The tailoring of crystal structures via the self-assembly of organic coordination compounds by N⋯I non-covalent halogen bonds: co-crystals of sterically hindered N-heterocycles and 1,4-diiodo-tetrafluorobenzene

摘要: The N-containing heteroaromatics 2,3,5,6-tetramethylpyrazine (tmpyr), 2,2′-bipyridine (2,2′-bpy), 2,4′-bipyridine (2,4′-bpy) and o-phenanthroline (phen) were each cocrystallized with 1,4-diiodo-tetrafluoro-benzene (TFDIB). effect of the sterically constrained aza cycles on supramolecular assembly crystal structure determining interactions is discussed. N⋯I non-covalent halogen bonds are main directing responsible for observed structures. Nevertheless, steric hindrance donor sites increases impact weaker intermolecular such as CH⋯F bonding π–π provoking changes in coordination behaviour modules. In spite constraints, co-crystals tmpyr·TFDIB (1) 2,2′-bpy·TFDIB (2) exhibit polymeric structures consisting infinite one-dimensional chains alternating electron donors (D) acceptors (A). contrast, cocrystals 2,4′-bpy·TFDIB (3) phen·TFDIB (4) reveal a packing termolecular [A1D2] complexes. It follows that type bonded assemblies can be tuned by choosing appropriate precursors.