Process Parameter Optimisation for Endohedral Metallofullerene Synthesis via the Arc-Discharge Method

Abstract

Fullerenes have a unique structure, capable of both encapsulating other molecules and reacting with those on the exterior surface. Fullerene derivatives have also been found to have enormous potential to address the challenges of the renewable energy sector and current environmental issues, such as in the production of n-type materials in bulk heterojunction solar cells, as antimicrobial agents, in photocatalytic water treatment processes, and in sensor technologies. Endohedral metallofullerenes, in particular, can possess unpaired electron spins, driven by the enclosed metal atom or cluster, which yield valuable magnetic properties. These properties have significant potential for applications in molecular magnets, spin probes, quantum computing, and devices such as quantum information processing,, atomic clocks, and molecular magnets. However, the intrinsically low yield of endohedral fullerenes remains a huge obstacle, impeding not only their industrial utilization but also the synthesis and characterization essential for exploring novel applications. The low yield and difficulty in separation of different types of endohedral fullerenes results in the usage of a large amount of solvents and energy, which is detrimental to the environment. In this paper, we analyse the methodologies proposed by various researchers and identify the critical synthesis parameters that play a role in increasing the yields of fullerenes.

Screening and Antiscreening Effects in Endohedral Nanotubes

“…Since the discovery of buckminsterfullerene (C 60 ), this complex has received intense study, also considering that although C 60 is the most stable and the most common naturally occurring fullerene, many other cage-like nanostructures have been obtained and can be hypothesized by both considering different numbers of carbon atoms and also replacing carbons with other atoms. Interestingly, by high-energy collisions of ionized fullerene species, harsh conditions of high temperature and pressure, electric arc, or organic synthesis methods (“molecular surgery”), it is nowadays possible to produce C 60 endohedral complexes with metal ions, noble gases, and small molecules, such as H 2 , N 2 , H 2 O, and CH 4 (the first organic molecule to be encapsulated). − Such recent achievements in the synthesis of endohedral fullerene complexes have stimulated many experimental and theoretical investigations since the cavity inside fullerenes provides a unique environment for the study of isolated atoms and molecules. Moreover, these systems represent ideal models to study how confinement effects can induce changes in the structural and electronic properties of small molecular species and also provide a possible way to alter the properties of the otherwise rather inert fullerenes.…”