The mechanism of the ozonolysis on the surface of C70 fullerene: the electron localizability indicator study

The formation of C70O from C70O3 monomolozonide is a three-step process with the isomer dependent last step leading either to c,c-C70O epoxide or d,d-C70O oxidoannulene. The process involves the open intermediate (first O-O then Cc-Cc/Cd-Cd bonds broken), oxidoannulene-like structure intermediate (new Cc-O/Cd-O bond formed) and finally the oxide product. On the formation of c,c-C70O isomer, the final release of O2 is followed by the restoration of Cc-Cc bond, which stabilizes the product. Neither Cd-Cd bond is restored nor the total energy essentially lowered upon d,d-C70O formation. At all steps of the studied process, the four CC bonds adjacent to Cc-Cc or Cd-Cd bond, respectively, play a crucial role donating or withdrawing the necessary electron density. C70(O)O2 products, with O2 bridging one of the bonds adjacent to the parent Cc-Cc/Cd-Cd one, may compete with the oxide products. The OO bond in such structures is weak as suggested by its low electron population. For both c,c-C70O3 and d,d-C70O3, the shape of the potential energy surfaces (0 K) and the related, reported earlier, room temperature-free energy surfaces differ. Graphical abstract.