Crystal structure of bis[4-(dimethylamino)pyridinium] bis(2-nitrobenzoate) trihydrate

Abstract

The title salt, 2C7H11N2+·2C7H4NO4−·3H2O, crystallized with two anions and two cations in the asymmetric unit, together with three water molecules. Both 4-dimethylaminopyridinium cations are protonated at their pyridine N atoms with the plane of the N(CH3)2 hetero atoms inclined to the pyridine ring by 4.5 (2) and 1.4 (2)°. In the 2-nitrobenzoate anions, the carboxyl and nitro groups are inclined to their respective benzene rings by 77.1 (3) and 20.0 (3)°, and 75.8 (2) and 20.9 (3)°. In the crystal, the anions are linked via O—H...O hydrogen bonds involving the water molecules, forming chains along [100]. The cations are linked to these chains by N—H...O hydrogen bonds. The chains are linked via C—H...O hydrogen bonds and C—H...π and π–π interactions [inter-centroid distances range from 3.617 (1) to 3.851 (1) Å], forming a three-dimensional structure.

Keywords

• crystal structure
• 4-dimethylaminopyrdidine
• 2-nitrobenzoic acid
• salt
• hydrogen bonds
• π–π interactions
• C—H...π interactions