VACUUM UV PHOTOCHEMISTRY IN CYCLODEXTRIN CAVITIES - SOLID-STATE Z-E PHOTOISOMERIZATION OF A CYCLOOCTENE BETA-CYCLODEXTRIN INCLUSION COMPLEX

An inclusion complex of (Z)-cyclooctene (1Z) with beta-cyclodextrin (beta-CD) was synthesized in aqueous solution and shown to be a stoichiometric 1:1 complex by thermogravimetry-differential thermal analysis (TG-DTA) and gas chromatography (GC) analysis. Direct photolysis at 185 nm of the inclusion complex (1Z-beta-CD) in the solid state led to reversible Z-E isomerization as the major photoreaction, yielding an apparent photostationary state (PSS) Z-E mixture on prolonged irradiation. The E to Z ratio obtained at the PSS (0.47) is considerably smaller than that (0.96) reported in direct photolysis in fluid solution. The optical yield of the isolated product (E)-cyclooctene (1E) was low: [alpha]D25 = 1.0-degrees, or 0.24%.