MOLECULAR COCRYSTALS OF CARBOXYLIC-ACIDS .19. THE CRYSTAL-STRUCTURES OF 2 ADDUCTS OF 3-AMINOBENZOIC ACID WITH 3,5-DINITROBENZOIC ACID - THE1-1 AND THE 2-2 HYDRATE COCRYSTALS

Two cocrystalline molecular adducts of 3-aminobenzoic acid (3-aba) wit h 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 th eir hydrogen-bonding associations determined by means of single-crysta l 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 associat ions. However, the 2:2 hydrate complex (2) has only one hetero-pair in volved in proton transfer, the other remaining neutral. With both comp ounds there is an extensive hydrogen-bonding network involving all sub stituent functional groups as well as the lattice water in compound (2 ).