PHOTOINDUCED CHARGE-TRANSFER INTERACTIONS AND HYDROGEN-TRANSFER IN DONOR SUBSTITUTED ARM, ALKYL KETONES

The temperature effect on the emission spectra and the influence of th e solvent polarity on the photoreactivity of aryl alkyl ketones with a n anisyl, amino or anilino substituent in beta-position have been inve stigated. The negative solvent effect reflects the competition between the solvation of the CT state and its deactivation to the ground stat e. The viscosity of the solvent matrix determines whether emission spe ctra of the beta-anilino ketones display n, n phosphorescence or exci plex emission. beta-Hydrogen transfer to form the 1,3-hydroxybiradical s requires a change of the close conformation of the CT state to a mor e extended one.