【作者】 韩晓晨；

【导师】 王军； 孙宝云；

【作者基本信息】 东北大学 ， 物理化学， 2008， 硕士

【摘要】 内包金属富勒烯在生物医学以及材料领域有广泛的应用,本文以镧系金属钆为例,对其合成和提取进行了系统研究。采用化学方法,将含钆的碳灰以及经邻二氯苯回流、N,N-二甲基甲酰胺(DMF)回流和DMF高温高压提取这三种不同提取方式得到的提取物分别进行化学还原反应,通过改变溶液中甲苯和四氢呋喃的比例而改变还原电位,将碳灰中具有更正还原电位的金属包合物还原。无需使用高效液相色谱(HPLC),而成功实现了碳灰中的Gd@C82等金属富勒烯和空心富勒烯的选择性分离,得到含金属Gd富勒烯负离子溶液。与HPLC分离提纯方法相比,这种化学还原的方法操作简单且成本较低。以C60负离子和Gd@C82负离子为参照,分别以二氯乙酸、乙酸和苯酚为氧化剂氧化C60负离子和Gd@C82负离子以及被还原后的含Gd@C82等金属富勒烯的碳灰,并分别用激光解吸飞行时间质谱、紫外-可见-近红外吸收光谱和高效液相色谱进行检测。实验结果表明,上述负离子可以被氧化成中性分子,因此可以利用还原后再氧化的方法分离出纯度较高的Gd@C82,比较而言,乙酸的氧化效果较好。本文也研究了富勒烯的合成实验条件和制备工艺。实验结果表明,如果放电前对碳棒进行活化,最后得到的Gd金属富勒烯的产率远高于未经活化而得到的产率：在压力为200±2 Torr氦气氛下,最佳放电条件：放电电流为160 A,放电电压为50 V,放电时两极间距为150 mm。实验研究表明,DMF高温高压法提取含金属Gd富勒烯的最佳提取条件：碳灰浓度为0.02 g/mL, DMF溶解碳灰时的加热温度为170℃,加热时间为20 h,加热后的冷却方式为烘箱内自然冷却至室温。上述提取条件为大量制备Gd@C82提供了保障。本文还在目前常用的分离金属富勒烯的HPLC方法基础上进行了改进,采取一次粗分、两次细分并交替使用不同色谱柱的方法,提高了含金属Gd富勒烯的分离效率及产物纯度。更多还原

【Abstract】 Synthesis and extraction of endohedral Gd-metallofullerenes, a typical lanthanide, were studied in this paper, which has a wide range of applications such as in the field of materials and biomedicine. A kind of chemical method was adopted to extract Gd@C82 from fullerene soot selectively and those extractants acquired by o-dichlorobenzene reflux, DMF reflux and DMF extraction under high-temperature and high-pressure respectively. The research results indicated that the reduction potentials of fullerenes can be varied by changing the ratio of THF and toluene in solution. Therefore, endohedral metallofullerenes and empty fullerenes were separated successfully. Compared with other commonly used separation processes such as HPLC, the chemical reduction process can be carried out easily and be cost effectively.Taking C6o anion and Gd@C82 anion as reference frame, and then dichloroacetic acid, acetic acid and phenol were utilized as oxidant to oxidize these anions mentioned above and reduced soot containing Gd-metallofullerenes. Moreover, characterization and analysis were performed by MALDI-TOF-MS, UV-Vis-NIR, HPLC(5PBB column). It turned out to be a possible approach to separate Gd@C82 at high purity and acetic acid was more appropriate to oxidize the samples that had been reduced in the chemical reduction process to produce neutral molecules.The experimental conditions and preparation method of fullerenes were also researched. Optimal DC arc-discharge conditions were achieved by improving discharging techniques and the yield of Gd@C82 increased significantly compared with those without activation and also by keeping the distance between anode and cathode remained 150 mm at the current 160 A, 50 V and under 200±2 Torr helium atmosphere.The extraction of metallofullerenes with DMF at high-temperature and high-pressure was analyzed further. The results showed that the proper concentration was 0.02 g/mL; the heating time was twenty hours, kept the temperature at 170℃and cooled inside the oven. These outcomes may pave the way for the preparation of Gd@C82 in bulk.In addition, some improvements were made on the basis of the widely used HPLC separation method. The purification was performed twice with complementary columns in this paper and this not only increased the purity but also improved the efficiency of extraction and separation.更多还原