Triplet state dynamics within cyclodextrin solid complexes

Time-resolved diffuse-reflectance laser-flash photolysis techniques were employed to determine the triplet state dynamics of 9,10-anthraquinone, benzil, 1,4-benzoquinone, 2,5-dimethyl-1,4-benzoquinone, 9,10-phenanthrenequinone, and alpha-terthienyl within beta-cyclodextrin solid complexes. The alpha- and gamma-cyclodextrin solid complexes of benzil and alpha-terthienyl were studied likewise. The average triplet lifetime for a- terthienyl increases as the size of the host cavity decreases, while that for benzil remains practically unchanged. In addition, the solid-state photoreduction of 1,2-dimethoxy-4-nitrobenzene triplets by 1-phenylethylamine within beta-cyclodextrin solid complexes was investigated. Observed lifetimes tend to diminish as the 1-phenylethylamine-to-1,2-dimethoxy-4-nitrobenzene molar ratio increases.