Department of Chemistry and Biochemistry, Utah State University, Logan, UT, 84322-0300, USA.
Chemistry. 2018 Jun 7;24(32):8167-8177. doi: 10.1002/chem.201800511. Epub 2018 May 9.
The additional substituents arising from hypervalency present a number of complicating issues for the formation of noncovalent bonds. The XF molecule (X=Cl, Br, I) was allowed to form a halogen bond with NH as the base. Hypervalent chalcogen bonding is examined by way of YF and YF (Y=S, Se, Te), and ZF (Z=P, As, Sb) is used to model pnicogen bonding. Pnicogen bonds are particularly strong, with interaction energies approaching 50 kcal mol , and also involve wholesale rearrangement from trigonal bipyramidal in the monomer to square pyramidal in the complex, subject to a large deformation energy. YF chalcogen bonding is also strong, and like pnicogen bonding, is enhanced by a heavier central atom. XF halogen bond energies are roughly 9 kcal mol , and display a unique sensitivity to the identity of the X atom. The crowded octahedral structure of YF permits only very weak interactions. As the F atoms of SeF are replaced progressively by H, a chalcogen bond appears in combination with SeH⋅⋅⋅N and NH⋅⋅⋅F H-bonds. The strongest such chalcogen bond appears in SeF H ⋅⋅⋅NH , with a binding energy of 7 kcal mol , wherein the base is located in the H face of the Lewis acid. Results are discussed in the context of the way in which the positions and intensities of σ-holes are influenced by the locations of substituents and lone electron pairs.
多中心键合所产生的额外取代基给非共价键的形成带来了一些复杂的问题。XF 分子（X=Cl、Br、I）被允许与 NH 形成卤素键作为碱基。通过 YF 和 YF（Y=S、Se、Te）来研究高键合的硫属元素键合，并用 ZF（Z=P、As、Sb）来模拟磷属元素键合。磷属元素键合特别强，相互作用能接近 50 kcal/mol，并且还涉及单体中的三角双锥到复合物中的四方锥的整体重排，这受到大变形能的影响。YF 硫属元素键合也很强，并且与磷属元素键合一样，受中心原子重量的影响较大。XF 卤素键能约为 9 kcal/mol，并且对 X 原子的特性具有独特的敏感性。YF 的拥挤八面体结构只允许非常弱的相互作用。随着 SeF 的 F 原子被 H 逐步取代，硫属元素键与 SeH⋅⋅⋅N 和 NH⋅⋅⋅F H 键结合出现。最强的硫属元素键出现在 SeF H ⋅⋅⋅NH 中，结合能为 7 kcal/mol，其中碱基位于路易斯酸的 H 面上。结果根据 σ 空穴的位置和强度受取代基和孤对电子位置的影响进行了讨论。
