Quinacridone was widely used as organic pigment for the applications of high-sensitivity photo-sensors or photoreceptors required for electro-photography

solar cells.Meanwhile

quinacridone was used often as a fluorescent guest in organic LED although it has no strong emission property in the solid state.In order to looking for derivatives of quinacridone with strong emission property in the solid state

4-tetrahydroquinolone as its derivative was designed and synthesized.The structure was also characterized by

1

H NMR and IR.4-tetrahydroquinolone exists fluorescence in the solid state.Both the absorption and emission spectra in solvents with different polarities and with different concentrations were determined.It was found that extinction effect exists with increase in concentration

it means 4-tetrahydroquinolone is a fluorescent derivative of quinacridone and the extinction effect may be caused by non-radiative process or by reabsorption in high concentrations.It was also found that both the absorption band in absorption spectra and the emission band in emission spectra exhibit red shifts with increase of the solvents polarity.The relationship between the Stoke's shifts and the polarity of non protonic solvents was depicted by Lippert equation and the relative coefficient is 0.999 8.It is concluded that the fluorescence come from the photo-induced intramolecular charge transfer in the excited state.The Stoke's shifts in methanol is much greater than that in non protonic solvents and is not suitable to Lippert equation.It means the change of dipole moment from the ground state to the excited state is larger in protonic solvent and hydrogen bond may exist between 4tetrahydroquinolone and methanol.In a word

4-tetrahydroquinolone is a new photo-induced intramolecular charge transfer fluorescent compound with emission property in the solid state

it may be used in electroluminescent device as a emitting compound.