Cocrystallization of a Tripyridyl Donor with Perfluorinated Iodobenzene Derivatives: Formation of Different N···I Halogen Bonds Determining Network vs Plain Packing Crystals

Two cocrystals (4, 5) have been obtained with 1,3,5-tris[4-pyridyl(ethenyl)]benzene (1), sym-triiodo-trifluorobenzene (2), and diiodo-tetrafluorobenzene (3), respectively. Cocrystal 4 contains both compounds 1 and 2 in a molecular ratio of 1:2, whereas cocrystal 5 contains both compounds 1 and 3 in a molecular ratio of 1:0.5 and the solvent used for crystallization, namely, chloroform. Both cocrystals (4, 5) contain N···I halogen bonds with distances of ∼80% of the sum of the van der Waals radii. Compound 1 forms four halogen bonding interactions in cocrystal 4, resulting in an infinite halogen-bonded network with two types of N···I halogen bonds, whereas in cocrystal 5, compound 1 forms only one type of halogen bonding interaction with compound 3.

本研究成功制备得到两种共晶（cocrystal）4与5：共晶4由1,3,5-三[4-吡啶基(乙烯基)]苯（1）与对称三碘三氟苯（2）制备得到，共晶5由1,3,5-三[4-吡啶基(乙烯基)]苯（1）与二碘四氟苯（3）制备得到。共晶4中化合物1与化合物2的摩尔比为1:2；共晶5中化合物1与化合物3的摩尔比为1:0.5，且结晶所用溶剂为氯仿（chloroform）。两种共晶4和5均存在N···I卤键（halogen bond），其键长约为范德华半径（van der Waals radii）之和的80%。在共晶4中，化合物1形成四个卤键相互作用，由此构建出包含两种N···I卤键的无限卤键网络；而在共晶5中，化合物1仅与化合物3形成一种卤键相互作用。