Theoretical analysis of substituent effects on building blocks of conducting polymers: 3, 4'-substituted bithiophenes

Date

1999

Authors

Salzner, U.
Kızıltepe, T.

Editor(s)

Advisor

Supervisor

Co-Advisor

Co-Supervisor

Instructor

BUIR Usage Stats
1
views
7
downloads

Citation Stats

Series

Abstract

Substituents are widely used to modify the properties of conducting polymers. To study substituent effects on energy levels and energy gaps systematically, CH3-, OH-, NH2-, CN-, and CCH-substituted bithiophenes were examined with density functional theory and NBO analysis. Total charges and :r-electron densities were analyzed separately to examine π- and σ-effects. Second-order perturbation theory was used to quantify conjugation in terms of orbital interactions. NBO orbital energies were employed to investigate the effect of alternating donor-acceptor substitution. Substituents in 3- and 4- positions shift HOMO and LUMO levels in parallel and hardly influence HOMO- LUMO gaps. For level shifting the π-donating and π-accepting abilities are most important; electronegativity mainly influences the σ-orbitals and is less crucial in determining energy gaps. Alternating donor-acceptor substitution leads to HOMO and LUMO energies that are average between those of the parent systems and has little effect on energy gaps.

Source Title

Journal of Organic Chemistry

Publisher

American Chemical Society

Course

Other identifiers

Book Title

Degree Discipline

Degree Level

Degree Name

Citation

Published Version (Please cite this version)

Language

English