THEORETICAL STUDIES ON THE EFFECT OF DOPING IONS ON THE REGIOCHEMISTRY OF  FULLERENE
Chen Zhongfang, Li Fangxing, Zhao Hongxi, Wang Guichang (Department of Chemistry, Nankai University, Tianjin, 300071)
Semiempirical MNDO method was employed to study the effect of doping some ions such as Li +,Na +,K +,F -,Cl - and Br - on the regiochemistry of  fullerene. It is found that the regiochemistry of C 70 H 2 can be affected by doping to some extent. By doping Li +, the 1,4 isomer C 70 H 2(2/19) becomes the most stable isomer. By doping Na + and K +, the 1,4 isomer C 70 H 2(6,45), in which hydrogen atoms are added to the carbon atoms spanning the equator of C 70 , becomes the second lowest energy isomer. Doping Br - also have some effects, whereas doping F - and Cl - has little effect on the regiochemistry of fullerene adducts C 70 H 2. The doping effect on the regiochemistry of C 70 H 2 can be explained by the different distances between the nonequivalent carbon atoms in C 70 and the dopant. This result indicated that the regiochemistry of C 70 may be controlled to some extent by doping.