Structural and Spectroscopic Properties of Homo- and Co-Oligomers of o‑Phenylenediamine and o‑Toluidine: Theoretical Insights Compared with Experimental Data
journal contributionposted on 17.11.2016 by Salma Bilal, Sania Bibi, Rudolf Holze, Anwar-ul-Haq Ali Shah
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Density functional theory (DFT) and time dependent density functional theory (TD-DFT) calculations have been performed to get insights into the structural, optical, and electronic properties of homo- and co-oligomers of o-phenylenediamine (OPD) and o- toluidine (OT). UV–vis spectral bands assigned to various neutral, cationic and dicationic homo- and co-oligomers of OPD and OT have been analyzed at TD-DFT UB3LYP/6-31G (d, p) level, and complete assignments/correlation with experimental results are reported. The calculated vibrational bands of both homo- and co-oligomers of OPD and OT at B3LYP/6-31G (d) level along with their assignments are compared with experimental frequencies. Electronic properties such as ionization potentials (IP), electron affinities (EA) and HOMO–LUMO bandgap energies of both homo- and co-oligomers of OPD and OT have been calculated and are compared in the present work. DFT calculations with the 6-31 G (d) basis set predict very accurately experimentally observed vibrational modes as well as energy bandgap values.