A latent photoreaction enhanced upon cyclodextrin encapsulation: Photochemistry of α-alkyl dibenzyl ketones in water

α-Alkyl dibenzyl ketones that are capable of undergoing both Norrish Type I and Type II reactions generally yield products of Norrish Type I reaction in organic solvents. These water insoluble ketones form water-soluble host–guest complexes with β and γ-cyclodextrins. Irradiation of the above β-cyclodextrin complexes in water leads to products of Norrish Type II reaction. This change in behavior between the guest alone in organic solvent and as host–guest complexes in water is consistent with the influence of other ordered media such as micelles and reactants such as benzoin alkyl ethers and alkyl deoxy benzoins.