Crystal structure and Hirshfeld surface analysis of two 5,11-methanobenzo[g][1,2,4]triazolo[1,5-c][1,3,5]oxadiazocine derivatives

Abstract

In the title compounds, 9-bromo-2,5-dimethyl-11,12-dihydro-5H-5,11-methanobenzo[g][1,2,4]triazolo[1,5-c][1,3,5]oxadiazocine, C13H13BrN4O (I), and 7-methoxy-5-methyl-2-(pyridin-4-yl)-11,12-dihydro-5H-5,11-methanobenzo[g][1,2,4]triazolo[1,5-c][1,3,5]oxadiazocine, C18H17N5O2 (II), the triazole ring is inclined to the benzene ring by 85.15 (9) and 76.98 (5)° in compounds I and II, respectively. In II, the pyridine ring is almost coplanar with the triazole ring, having a dihedral angle of 4.19 (8)°. In the crystal of I, pairs of N—H...N hydrogen bonds link the molecules to form inversion dimers with an R22(8) ring motif. The dimers are linked by C—H...π and C—Br...π interactions forming layers parallel to the bc plane. In the crystal of II, molecules are linked by N—H...N and C—H...O hydrogen bonds forming chains propagating along the b-axis direction. The intermolecular interactions were investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots, and the molecular electrostatic potential surface was also analysed. The Hirshfeld surface analysis of I suggests that the most significant contributions to the crystal packing are H...H (42.4%) and O...H/H...O (17.9%) contacts. For compound II, the H...H (48.5%), C...H/H...C (19.6%) and N...H/H...N (16.9%) interactions are the most important contributions.

Keywords

• crystal structure
• Biginelli condensation
• benzoxadiazocine
• hydrogen bonding
• C—H...π interactions
• C—Br...π interactions
• Hirshfeld surface analysis