Crystal structure and Hirshfeld surface of 5-bromo-salicylic acid di-methyl-formamide mono-solvate.

Abstract

The structure of the title compound, C₇H₅BrO₃·C₃H₇NO, at 173 K has triclinic (P1) symmetry with Z = 4. The asymmetric unit comprises two mol-ecules of 5-bromo-salicylic acid and two mol-ecules of N,N-di-methyl-formamide (DMF). The crystal structure is dominated by strong O-H⋯O hydrogen bonds between the carb-oxy-lic acid group of the 5-bromo-salicylic acid molecules and the carbonyl oxygen atom of the DMF mol-ecules, with the solvent acting as a hydrogen-bond acceptor. This inter-action prevents the formation of the common carb-oxy-lic acid dimer observed in many benzoic acid derivatives. Additional C-H⋯O hydrogen bonds and Br⋯O non-covalent inter-actions between neighbouring mol-ecules contribute to the cohesion of the structure. Aromatic π-π stacking inter-actions between adjacent benzene rings further consolidate the crystal structure and generate a three-dimensional supra-molecular assembly. Hirshfeld surface analysis confirms that H⋯H, H⋯O/O⋯H and Br⋯H/H⋯Br contacts make the largest contributions to the crystal packing. The inclusion of DMF therefore plays a significant role in directing the inter-molecular inter-actions and overall supra-molecular packing of the crystal structure.