On the Emission of Excited Complexes Formed between Condensed Aromatic Hydrocarbons and Aliphatic Amines

Anomalous emission observed at long wavelengths in the systems of condensed aromatic hydrocarbons and aliphatic tertiary amines has been studied. The anthracene-tri-n-butylamine system has been dealt with in detail. On the basis of the absorption spectrum, the temperature dependence of the long-wavelength emission and the relation between the quenching of the hydrocarbon fluorescence and the intensity of the long-wavelength emission, it has been concluded that this emission originates from the excited complex formed between an excited hydrocarbon and an amine. The interaction involved in excited-complex formation is of a charge-transfer type. This was confirmed by the correlation of the wavelengths of the excited-complex emission with the ionization potentials of amines and the electron affinities of aromatic hydrocarbons and by the large dipole moment of the excited complex.