Tb@C_(82)异构体的分离及其电化学性质研究  

Isolation and Electrochemical Property of Tb@C_(82) Isomers

作　　者：董薇[1] 聂梦思 廉永福[1] 

机构地区：[1]黑龙江大学化学化工与材料学院功能无机材料化学教育部重点实验室,哈尔滨150080

出　　处：《化学学报》2017年第5期453-456,共4页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.21271067;51572071);教育部高校创新团队计划(No.IRT-1237)资助~~

摘　　要：通过制备型高效液相色谱分离获得了Tb@C_(82)的两种同分异构体,依据它们的UV-Vis-NIR吸收光谱推断它们分别具有C_(2v)和C_s对称性的碳笼结构,而且Tb是以+3价的形态内嵌于碳笼中的.电化学研究表明,C_(82)碳笼的对称性对Tb@C_(82)的还原过程的影响较小,而对其氧化过程影响较大.Tb@C_(82)的两种异构体的第一还原电位都比较高,是较好的电子受体材料;而且与Tb@C_(2v)(9)-C_(82)相比,Tb@Cs(6)-C_(82)氧化还原电位更高一些,说明后者比前者具有更好的接受电子能力.此外,我们观察到了Tb@C_(2v)(9)-C_(82)的七对可逆的氧化-还原电位,丰富并修正了前人报道的结果.Carbon soot containing terbium endohedral fullerenes was prepared by vaporizing a graphite rod filled with Tb4O7 and graphite powder in an electric arc-discharge chamber. After reflux extraction with 1,2,4-trichlorobenzene and ro- tary evaporation of solvent, the residue was ultrasonically dissolved in toluene. The obtained solution was filtered with a 0.2 μm PTFE film, and then subjected to a three-stage high-performance liquid chromatographic （HPLC） isolation process to achieve two individual isomers of Tb@C82. The successful isolation of Tb@C82 isomers was confirmed by matrix-assisted laser desorption time-of-flight mass spectrometry and analytical HPLC. According to their UV-Vis-NIR absorption spectra, the carbon cages of the isolated Tb@C82 isomers are estimated to be of C2v and C8 symmetry, respectively, and Tb atom is encapsulated in carbon cage at a valence state of ＋3. The cyclic voltammetry （CV） of the two Tb@C82 isomers was record- ed in a 0.1 mol/L ortho-dichlorobenzene （o-DCB） solution of tetrabutylammonium hexafluorophosphate （TBAPF6） by refer- ring the ferrocene/ferrocenium couple （Fc/Fc＋）. The working electrode and the counter electrode were platinum wires, and the reference one was a Ag/AgC1 electrode. Tb@C82 （I） exhibits two pairs of reversible oxidative and five pairs of reversible reductive peaks, and Tb@C82 （II） shows one reversible oxidative and six reversible reductive ones. It is found that the sym- metry of C82 cage has little effect on the reduction potentials but great effect on the oxidation potentials of Tb@C82 isomers. Moreover, the first reduction potential of both Tb@C82 isomers is relatively high, indicating that they are good electron ac- cepting materials. Additionally, the corresponding redox potentials of Tb@C82 （II） are relatively higher than those of Tb@C82 （I）, therefore it is concluded that Tb@C82 （II） is of better electron accepting ability than Tb@C82 （I）. In comparison with those reported previously, three pairs of revers

关 键 词：内嵌金属富勒烯 铽 异构体 电化学 氧化-还原电位 

分 类 号：O611.3[理学—无机化学]