| Abstract: | Poly(aniline) is a subject of considerable scientific and technological interest. Its homologs such as poly(m‐chloroaniline) potentially offer similar physical‐chemical properties. In this work we present a comparative theoretical study between aniline and the m‐chloroaniline species at several levels of theory. To envisage the possible mechanism of polymerization, we have obtained geometries and electronic structures for the monomers and dimers as well as the corresponding cations and dications. Based on the monomer‐optimized geometries, atomic charges, bond orders, and spin densities, a head‐to‐tail coupling in the electrochemical polymerization is suggested. We have also calculated band gaps and ionization potentials. For the cationic dimers of aniline and m‐chloroaniline, the highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) energy difference has a smaller value, and oxidation at specific sites may be observed. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 78: 99–111, 2000 |
