Phenylacetic acid co-crystals with acridine, caffeine, isonicotinamide and nicotinamide: Crystal structures, thermal analysis, FTIR spectroscopy and Hirshfeld surface analysis

Co-crystals of phenylacetic acid (PAA) with acridine (ACR), caffeine (CAF), isonicotinamide (INM) and nicotinamide (NAM) have been successfully prepared and characterised by single crystal X-ray diffraction, FTIR spectroscopy, thermal analysis and Hirshfeld surface analysis. The ACR, INM and NAM co-crystals with PM exhibit the carboxylic acid-pyridine heterosynthon. Furthermore the amide-amide supramolecular homosynthon is observed in the PM co-crystals with INM and NAM as well as N-H center dot center dot center dot O interactions between the acid and the respective base. The CAF co-crystal exhibits hydrogen bonding between the imidazole nitrogen and the COOH group of the PM. The compounds demonstrate different stoichiometries; for PAA center dot ACR and PAA center dot INM a 1:1 ratio is displayed, a 2:1 in 2PAA center dot CAF and a 2:2 in the case of 2PAA center dot 2NAM. (C) 2017 Elsevier B.V. All rights reserved.