| Abstract: | Fluorescence Quenching of N-Arylurethanes by Ketones Fluorescence and photo-Fries reaction of N-aryl-urethanes can be quenched by diffusion-controlled energy transfer to biacetyl, acetone and other aliphatic ketones. Quenching of the photo reaction and fluorescence obeys the Stern- Volmer Equation. The efficiency of quenching may by influenced by solvents and substituents changing the S1 energies of donors and acceptors. The identical rate constants determined by independent methods demonstrate that quenching of urethane fluorescence and photoreaction by aliphatic ketones occurs completely by singlet energy transfer. |
