Conformational analysis and optical characterization of oligothiophene inclusion compounds

The conformations and the optical properties of quinquethiophene molecules included in a peryhydrotriphenylene matrix are discussed from a critical comparison of experimental and theoretical data and compared to the situation encountered in solutions and crystals. The complex absorption and emission patterns and the lack of a mirror symmetry between the two spectra are consistent with the presence of two different absorbing and emitting conformations characterized by a different degree of inter-ring twisting. These new results provide insight into the properties of single oligothiophenes upon photoexcitation.