Cappelletti David, Bartocci Alessio, Grandinetti Felice, Falcinelli Stefano, Belpassi Leonardo, Tarantelli Francesco, Pirani Fernando
Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia via Elce di Sotto 8, 06123 Perugia (Italy); Istituto di Scienze dell'Atmosfera e del Clima del CNR via P. Gobetti 101, 40129 Bologna (Italy).
Chemistry. 2015 Apr 13;21(16):6234-40. doi: 10.1002/chem.201406103. Epub 2015 Mar 6.
The complexes of helium and neon with gaseous neutral molecules are generally perceived to be van der Waals adducts held together by physical (non-covalent) forces, owing to the combination of size (exchange) repulsion with dispersion/induction attraction. Molecular beam experiments confirm that this is the case for He-CF4 , Ne-CF4 adducts, but revealed that the interaction of He and Ne with CCl4 features an appreciable contribution of chemical components that arise from the anisotropy of the electron density of CCl4 that enhances a charge transfer from Ng (Ng=He, Ne). These findings furnish a novel assay of the bonding capabilities of helium and neon, and invite to revisit the neutral complexes of these elements as systems of chemical relevance. The CCl4 -Ng are also peculiar examples of halogen bonds, a group of interactions of major current concern. Finally, this investigation is a prelude to the development of semi-empirical models for force fields aimed to the unified description of static and dynamical properties of systems of comparable or higher complexity.
氦和氖与气态中性分子形成的配合物通常被认为是通过物理（非共价）力结合在一起的范德华加合物，这是由于尺寸（交换）排斥与色散/诱导吸引的综合作用。分子束实验证实He-CF₄、Ne-CF₄加合物确实如此，但研究表明，He和Ne与CCl₄的相互作用具有明显的化学成分贡献，这是由CCl₄电子密度的各向异性增强了来自Ng（Ng = He、Ne）的电荷转移所致。这些发现为氦和氖的键合能力提供了一种新的分析方法，并促使人们重新审视这些元素的中性配合物，将其视为具有化学相关性的体系。CCl₄-Ng也是当前备受关注的一类相互作用——卤键的特殊例子。最后，这项研究是开发半经验力场模型的前奏，该模型旨在统一描述具有相当复杂性或更高复杂性体系的静态和动态性质。
