A DFT and ab initio direct dynamics study on the hydrogen abstract reaction of H3BNH3 → H2 + H2BNH2

A direct ab initio dynamics study is presented on the hydrogen abstraction reaction of H3BNH3 → H2 + H2BNH2. The geometries of all the stationary points are optimized at the B3LYP and MP2 levels of theory with a series of basis sets up to aug-cc-pVTZ. The energies are refined using the G3, G3MP2, G3MP2B3, CBS-Q, CBS-Q//B3, and a combined high-level (HL) method based on the geometries optimized using the B3LYP/aug-cc-pVTZ level of theory. The rate constants are evaluated using the conventional transition-state theory and canonical variational transition-state theory (CVT). The fitted Arrhenius expression calculated from the CVT/SCT method is k ( T ) = 6.86 × 10 6 × T 1.69 × e ( - 1.37 × 10 4 / T ) s - 1 . The estimated apparent activation energy is in accordance with experimental results.