Photodissociation Dynamics of Gaseous CpCo(CO)2 and Ligand Exchange Reactions of CpCoH2 with C3H4, C3H6, and NH3

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2012-05, Vol.116 (21), p.5039-5044
• Main Authors: Oana, Melania, Nakatsuka, Yumiko, Albert, Daniel R, Davis, H. Floyd
• Format: Article
• Language: English
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp3018919

The photodissociation dynamics of CpCo(CO)2 was studied in a molecular beam using photofragment translational energy spectroscopy with 157 nm photoionization detection of the metallic products. At 532 and 355 nm excitation, the dominant one-photon channel involved loss of a single CO ligand producing CpCoCO. The product angular distributions were isotropic, and a large fraction of excess energy appeared as product vibrational excitation. Production of CpCO + 2CO resulted from two-photon absorption processes. The two-photon dissociation of mixtures containing CpCo(CO)2 and H2 at the orifice of a pulsed nozzle was used to produce a novel 16-electron unsaturated species, CpCoH2. Transition metal ligand exchange reactions, CpCoH2 + L → CpCoL + H2 (L = propyne, propene, or ammonia), were studied under single-collision conditions for the first time. In all cases, ligand exchange occurred via 18-electron association complexes with lifetimes comparable to their rotational periods. Although ligand exchange reactions were not detected from CpCoH2 collisions with methane or propane (L = CH4 or C3H8), a molecular beam containing CpCoCH4 was produced by photolysis of mixtures containing CpCo(CO)2 and CH4.