Photoelectron spectroscopy of CoC2H2(-) and density functional study of Co(n)C2H2 (n = 1-3) anion and neutral clusters.

The anionic and neutral ConC2H2 (n = 1-3) clusters were investigated using anion photoelectron spectroscopy and density functional calculations. The adiabatic detachment energies and vertical detachment energies of ConC2H2(-) (n = 1-3) were determined. Our results show that the most stable geometries of anionic ConC2H2(-) (n = 1-2) and neutral ConC2H2 (n = 1-3) are composed of ConC2H clusters adsorbing a hydrogen atom on the top or bridge sites of Con, whereas Co3C2H2(-) consists of a five-member ring of Co3C2 carbide adsorbing two hydrogen atoms on two bridge sites of Co3. The reaction mechanisms show that the inserted isomer HCoC2H can convert into the vinylidene complex Co═C═CH2 via a side-on isomer M-η(2)-(C2H2).