Theoretical Study on Structure and Electronic Properties of Aniline-5-Membered Heterocyclic Co-oligomers

With the aim of exploring the electronic and optical properties of some interesting conductive copolymers in view of potential applications, a regular oligomer systems made of aniline and three reference heterocyclic compounds (pyrrole, thiophene and furan) are studied using density functional theory (DFT) and time dependent DFT (TDDFT) calculations at B3LYP/6-31+G(d,p) level. It was found that poly (aniline-co-pyrrole) has the lowest ionization potential (4.48 eV) and electro affinity (0.77 eV) while poly (aniline-co-thiophene) has the lowest band gap and longest (3.21 eV) wavelength of absorption (and therefore the highest electronic conjugation) among the studied molecules. Comparison of the theoretical data and spectroscopic results obtained by DFT calculations with those experimentally obtained show very good agreement.