Excited State Localization or Delocalization in C 3 -symmetric Amino-substituted Triphenylbenzene Derivatives

The site-to-site intramolecular excitation transfer and excitation trapping on one site in amino-substituted triphenylbenzene derivatives, which are characterized by a 3-fold symmetry, have been studied by fluorescence spectroscopy and time-resolved microwave conductivity (TRMC). The importance of dipole relaxation due to intramolecular energy transfer has been demonstrated in the interpretation of the limiting anisotropy on one hand and the change of the dipole moment and polarizability upon excitation on the other hand. The interpretation of the experimental results is based on the comparison of the molecules with C 3 -symmetry with biphenyl model compounds.