The 1:1 proton-transfer compounds of 4-(phenyldiazenyl)aniline (aniline yellow) with 3-nitrophthalic, 4-nitrophthalic and 5-nitroisophthalic acids
Acta Crystallographica Section C
Volume 64, Issue 3, pages o123–o127, March 2008
How to Cite
Smith, G., Wermuth, U. D., Young, D. J. and White, J. M. (2008), The 1:1 proton-transfer compounds of 4-(phenyldiazenyl)aniline (aniline yellow) with 3-nitrophthalic, 4-nitrophthalic and 5-nitroisophthalic acids. Acta Crystallographica Section C, 64: o123–o127. doi: 10.1107/S0108270108001595
The structures of the anhydrous 1:1 proton-transfer compounds of the dye precursor aniline yellow [4-(phenyldiazenyl)aniline], namely isomeric 4-(phenyldiazenyl)anilinium 2-carboxy-6-nitrobenzoate, C12H12N3+·C8H4NO6−, (I), and 4-(phenyldiazenyl)anilinium 2-carboxy-4-nitrobenzoate, C12H12N3+·C8H4NO6−, (II), and 4-(phenyldiazenyl)anilinium 3-carboxy-5-nitrobenzoate monohydrate, C12H12N3+·C8H4NO6−·H2O, (III), have been determined at 130 K. In (I) the cation has longitudinal rotational disorder. All three compounds have substructures comprising backbones formed through strong head-to-tail carboxyl–carboxylate hydrogen-bond interactions [graph set C(7) in (I) and (II), and C(8) in (III)]. Two-dimensional sheet structures are formed in all three compounds by the incorporation of the 4-(phenyldiazenyl)anilinium cations into the substructures, including, in the cases of (I) and (II), infinite H—N—H to carboxylate O—C—O group interactions [graph set C(6)], and in the case of (III), bridging through the water molecule of solvation. The peripheral alternating aromatic ring residues of both cations and anions give only weakly π-interactive step features which lie between the sheets.