This dissertation addresses the exohedral cage functionalization and potential applications of the Sc₃N@C₈₀ and Sc₃N@C₇₈ trimetallic nitride endohedral metallofullerenes. In addition, this dissertation discusses miscellaneous research that is relevant to the aformentioned metallofullerenes and their applications, such as the discovery of a new cage isomer <i>(D<sub>5h</sub>)</i> of Sc₃N@C₈₀, the synthesis of Lu₃N@C₈₀ as a novel X-ray contrasting agent, and the synthesis of Sc₃¹⁵N@C₈₀ with ¹⁵N₂ gas.
The first derivative of Sc₃N@C₈₀ was synthesized by functionalizing the exterior of the cage via a [4 + 2] cycloaddition reaction with a ¹³C-labeled intermediate. Addition occurred across the [5,6] ring-juncture of the cage to form a mono-adduct, which has a mirror plane of symmetry as observed from the time-averaged ¹³C NMR spectrum. The structure of the mono-adduct was confirmed by X-ray crystallography. Diethyl and dibenzyl malonate adducts of Sc₃N@C₈₀ were synthesized, in addition to a ¹⁵N-labeled terminal amine derivative. Water-soluble metallofullerenols, Sc₃N@C₈₀(OH)<sub>~10</sub>(O)<sub>~10</sub>, were synthesized from polyanionic intermediates.
The Sc₃N@C₇₈ metallofullerene was derivatized with a ¹³C-labeled reagent to afford mono-, di- and tri-adducts. A single structural isomer of the mono-adduct was found, while several isomers of the di- and tri-adducts were observed by HPLC. ¹³C and ¹H NMR data of the mono-adduct support a structure that results from addend addition to an asymmetric site on the C₇₈ carbon cage.
The HPLC isolation and characterization of Lu₃N@C₈₀ is discussed. When irradiated with X-rays, Lu₃N@C₈₀ provided a small level of contrast that can only be attributed to the large atomic number (Z) of the lutetium atoms. Mixed-metal species that contains gadolinium and lutetium or holmium and lutetium could be employed as multifunctional contrasting agents for X-ray, MRI and radiopharmaceuticals, thereby eliminating the need for three separate agents.
A new cage isomer of the Sc₃N@C₈₀ metallofullerene was synthesized and partially isolated by HPLC. This carbon cage possesses <i>D<sub>5h</sub></i> symmetry, as indicated by the time-averaged six line ¹³C NMR spectrum with a 1:2:2:1:1:1 ratio.
The internal metal-nitride cluster of Sc₃N@C₈₀ was synthesized with a ¹⁵N-label for studying the motion(s) of the cluster (within the carbon cage) at various temperatures using ¹⁵N NMR spectroscopy. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/29325 |
| Date | 24 October 2003 |
| Creators | Iezzi, Erick B. |
| Contributors | Chemistry, Dorn, Harry C., Deck, Paul A., Tanko, James M., Long, Timothy E., Hanson, Brian E. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | E.B.Iezzi-PhD-dissertation.pdf |
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