Three 2,4,6-trimethylpyridine-benzoic acid complexes at 150 K

The crystal structures of three 1:1 adducts of 2,4,6-trimethylpyridine with benzoic acid, C8H11N . C7H6O2, (I), 2-nitrobenzoic acid, C8H12N+. C7H4NO4-, (II), and 3,5-dinitrobenzoic acid, C8H12N+. C7H3N2O6- (III), determined at 150 K show that the carboxylic proton has been transferred to the pyridine-N atom only in the nitrobenzoic derivatives, (II) and (III). In all three structures, both moieties are hydrogen bonded to each other via their respective OH, (I), and N+H, (II) and (III), groups with N ... O distances of 2.613 (4), 2.596 (3) and 2.597 (2) Angstrom, respectively.