Theoretical Survey of the Gas-Phase Reactions of Allylamine with Co<sup>+</sup>

Density functional theory calculations have been carried out to survey the gas-phase reactions of allylamine with Co<sup>+</sup>. The geometries and bonding characteristics of all the stationary points involved in the reactions have been investigated at the B3LYP/6-311++G(d,p) level. Final energies are obtained by means of the B3LYP/6-311+G(2df,2pd) single-point calculations. The performance of these theoretical methods is valuated with respect to the available thermochemical data. Co<sup>+</sup> strongly binds allylamine by forming a chelated structure in which the metal cation binds concomitantly to the two functional groups of the neutral molecule. Various mechanisms leading to the loss of NH<sub>3</sub>, NH<sub>2</sub>, C<sub>2</sub>H<sub>2</sub>, and H<sub>2</sub> are analyzed in terms of the topology of the potential energy surface. The most favorable mechanism corresponds to the loss of NH<sub>3</sub>, through a process of C−N activation followed by a concerted β-H shift. The accompanying NH<sub>2</sub> elimination is also discussed. The loss of C<sub>2</sub>H<sub>2</sub> is also favorable, through C−C activation and stepwise β-H shift, giving Co<sup>+</sup>(NH<sub>2</sub>CH<sub>3</sub>) and Co<sup>+</sup>H(NH<sub>2</sub>CH<sub>2</sub>) as the product ions. Various possible channels for the loss of H<sub>2</sub> are considered. The most favorable mechanism of the H<sub>2</sub> loss corresponds to a pathway through which the metal acts as a carrier, connecting a hydrogen atom from the methylidyne group of allylamine with a hydrogen atom of the terminal methylene group. The product ion of this pathway has a tricoordinated structure in which Co<sup>+</sup> binds to the terminal two Cs and N atoms of the NH<sub>2</sub>CH<sub>2</sub>CCH moiety.