Quest: structure and properties of BTF–nitrobenzene cocrystals with different ratios of components

Abstract

Using the methods of quantum chemistry and atom–atom potentials, the structure of benzotrifuroxan (BTF) cocrystals with nitrobenzenes (nitrobenzene, 1,2-, 1,3-, 1,4-dinitrobenzene, 1,3,5-trinitrobenzene, and hexanitrobenzene) with different ratios of components (1 : 1, 1 : 2, 1 : 3 and in reverse order) is modeled. Based on the estimation of the energy of cocrystallization, a prediction was made of the possibility to obtain cocrystals, some of which were obtained and investigated by single-crystal XRD. For the first time, a cocrystal with three BTF molecules and one coformer molecule (1,4-DNB) in a unit cell was obtained. An analysis of the contacts of the crystal packing of the studied cocrystals shows that the polarizing effects of oxygen and nitrogen atoms in the BTF ring, which is a π system with a low electron content, form pseudo-hydrogen bonds and π–π interactions with nitro groups of coformers relatively rich in electrons, which leads to the formation of cocrystals. It was experimentally shown that the formation of cocrystals, in addition to the structural features of nitrobenzenes, is also influenced by thermodynamic factors (the polarity of the solvent and the ratio of the components used for cocrystallization).