Steady-state and time-resolved fluorescence anisotropy of 7-azaindole and its derivatives

Abstract

The fluorescence excitation and excitation anisotropy spectra at -60 o C in a propylene glycol glass are reported for 7-azaindole and three related derivatives: 7-azatryptophan, N 1 -methyl-7-azaindole (1M7AI), and 7-methyl-7H-pyrrolo[2,3-b]pyridine (7M7AI). At the reddest excitation wavelengths, steady-state anisotropy values are observed in the range 0.17 to 0.23, which is significantly less than theoretical limiting anisotropy of 0.4. The anisotropy spectra indicate the presence of closely-spaced 1 L a and 1 L b bands as in indole