Organic Crystal Engineering
What is it about?
In this article, we describe the synthesis and crystal structure of an imidazolium oxalate salt . The crystal structure confirms two proton transfers from oxalic acid to the pyrimidine-type N atoms of two imidazole rings of 3-(4,5-diphenyl-1H imidazol-2-yl)phenol. Each oxalate ion accepts hydrogen bonds from four protonated imidazolium cations via N—H O and O—H O interactions (Fig. 2 and Table 1). All three phenyl rings in the 2-(3-hydroxyphenyl)-4,5-diphenyl-1H-imidazol-3-ium cation are in different planes. The values of the torsion angles between the imidazole ring and the pendant phenyl rings are N3—C11—C6—C5 = 16.8 (2), N4—C17—C15—C22 = 47.4 (2) and N3—C18—C14—C10 = 41.0 (2).
Why is it important?
Compounds containing an imidazole moiety have therapeutic properties, such as antiviral, antihistaminic, antiulcer, antibacterial, antifungal, anticancer, antioxidant and antihypertension. A number of cocrystals of oxalic acids with different drugs are known, where the introduction of the cocrystallized substance improves the solubility, stability and tabletability of drugs.