2-Chloro-4-nitrobenzoic acid as a coformer with pharmaceutical cocrystals and molecular salts

A series of five binary complexes, i.e. three cocrystals and two molecular salts, using 2-chloro-4-nitrobenzoic acid as a coformer have been produced with five commonly available compounds, some of pharmaceutical relevance, namely, 2-chloro-4-nitrobenzoic acid-isonicotinamide (1/1), C₇H₄ClNO₄·C₆H₆N₂O, 2-chloro-4-nitrobenzoic acid-3,3-diethylpyridine-2,4(1H,3H)-dione (2/1), 2C₇H₄ClNO₄·C₉H₁₃NO₂, 2-chloro-4-nitrobenzoic acid-pyrrolidin-2-one (1/1), C₇H₄ClNO₄·C₄H₇NO, 2-carboxypiperidinium 2-chloro-4-nitrobenzoate, C₆H₁₂NO₂^-·C₇H₃ClNO₄^-, and (2-hydroxyethyl)ammonium 2-chloro-4-nitrobenzoate, C₂H₈NO⁺·C₇H₃ClNO₄^-. The coformer falls under the classification of a `generally regarded as safe' compound. All five complexes make use of a number of different heteromeric hydrogen-bonded interactions. Intermolecular potentials were evaluated using the CSD-Materials module.