Encapsulation of C 60 fullerene in γ-cyclodextrin: a new concept in the protection of organic substrates and polymers from ozone attack : Kinetic aspects on the reactivity between C 60 and O 3

Abstract

C 60 fullerene is able to form a complex with γ-cyclodextrin (CD). The supramolecular structure of this complex involves the encapsulation of the C 60 molecule inside two CD molecules. Under these conditions the reactivity of C 60 with ozone becomes about 200 times slower in comparison to free uncomplexed C 60 as shown from a comparison of the kinetic rate constants. This novel approach, which involves the encapsulation of the molecule to be protected inside opportune host molecules, can be considered as a new conceptual tool in the protection of molecules and polymeric substrates from ozone degradation. The relative kinetic rate constants at room temperature for the ozonation of pure C 60 in CCl 4 have been measured, both at constant C 60 concentration (changing the ozone feeding rate) and at constant ozone feeding rate (changing the C 60 concentration). Preliminary results suggest that C 60 ozonation seems to conform to the kinetic law v= k[O 3]/[C 60].