Photoinduced electron transfer in a supramolecular species building of mono-6-p-nitrobenzoyl-β-cyclodextrin with naphthalene derivatives

Photoinduced electron transfer was observed in the supramolecular complexes of p-nitrobenzoyl-β-cyclodextrin (NBCD) with a number of naphthalene derivatives, which were stabilized clearly via hydrophobic interactions in aqueous solution. Both steady-state and time-resolved fluorescence measurements were conducted, which revealed that there were two routes of electron transfer, i.e., electron transfer between the free donor and free acceptor in solution and electron transfer between the donor and acceptor bound in a supramolecular assembly. The evidence collected demonstrates that the latter route was very efficient. As a result, the rate and quantum yield of the fluorescence quenching in the present supramolecular system were appreciably large.