Abstract
The title compound, [(1-{4-[2-(2,4-dihydroxyphenyl) diazen-1-yl] phenyl} ethylidene) amino] thiourea, 1,1,2,2-tetrachloroethane monosolvate, C15H15N5O2S center dot C2H2Cl4, was prepared from 4-(4-acetylphenyldiazendiyl) resorcinol and thiosemicarbazide and recrystallized from mixed solvents of tetrachloroethane and n-hexane. H-1 NMR and X-ray diffraction data are in support of the thione tautomeric form. The X-ray analysis shows the molecule crystallizes as a zwitterion, with proton transfer from the nominal phenol to the azide group; the N-N bond length is 1.291 (5) angstrom, and an intramolecular N-H center dot center dot center dot O hydrogen bond is formed. In the crystal, N-H center dot center dot center dot O, N-H center dot center dot center dot N and O-H center dot center dot center dot S hydrogen bonds connect the molecules into a three-dimensional network. The tetrachloroethane solvent molecules are linked to this network through weak C-H center dot center dot center dot O linkages.