Electron transfer between N-substituted phenothiazines and the 1-oxopiperidinium ion in the presence of beta-cyclodextrin

The electron-transfer reactions between N-substituted phenothiazines and 4- acetoxy-2,2,6, 6-tetramethyl-1-oxopiperidinium hexachloroantimonate (ATPO) in the presence of beta-cyclodextrin (beta-CD) in an aqueous solution have been studied. N-phenylphenothiazine (PPT) and N-phenethylphenothiazine (PEP T), included by beta-CD, can transfer an electron to the beta-CD.ATPO compl ex. However, no electron-transfer reaction between the beta-CD.N-benzylphen othiazine (beta-CD.BPT) complex and the beta-CD.ATPO complex was observed u nder the same conditions. It has been suggested that the electron-transfer reactions were controlled by the conformations of the N-substituted phenoth iazines in the cavity of beta-CD.