CoII-catalysed synthesis of N-(4-methoxyphenyl)-5-(pyridin-4-yl)-1,3,4-oxadiazol-2-amine hemihydrochloride monohydrate

The title compound, C 14 H 12 N 4 O 2 ·0.5HCl·H 2 O or H(C 14 H 12 N 4 O 2 ) 2 + ·Cl − ·2H 2 O, arose from the unexpected cyclization of isonicotinoyl- N -phenyl hydrazine carbothioamide catalysed by cobalt(II) acetate. The organic molecule is almost planar and a symmetric N...H + ...N hydrogen bond links two of them together, with the H atom lying on a crystallographic twofold axis. The extended structure features N—H...O and O—H...Cl hydrogen bonds, which generate [001] chains. Weak C—H...Cl interactions cross-link the chains. The chloride ion has site symmetry 2. The major contributions to the Hirshfeld surface are from H...H (47.1%), Cl...H/H...Cl (total 10.8%), O...H/H...O (7.4%) and N...H/H...N (6.7%) interactions.