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利用MNDO,AM1和PM3半经验量子化学计算方法对硅杂富勒烯C_(59)Si和C_(69)Si进行了系统的理论研究.计算了稳定构型、生成热、前沿轨道能级差、电离势、电子亲和势、绝对电负性和整体硬度.结果表明,硅杂富勒烯的稳定性虽然低于全碳富勒烯,但也具有相当的稳定性.C_(59)Si的稳定性比已经合成的C_(58)X_2(X=B,N)高,C_(69)Si与C_(70)的稳定性差异也很小,因此在适宜条件下文中所讨论的硅杂富勒烯是应该能够合成的.在C_(69)Si各异构体中,取代位置在赤道的异构体具有最低的能量和最大的前沿轨道能级差,也是最稳定的异构体.与全碳富勒烯C_(60)和C_(70)相比,C_(59)Si和C_(69)Si具有较小的电离势和电子亲和势,表明硅杂富勒烯容易被氧化,而被还原的难度要大些,但是仍容易发生还原反应而生成负离子.因此硅原子的掺杂能够使富勒烯的氧化还原性能得以改善.C_(59)Si和C_(69)Si更容易与亲电试剂反应,而发生亲核反应的活性要相对小一些.硅杂富勒烯C_(59)Si和C_(69)Si的绝对电负性和硬度都小于相对应的全碳富勒烯,对电子的束缚力要相对小一些.
The semi-empirical quantum chemical calculations of MNDO, AM1 and PM3 have been used to systematically study the C_ (59) Si and C_ (69) Si of fullerenes. The stable configurations, formation heat, Ionization potentials, electron affinities, absolute electronegativities and overall hardness.The results show that although the stability of sila fullerene is lower than that of all-carbon fullerenes, it also has considerable stability.C 59 Si The stability of C_ (58) X_2 (X = B, N) is higher than that of C_ (58) X_2. The stability of C_ (69) Si and C_ (70) is also very small. Therefore, under appropriate conditions, In the C_ (69) Si isomers, the isomers at the substitution position have the lowest energy and the largest difference in frontier orbital energy levels, and are also the most stable isomers. The C_ (59) Si and C_ (69) Si have smaller ionization potentials and electron affinities compared to those of C_ (60) and C_ (70), which indicates that SFTs are easily oxidized, However, the reduction reaction is still easy to generate negative ions, so the doping of silicon atoms can improve the redox properties of fullerenes.C_ (59) Si and C_ (69) Si are easier to react with The reaction of reactants and the activity of nucleophilic reaction are relatively small.The absolute electronegativity and hardness of fullerenes C 59 Si and C 69 Si are less than those of corresponding fullerenes, The binding power of electrons should be relatively small.