title: Double Hole-Lump Interaction between Halogen Atoms.
abstract: In this paper a theoretical study has been carried out to investigate the nature of the unusual halogen-halogen contacts in the complexes R-X···X-R (with R = -H, -Cl, -F and X = Cl, Br, I). AIM, NBO, and MEP analyses have been used to characterize X···X interactions. Formation of the unusual X···X interactions leads to a significant increase of electron charge density in the bonding region between the two halogen atoms. The geometry and stability of these complexes is mainly due to electrostatic interactions lump(X1) → hole(X2) and lump(X2) → hole(X1) [or equivalently [VS,min(X1) → VS,max(X2) and VS,min(X2) → VS,max(X1)] and the charge transfers LP(X1) → σ*(R-X2) and LP(X2) → σ*(R-X1). In other words, these findings suggest that the electrostatic interactions and the charge transfer play a substantial role in determining the optimal geometry of these complexes, as in conventional halogen bonds, even though the dispersion term is the most important attractive term for all the complexes studied here, save one.
authors.affiliation: †Laboratorio de Estructura Molecular y Propiedades, Área de Química Física-Departamento de Química, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad 5460, 3400 Corrientes, Argentina.
authors.forename: Darío J R
authors.initials: DJ
authors.lastname: Duarte
authors.affiliation: †Laboratorio de Estructura Molecular y Propiedades, Área de Química Física-Departamento de Química, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad 5460, 3400 Corrientes, Argentina.
authors.forename: Nélida M
authors.initials: NM
authors.lastname: Peruchena
authors.affiliation: §Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006 Madrid, Spain.
authors.forename: Ibon
authors.initials: I
authors.lastname: Alkorta
mesh_terms: D006219:Halogens / Q000737:chemistry*; D011789:Quantum Theory; D055672:Static Electricity
chemical_list: D006219:Halogens