Single and double reduction of C₆₀ in 2:1 γ-cyclodextrin/[60]fullerene inclusion complexes by cyclodextrin radicals

Authors

• Annamaria Quaranta, Laboratoire de Chimie et Biochimie des Substances Naturelle, CNRSFollow
• Yongmin Zhang, Université Pierre and Marie Curie, ParisFollow
• Yali Wang, University of Nebraska-LincolnFollow
• Ruth Edge, Free Radical Research Facility, STFC Daresbury Laboratory
• Suppiah Navaratnam, University of Salford
• Edward J. Land, Keele University
• René V. Bensasson, Laboratoire de Chimie et Biochimie des Substances Naturelle, CNRS

Document Type

Article

Date of this Version

2008

Citation

Published in Chemical Physics 354 (2008), pp. 174–179; doi:10.1016/j.chemphys.2008.10.014

Comments

Copyright © 2008 Elsevier B.V. Used by permission.

Abstract

Spectroscopic and chemical properties of γ-CD^• radicals, resulting from the abstraction by HO^• radicals of hydrogen atoms, have been investigated using pulse radiolysis. The reactions of γ-CD^• radicals with C₆₀ in 2:1 γ-CD/C₆₀ inclusion complexes have been studied in aqueous solutions. It has been demonstrated that the γ-CD_ radicals are reducing species producing C₆₀^•— monoanion radicals, as well as doubly reduced C₆₀^2— , well characterized by their absorption spectra in the near IR. The oxidation potential of γ-CD^• radical is estimated to be more negative than –390 mV vs. NHE. The kinetics of the C₆₀ reduction by γ-CD^• radicals have been determined and compared with kinetics by other reducing species including the solvated electron (e^—_aq) and CO₂^•— radicals. It was observed that the method of preparation of the 2:1 γ-CD/C₆₀ inclusion complexes modifies the C₆₀ reduction mechanism.