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 preparedin 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 thestructures have shown the COOH/N heterosynthon. The thermal stability of the co-crystalswas investigated by using DSC and it was determinated that the melting points of the cocrystals1 and 2 were lower and in-between from those of their coformers, respectively.