title: The 1:1 proton-transfer compounds of 4-(phenyldiazenyl)aniline (aniline yellow) with 3-nitrophthalic, 4-nitrophthalic and 5-nitroisophthalic acids.
abstract: 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, C(12)H(12)N(3)(+) x C(8)H(4)NO(6)(-), (I), and 4-(phenyldiazenyl)anilinium 2-carboxy-4-nitrobenzoate, C(12)H(12)N(3)(+) x C(8)H(4)NO(6)(-), (II), and 4-(phenyldiazenyl)anilinium 3-carboxy-5-nitrobenzoate monohydrate, C(12)H(12)N(3)(+) x C(8)H(4)NO(6)(-) x H(2)O, (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 pi-interactive step features which lie between the sheets.
authors.affiliation: School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia. g.smith@qut.edu.au
authors.forename: Graham
authors.initials: G
authors.lastname: Smith
authors.forename: Urs D
authors.initials: UD
authors.lastname: Wermuth
authors.forename: David J
authors.initials: DJ
authors.lastname: Young
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D010795:Phthalic Acids / Q000737:chemistry*; D011522:Protons; D010128:p-Aminoazobenzene
chemical_list: C527946:3-nitroisophthalic acid; C527945:4-nitroisophthalic acid; D000814:Aniline Compounds; D001391:Azo Compounds; D010795:Phthalic Acids; D011522:Protons; D010128:p-Aminoazobenzene; C527944:5-nitroisophthalic acid