Use of quantum chemical methods to study concomitant polymorphs of a new benzimidazole-1,2,3-triazole hybrid compound

Abstract

A novel benzimidazole-1,2,3-triazole hybrid molecule, 4-(1H-benzo[d]imidazol-2-yl)-1-(2-methoxyphenyl)-1H-1,2,3-triazol-5-amine, was synthesized. Two concomitant polymorphs of the title compound were crystallized from the same solution simultaneously. Various quantum chemical methods were used to explain the formation of these polymorphic structures and predict their stability to external influence. Studying the possibility of changing the conformation by rotating aromatic rings around single bonds using the m06-2x/cc-pVTZ method and analyzing the molecular structure of the compound in the obtained crystal forms showed that the studied polymorphs differ in the conformation of the molecules. Both polymorphic structures have close lattice energies calculated in a plane wave approximation and energetic structures constructed using pairwise interaction energies. Two polymorphic forms can be classified as a columnar-layered packing of the dimeric building units. Quantum chemical modeling of the displacement of layers relative to each other allows us to state that both concomitant polymorphs are resistant to external mechanical influence. Thus, it can be assumed that the studied concomitant polymorphs were formed not due to kinetic and thermodynamic factors affecting the crystallization process, but due to the ability of two conformers with close energies to form crystals very similar in structure.