A large structural polarization by intermolecular forces: Ab initio theoretical investigation of the H3N···H2CN and H3N···B(CN)3 interactions

✍ Scribed by Anna Jagielska; Robert Moszynski; Lucjan Piela

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 214 KB
• Volume: 75
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1999)75:3<177::aid-qua7>3.0.co;2-g

✦ Synopsis

The structure, binding energies, harmonic vibrational frequencies, and nuclear quadrupole coupling constants of the cyanodihydroborate and boron tricyanide Ž . known compounds, but no structural experimental data available complexes with ammonia were calculated using the Møller᎐Plesset perturbation theory through the fourth order and by the coupled-cluster method including single, double, and approximate triple excitations. The origins of the bonding in these complexes were investigated by symmetry-adapted perturbation theory. The computed complex dissociation energies corrected for the basis-set superposition error are large: 27 and 36 kcalrmol, respectively. A peculiar change of the character of the HOMO orbital is taking Ž . place when the molecules approach each other. In both complexes, a large umbrellalike structural change of the boron moiety occurs due to the interaction with the virtually unchanged ammonia molecule and the accompanying large change of the dipole moment is taking place.