Wen Congtao, Shi Yulong, Lu Yunxiang, Xu Zhijian, Liu Honglai
State Key Laboratory of Chemical Engineering and School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China.
Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
J Phys Chem A. 2021 Oct 7;125(39):8572-8580. doi: 10.1021/acs.jpca.1c05439. Epub 2021 Sep 24.
Specific 2Ch-2N square interactions between pairs of heterocyclic rings have been the target of many recent crystallographic and computational studies. According to our search of the Cambridge Structural Database (CSD), a number of crystal structures of the derivatives of 1,2,3,5-dichalcogenadiazolyl (DChDA) radicals, which consist of 2Ch-2N square motifs in the dimer units, were extracted. On the basis of the CSD survey results, a set of dimeric complexes of DChDA-based radicals with diverse aryl substituents at the 4-position were selected to model such squares. Similar to that in conventional chalcogen bonds, 2Ch-2N square interactions become stronger as the atomic size of chalcogens increases. Both the orbital term and electrostatics contribute significantly to the attraction of these interactions, while the dispersion contribution is small but unneglectable. Some five-membered aryl substituents, such as imidazole, thiazole, and oxazole, produce markedly enhanced square interactions, leading to a pronounced influence on the distribution of spin populations on DChDA rings.
杂环对之间特定的2Ch-2N方形相互作用一直是近期许多晶体学和计算研究的目标。根据我们对剑桥结构数据库（CSD）的检索，提取了一些1,2,3,5-二硫属元素二氮唑基（DChDA）自由基衍生物的晶体结构，其在二聚体单元中由2Ch-2N方形基序组成。基于CSD的调查结果，选择了一组在4-位具有不同芳基取代基的基于DChDA的自由基二聚体配合物来模拟此类方形结构。与传统硫属元素键类似，随着硫属元素原子尺寸的增加，2Ch-2N方形相互作用变得更强。轨道项和静电作用对这些相互作用的吸引力都有显著贡献，而色散作用贡献虽小但不可忽略。一些五元芳基取代基，如咪唑、噻唑和恶唑，会产生明显增强的方形相互作用，从而对DChDA环上自旋布居的分布产生显著影响。
