Abstract: In this work, a series of substituted phenyl diazonium salts have been synthesized. Results in the direct photolysis indicated that the diazonium salt with electron-repulsive group possesses higher rate of photolysis reaction. But in the sensitized photolysis it was found that the diazonium salts which contain electron-withdrawing group possess stronger abilities than that with electron-repulsive group either in the sensitized photolysis or in the process of fluorescence quenching of sensitizers. It indicated evidently that the process of sensitization was realized by the reaction of electron transfer. It was also found it this work that the charge transfer complex (CTC) between diazonium salts and N,N-dimethyl aniline can be formed in the ground state. According to the results obtained from the Benesi-Hildebrand equation, the formed complex was the 1:1 charge transfer complex.

Key words: diazonium salt compounds, charge transfer complex, electron transfer sen-sitization reaction, fluorescence quenching