2-Propanol cyclodextrin inclusion complexes with

Molecular model studies have shown that PMVE, PEVE, and PnPVE chains are capable to penetrate y -CD cavities. Model studies further indicate that the single cavity can accommodate three monomer units. The inclusion complex formation of polymers with cyclodextrins is entropically unfavorable. However, formation of the complexes is thought to be promoted by hydrogen bond formation between cyclodextrins. Therefore, the head - to - head and tail - to - tail arrangement, which results in a more effective formation of hydrogen bonds between cyclodextrins, is thought to be the most probable structure. This structure was proved by X-ray studies on a single crystal of the complex between y -CD and 1-propanol. 

Coumarin, potassium bromide, and potassium ferrioxalate were reagent grade and used without further purification. 3-Cyclodextrin was purchased from Nichiden Chemical Co. Ltd. and purified by recrystallization once from 1-propanol and twice from water. Reagent grade organic solvents were purified and dried by standard methods [19]. Cis- and trans-head-to-head dimers of coumarin were obtained from the irradiation of coumarin in formic acid and in benzene without or with a small amount of benzophenone, respectively, by the similar method of Schenck and Krauch [12,14], An inclusion complex of coumarin with 3-cyclodextrin was obtained as follows equimolar aounts of coumarin and the cyclodext-... 

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