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.