Experimental and theoretical IR, Raman, NMR spectra of 2-, 3- and 4-aminobenzoic acids

The influence of amino group position towards the carboxylic group on the vibration structure of the molecule was estimated. The calculated parameters were compared to experimental characteristic of these molecules. FT-IR, FT-Raman and NMR spectra of the title compounds were recorded and analyzed. The most important vibration bands due to amino and carboxyl groups and the benzene ring were assigned. Wavenumbers and intensities for the three studied acids were compared and discussed in terms of location of the carboxylic group. A linear correlation between proton and carbon GIAO NMR shieldings of studied compounds and experimental data was found.