Toward an Alkene Hydroamination Catalyst:  Static and Dynamic ab Initio DFT Studies

The catalytic hydroamination of alkenes via alkene activation and subsequent nucleophilic attack has been investigated with Car−Parrinello ab initio molecular-dynamics calculations using the projector-augmented wave method. The complete cycle including all intermediates and transition states was studied with d8 transition-metal complexes of the type {MCl(PH3)2}z+ (M = Co, Rh, Ir [z = 0] and Ni, Pd, Pt [z = 1]) as catalysts, comparing the different metals for their suitability. For group 9, nucleophilic attack was identified as the rate-determining step, while the cleavage of the M−C bond is rate-determining for group 10. Overall, group 10 is more favorable than group 9. In particular, nickel complexes were found to be the best-suited potential catalysts with an activation barrier for the rate-determining step of 108 kJ mol-1. β-Hydride elimination as a competing side reaction was found to be kinetically competitive, but thermodynamically disfavored.