The fluorescence lifetimes τ and quantum yields φF of 4-dimethylamino-ω-diphenylphosphinyl- trans-styrene (2a) and 4-dimethylamino-ω-methylsulphonyl-trans-styrene (3a) were measured in n-paraffins (n = 6 to n = 16) at 293 K. The ratio τ/φF was found to be viscosity independent and equal to the radiative lifetime τ0′ calculated from the integrated absorption spectrum. The strong fluorescence quenching and the shortening of the lifetime τ when reducing the viscosity are due to twisting around the double bond, resulting in trans-cis isomerization.
|Number of pages||6|
|Journal||Journal of Photochemistry and Photobiology, A: Chemistry|
|State||Published - 15 Sep 1992|