Vibrational spectra of end-capped thiophenes: a combined experimental and theoretical study

We report the FT-IR and FT-Raman spectra of the first members of a series of recently synthesized cycloalkane end-capped oligothiophenes. Theoretical equilibrium structures, vibrational spectra and the IR and Raman intensities of these compounds were calculated at the ab initio SCF level in order to assist in the interpretation and the assignment of the experimental spectra. Furthermore, the relationship of these data to the structures and vibrational spectra of unsubstituted thiophene, 2,2′-bithiophene and cyclohexene is discussed.