Ab initio calculations and vibrational spectroscopy on the phenylenediamine isomers

Molecular orbital calculations at HF and MP2 levels have been performed using the 6-31G** basis set for full geometry optimization of the phenylenediamine isomers. Our results show that only a transoid conformer is found for o-phenylenediamine, whereas cis and trans conformers exist for m-and p-phenylenediamine. Vibrational normal modes have been also analyzed for the gas phase and in chloroform solution, and compared with experimental data we have obtained using FTIR spectroscopy. (C) 1998 Elsevier Science B.V.