Energy transport in carbohydrates. Part V. Mechanism of intermolecular energy transfer in cycloamylose complexes

Abstract

The factors which influence energy transfer in cycloamylose inclusion complexes have been examined. Energy transfer, following γ-irradiation, results in chemical protection of the dextrin with an efficiency which may be correlated with the position of the first singlet excited level (E₁) of the included molecule. Evidence is presented that intermolecular resonance transfer of electronic energy occurs via singlet states. It is unlikely that charged species or triplet states participate in the process. The form of the resonance curve sets a limiting value of ca. 5 ev for the energy of the collective excitation states formed in the cyclic dextrin on γ-irradiation. The e.s.r. spectra of irradiated 1-methylnaphthalene and benzene complexes suggest that H-atom attachment to the included molecule may occur. The energy-scavenging method which has been devised can reduce –G(cycloamylose) from 17 to 1.