Molecular structure of 4-aminobenzoic acid salts with alkali metals

The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 4-aminobenzoic acid was studied. The vibrational (FF-IR, FT-Raman) and NMR (H-1 and C-13) spectra for 4-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done. Characteristic shifts of bands and the changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons (H-1 NMR) and carbons (C-13 NMR) in the series of studied alkali metals 4-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by HF, B3PW91, B3LYP methods using 6-311 + + G** basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds. (c) 2006 Published by Elsevier B.V.