In this work, a series of 2,4,6-trisubstituted pyrylium compounds were synthesized. The photophysical behavior of these compounds in solvents with different polarities has also been measured. Results indicated that introduction of electrondonating or accepting substituents and their positions (X- or Y-chromophore) have signiticant effect on the luminescence behavior of these compounds. Fluorescence depolarization method proved that intramolecular energy transfer may occur between X- and Y-chromophore in 2,4,6- trisubstituted pyrylium. It was also found that pyrylium compounds with N,N-dimethylamino phenyl groups could be used as a potential fluorescence indicator in non-aqueous solution by the transformation of tertiary amine into quaternary ammonium salt with addition of trifluoroacetic acids.

Key words: SPECTROGRAPHIC ANALYSIS, TRIFLUOROACETIC ACID, FLUORESCENCE INDICATORS, OXONIUM SALTS