THEORETICAL-STUDIES OF BORYLPHOSPHINE AND ITS CONJUGATE BASE .2. INTERNAL-ROTATION AND INVERSION TRANSITION-STATES

The rotational transition states of BH2PH2 and BH2PH- have been investigated by the methods of ab initio molecular electronic structure theory using basis sets of high quality, and we have characterized them with respect to their molecular geometries, energies, dipole moments, normal vibrational modes, and harmonic vibrational frequencies. The BH2PH2 molecule has two rotational transition states, one of C(s) symmetry at 10.0 kcal/mol and one of C(2-upsilon) symmetry at 46.4 kcal/mol above the nonplanar ground state. The BH2PH- anion has a rotational transition state of C(s) symmetry that is 33.5 kcal/mol higher in energy than the planar ground state and an inversion transition state of C(2-upsilon) symmetry at 53.5 kcal/mol. Results for these molecules are compared with experimental data for derivatives of BH2PH2 and BH2PH- and with the BH2NH2 molecule.