Resumo

FORERO, Neftalí; GONZALEZ, Sergio A  e  REYES, Andrés. THEORETICAL STUDY OF THE HYDROGEN ISOTOPE EFFECT ON THE BORANE-CARBONILE ADDUCT. Rev.Colomb.Quim. [online]. 2009, vol.38, n.1, pp.135-141. ISSN 0120-2804.

We have investigated the hydrogen isotope effect on the geometry, the electronic structure and the stability of the borane-carbonile adduct, by using the nuclear-electronic molecular orbital method (NEMO) which has been implemented in the APMO software. We have found that an increase of the mass of the hydrogen isotope reduces the boron-hydrogen and carbon-oxygen bond lengths while increasing the boron-carbon distance. In this study, the stability of the adduct has been analyzed in terms of formation energies and B-C bond distances. We have found that the increase of the isotope mass weakens the B-C bond. We tried to give an explaination to this phenomenon based on Lewis acidity concept but it predicted the wrong results. A reactivity model based on the energy differences of borane LUMO orbitais offered a correct explaination to this effect.

Palavras-chave : hydrogen isotope effect; borane-carbonile adduct; electron donor-aceptor complex; nuclear-electronic molecular orbital method; any particle molecular orbital (APMO); Born-Oppen-heimer approximation (ABO).

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