Sinnwell Michael A, Blad Jared N, Thomas Logan R, MacGillivray Leonard R
Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA.
IUCrJ. 2018 Jun 22;5(Pt 4):491-496. doi: 10.1107/S2052252518007583. eCollection 2018 Jul 1.
Halogen bonds have emerged as noncovalent forces that govern the assembly of molecules in organic solids with a degree of reliability akin to hydrogen bonds. Although the structure-directing roles of halogen bonds are often compared to hydrogen bonds, general knowledge concerning the fundamental structural behavior of halogen bonds has had limited opportunity to develop. Following an investigation of solid-state reactions involving organic syntheses and the development of photoresponsive materials, this work demonstrates the ability of the components of intermolecular N⋯I halogen bonding - a 'workhorse' interaction for the crystal engineer - to support a single-crystal-to-single-crystal [2+2] photodimerization. A comparison is provided of the geometric changes experienced by the halogen-bonded components in the single-crystal reaction to the current crystal landscape of N⋯I halogen bonds, as derived from the Cambridge Structural Database. Specifically, a linear-to-bent type of deformation of the halogen-bonded components was observed, which is expected to support the development of functional halogen-bonded materials containing molecules that can undergo movements in close-packed crystal environments.
卤键已成为一种非共价作用力，它能以类似于氢键的可靠程度控制有机固体中分子的组装。尽管卤键的结构导向作用常与氢键相比较，但关于卤键基本结构行为的一般知识却鲜有机会得到发展。在对涉及有机合成的固态反应以及光响应材料的开发进行研究之后，这项工作证明了分子间N⋯I卤键（晶体工程中的一种“主力”相互作用）的组成部分能够支持单晶到单晶的[2 + 2]光二聚反应。将单晶反应中卤键连接组分经历的几何变化与源自剑桥结构数据库的当前N⋯I卤键晶体格局进行了比较。具体而言，观察到卤键连接组分发生了从线性到弯曲的变形，这有望推动含卤键功能材料的开发，这类材料中的分子能够在紧密堆积的晶体环境中发生移动。
