Ion Beam Studies of the Reactions of Atomic Cobalt Ions with Alkanes: Determination of Metal-Hydrogen and Metal-Carbon Bond Energies and an Examination of the Mechanism by which Transition Metals Cleave Carbon-Carbon Bonds

Article abstract of DOI:10.1021/ja00394a010

An ion beam apparatus is employed to study the reactions of singly charged cobalt positive ions with hydrogen and 17 alkanes.Reaction cross sections and product distributions as a function of kinetic energy are determined.Exothermic carbon-carbon bond cleavage reactions are observed for all alkanes but methane and ethane.A mechanism involving oxidative addition of C-C and C-H bonds to cobalt as a first step is demonstrated to account for all major reactions at all energies.Interpretation of several endothermic processes allows the extraction of thermochemical data.The bond dissociation energies obtained are D^o(Co⁺-H)=52+/-4 kcal/mol, D^o(Co-H)=39+/-6 kcal/mol, D^o(Co⁺-CH3)=61+/-4 kcal/mol, and D^o(Co-CH3)=41+/-10 kcal/mol.