Ozonization of C70 and subsequent thermolysis of ozonide 1,2-C70O3: A theoretical study

Semiempirical method AM1 was employed to investigate the ozonization of [70]fullerene (C70) and the following extrusion of molecular oxygen from ozonide 1,2-C70O3. Our computational results show that (i) among the eight different bonds of C70 that may react with ozone, the C1C2 and C5C6 bonds are the two most active pair sites with near the same energy barriers; (ii) there are six different pathways to extrude molecular oxygen from ozonide 1,2-C70O3, of which one results in 1,6-oxidoannulene, one affords 2,3-oxidoannulene, the other four lead to 1,2-epoxide. It is most likely that the formation of 1,2-epoxide proceeds via two parallel routes with similarly lower-energy profiles, which are favored both thermodynamically and kinetically. Several new intermediates and transition states have been located for the thermolysis of ozonide 1,2-C70O3 to epoxide 1,2-C70O. Four steps are required for the seemly simple conversion of 1,2-C70O3 to 1,2-C70O.