engleski

Cocrystalization of halogenide salts of organic bases with 1, 4-diiodotetrafluorobenzene

Halogen bond is intermolecular short-range interaction that plays a significant role in crystal packing and is therefore of great importance to crystal engineering. Interaction is achieved between a molecule with a partially positively charged halogen atom connected to an electron- withdrawing group (halogen bond donor) and a Lewis base (halogen bond acceptor). With regard to the wide spectrum of organic bases studied to date, halogenide ions are poorly investigated halogen bond acceptors.[1], [2] In this study, with the aim of studying the halogen bonded motifs with halide ions, we attempted to prepare a series of cocrystals of 1, 4- diiodotetrafluorobenzene (1, 4-tfib) with halogenides of several nitrogen bases. Halogenide salts were prepared by addition of hydrohalic acids in ethanol solution of a nitrogen base, whereupon precipitation of the product immediately started. Cocrystals were obtained by dissloving corresponding salt and 1, 4-tfib in ethanol. A number of crystallization experiments yielded crystals of sufficient quality for diffraction experiments and molecular and crystal structures of cocrystals have been determined. In prepared compounds, 1, 4-tfib and halogenide ions were linked in zig-zag chains with C–I⋯X− halogen bonds, while organic cations were hydrogen bonded to the halogenide ions through N–H⋯X− hydrogen bonds. It is interesting to note that in the case of 2, 4, 6- trimethylpyridinium bromide there was one hydrogen bond of type N–H⋯Br− for every bromide and organic cation, whereas in the case of iodide of the aforementioned cation, the N–H⋯I− hydrogen bonds were bifurcated, interconnecting pairs of iodides belonging to adjacent zig-zag chains.

cocrystalization, halogenide salts, 1, 4- diiodotetrafluorobenzene, halogen bonding

nije evidentirano