Duarte Darío J R, Peruchena Nélida M, Alkorta Ibon
†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.
§Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006 Madrid, Spain.
J Phys Chem A. 2015 Apr 23;119(16):3746-52. doi: 10.1021/jp511118s. Epub 2015 Apr 9.
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.
本文开展了一项理论研究，以探究配合物R-X···X-R（其中R = -H、-Cl、-F且X = Cl、Br、I）中异常卤-卤相互作用的本质。采用了AIM、NBO和MEP分析来表征X···X相互作用。异常X···X相互作用的形成导致两个卤原子之间键合区域的电子电荷密度显著增加。这些配合物的几何结构和稳定性主要归因于静电相互作用lump(X1) → hole(X2)和lump(X2) → hole(X1) [或等效地[VS,min(X1) → VS,max(X2)和VS,min(X2) → VS,max(X1)]以及电荷转移LP(X1) → σ*(R-X2)和LP(X2) → σ*(R-X1)。换句话说，这些发现表明，静电相互作用和电荷转移在确定这些配合物的最佳几何结构中起着重要作用，就像在传统卤键中一样，尽管色散项是此处研究的所有配合物（除了一个）中最重要的吸引项。
