Excited singlet states of fluoranthene: Linear dichroism, polarized fluorescence excitation, and anodic oxidation of the aminofluoranthenes

Abstract

Transition energies, intensities, and polarization directions have been determined for six to nine transitions in each of the five isomeric aminofluoranthenes, using absorption, polarized excitation and emission, and linear dichroism in stretched polyethylene. Probable error limits for the stretched-sheet method are discussed. Most of the transitions have been further characterized by the sign of the corresponding peak in magnetic circular dichroic spectrum. The low-energy transitions have been correlated with those of fluoranthene. Interesting differences between the isomers are noted. Simple Pariser-Parr-Pople theory accounts well for most observations but predictions of polarization directions of higher-energy transitions are poor. Anodic polarographic oxidation of the five aminofluoranthenes, the six aminobenzo[c]phenanthrenes, and some additional arylamines has been studied, and the relationship to the spectroscopic results noted. A fair correlation has been found between the anodic half-wave potentials of 24 arylamines and the calculated energies of their highest occupied molecular orbitals.