Artículos de revistas
The role of stereoelectronic interactions in the conformational isomerism of some phosphorus-containing model compounds
Registro en:
Journal Of Physical Organic Chemistry. John Wiley & Sons Ltd, v. 21, n. 6, n. 505, n. 509, 2008.
0894-3230
WOS:000257090800010
10.1002/poc.1372
Autor
Freitas, MP
Rittner, R
Tormena, CF
Abraham, RJ
Institución
Resumen
The rotational isomerism of model phosphorus-containing compounds was evaluated by using theoretical methodologies. The trans rotamer of chloromethylphosphonic acid dichloride (1) was found to be the prevailing form in the gas phase and in non-polar solvents, with an inverse behaviour from chloroform solution. Although the use of direct spin-spin coupling constants (SSCCs) do not apply for the quantitative determination of conformers in 1, due to the small dependence of J with conformation, the observed measurements and calculated individual couplings suggest that the gauche conformer is progressively stabilized with increasing the solvent polarity. In addition, theoretical calculations at the CBS-Q level for the corresponding phosphine of 1 (compound 2) showed the gauche rotamer as the prevailing one in the isolated state. Natural Bond Orbital (NBO) analysis indicated that steric and electrostatic effects rule the rotational isomerism of 1, while the anomeric effect n(P) -> sigma(CCl)* also plays an important role on the conformational equilibrium of 2. Copyright (C) 2008 John Wiley & Sons, Ltd. 21 6 505 509