Role of micellar inclusion in the photochemistry of 2-pyridyl phenyl ketone. A steady-state and laser flash photolytic study

Abstract

The photochemical behavior of the 2-pyridyl phenyl ketone was studied by stationary techniques in sodium dodecyl sulfate submicellar and micellar solutions. Nanosecond laser flash photolysis was employed to identify the primarily produced transients. The photochemistry is mainly due to fast intramolecular photocyclization, followed by photoaddition of water, with no competition by hydrogen abstraction from the surfactants by the triplet ketone. The intramicellar water molecules are more reactive in photoaddition than bulk water molecules. Transient absorption spectra and lifetimes were determined. By using quenchers which are solubilized in the micelle (biphenyl) or in the bulk water (CuCl2), intra- and extra-micellar processes were characterized. Copyright © 1999 John Wiley & Sons, Ltd.