✦ LIBER ✦
Evidence for enhanced intersystem crossing on pyrene fluorescence quenching with stable free radicals
✍ Scribed by Tadashi Suzuki; Kinichi Obi
- Book ID
- 103031361
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 331 KB
- Volume
- 246
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
The quenching mechanism for pyrene fluorescence by TEMPO and galvinoxyl radicals has been studied by measuring the time evolution of the transient absorption. The quenching rate constants by both radicals were determined to be 1.6 x 101° mo1-1 dm 3 s -1 for TEMPO and 1.2 x 101° tool -1 dm 3 s -~ for galvinoxyl. It is demonstrated from an analysis of the dual exponential time profiles of the transient absorption due to S m ~ S 1 and T, ~ T 1 transitions that radicals largely enhance the intersystem crossing from the S 1 state to triplet manifolds. The detailed mechanism is discussed.