Molbank, Vol. 2019, Article M1047: 4-(4-Chlorophenyl)-4,5-dihydro-1H-1,2,4-triazole-5-thione (Molbank)

The title compound, 4-(4-chlorophenyl)-4,5-dihydro-1H-1,2,4-triazole-5-thione (1), was synthesized by a hetero-cyclization reaction of 4-chlorophenyl isothiocyanate and formic hydrazide. Compound 1 was characterized by a single-crystal X-ray structure determination as well as 1H and 13C{1H} NMR, IR, and UV spectroscopy, and microelemental analysis. X-ray crystallography on 1 confirms the molecule exists as the thione tautomer and shows the five-membered ring to be planar and to form a dihedral angle of 82.70(5)° with the appended chlorophenyl ring, indicating an almost orthogonal relationship. In the molecular packing, supramolecular dimers are formed via thioamide-N-H···S(thione) hydrogen bonds and these are connected by C=S···?(triazolyl) and C-Cl···?(triazolyl) interactions, leading to a three-dimensional architecture.