engleski

One-pot three-component mechanosynthesis of imine cocrystals with halogen bond donors

A century long interest in o-hydroxy imines can be attributed to their photo- and/or thermochromic properties in the solid state which can be tuned by means of cocrystallization. Herein we report one-pot mechanosynthesis which combines the formation of covalent bonds and halogen bonds to obtain imine cocrystals with halogen bond donors. In order to explore the potential of pyridyl fragments as halogen bond acceptor species in comparison/competition with hydroxy and methoxy groups we used imines derived from o-vanillin (ov) and aminopyridines (3amp and 4amp) and as halogen bond donors we selected commonly used perfluorinated compounds: 1, 2-, 1, 3- and 1, 4- diiodotetrafluorobenzene (12tfib, 13tfib and 14tfib) as well as 1, 3, 5- triiodotrifluorobenzene (135titfb). We obtained eight cocrystals by one-pot grinding of a mixture of ov, aminopyridine and halogen bond donors in 1:1:1 or 2:2:1 molar ratios. To observe mechanosynthesis, as well as to facilitate the characterization of the new cocrystal by single-crystal X-ray diffraction, mechanochemical experiments were accompanied by crystallization. All reactants and products were characterized by means of powder X-ray diffraction. In all obtained cocrystals the molecules are connected by means of I···N halogen bonds between halogen bond donor iodine atoms and pyridine nitrogen atoms.

One-pot mechanosynthesis, halogen bond, o-hydroxy imine, cocrystal

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