Crystal structures of 1-aryl-1H- and 2-aryl-2H-1,2,3-triazolyl hydrazones. Conformational consequences of different classical hydrogen bonds

Abstract

The crystal structures of (Z)-1-phenyl-4-[((2-phenylhydrazono)methyl)]-1H-1,2,3-triazole, (Z)-4-[(2-(2,4-dimethylphenyl)hydrazono)methyl]-2-phenyl-2H-1,2,3-triazole, (E)-4-[(2-(2,4-dinitrophenyl)hydrazono)methyl]-2-phenyl-2H-1,2,3-triazole, and (E)-N (E)-N'-((2-phenyl-2H-1,2,3-triazol-4-yl)methylene)isonicotinohydrazide dihydrate are reported. The formations of (Z)- configurations about the C=N bonds in the first two compounds arise from the stabilizing presence of intramolecular N-H⋯N hydrogen bonds, while in the third compound, the presence of intramolecular N-H⋯O hydrogen bonds promotes an (E) geometry. The arrangement about the CONHC=N fragment in the hydrated acylhydrazone is EC(O)NH/EC=N. Also present in (E)-N′-((2-phenyl-2H-1,2,3-triazol-4-yl)methylene)isonicotinohydrazide is an interesting R44(8) ring formed from hydrogen bonds generated from four water molecules. Significant π⋯π stacking interactions are exhibited in three compounds, but not in the least planar first compound, in which the dominant intermolecular interactions are C-H⋯π interactions. Other intermolecular interactions in one of the compounds are C-H⋯π interactions, in another compound are C-H⋯O hydrogen bonds and N-O⋯π interactions, and in the last compound are O-H⋯X (X = O and N), N-H⋯O and C-H⋯O hydrogen bonds.