Molecular Cocrystals of Carboxylic Acids. XIX. The Crystal Structures of Two Adducts of 3-Aminobenzoic Acid With 3,5-Dinitrobenzoic Acid: the 1:1 and the 2:2 Hydrate Cocrystals

Abstract

Two cocrystalline molecular adducts of 3-aminobenzoic acid (3-aba) with the aromatic carboxylic acid 3,5-dinitrobenzoic acid (dnba), [(3-aba)(dnba)](1) and [(3-aba)₂(dnba)₂(H₂O)] (2), have been prepared and their hydrogen-bonding associations determined by means of single-crystal X-ray diffraction. Complex (1) is similar to known 1:1 complexes of 4-aminobenzoic acid with other aromatic acids, with protonation of the amine group and carboxylic acid-carboxylate hydrogen-bonding associations. However, the 2:2 hydrate complex (2) has only one hetero-pair involved in proton transfer, the other remaining neutral. With both compounds there is an extensive hydrogen-bonding network involving all substituent functional groups as well as the lattice water in compound (2).