| Summary: | <p>Endohedral fullerenes are remarkable molecules with unique electronic, magnetic, photovoltaic and quantum properties. They have found a number of applications in various fields. Among all the potential applications, one particularly interesting application is to employ them as building blocks for a quantum computer. However, the scientific and commercial exploitation of these materials is held back by their low productivity. In this project, the arc discharge synthesis of endoedral fullerenes which remains the most promising candidate for producing bulk quantities of Endohedral Metallofullerenes (EMFs) was divided into 4 steps, and in this thesis, I discuss the attempts that had been made to optimise each of them. In this project, I focus on Y&commat;C<sub>82</sub>, which is a spin active endohedral fullerene with attractive quantum properties. I obtained sights into the dynamics of the Soxhlet extraction of fullerenes, and developed an optimised Soxhlet scheme which is able to extract 95% of Y&commat;C<sub>82</sub> from the soot within 60 hours (Chapter 4). Further progress on the optimization of Soxhlet extraction was made when a two-stage Soxhlet extraction/purification was independently developed (chapter 9). This method employs two solvents (toluene and DMF) to extract fullerenes with different dipolar moment. It was not only able to extract fullerenes effectively from the soot, but also to purify EMFs/Trimetallic nitride template(TNT) into high purity (97%).</p> <p>Efforts were made to search for the best conditions for generating Y&commat;C<sub>82</sub> with a patented pilot arc discharge system. After analysing the data of the yield of fullerenes in various conditions with a "2<sup>2</sup> factorial design of experiment", I believe the yields of Y&commat;C<sub>82</sub> can be increased by using high He pressure (Chapter 5).</p> <p>The scaling up the production of EMFs was also tackled from a more fundamental and theoretical aspect. Although fullerenes have been efficiently synthesized by several methods to date, the formation mechanism of these materials remains a mystery. The study of the fullerene formation mechanism in arc discharge is particularly rare due to intrinsic technical difficulties. In chapter 6, I propose a new "bottom up" formation scenario in the arc discharge synthesis of fullerenes that adopts the so called "closed network growth".</p> <p>Attempts that were made to improve the efficiency and safety of the current system were introduced in Chapter 7. Concepts to develop a more efficient safe arc discharge system were suggested and discussed in the same chapter. The Lewis acid separation method was reported to be an efficient approach to remove the empty cages from the EMFs<sup>1</sup>, however, this method is only suitable for a lab equipped with specialized facilities and cannot be characterized as generic (Chapter 8).</p> <p>Finally, I have applied a functionalization scheme to C<sub>60</sub> which may be a promising scheme to functionalize spin-active metallofullerenes to produce a two-qubit quantum information system (Chapter 10).</p>
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