Halogen Bonding. A Study based on the Electronic Charge.

MARTINEZ AMEZAGA, NANCY; PAMIES, SILVANA; PERUCHENA, N. M.; SOSA, G. L.

JOURNAL OF PHYSICAL CHEMISTRY A

ACS Publications

Año: 2010 vol. 114 p. 552 - 562

1089-5639

Density Functional Theory (DFT) and Atoms in Molecules Theory (AIM) were used to study thecharacteristic of the non-covalent interactions in complexes formed between Lewis bases (NH3, H2O and H2S) and Lewis acids (ClF, BrF, IF, BrCl, ICl and IBr). In order to compare halogen and hydrogen bonds interactions, this study included hydrogen complexes formed by some Lewis bases and HF, HCl and HBr Lewis acids. Ab initio, wave functions were generated at B3LYP/6−311++G(d,p) level with and HBr Lewis acids. Ab initio, wave functions were generated at B3LYP/6−311++G(d,p) level with and HBr Lewis acids. Ab initio, wave functions were generated at B3LYP/6−311++G(d,p) level with optimized structures at the same level. Criteria based on a topological analysis of the electron density were used in order to characterize the nature of halogen interactions in Lewis complexes. The main purpose of the present work is to provide an answer to the following questions: a) why electronegative atoms such as halogens, can act as bridges between two other electronegative atoms?. Can a study based on the electron charge density answer this question?. Considering this, we had performed a profound study of halogen complexes in the framework of the AIM theory. A good correlation between the density at the intermolecular bond critical point and energy interaction was found. We had also explored the concentration and depletion of the charge density, displayed by the Laplacian topology, in the interaction zone and in the X-Y halogen donor bond. From the atomic properties it was generally observed that the two halogen atoms gain electron population in response to its own intrinsic nature. Due to this fact, both atoms result energetically stabilized.