Infrared spectra and structure of molecular complexes of aromatic acids

FTIR spectra of pharmacologically active molecules of benzoic acid and its derivatives have been measured in CCl4 solutions and in microcrystals. Features of the formation of intra-and intermolecular hydrogen bonds have been analyzed. Spectral attributes have been revealed that characterize the participation of a carboxyl group in different types of intermolecular interactions with the formation of cyclic, linear, and criss-cross dimers. Mechanisms of the intermolecular interactions are shown to be defined by the character of the substituents attached to the benzene ring in the para- and meta-positions relative to the carboxylic group.