Theoretical studies on the structures and stabilities of various possible isomers of C70O3

Abstract

The equilibrium geometrical structures, relative stabilities and vibrational frequencies for the possible isomers of the fullerene derivatives C70O3 have been investigated using the semi-empirical methods AM1, PM3 and MNDO. The 43 isomers of C70O3 have been studied on the basis of the most stable isomer of C70O2(1,2 and 5,6-epoxy[70] fullerene) The calculation results show that there are 38 epoxide-like structures and five annulene-like structures. The epoxide-like structures are formed by oxygen atoms bridging across the unequatorial belt 6–6 bonds, while the annulene-like structures are formed with one oxygen atom bridging across the equatorial belt 6–6 bonds. Among these epoxide-like structures, the isomer-1, with three oxygen atoms bridging across the 6–6 bonds on the same six-membered ring closest to the pole of C70, is the most stable one. Among the annulene-like structures, the most energetically preferred structure is isomer-39, in which the three oxygen atoms are positioned within the nearest neighboring six-membered rings.