Synthesis and Functionalizations of Trimetallic Nitride Template Endohedral Metallofullerenes (TNT-EMFs)

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dc.contributor.authorWang, Xueleien
dc.contributor.committeechairDorn, Harry C.en
dc.contributor.committeememberAnderson, Mark R.en
dc.contributor.committeememberHanson, Brian E.en
dc.contributor.departmentChemistryen
dc.date.accessioned2014-03-14T20:41:16Zen
dc.date.adate2006-09-29en
dc.date.available2014-03-14T20:41:16Zen
dc.date.issued2006-06-29en
dc.date.rdate2006-09-29en
dc.date.sdate2006-07-10en
dc.description.abstractThis thesis addresses the synthesis of a new mix-metal trimetallic nitride template endohedral metallofullerene (TNT-EMF) and the functionalizations of M3N@C80 (M = Sc, Gd, Ho) under the high-speed vibration milling (HSVM) condition. In addition, this thesis discusses the internal motion of the cluster, Sc3N inside three different carbon cages, C68, C78 and C80. Water-soluble derivatives of endohedral metallofullerenes possess a unique potential for medical applications, such as magnetic resonance imaging (MRI) contrast agents, X-ray contrast agents and nuclear medicine. The TNT-EMFs have inherent advantages over other endohedral metallofullerenes, such as M@C60 and M@C82, due to the encapsulation of up to three metal atoms inside the carbon cages. M3N@C80(OH)m(O)n (M = Sc, Gd, Ho) were synthesized under the HSVM condition and characterized by FT-IR, MALDI-TOF and XPS. The relaxivity studies on these water-soluble derivatives have shown that Gd-based metallofullerols have significantly higher relaxivities than commercially used MRI contrast agents (e.g. OmniscanTM) and can be the next generation MRI contrast agent. The Ho containing species has a high R2/R1 ratio compared to other samples showing the potential to be a T2 agent. In contrast to homonuclear M3N clusters, there is a paucity of mixed-metal cluster cases of TNT-EMFs reported to date because the mixed-metal metallofullerenes are difficult to be separated and purified. In this thesis, CeSc2N@C80 was synthesized, separated in pure form and fully characterized. Single-crystal X-ray diffraction shows that CeSc2N@C80 consists of a four atom asymmetric top (CeSc2N) inside a C80 (Ih ) carbon cage and the nitride ion is not located at the center of the carbon cage but is offset by 0.36 Å. The NMR studies, together with the XPS results, show that CeSc2N@C80 is a weakly paramagnetic system with a single buried f electron spin. A new cage isomer of the Sc3N@C80 (D5h) metallofullerene was also isolated from the Ce-Sc mixture and the cage symmetry was confirmed by single-crystal X-ray diffraction. The internal motion of the metal-nitride cluster, Sc3N within the carbon cages (C68, C78 and C80) was studied at various temperatures using 45Sc NMR spectroscopy. The reorientation barriers (presumably dominated by motion internal to the cage) were calculated for these three TNT-EMFs. The preliminary results show that the quadrupole coupling constant of Sc3N@C80 (Ih) is quite close to that of Sc3N@C68.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-07102006-175022en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07102006-175022/en
dc.identifier.urihttp://hdl.handle.net/10919/33954en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartThesisfinal.pdfen
dc.relation.haspartTableofContents2.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjecthigh-speed vibration millingen
dc.subjectTrimetallic nitride templateen
dc.subjectendohedral metallofullereneen
dc.subjectfunctionalizationen
dc.titleSynthesis and Functionalizations of Trimetallic Nitride Template Endohedral Metallofullerenes (TNT-EMFs)en
dc.typeThesisen
thesis.degree.disciplineChemistryen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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