Studies on the Electronic Absorption Spectra of 2,2′-Bithienyl and Some of Its Derivatives. A Molecular Orbital Treatment

The electronic absorption spectra of 2,2′-bithienyl and a number of its derivatives have been investigated. The predominant conformer as well as the polarity of the molecule were predicted from the spectrum. Molecular orbital calculations were performed on different conformers of 5-formyl-2,2′-bithienyl and the s-trans geometry proved to be the predominant conformer of the molecule. A good agreement is observed between calculated and observed transition energy and intensity.