Transition metal catalyzed reactions of fullerenes and carbon nanotubes

Abstract

Carbon nanomaterials such as fullerenes and single-walled carbon nanotubes (SWNTs) have opened up an exciting new field of research in chemistry. Fullerene research thus far has focused on modification to the outside of the carbon cage to change specific chemical properties, such as solubility or reactivity, to suit a particular target application. Although fullerenes have been shown to undergo facile reduction and to readily react with nucleophiles, oxidation has presented a problem. We have employed a transition metal catalyst to epoxidize fullerenes and create open-caged fullerenes. We have investigated the reactivity of hydroxyfullerene with a variety of metal salts under ambient aqueous conditions as well as replicating possible environmental exposure. We have proven fullerenol reacts irreversibly across a wide pH range with a variety of metal salts to form insoluble cross-linked polymers. It is clear that the interaction of hydroxyfullerenes with metals is an important issue with regard to waste treatment, fullerene exposure in the environment, and fullerene-based pharmaceutical agents. There is much interest in the development of methods that allow for the synthesis of SWNTs with particular helicities, which determines the electronic properties of SWNTs. It would be desirable to use pre-formed SWNTs as seeds for the growth of longer SWNTs. In order to accomplish this goal, it is necessary that a catalyst particle be preferentially docked to the end of an individual SWNT. Purification and characterization of a suitable iron-molybdenum nanocluster and the methodology for coupling catalyst precursors to a pre-formed SWNT are discussed. We have discovered a new method of solubilizing SWNTs in organic solvents. This was accomplished by creating a SWNT salt with a crown ether encapsulated sodium counter ion. Lastly, the effect of carbon nanomaterials on mineral formation was investigated. Water-soluble fullerene and SWNT derivatives produced new and interesting morphologies of calcium carbonate and barium carbonate