C72O3的结构和光谱的理论研究

采用AM 1方法理论研究了C70 五元环酸酐衍生物C72 O3 的 8种可能异构体的结构和稳定性 ;以各异构体稳定构型为基础 ,分别用AM 1和ZINDO/CI方法计算了它们的振动光谱和电子光谱。结果表明 ,酸酐基团—C2 O3 主要加成在CⅠ CⅡ(异构体A)和CⅢ CⅢ(异构体B)键上形成闭环结构 ,异构体B的稳定性与实验已证实存在的异构体A十分相近 ;异构体A的振动光谱理论计算值与实验值符合较好 ,B的振动光谱理论计算值与A相似 ;对C72 O3 各异构体的电子跃迁进行了理论指认 ,讨论了其电子光谱的红移现象 ;其他异构体的振动和电子光谱属于理论预测。

Theoretical Study on the Structure and Spectra of C72O3

The optimized geometries and stability of eight different isomers of C72O3, the five-membered ring derivatives of C70 fullerenes, were investigated by using AM1 method. According to the optimized geometries of eight different isomers, AM1 and ZINDO/Cl method were employed to study the vibrational spectra and electronic spectra, respectively. The calculated results indicate that the -C2O3 groups are added preferably to the seats of CI-CII and CIII-CIII bond to form the isomers of A and B. The additive C-C bond is elongated to become primarily a single bond. The stability of isomer B is very similar to that of isomer A that has been prepared experimentally. The calculated vibrational spectra of isomer A, similar to those of isomer B, are consistent well with the results from the experiment. The electronic transitions of isomers of C72O3 were assigned and the red shift of electronic spectra was discussed. The spectra of other isomers were predicted theoretically.