Lawrence T. Sein

Evolution of the electronic states of polyaniline : an ab initio analysis of the orbital states of PAni synthons

Abstract In this work, ab initio computations performed using the B3LYP hybrid density functional are applied to describe the full electronic character of polyaniline (PAni) in terms of its logical structural subunits and/or its synthons. A complete description of bonding, redox states, and spectroscopic terms is obtained from this analysis, suggesting that structural and electronic properties of PAni are attributable to its synthons; aniline, p -phenylene diamine, and N , N ′-bis(4′-aminophenyl)-1,4-quinonediimine. Though previous modeling attempts with semi-empirical or simple Hartree–Fock methods have provided useful qualitative data, the ab initio/DFT approach used here has been shown to be quantitatively accurate. The general approach to understanding properties of complex materials in terms of its smaller structural units and synthons will be generally useful for polymers and complex clusters.

The role of adsorption of aniline trimers on the corrosion inhibition process: a ZINDO/1 study

Abstract The semi-empirical ZINDO/1 method is used to calculate the electronic structure and thermodynamic properties of aniline trimers adsorbed onto cluster models of the Al(100) and Fe(100) surfaces. The effects of progressive oxidation and protonation of the trimers on corrosion inhibition are interpreted in terms of these calculations.

Theoretical analysis of 2,6-dialkyl-substituted aniline trimers

Abstract DFT calculations on emeraldine trimers are used to clarify the conformation and electronic effects of 2,6-dialkyl-substitution. Such calculations are compared to results of UV–Vis spectroscopy. An intriguing diminishment of band gap on interconversion from the syn to the anti form is discovered.

Synthesis of iodine-capped aniline trimers and analysis of their electronic spectrum

Abstract Iodine-capped emeraldine trimers are synthesized by a modified Sandmeyer reaction. The electronic spectra of the trimers are captured by UV–Vis spectroscopy. The absorption bands are compared to the results of DFT calculations, and the electronic states responsible for those bands assigned. Additional thermodynamic parameters are calculated for the iodine-capped trimers, and compared to those for the traditional amino-capped trimers.

RETRACTED: Electronic states of N,N′-bis(4′-aminophenyl)-1,4-quinonediimine: comparison of results from ab initio calculations with electronic spectra

Abstract This article has been retracted at the request of the Editor. Reason: With regret, the Editors of Theochem have decided to retract this previously published paper. It has come to their attention that the substance of the paper had been published in essentially the same form as: International Journal of Quantum Chemistry 75 (1999) 623–629. Anomalous failure of the configuration interaction-singles (CIS) method in the computation of the electronic states of N,N′-bis(4′-aminophenyl)-1,4-quinonediimine. Readers who wish to cite this work should cite the IJQC publication.