Comparative study of the sensitized photooxidation of n-methyle phenothiazine in homogeneous and microheterogeneous media

✍ Scribed by Esther Oliveros; Pascal Pheulpin; Andre M. Broun

• Publisher: Elsevier Science
• Year: 1987
• Tongue: French
• Weight: 875 KB
• Volume: 43
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)90283-2

✦ Synopsis

Apparent rate constants and quantum yields have been deterzoned for the rose bengal sensitized photooxidation of lo-methyl phenothiazinc in rethanol and in O/Q and W/O microemulsions. A Stern-Volmer analysis of the luminescence of singlet oxygen in solutions of CD30D containing different concentrations of the phenothiazine derivative revealed a vary efficient quenching of the triplet state of rose bengal by the substrate, No such energy transfer is found in micelles of sodium 12-(lO'-phenothiazinyl)dodecyl-l-sulfonate which show an enhanced rate of photooxidation. Evaluation of rate constants and local concentrations leads to the conclusion that the rather low quantum yields of photooxidation of iO-methyl phenothiatine in the three media investigated is mainly due to the efficiently competing deactivation of the triplet state of the sensitizer by the substrate.