Iridium Dimer Anion-Mediated C C Triple Bond Cleavage and Successive Dehydrogenation of Acetylene in the Gas Phase

The reactions of the iridium dimer anion [Ir-2](-) with acetylene have been studied by mass spectrometry in the gas phase, which indicate that the [Ir-2](-) anion can consecutively react with C2H2 molecules to form the [Ir2C2x](-) (x = 1, 2) and [Ir2C2yH2](-) (y = 3-5) anions as major products with the successive release of H-2 molecules at room temperature. The reactions are confirmed by the reactions of the mass-selected product [Ir2C2](-) anion with C2H2 to produce [Ir2C4](-) and [Ir2C2yH2](-) (y = 3-5). Photoelectron spectra and quantum chemistry calculations confirm that the [Ir2C2x](-) (x = 1, 2) product anions possess cyclic [Ir(mu-C)(2)Ir](-) and [Ir(mu-C)(mu-C-3)Ir](-) structures, implying that the robust C C triple bond of acetylene can be completely cleaved by the [Ir-2](-) anion.