Acid-base bifunction and umpolung of the bridging hydride in a coordinatively unsaturated mesylimido- and hydrido-bridged diiridium complex

The mono(mesylamido)-bridged diiridium(III) complex [(CP*IrCl)(2)(mu(2)-H)(mu(2)-NHMS)] (CP* = eta(5)-C-5(CH3)(5), MS = SO2CH3) undergoes reversible dehydrochlorination to afford the unsaturated imido-bridged dinuclear complex [Cp*Ir(mu H2-)(mu(2)-NMs)IrClCP*] (2) The reaction of 2 with trimethylphosphine gives the simple adduct [Cp*Ir[P(CH3)(3)}(mu(2)-H)(mu(2)-NMs)IrClCp*], while the reaction with CO results in sequential formation of the mono- and dicarbonyl Ir(II) complexs [Cp*Ir(CO)(mu(2)-NHMs)IrClCp*] and [{Cp*Ir(CO)}(2)(mu(2)-NMs)] and with concomitant umpolung of the bridging hydrido ligand in 2 to the amido proton.