The novel one-pot reaction of α-monosubstituted 2,4,5-triphenylpyrylium perchlorate with substituted primary amines was proved to give the corresponding α-monosubstituted pyridinium salts in high yield. New phenanthridinium salt was synthesized via photochemical reaction of α-monosubstituted pyridinium salts. The photophysical properties of compounds were investigated by UV-Vis and fluorescent spectroscopy. It was found that increase of electron donating ability of N-substituents induced the clear red shift of the emission spectra and the decrease of the fluorescence intensity. Furthermore, the more planarity of phenanthridinium salt compared to pyridinium salt extremely enhanced the fluorescence intensity.

Key words: pyrylium salt, α-monosubstituted pyridinium salt, phenanthridinium salt, photochemical reac-tion, fluorescence property