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

Abstract

a b s t r a c tSpectroscopic and chemical properties of c-CD Å radicals, resulting from the abstraction by HO Å radicals of hydrogen atoms, have been investigated using pulse radiolysis. The reactions of c-CD Å radicals with C 60 in 2:1 c-CD/C 60 inclusion complexes have been studied in aqueous solutions. It has been demonstrated that the c-CD Å radicals are reducing species producing C ÅÀ 60 monoanion radicals, as well as doubly reduced C 2À 60 , well characterised by their absorption spectra in the near IR. The oxidation potential of c-CD Å radical is estimated to be more negative than À390 mV vs. NHE. The kinetics of the C 60 reduction by c-CD Å radicals have been determined and compared with kinetics by other reducing species including the solvated electron (e À aq ) and CO ÅÀ 2 radicals. It was observed that the method of preparation of the 2:1 c-CD/C 60 inclusion complexes modifies the C 60 reduction mechanism.

Search for the form of fullerene C60 in aqueous medium

“…It was also not possible to extract fullerenes by toluene from this aqueous dispersion. 41 By contrast, C 60 dissolved in water via complexation with g-cyclodextrin [46][47][48] can be easily extracted to toluene. 49,50 However, the stability of C 60 dispersion is affected by the salt addition.…”