Isostructurality, Polymorphism and Mechanical Properties of Some Hexahalogenated Benzenes: The Nature of Halogen⋅⋅⋅Halogen Interactions
作者:C. Malla Reddy、Michael T. Kirchner、Ravi C. Gundakaram、K. Anantha Padmanabhan、Gautam R. Desiraju
DOI:10.1002/chem.200500983
日期:2006.3.1
both the monoclinic and triclinic structures, and the reasons for polymorphism are suggested. To summarise, both chemical and geometrical models need to be considered for X...X interactions in hexahalogenated benzenes. The X...X interactions in the monoclinic group are nonspecific, whereas in the triclinic group some X...X interactions are anisotropic, chemically specific and crystal-structure directing
卤素原子X ... X(X = Cl,Br,I)之间的分子间相互作用的性质继续引起人们的关注,因为这些相互作用可以用作晶体工程中的设计元素。六卤代苯(C6Cl(6-n)Br(n),C6Cl(6-n)I(n),C6Br(6-n)I(n))结晶成两种主要堆积模式,这些模式采用单斜空间群P2 (1)/ n和三斜线空间群P1。与C6Cl6同构的前者更为常见。对于缺乏反演对称性的分子,采用这种单斜晶结构必然会导致晶体学紊乱。在C6Cl6中,平面分子形成Cl ... Cl接触以及pi ... pi堆积相互作用。当C6Cl6晶体沿其针长机械压缩时,即[010],会发生弯曲变形,因为在堆叠方向上的相互作用更强。进一步的压缩以类似于蛇的运动连续传播通过晶体,这与位错运动中所建议的相似。与更强的pi ... pi堆积相互作用相比,C6Cl6晶体的弯曲与Cl ... Cl相互作用的弱点有关。三斜堆积不太普遍,并且限于具有对称的(1