ELECTRONIC STRUCTURES AND SPECTROSCOPIC PROPERTIES OF N-VINYLCARBAZOLE OLIGOMERS

摘要

Oligo(N-vinylcarbazoIe) derivatives have been theoretically studied using the PM3 method. Based on PM3 optimized geometries, the electronic spectra and IR spectra of the derivatives have been calculated using INDO/CIS and PM3 methods. The main chains in the derivatives are only carriers, whereas the side chains with the carbazole rings are used to transfer electrons through the weak n-n stacking interaction and excimer formation. The energy gaps of the oligomers are gradually decreased, and the main absorptions in the electronic spectra are red-shifted with the increase in the chain lengths. The energy gaps of the derivatives are also decreased in the presence of the electron-donating substituents. The IR frequencies of the C=C bonds on the carbazole rings in the presence of the electron-attracting groups compared with those of the parent compound are blue-shifted due to the increased electron density on the rings.