Pirani Fernando, Cappelletti David, Falcinelli Stefano, Cesario Diego, Nunzi Francesca, Belpassi Leonardo, Tarantelli Francesco
Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, via Elce di Sotto 8, 06213, Perugia, Italy.
Dipartimento di Ingegneria Civile ed Ambientale, Università degli Studi di Perugia, via G. Duranti 93, 06215, Perugia, Italy.
Angew Chem Int Ed Engl. 2019 Mar 22;58(13):4195-4199. doi: 10.1002/anie.201812889. Epub 2019 Feb 20.
Molecular-beam scattering experiments and theoretical calculations prove the nature, strength, and selectivity of the halogen bonds (XB) in the interaction of halogen molecules with the series of noble gas (Ng) atoms. The XB, accompanied by charge transfer from the Ng to the halogen, is shown to take place in, and measurably stabilize, the collinear conformation of the adducts, which thus becomes (in contrast to what happens for other Ng-molecule systems) approximately as bound as the T-shaped form. It is also shown how and why XB is inhibited when the halogen molecule is in the Π excited state. A general potential formulation fitting the experimental observables, based on few physically essential parameters, is proposed to describe the interaction accurately and is validated by ab initio computations.
分子束散射实验和理论计算证明了卤素分子与一系列稀有气体（Ng）原子相互作用中卤键（XB）的性质、强度和选择性。结果表明，伴随着电荷从Ng转移到卤素的XB发生在加合物的共线构象中，并使其可测量地稳定，因此（与其他Ng-分子体系的情况相反）共线构象变得与T形构象一样稳定。研究还表明了当卤素分子处于Π激发态时XB被抑制的方式和原因。基于少数几个物理基本参数，提出了一种拟合实验观测值的通用势能公式，以准确描述这种相互作用，并通过从头计算进行了验证。
