Syntheses, crystal structures and intermolecular interactions of six novel pyrimidin-2-yl-substituted triaryltriazoles

Abstract

Six new pyrimidin-2-yl-substituted triaryltriazoles, namely, 4-(4-R-phenyl)-3-(pyridin-2-yl)-5-(pyrimidin-2-yl)-1,2,4-triazoles [L1 : R = methoxy (OCH3); L2 : R = methyl (CH3); L3 : R = nil (H); L4 : R = bromo (Br); L5 : R = chloro (Cl); L6 : R = fluoro (F)] have been successfully synthesized with yields in the range 68.3–81.7%. Compounds L1–6 have been characterized by UV–Vis, FT–IR, 1H NMR and ESI–MS spectroscopy, and elemental analysis. In addition, the structures of L2–6 and the ethanol monosolvate of L2 (L2 ·C2H5OH) have been determined by single-crystal X-ray diffraction. A combination of intermolecular O—H...N, C—H...O, C—H...N and C—H...π hydrogen bonds connects the components of L2 ·C2H5OH into a three-dimensional (3D) framework. A combination of three intermolecular C—H...N hydrogen bonds links the molecules of L2 or L3 into two different 3D networks. Both L4 and L5 show a similar 3D net structure through two intermolecular C—H...N hydrogen bonds and one kind of C—H...π interaction. However, L6 displays a more complicated 3D net structure via three intermolecular C—H...N hydrogen bonds and one kind of C—H...π interaction. Notably, an interaction between the π-electrons and the lone-pair p-electrons of a halogen atom (Br, Cl and F) is observed in L4–6 , which will further stabilize the 3D networks. The intermolecular interactions in L2 ·C2H5OH and L2–6 were further investigated by 3D Hirshfeld surface analyses and 2D fingerprint plots to show that the prominent interactions are H...H, N...H/H...N and C...H/H...C contacts.