Reuter Hans
Chemistry, Department of Biology/Chemistry, Osnabrück University, Barbarastr. 7, D 49069 Osnabrück, Germany.
Molecules. 2025 Jun 23;30(13):2700. doi: 10.3390/molecules30132700.
As part of a systematic study on the structures of the mixed halide isothiocyanates, SnHal(NCS), their single crystals were grown and structurally characterized. For Hal = F (), the SnClF structure type was confirmed, while with Hal = Cl (), Br (), and I (), there are three isostructural compounds of a new structure type, and for Hal = Cl (), there is a second modification of a third structure type. These structure types have been described with respect to the composition and coordination geometry of the first, second, and van der Waals crust coordination spheres and their dependence on the halogen size and thiocyanate binding modes. With respect to the first coordination spheres, all three structure types constitute one-dimensional coordination polymers. In , "ladder"-type double chains result from μ-bridging fluorine atoms, and in -, single-chains built up from μ-halogen atoms are pairwise "zipper"-like interconnected via -bridging NCS ligands, which manage the halogen-linked chain assembly in the double chains of . Based on the octet rule, short atom distances are interpreted in terms of 2c-2e and various (symmetrical, quasi-symmetrical, and asymmetrical) kinds of 3c-4e bonds. Weak contacts, the topology of which suggests the extension of the latter bonding concept, are identified as electron-deficient, bifurcated tetrel bonds.
作为对混合卤化物异硫氰酸酯SnHal(NCS)结构进行系统研究的一部分，我们生长了它们的单晶并进行了结构表征。对于Hal = F ()，确认了SnClF结构类型，而当Hal = Cl ()、Br ()和I ()时，存在三种新结构类型的同构化合物，对于Hal = Cl ()，存在第三种结构类型的第二种变体。这些结构类型已根据第一、第二和范德华外层配位球的组成和配位几何及其对卤素大小和硫氰酸酯结合模式的依赖性进行了描述。关于第一配位球，所有三种结构类型都构成一维配位聚合物。在 中，“梯子”型双链由μ-桥连氟原子形成，而在 - 中，由μ-卤素原子构成的单链通过 - 桥连NCS配体成对“拉链”状互连，这在 的双链中管理卤素连接的链组装。基于八隅体规则，短原子距离根据2c-2e和各种（对称、准对称和不对称）类型的3c-4e键来解释。其拓扑结构表明后一种键合概念扩展的弱接触被确定为缺电子的、分叉的四元键。
