Networks of intermolecular interactions involving nitro groups in the crystals of three polymorphs of 9-aminoacridinium 2,4-dinitrobenzoate⋅2,4-dinitrobenzoic acid

• Published in: Journal of molecular structure Vol. 1049; pp. 90 - 98
• Main Authors: Sikorski, Artur, Trzybiński, Damian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2013
• Subjects: 2,4-Dinitrobenzoic acid; 9-Aminoacridinium; Asymmetry; Carboxylic acids; Crystal structure; Crystals; Diffraction; Dimers; Hydrogen bonds; Interactions involving nitro groups; Polymorphism; X-rays; 2,4-Dinitrobenzoic acid; Interactions involving nitro groups; Hydrogen bonds; 9-Aminoacridinium; Polymorphism; Crystal structure
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2013.06.031

•Three polymorphs of 9-aminoacridinium 2,4-dinitrobenzoate⋅2,4-dinitrobenzoic acid have been structurally characterized.•The N–H⋯O and O–H⋯O hydrogen bonds between 9-aminoacridine and carboxylic acid have been analysed.•The intermolecular interactions involving nitro groups have also been analysed.
We report on the crystal structures of three polymorphs of 9-aminoacridinium 2,4-dinitrobenzoate⋅2,4-dinitrobenzoic acid (I, II and III). Single-crystal X-ray diffraction measurements show that the title compound forms three polymorphs with the space groups P21/n (I) and P1¯ (II and III). The asymmetric units of all the polymorphs consist of 9-aminoacridinium cation, the 2,4-dinitrobenzoate anion and the 2,4-dinitrobenzoic acid molecule. The neutral and ionic forms of 2,4-dinitrobenzoic acid are linked via O–H⋯O hydrogen bonds with a D graph-set motif, forming monoanionic dimers. The amine and carboxylic acid moieties are linked via N–H⋯O, O–H⋯O and C–H⋯O hydrogen bonds. The acridinium skeletons in the crystal packing form π-stacked columns, whereas the monoanionic dimers of 2,4-dinitrobenzoic acid are linked by different types of intermolecular interactions, especially those involving nitro groups. To the best of our knowledge, the crystal structure of 9-aminoacridinium 2,4-dinitrobenzoate⋅2,4-dinitrobenzoic acid is the first in which the appearance of monoanionic dimers of 2,4-dinitrobenzoic acid has been documented.