A method and apparatus for high-throughput controlled synthesis of fullerenes and endohedral metal fullerenes

A method for synthesis of carbon nanostructures in a high-frequency arc discharge in the flow of helium (3–4 L/min) is presented. It is shown that the plasma-chemical synthesis of fullerenes and endohedral metal fullerenes (EMFs) can be controlled by changing helium pressure in the chamber. Temperature and electron concentration along the line normal to the discharge axis decrease upon moving away from the axis to the periphery; the larger the pressure, the sharper is the decrease in these parameters. The optimal helium pressure of 98 kPa was found in obtaining the Gd@C₈₂ EMF which corresponds to the maximal EMF yield of 5 wt %.     

内包金属富勒烯C_(66)-C_(84)团簇的结构特征

从富勒烯笼五六元环的分布情况评述了内包单金属、双金属、三金属以及三金属氮化物(M_3N)和碳化物(M_2C_2)富勒烯C_(66)～C_(84)团簇的结构特征.富勒烯满足五元环最大分离规则,内包不同类型的金属团簇不仅改变了笼的稳定性顺序,也使C_(66)、C_(68)、C_(70)、C_(72)、C_(74)、C_(78)和C_(84)的部分异构体违背五元环最大分离规则 .     

Computational Study of Structure and Thermochemistry of Some Endo‐ and Exohedral Fullerene Derivatives

Abstract

DFT calculations were applied to the problem of fullerene isomerism. Two classes of thermally stable fullerene derivatives are considered: endohedral metallofullerenes, which in some cases reveal carbon cage topology different from that observed in the empty fullerenes of the same size, and fullerene fluorides, which have uniquely rich number of theoretically possible isomers.     

ISOLATION AND SPECTROSCOPIC STUDY OF A SERIES OF MONOTERBIUM ENDOHEDRAL METALLOFULLERENES

A series of monoterbium endohedral metallofullerenes Tb@C₈₀, Tb@C₈₆, and the second isomer of Tb@C₈₂ (II) has been produced and isolated from various hollow fullerenes and endohedral metallofullerenes by an efficient multi-stage chromatographic separation process for the first time. All these newly isolated metallofullerenes are characterized by laser-desorption time-of-flight (LD-TOF) mass spectrometry and UV-Vis-NIR absorption spectroscopy. Their possible molecular symmetries are discussed according to their HPLC retention time and absorption spectra.     

Interaction between fullerenes and single-wall carbon nanotubes: the influence of fullerene size and electronic structure

A series of fullerenes and endohedral metallofullerenes peapods have been synthesized by supercritical method in high filling rate. The interaction between SWNTs and various kinds of fullerenes (C60, C70, C78, C84) and metallofullerenes (Gd@C82, Er@C82, Ho@C82, Y@C82) has been further investigated. The slight blue shift of G-band in Raman spectra with respect to pristine SWNTs was attributed to the charge transfer from SWNTs to fullerenes cage. The obvious RBM shift strongly depended on the distance between the inner wall of the SWNTs and the fullerene cage and also partly associated with the electronic structure of the fullerene. These results indicated that the interaction between fullerenes and SWNTs, which was considered to be the van de walls interaction, can be influenced by the cage size and the kind of fullerenes.     

ISOLATION AND SPECTROSCOPIC STUDY OF A SERIES OF MONOTERBIUM ENDOHEDRAL METALLOFULLERENES

ABSTRACT

A series of monoterbium endohedral metallofullerenes Tb@C₈₀, Tb@C₈₆, and the second isomer of Tb@C₈₂ (II) has been produced and isolated from various hollow fullerenes and endohedral metallofullerenes by an efficient multi-stage chromatographic separation process for the first time. All these newly isolated metallofullerenes are characterized by laser-desorption time-of-flight (LD-TOF) mass spectrometry and UV-Vis-NIR absorption spectroscopy. Their possible molecular symmetries are discussed according to their HPLC retention time and absorption spectra.     

内嵌放射性金属同位素富勒烯的制备及生物学研究

综述了内嵌放射性金属同位素富勒烯的制备及医用研究现状。内嵌金属富勒烯的制备目前主要采用电弧放电法,但产率还较低;而放射性内嵌金属富勒烯的合成,主要是利用镧系区域的钬、钐和镥等具有合适的中子捕获截面及适当的半衰期的元素首先由电弧法制备,然后在中子的辐照下形成。因中子辐照会破坏碳笼,故放射性内嵌金属富勒烯的产率更低。动物实验是利用BALB/c小鼠和Fischer大鼠进行活体代谢实验,结果表明,放射性钬内嵌金属富勒烯主要分布于骨骼和肝脏,毒性低而靶向性高。放射性内嵌金属富勒烯有望成为新型放射性药物或示踪剂。     

金属氮化物富勒烯的研究现状

内嵌金属氮化物簇富勒烯的发现极大地扩展了内嵌富勒烯家族。内嵌金属氮化物富勒烯是一类将含有金属原子的氮化物(Mx-N,AxM3-x-N)包裹在富勒烯碳笼中的化合物,因其具有独特的分子结构和性质而受到人们广泛的研究和关注。阐述了合成金属氮化物富勒烯的方法,着重介绍了电弧法,探讨了氮源对电弧法合成金属氮化物富勒烯产量的影响,介绍了金属氮化物富勒烯常用的分离提纯方法,最后讨论了金属氮化物富勒烯的结构特点、性质和潜在应用。     

金属富勒烯包合物衍生物的合成进展

综述了近年来对合成金属富勒烯包合物衍生物的研究进展.Diels-Alder、1,3-偶极、硅烷化、羟基化、Bingel-Hirsch等是合成金属富勒烯包合物衍生物的主要方法,而碳笼内包合的簇的种类不同程度上影响着化学反应过程和金属富勒烯包合物衍生物的性能,这些金属富勒烯包合物衍生物所具有的新性能,在医药、材料和电子器件具有广阔的应用前景,同时展望了今后的工作.     

Biomedical activities of endohedral metallofullerene optimized for nanopharmaceutics

Endohedral metallofullerenes, a novel form of carbon-related nanomaterials, currently attract wide attention for their potential applications in biomedical fields such as therapeutic medicine. Most endohedral metallofullerenes are synthesized using C60 or higher molecular weight fullerenes because of the limited interior volume of fullerene. It is known that the encapsulated metal atom has strong electronic interactions with the carbon cage in metallofullerenes. Gd@C82 is one of the most important molecules in the metallofullerene family, known as Magnetic Resonance Imaging (MRI) contrast agent candidate for diagnostic imaging. Gadolinium endohedral metallofullerenol (e.g., Gd@C82(OH)22) is a functionalized fullerene with gadolinium trapped inside carbon cage. Our group previously demonstrated that the distinctive chemical and physical properties of Gd@C82(OH)22 are dependent on the number and position of the hydroxyl groups on the fullerene cage. The present article summarizes our latest findings of biomedical effects of Gd@C82(OH)22 and gives rise to a connected flow of the existing knowledge and information from experts in the field. It briefly narrates the synthesis and physico-chemical properties of Gd@C82(OH)22. The polyhydroxylated nanoparticles exhibit the enhanced water solubility and high purity, and were tested as a MRI contrast agent. Gd@C82(OH)22 treatment inhibited tumor growth in tumor-bearing nude mice. Although the precise mechanisms of this action are not well defined, our in vitro data suggest involvements of improved immunity and antioxidation by Gd@C82(OH)22 and its size-based selective targeting to tumor site. The review critically analyzed the relevant data instead of fact-listing, and explained the potential for developing Gd@C82(OH)22 into a diagnostic or therapeutic agent.     

Water-soluble fullerenes for medical applications

Research on fullerenes occupies a unique position in the scientific arena. Synthesis and characterisation of this nanomaterial blur the line between materials science and chemistry; careful tuning of the processing methods gives birth to a whole family of molecules and their functionalised derivatives, whose unusual properties at this nanoscopic scale can be exploited in cutting-edge technological applications. This review focuses on the functionalisation of fullerenes for use in medical applications. The first half gives an introduction to the fullerenes themselves and how their fundamental properties lead to a very rich chemistry, enabling both exohedral (external) and endohedral (internal) functionalisations of the cage. Emphasis is placed on the need for safe and reproducible synthesis routes if fullerenes are ever going to make it to the pharmaceutical market. In line with this, a selection of exohedral functionalisation protocols receives particular attention. Coverage of endohedral fullerene synthesis routes is limited to the endohedral metallofullerenes. In the second half, myriad applications of fullerenes in biomedical contexts are introduced and certain synthesis routes are critically evaluated. Discussion of the need to water solubilise the hydrophobic fullerene cages precedes an overview of fullerene-based diagnostic and therapeutic technologies. A final moment is spent on toxicity studies of fullerenes. The concluding remarks emphasise the positive effects of incorporating fullerenes into biomedical technologies, while looking at how these are perceived by the general public. A case is made for fullerenes being the optimal choice as standard bearers in the advance of nanomaterials into the medical field.

This is the winning review of the 2016 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining, run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged.     

A Review on Endohedral Metallofullerenes: Structures and Properties

The present review deals with some recent results on endohedral metallofullerenes obtained by the Nagoya group. The present structural analyses reveal unique of endohedoral metallofullerenes: (1) the presence of structural isomers with different fullerene cage structures; (2) encaged metal atoms are situated close to the carbon cage and not in the center of the cage; (3) metal atoms in Y@C82 and Sc2@C84 are at a standstill, not moving around, even at room temperature.     

Quantitative analysis of endohedral metallofullerenes by Rutherford backscattering of protons

Samples containing endohedral metallofullerenes of gadolinium (Gd@C₈₂) and dysprosium (Dy@C₈₂) are investigated by the Rutherford backscattering of protons. It is shown that the concentration of endohedral metallofullerenes can be determined to within a few percent. The measured concentration of endohedral metallofullerenes Gd@C₈₂ and Dy@C₈₂ in samples prepared by selective multistep extraction is ∼60%. Pis’ma Zh. Tekh. Fiz. 25, 24–30 (May 26, 1999)     

Fullerenes and Carbon Nanotubes Formed in an Electric Arc at and Above Atmospheric Pressure

[60]Fullerene and carbon nanotubes have been obtained with an electric arc discharge in helium or argon at the pressure of 0.1-3.0 bar (i.e. from -0.9 up to 2.0 bar above the atmospheric pressure, respectively). The yield of the process is about 10 times higher in helium with a maximum at the pressure of 0.2 bar, while in argon the maximum is observed at 0.4 bar. It is not very important, what kind of the inert gas (He or Ar) is used in a process carried out at the atmospheric pressure and higher. In this case, the yield is usually better or comparable with other alternative methods, e.g. the solar furnace synthesis. We found that the oxygen plays a crucial role reducing the yield of fullerenes and carbon nanotubes. Even traces of O₂ must be removed from the reactor chamber, otherwise yellow coloured fullerene derivatives (oxidation products) are formed instead of C₆₀.     

A density functional theory investigation for the open-shell metal-carbide endofullerene Lu3C2@C88(D2:35) and closed-shell metal-nitride endofullerene Lu3N@C88(D2:35)

By means of the density functional theory calculations, two C88(D2:35)-based endohedral fullerenes, Lu3C2@C88(D2:35) and Lu3N@C88(D2:35) which encapsulate tri-lutetium carbide and tri-lutetium nitride cluster were investigated. For the cores in Lu3C2@C88 and Lu3N@C88, the trivalent C2 and N respectively template a butterfly-shaped endohedral moiety and a planar tri-lutetium cluster within the same D2-symmetric C88 cage. Moreover, Lu3N@C88 - D2 has a closed-shell electronic structure but for LuC3C2@C88 - D2, it owns an unpaired electron mainly localized on the internal Lu3C2 cluster. These results clearly showed that the core unit C2(3) as well as N3- play an important role in constructing molecular structures and electronic features of metallofullerenes. Furthermore, the electrochemical redox potentials, and vibrational frequencies of the two endofullerenes agree well with our experimental results. The electronic structures, ionization energies, electron affinities, inner clusters' dynamic motions of them have been predicted to further disclose the characters of these two metallofullerenes.     

Fullerene Research in Poland

Main results of the investigations of fullerene and its derivatives are briefly reviewed. Such topics as plasma spectroscopy, fullerenes and nanotubes formation, C₆₀ carbyne knots, fullerene reduction and doping, charge transfer states and electroabsorption of C₆₀, electrical conductivity, superconductivity, ESR properties, fullerene clathrates, C₆₀/C₇₀ complexes with organic donors, fullerene adducts, hydrogenated fullerenes, metallofullerenes and carbon nanotubes are discussed.     

Kinetics of Fullerene Formation in a Contact Arc Generator

A kinetic model of the fullerene growth process in a contact arc generator is developed. On the basis of the kinetic model, the yield of the magic fullerenes C₆₀ and C₇₀ is calculated. The fullerene yield is determined by the temperature gradient in the fullerene formation zone, the carbon vapor concentration and the helium jet velocity in the interelectrode space. We found that the upper boundary value of the magic fullerene yield was about 20%.     

Kinetics of Fullerene Formation in a Contact Arc Generator

Abstract

A kinetic model of the fullerene growth process in a contact arc generator is developed. On the basis of the kinetic model, the yield of the magic fullerenes C₆₀ and C₇₀ is calculated. The fullerene yield is determined by the temperature gradient in the fullerene formation zone, the carbon vapor concentration and the helium jet velocity in the interelectrode space. We found that the upper boundary value of the magic fullerene yield was about 20%.     

Raman spectroscopy of fullerenes and fullerene-nanotube composites

The discovery of fullerenes in 1985 opened a completely new field of materials research. Together with the single-wall carbon nanotubes (SWCNTs) discovered later, these curved carbon networks are a playground for pure as well as applied science. We present a review of Raman spectroscopy of fullerenes, SWCNTs and composite materials. Beginning with pristine C(60), we discuss intercalated C(60) compounds and polymerized C(60), as well as higher and endohedral fullerenes. Concerning SWCNTs, we show how the diameter distribution can be obtained from the Raman spectra and how doping modifies the spectra. Finally, the Raman response of C(60) encapsulated into SWCNTs (C(60) peapods) is discussed.     

Radiochemical approaches for formation of endohedral fullerenes and MD simulation

The formation of atom-doped fullerenes has been investigated by using several types of radionuclides produced by nuclear reactions. From the trace of the radioactivities after a high performance liquid chromatography, it was found that formation of endohedral fullerenes (or heterofullerenes) of small atoms (Be, Li), noble-gas atoms (Kr, Xe) and 4B–6B elements (Ge, As, Se, Sb, Te, etc.) is possible by a recoil process following the nuclear reaction. In order to show the possibility of creating endohedral fullerenes with a suitably high kinetic energy of foreign atoms, we have carried out large-scale ab initio molecular dynamics simulations on the basis of the all-electron mixed-basis approach with atomic orbitals and plane waves for several atoms.