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

Six new pyrimidin-2-yl-substituted triaryltriazoles, namely, 4-(4-R-phenyl)-3-(pyridin-2-yl)-5-(pyrimidin-2-yl)-1,2,4-triazoles [L 1 : R = methoxy (OCH 3 ); L 2 : R = methyl (CH 3 ); L 3 : R = nil (H); L 4 : R = bromo (Br); L 5 : R = chloro (Cl); L 6 : R = fluoro (F)] have been successfully synthesized with yields in the range 68.3-81.7%. Compounds L 1-6 have been characterized by UV-Vis, FT-IR, 1 H NMR and ESI-MS spectroscopy, and elemental analysis. In addition, the structures of L 2-6 and the ethanol monosolvate of L 2 (L 2 ·C 2 H 5 OH) 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 L 2 ·C 2 H 5 OH into a three-dimensional (3D) framework. A combination of three intermolecular C-H...N hydrogen bonds links the molecules of L 2 or L 3 into two different 3D networks. Both L 4 and L 5 show a similar 3D net structure through two intermolecular C-H...N hydrogen bonds and one kind of C-H...π interaction. However, L 6 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 L 4-6 , which will further stabilize the 3D networks. The intermolecular interactions in L 2 ·C 2 H 5 OH and L 2-6 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.