Studies On The Syntheses And The Properties Of The Novel Photosensitizer Thioacridones

In this paper the photosensitizer thioacridones in whieh there was ethoxy in the 2 site on acridine ring were synthesized, and their photosensitivity and the photoreaction mechanism also were studied, the specific work were as follows:1. Three kinds of different structural thioacridones in which there was ethoxy in the 2 site on acridine ring were synthesized after the best conditions of the dehydro-cyelizing reaction were groped by means of the cross experiments. The structures of intermediates and objective products were confirmed by IR,MS analysis methods;2. The photosensitivity of different structural thioacridones ,such as the maximum absorption wavelength, max, photodecomposition speed constant, and the photosensitivity of the photosensitive coatings having the thioacridone were researched;3. The fluorescence property of acridone or thioacridone was studied, and the fluorescence of different acridones quenched by different diphenyl iodium salts were discussed in more detail;4. The UV-visible spectra, mass spectra and fluorescence spectra of the thioacridones before and after exposed to the visible light of Xe lamp were analysed, and the mechanism of the photopolymerizable reaction system was preliminary discussed. The results showed that the maximum absorption wavelength of the thioacridones in which there was ethoxy in the 2 site on acridine ring were up to 500nm. The initiation effect of the photopolymerizable system comprising the N-butyl-2-ethoxy thioacridone, the biphenyl iodium salt and thiosalicylic acid was the best, the photosensitivity of the system was also the best. The mechanism of the photopolymerizable reaction system comprising the N-butyl-2-ethoxy thioacridone was that the thioacridone was transformed to the corresponding acridone after exposed to the Xe lamp, and in the two or three components initiation systems comprising thioacridone and the biphenyl iodium salt, after the thioacridone absorbed the longer wavelength light and transformed the excited acridone, the monomer was initiated and polymerized. The test of the fluorescence of acridone quenched by the diphenyl iodium salt illustrated that the related quenching curves conformed to the equation of Stern-Volmer, and the electron transfer free energies corresponding to the constants of quenching rate were all below zero. The experiment confirmed that the reaction between the diphenyl iodium salt and acridone derivatives was the mechanism of electron transfer.