A theoretical study: Structures and stabilities of alternant BN open-chain compounds of B3N3H8 rotamers

We report ab initio HF, density functional theory (DFT) B3LYP and MP2 electronic structure calculations on the alternant boron nitrogen open-chain compounds of H2BNHBHNHBHNH2 rotamers. Structures and energies of the rotamers are calculated at the HF/cc-pVDZ, B3LYP/cc-pVDZ and MP2/cc-pVDZ levels of theory. The harmonic vibrational frequencies and their infrared intensities are predicted with B3LYP/cc-pVDZ methods. In order to obtain reliable energies, single-point energy calculations are carried out at the CCSD (T)/cc-pVDZ level of theory based on the B3LYP/cc-pVDZ results. The relative stability of the rotamers are analyzed. The analyses of Milliken population, π-molecular orbital components and orbital energy levels were used to evaluate the relative stabilities of these rotamers.