富勒烯C70笼内掺杂离子对其加成反应立体选择性影响的理论研究

利用半经验 MNDO方法 ,研究了碱金属和卤素离子笼内掺杂对富勒烯 C70 加成物 C70 H2 立体选择性的影响 .研究结果表明 ,Li 的掺杂使 1 ,4 -异构体 C70 H2 ( 2 /1 9)成为 Li @C70 H2 的最稳定异构体 ,而 Na 和 K 的掺杂使 1 ,4 -异构体 C70 H2 ( 6,4 5)成为稳定性排在第二位的异构体 :Br- 的掺杂也使 1 ,4 -异构体的稳定性得以提高 ,而F- 和 Cl- 的掺杂对于 C70 H2 异构体的稳定性顺序几乎没有任何影响

THEORETICAL STUDIES ON THE EFFECT OF DOPING IONS ON THE REGIOCHEMISTRY OF [70] FULLERENE

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 70] 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.