The Photophysical and Photochemical Properties of 2-Styrylquinoline Derivatives：(a) 5-Member Hetero-ring series (b) 8-Hydroxyquinoline series

• Main Authors: Yu-Fang, Jhang, 張玉芳
• Other Authors: Shun-Li, Wang
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/4jws85

碩士 === 國立嘉義大學 === 應用化學系研究所 === 96 === 　　Different 2-styrylquinoline derivatives possessing intramolecular charge transfer characters, including 5-member heterocyclic or 8-hydroxyquinoline, were synthesized to study the influence of substituent on the photophysics and photochemistry. For 5-member heterocyclic derivatives, the basicity of the quinoline ring are enhanced in excited state (pKa ⊿= 8 ~ 10). Comparing with thiophene derivatives, pyrrole ring possesses a stronger electron-donating ability. However, these molecules all practiced an excited state proton transfer (ESPT) reaction in strong hydrogen donor solvents, such as the mixed solvents (dichloromethane and trifluoroethanol). 　　The electronic effect of the hydroxyl group depends on the substituent effect for the 8-hydroxyquinoline derivatives. When a strong electron-donating group, such as –NMe2, appeared as a donor part on the 8-hydroxyquinoline derivatives, the hydroxyl group behaves an electron-withdrawing group. However, the hydroxyl group becomes as an electron-donating group when –NMe2 was replaced by –NO2 or protonated –NMe2. The discovery of the electronic-effects inversion for the hydroxyl group on the 8-hydroxyquinoline derivatives is important in studying the mechanism of the ESPT.