Excited-state lifetime distributions of tryptophan fluorescence in polar solutions. Evidence for solvent exciplex formation
✍ Scribed by Nikolai Vekshin; Michel Vincent; Jacques Gallay
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 519 KB
- Volume
- 199
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
Using the time-correlated single-photon counting technique and maximum entropy method of analysis, it is shown that tryp tophan and N-acetyl-tryptophanamide fluorescence intensity decays recorded in the "blue" region of the emission spectrum either in glycerol, ethanol or water are described by a three-or two-exponential model. In the "red" region, a poor lit of the curves is obtained, except when the presence of negative preexponential terms is allowed or when the rising part of the fluorescence curve was skipped. The data are rationalized by considering superposition of monomer and solvent exciplex emissions, occurring from the photoexcited indole chromophore quenched by its solvation shell.