Synthesis, Separation And Characterization Of High Sm-endohedral Metallofullerenes

We synthesized a serious of Sm-containing metallofullerenes used the DC arc discharge method with high current efficiently; the collected soot was extracted by o-dichlorobenzene that excellently raised the extraction efficiency of high metallofullerenes; then the isolation process was performed by multi-stage high-performance liquid chromarography(HPLC) by using chlorobenzene as the mobile phase which greatly improved the isolation efficiency; finally, we purified a serious of high Sm-endohedral metallofullerenes containing a serious of mono-Sm endohedral metallofullerenes: Sm@C2n(96≤2n≤102), and a serious of di-Sm endohedral metallofullerenes: Sm2@C2n(94≤2n≤100), along with a serious of hollow fullerenes: C2n(98≤2n≤104).The isolated mono-Sm endohedral metallofullerenes: Sm@C96(I-VII) 、Sm@C100(I-III)、Sm C102(I-V) and di-Sm endohedral metallofullerenes: Sm2@C94、Sm2@C96、Sm2@C98、Sm2C100(I、II) were firstly isolated and purified experimentally.Furthermore, all these Sm-endohedral metallofullerenes were characterized by UV-vis-NIR sepectra. Which was Sm@C96(I) has similar UV-vis-NIR spectra with early reported Sm@C96 isomer. UV-vis-NIR sepectra of Sm2@C94, Sm2@C96 and Sm2@C100(I) resemble to Gd2C96,Gd2C98 and Gd2C102 respectively.We isolated and purified three di-samarium metallofullerenes of known structure,Sm2@D2(35)-C88, Sm2@C1(21)-C92 and Sm2@D3d(822)-C104. These three di-samarium metallofullerenes have been characterized by cyclic voltammetry(CV)and differential pulse voltammetry(DPV) which is the first report about electrochemical studies of dimetallofullerenes containing divalent metal atoms. The electrochemical studies of these three compounds show much weaker electron-donating capacity and stronger electron-accepting capacity compared with corresponding Sm-EMFs, fullerenes, or cluster-metallofullerenes. Interestingly,further analysis shows that normal-metallofullerenes used to present narrowerelectrochemical potential gaps comparing with cluster-metallofullerenes which might attribute to their stronger interaction between inner metal ions and carbon cage.