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.