The red edge effect as a tool for investigating the origin of the anomalous fluorescence band of 9,9′-bianthryl in rigid polar polymer matrices

Abstract

The excitation wavelength dependence of the fluorescence of 9,9′-bianthryl (BA) in polar polymer matrices at room temperature is attributed to the presence of different conformers (angular distribution of the two anthryl moieties) trapped in sites with different solvation and absorbing at different energies. The broadening of the fluorescence at the red edge excitation of BA in polar polymer matrices is due to a twisted intramolecular charge transfer (TICT) band. This case of the red edge effect (REE) exhibited by BA represents a converse example to the REE observed for flexible molecules with one fluorescence band and a sharpening of the fluorescence.