Structural studies of 1-phenyl-2,3-dimethyl-5-oxo-1,2-dihydro-1H-pyrazol-4-ammonium 2[(2-carboxyphenyl) disulfanyl]benzoate

Reaction of 4-aminoantipyrine with 2-mercaptobenzoic acid afforded a proton transfer derivative, 1-phenyl-2,3-dimethyl-5-oxo-1,2-dihydro-1H-pyrazol-4-ammonium 2[(2-carboxyphenyl) disulfanyl]benzoate, (HAAP+⋅HTBA−), via the oxidation of 2-mercaptobenzoic acid into 2,2′-dithiobis(benzoic acid). The compound has been characterized on the basis of elemental analysis, IR, 1H and 13C NMR and mass spectral data. The infrared spectrum suggests the existence of an ion-pair compound, which is further established by the single crystal X-ray analysis to be an extended 1D supramolecular chain network extending along ‘b’ cell direction. The compound shows good thermal stability.