Synthesis and Characterization of Two New Co-Crystals: p-Aminobenzoic Acid with Isonicotinamide and Pyrazine 1:1

Abstract

Two co-crystals of p-aminobenzoic acid with isonicotinamide and pyrazine were prepared in acetone-ethanol solution by solvent evaporation method in the 1:1 cytochiometric ratio. Their structures were characterized by FT-IR, 1H NMR and 13C NMR spectroscopies, powder X-Ray diffraction and differential scanning calorimetry DSC method. Both of the structures have shown the COOH/N heterosynthon. The thermal stability of the co-crystals was investigated by using DSC and it was determinated that the melting points of the cocrystals 1 and 2 were lower and in-between from those of their coformers, respectively