Crystal structures and hydrogen bonding in the co-crystalline adducts of 3,5-dinitrobenzoic acid with 4-aminosalicylic acid and 2-hydroxy-3-(1H-indol-3-yl)propenoic acid

Abstract

The structures of the co-crystalline adducts of 3,5-dinitrobenzoic acid (3,5-DNBA) with 4-aminosalicylic acid (PASA), the 1:1 partial hydrate, C7H4N2O6·C7H7NO3·0.2H2O, (I), and with 2-hydroxy-3-(1H-indol-3-yl)propenoic acid (HIPA), the 1:1:1 d6-dimethyl sulfoxide solvate, C7H4N2O6·C11H9NO3·C2D6OS, (II), are reported. The crystal substructure of (I) comprises two centrosymmetric hydrogen-bonded R22(8) homodimers, one with 3,5-DNBA, the other with PASA, and an R22(8) 3,5-DNBA–PASA heterodimer. In the crystal, inter-unit amine N—H...O and water O—H...O hydrogen bonds generate a three-dimensional supramolecular structure. In (II), the asymmetric unit consists of the three constituent molecules, which form an essentially planar cyclic hydrogen-bonded heterotrimer unit [graph set R32(17)] through carboxyl, hydroxy and amino groups. These units associate across a crystallographic inversion centre through the HIPA carboxylic acid group in an R22(8) hydrogen-bonding association, giving a zero-dimensional structure lying parallel to (100). In both structures, π–π interactions are present [minimum ring-centroid separations = 3.6471 (18) Å in (I) and 3.5819 (10) Å in (II)].

Keywords

• co-crystal structures
• carboxylic acid molecular adducts
• 3,5-dinitrobenzoic acid
• 4-aminosalicylic acid
• 2-hydroxy-3-(1H-indol-3-yl)propenoic acid
• hydrogen bonding
• homodimers
• heterodimers
• π–π interactions.