Fluorescence Decay Measurements of 1-Methylindole in Alcohol Solutions: Direct Observation of Solvent Reorientation Kinetics at Ambient Temperatures
The understanding of the photophysical processes of indoles is crucial to the application of fluorescence spectroscopy of the indole amino acid, tryptophan in studies of protein structure and dynamics. The elucidation of the origin of the large Stokes shift of indole fluorescence spectra when in polar environments continues to be an important issue. It is well established that there is a large change in the dipole moment of indoles when they are excited into lowest singlet state. Earlier we had shown that in dilute alcoholic solutions of indoles, 1-methylindole (1-MeI) formed weak ground state complexes with alcohols (Skalski et al., 1980). In this report we present time resolved fluorescence data on 1-MeI in alcohols which provides direct evidence for the solvent reorganization in these complexes and show that it is viscosity dependent.
KeywordsDecay Time Large Stokes Shift Photophysical Process Instrument Response Function Fluorescence Decay Time
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