Double-Toroid,Almost-Polyhex Fullerenes

Abstract

This study presents examples of double-toroid fullerenes comprised entirely of hexagonal faces except as required by Euler's polyhedron closure rule. Kekulé structure counts give a rough idea of stability of these structures relative to each other and to other types of fullerenes with the same carbon number (C₁₂₀). Electronic constraints demanded by the various atomic arrangements are discussed, along with possible applications.     

Zirconium Cage-Doped Fullerenes

Some zirconium containing fullerenes were synthesized by vaporizing a zirconium-containing graphite anode with DC arc discharge technique, extracted by CS2 through low temperature extraction method, and characterized by field desorption mass spectra (FDMS). The results show that these doped fullerenes were zirconium cage-doped fullerenes.     

Zirconium Cage-Doped Fullerenes

Abstract

Some zirconium containing fullerenes were synthesized by vaporizing a zirconium-containing graphite anode with DC arc discharge technique, extracted by CS2 through low temperature extraction method, and characterized by field desorption mass spectra (FDMS). The results show that these doped fullerenes were zirconium cage-doped fullerenes.     

Fullerenes and Viruses

Abstract

It is well known that any, sometimes very small, changes in the chemical structure can lead to the dramatic changes in biological properties. Therefore it is necessary to divide into two different topics the studies of biological properties of fullerene and fullerene‐like compounds. In the enormous variety of data on the biological activity of fullerenes it is possible to select some with defined mechanism of action. This selection showed that in case of using the fullerene‐containing compositions the main mechanisms of drug action, namely unspecific, specific (ligand–receptor) interaction and membranotropic can be obtained. Therefore fullerenes as compounds with broad biological potential are very promising not only for the design of antiviral compounds, but also for the design of various types of drugs.     

Fullerenes with Non-Positive Gaussian Curvature: Holey-Balls and Holey-Tubes

Classical fullerenes such as C₆₀ and C₇₀ need 12 pentagonal rings of carbon for the closure of the cage. These pentagons produce the positive Gaussian curvature which gives the characteristic spherical shape. In this paper we propose a new family of fullerene-like structures which do not have pentagonal rings (no positive Gaussian curvature), no dangling bonds, possesing hexagons and heptagons only. The topology of this new family of perforated fullerenes (holey-balls) and nanotubes (holey-tubes) is higher than classical fullerenes presenting genus 5, 11 up to 21. Holey balls can be icosahedral (I_h) and cubic (O_h). The geometry, elastic stabilities and possible applications of holey-balls and holey-tubes are studied.     

An Invariant of Carbon Arc Synthesis of Fullerenes

The yields of fullerenes C₆₀ and C₇₀ were determined in a wide range of controlled parameters. The total yield of fullerenes varied from 3 to 24%. The molar relative contents C₆₀/C₇₀ appeared to be constant for all samples of toluene extracts of the soot and equal to 5.06 ± 0.1. The accuracy of this constancy (± 2%) was determined by application of a special mathematical processing to the spectra of toluene extracts.     

Oxidation of Fullerenes by Ozone

Like typical alkenes, fullerenes can be oxidized by ozone. Epoxidation reaction takes place on C₆₀, and C_6oOn (n = 1-5) are formed. Mass spectrometry and chromatography identified the stable existence of two isomers for the dioxides and three for the trioxides in the product mixtures. At lower temperatures, fragmentation occurs and results in the formation of the polar products. C₇₀ and carbon nanotubes also react with ozone but at a much slower rate.     

Dependence of Endohedral Fullerenes Formation on Laser Ablation Parameters of Carbonaceous Materials

Endohedral fullerenes containing yttrium atoms were produced by laser irradiation of mixtures of carbonaceous compounds and yttrium oxide targets. The laser irradiance, the temperature, the ablation wavelength and the nature of the target were studied more precisely. The analyses are performed with a Laser Microprobe coupled with Mass Spectrometry (LMMS). The study of spectral fingerprints on both positive and negative modes allows to evaluate the relative distribution of metalfofullerenes compared to classical fullerenes according the laser ablation parameters.     

An Invariant of Carbon Arc Synthesis of Fullerenes

Abstract

The yields of fullerenes C₆₀ and C₇₀ were determined in a wide range of controlled parameters. The total yield of fullerenes varied from 3 to 24%. The molar relative contents C₆₀/C₇₀ appeared to be constant for all samples of toluene extracts of the soot and equal to 5.06 ± 0.1. The accuracy of this constancy (± 2%) was determined by application of a special mathematical processing to the spectra of toluene extracts.     

On the Limitation of Net Algorithm for Enumerating Isomeric Structures of Giant Fullerenes

Application of our net algorithm to the generation of all possible IPR isomers for giant fullerenes C_n, n=102 to 120, missed nine out of 39,621 possible structures. Analysis revealed that the omission of too small and too large cap triangles was the reason. Within the range of fullerenes studied, the missed structures are of high-energy and do not affect the distribution of significantly low-energy isomers.     

Study of Fullerenes, Nanotubes and Nanowires by Transmission Electron Microscopy

The arc discharge reactor developped by Kratschmer et al^l produces a variety of new carbonaceous solids, including fullerenes and different kinds of graphitic cages of nanometric size, which can be hollow or filled with various materials. Complementary to neutron and X ray diffraction techniques, transmission electron microscopy rapidly appeared among the most important techniques for studying the structures of fullerenes and fullerites^2-6. Very generally, it allows us to obtain diffraction patterns of micronic size crystallites and the different imaging modes provide an unique tool to investigate in real space the morphology of the crystallites, structural defects faults at microscopic and nanometric scales^6-8. It is possible to perform very local chemical analysis and to study chemical environments in order to determine the nature of chemical bonds⁹. Futhermore, it is possible to study phase transitions through in situ experiments^5,10-12 and the behaviour of fullerites upon electron irradiation¹³. The interest of this technique has appeared even more crucial with the discovery of narotubes¹⁴ and their ability to be filled¹⁵ since, because of their nanometric size, the electron microscopy is at the moment the unique tool allowing their study and is therefore a challenge in the development of these new materials for applications in nanotechnology.     

On the Limitation of Net Algorithm for Enumerating Isomeric Structures of Giant Fullerenes

Abstract

Application of our net algorithm to the generation of all possible IPR isomers for giant fullerenes C_n, n=102 to 120, missed nine out of 39,621 possible structures. Analysis revealed that the omission of too small and too large cap triangles was the reason. Within the range of fullerenes studied, the missed structures are of high-energy and do not affect the distribution of significantly low-energy isomers.     

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。     

Study of Fullerenes,Nanotubes and Nanowires by Transmission Electron Microscopy

Abstract

The arc discharge reactor developped by Kratschmer et al^l produces a variety of new carbonaceous solids, including fullerenes and different kinds of graphitic cages of nanometric size, which can be hollow or filled with various materials. Complementary to neutron and X ray diffraction techniques, transmission electron microscopy rapidly appeared among the most important techniques for studying the structures of fullerenes and fullerites^2?6. Very generally, it allows us to obtain diffraction patterns of micronic size crystallites and the different imaging modes provide an unique tool to investigate in real space the morphology of the crystallites, structural defects faults at microscopic and nanometric scales^6?8. It is possible to perform very local chemical analysis and to study chemical environments in order to determine the nature of chemical bonds⁹. Futhermore, it is possible to study phase transitions through in situ experiments^5,10–12 and the behaviour of fullerites upon electron irradiation¹³. The interest of this technique has appeared even more crucial with the discovery of narotubes¹⁴ and their ability to be filled¹⁵ since, because of their nanometric size, the electron microscopy is at the moment the unique tool allowing their study and is therefore a challenge in the development of these new materials for applications in nanotechnology.     

Extraction of Exotic Fullerenes and Purification of Single-Walled Nanotubes

In this report, we presented a novel and simple extraction method, namely Hydrothermally Initiated Dynamic Extraction (HIDE) method, which allows the extraction of exotic fullerenes remaining in the fullerene soot. In the HIDE method, the soot was treated in boiling water that neither dissolved fullerenes nor produced minimal by-products but untangles the fullerenes from the soot, prior to the extraction by organic solvent. As a result, the HIDE method allowed the extraction of exotic fullerenes, such as dimeric fullerene oxides, higher fullerenes having a low symmetry and oxidized higher fullerenes. Accordingly, the single walled nanotubes (SWNTs) with a purity of 99% by wt was achieved for the first time with the application of the HIDE method.     

Extraction of Exotic Fullerenes and Purification of Single-Walled Nanotubes

Abstract

In this report, we presented a novel and simple extraction method, namely Hydrothermally Initiated Dynamic Extraction (HIDE) method, which allows the extraction of exotic fullerenes remaining in the fullerene soot. In the HIDE method, the soot was treated in boiling water that neither dissolved fullerenes nor produced minimal by-products but untangles the fullerenes from the soot, prior to the extraction by organic solvent. As a result, the HIDE method allowed the extraction of exotic fullerenes, such as dimeric fullerene oxides, higher fullerenes having a low symmetry and oxidized higher fullerenes. Accordingly, the single walled nanotubes (SWNTs) with a purity of 99% by wt was achieved for the first time with the application of the HIDE method.     

A Note on Fullerenes

The existence of fullerenes with any number of hexagons different from 1 is proven in a simple way.     

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。     

A New Molecular Mechanics Computer Program for Giant Fullerenes and Nanotubes

The molecular mechanics computer program is designed to study the structure of fullerenes with icosahedral symmetry and carbon nanotubes. The program takes full advantage of symmetry. The program predicts meaningful conformations, energies of formation for symmetrical fullerenes as well as for the carbon nanotubes for which also the elastic properties are calculated.

The systematic IUPAC nomenclature of fullerenes and fullerenes derivatives is discussed. Comments are made on terminology questions and on the chemical non-aromaticity of fullerenes.     

Gas Effusion Spectra of Fullerenes

Gas effusion spectra of fullerenes are studied. Three peaks of toluene are found in gas effusion spectra dp/dT-T. Two peaks of oxygen are found in gas effusion spectra dN/dt-T of samples kept in the air after annealing to avoid the toluene. These phenomena confirmed to be reversible are discussed by treating fullerenes as intercalated materials.