Figure 11: Fluorescence spectra and fluorescence lifetime of 13 (1.0 mM) in solvents of varying viscosity (A) and polarity (C); fluorescence lifetime of the probe(Bodipy moiety at 516 nm and Nile Red moiety at 635 nm) was measured using a time-correlated single photon counting (TCSPC) system, excited at 375 nm(B); and the fluorescence intensity ratios for Nile Red (I575/I625) were determined in solvents of varying polarity, using an excitation wavelength of 488 nm (D). Reproduced by permission of the Royal Society of Chemistry. All rights reserved.