PPh2Me)]BF4 that displays quantum mechanical exchange coupling. Reaction of [Cp*IrCl2(PPh2Me)] with CO gave the half-sandwich iridium carbonyl compound [Cp*IrCl(CO)(PPh2Me)]Cl which, by reaction with NaBPh4, yielded yellow microcrystals of [Cp*IrCl(PPh2Me)(CO)]BPh4 adequate for X-ray diffraction analysis.