Photoisomerization of a benzopyrromethenone derivative in micelles and organic solvents

The photophysics of a benzopyrromethenone derivative have been studied using UV–visible, fluorescence, and ultrafast transient absorption spectroscopy in solvents of varying polarity and viscosity, including ethanol, TX-100 micelles, hexane, and glycerol. The fluorescence quantum yields (Φf) were solvent dependent and were lower in ethanol and TX-100 and higher in glycerol and hexane. The excited state decay dynamics were best fit with a triple exponential in ethanol and TX-100 and a double exponential in hexane and glycerol. The fastest component (∼2 ps) in ethanol and TX-100, which was not observed in hexane and glycerol, is attributed to photoisomerization.