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

Abstract

C o-crystals are made up of two or more molecular or ionic compounds combining at a cytochiometric rate, having a different crystallographic pattern than the precursor compounds, and being two or multi-component molecular crystals [1-3]. Molecules forming them are connected to each other by intermolecular interactions such as hydrogen bonds, π-π stacking interactions, C-H…π and Van der Waals forces [4,5]. The most preferred methods used in the preparation of the co-crystals are precipitation, slurry formation, cooling crystallization, grinding, as well as the evaporation that is the most common method. These methods can be applied differently within themselves [6-10]. Co-crystals have been widely used in the field of pharmacology, cosmetics, agriculture, paint, food, optoelectronic and photonic device industries in recent years. A co-crystal usually has some different properties than its constituent compounds, such as resolution, crystallization, melting point, optical properties, biocompatibility and thermodynamic stability [4, 11-14]. In previous studies, two new co-crystals composed of benzoic acid derivatives and pyridine derivatives have been reported. Many different biological activities of these organic ligands and their metal complexes have been investigated, and these complexes have been proven to be more biologically active compounds than free ligands. This phenomenon is not only for metal complexes but