The photochemistry of "super" photoacid n-methyl-6-hydroxyquinolinium and other novel photoacids

Quinolinium;Excited-state proton transfer;Photoacid;Photochemistry

Gould, Elizabeth-Ann ; Chemistry and Biochemistry

University:Georgia Institute of Technology

Department:Chemistry and Biochemistry

关键词: Quinolinium;    Excited-state proton transfer;    Photoacid;    Photochemistry;   

Others  :  https://smartech.gatech.edu/bitstream/1853/43706/1/gould_elizabeth-ann_201205_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

The photochemistry of several novel photoacids was addressed experimentally and theorectically. Initial studies focused on the excited-state proton transfer (ESPT) of several chiral phtoacids and explored the effects of chirality on ESPT; subsequent studies examined photochemistry and photophysics of "super" photoacid N-methyl-6-hydroxyquinolinium (MHQ).In the initial studies, no enantioselectivity was observed from the chiral photoacids to various chiral proton acceptors. In the later studies examining ESPT in MHQ both experimentally and theoretically, the excited-state acidity constant of the photoacid was determined to be an unprecedented -7, making it the strongest photoacid reported in the literature to-date. Consideration was then given to applications of the novel photoacid including its properties as a photoinitiator in cationic polymerizations and as a photochemical probe in gas-expanded liquids and in the Nafion membrane. In the course of these studies, an interesting fluorescence quenching effect was observed that became the subject of some exploratory studies that suggest a nucleophilic quenching mechanism.