Functionalization Of Higher Empty And Endohedral Fullerenes

Fullerenes have attracted worldwide research interest due to its unique structure and properties as well as potential applications in the field of biotnedicine, organic photovoltaics and nano-materials. Functionalization of fullerenes is beneficial for structural characterization of fullerenes, especial for higher fullerene with low yield and huge number of isomers. On the other hand, it can provide valuable information about the chemistry of fullerenes which is helpful for the applications of fullerenes. In this dissertation, we focus on fuctionalization of higher empty and endohedral fullerenes, and have carried out the following works:1) We synthesized a mixture of empty fullerenes by DC-arc discharge method and isolated the Cgg-and C98-containing fraction by high performance liquid chromatography (HPLC). The fractions were chlorinated with VCI4 and SbCl5 as the chlorination reagents. We characterized the structure of chloride derivatives by using synchrotron radiation X-ray crystallograghy. The determined chlorinated products of C88 are C88(7)Cl12/24, C88(17)Cl22, and C88(33)Cl12/14 for which the chlorine addition patterns are unusual. Especially surprising are the presence of unoccupied pentagons in the molecules with 12 or more (up to 24) attached chlorine atoms in C88(7)Cl12, C88(7)Cl24, and C88(33)C112 as well as the attachment of one chlorine to the position of a triple hexagon junction in C88(7)Cl12. The chlorinated products of C98 are C98Cl22 and C98Cl20, which correspond to isomer C98(248) and C9g(116) respectively. As the firstly reported isomers of C98, the former is the most stable isomer based on DFT calculation and the latter is less stable.2) We isolated a C100-containing fraction from the mixture of empty fullerenes by using HPLC. The C100-containing fraction was chbridized with VCl4 and SbCl5 as the chloride reagents, followed by the structural characterization by synchrotron radiation single crystal X-ray diffraction. Unexpectedly, the obtained chlorinated product is C96Cl20, which is a non-classical (NNC) carbon cage containing three heptagons. The carbon cage also contains pentagon fusions such as pentagon pairs and pentagon triples. Three heptagons were formed via two successive C2 bsses and a Stone-Wales rearrangement According to structural reconstruction, we established C2-C100O8) as the starting IPR isomer.3) We isolated a series of giant fullerene C100,C102, C104, C106, and C108 from the mixture of empty fullerenes by using HPLC. The individual fractions were chlorinated with VCl4 and SbCl5 as the chloride reagents, and the chlorinated products were characterized by synchrotron radiation X-ray diffraction systematically. Chloride products of C100 are determined to include C1-C100(425)Cl22, C2-C100(18)Cl28/30, and Cs-C100(417)Cb8, which correspond to IPR isomer C100(425), C100(18), and C100(417), respectively. Cs-C100(417)Cb8 undergoes a skeletal transformation by the loss of a C2 fragment, resulting in the formation of a non-classical (NC) C1-C98(NC)Cl26 with a heptagon in the carbon cage. According to C 102(603)Cl18/20 and C104(234)Cl16-22, the DFT calculated most stable isomer C102<603) and C104(234) were first experimentally confirmed. For C106 and C108, according to C106(1155)Cl24 and C108(1771)Cl12, the starting isomers were confirmed as C106(1155) and C108(1771), and this is the first time to report the isomer structure of C106 and C108. C106(H55)Ch4 and C104(NC)Cl24 were presence in the same crystallography site, the latter is a non-classic fullerene.4) We synthesised and characterized a Bingel-Hirsch derivative of a mixed metal nitride clusterfullerene (MMNCF) TiY2N@Ih-C80 based on a higher endohedral fullerene cage. According to the mass spectrometry, the Bingel-Hirsch derivative of TiY2N@Ih-C80 is a monoadduct labed as TiY2N@Ih-C80-Mono. The structure of TiY2N@Ih-C8o-Mono was characterized by single crystal X-ray diffraction, revealing that it was a singly bonded derivative. It differs to the conventional cyclopropane derivative of trimetallic nitride cluster fullerenes (NCFs). The reactivity of TiY2N@Ih-C80 was found to be significantly improved relative to that of Y3N@IIh-Cgo. The regioselectivity of TiY2N@C80-Mono is much higher than that of the analogous MMNCF TiSc2N@C80. UV/vis/NIR spectroscopy revealed that the peculiar single-bond addition pattern led to a considerable change in the electronic structure of TiY2N@C80. On the basis of theoretical calculations, we were able to propose the formation mechanism of TiY2N@C80-Mono. Upon substituting one endohedral yttrium (Y) atom of Y3N@Ih-C80 with titanium (Ti), the Bingel-Hirsch derivative changes from the cyclopropane to the singly bonded monoadduct, which reveal that not only the reactivity but also the addition pattern of NCFs can be manipulated through one endohedral metal atom substitution...