Investigation of condensed products of graphite evaporation in an electric arc in argon and helium atmosphere

The composition of products formed in the discharge chamber at the synthesis of nanostructures by arc discharge was investigated. The fullerene soot obtained in an argon atmosphere was shown to contain at least three structural phases: amorphous carbon, fullerenes, and graphitized particles. In the process of thermal desorption, the water and oxygen adsorbed from the atmosphere, as well as carbon oxides generated at the oxidation evolve from the argon soot. By the reactivity, the fullerene black obtained in different buffer gases form a series: special helium, argon, usual helium. The cathode deposit of the arc discharge in argon, as in helium, contains multiwall nanotubes in its soft parts.     

Fused five-membered rings determine the stability of C60F60

The structure and stability of a set of (CF)60 isomers have been computed at the B3LYP/6-31G(d) density functional theory level. The most stable isomer (6, F4@C60F56) has tube-like structure with four endo C-F bonds and fused five-membered rings at the end of the tube, while the reported most stable cage structure (2, F8@C60F52) with eight endo C-F bonds is higher in energy by 22.6 kcal/mol. This is in contrast to the isolated pentagon rule for the stability of fullerenes. The mean bond dissociation energy of 6 is larger than those of the experimental known C60F36, C60F48, and graphite fluoride. The relative energy per CF unit of 6 to graphite fluoride (CF)n is 3.7 kcal/mol, which is smaller than that of C60 fullerene per carbon to graphite (about 9-10 kcal/mol).     

提高大分子Fullerene含量的有效方法

通过用掺有异相物质的石墨电极进行电弧反应，所得的混合物中大分子Ｆｕｌｌｅｒｅｎｅ的含量在１０％以上，为进一步分离，提纯以及深入研究大分子Ｆｕｌｌｅｒｅｎｅ打下了基础。研究发现，阳极材料中完整石墨结构的存在是生成Ｆｕｌｌｅｒｅｎｅ的必要条件，异相物质的存在为Ｆｕｌｌｅｒｅｎｅ的生长提供了热的载体，从而使产物中大分子Ｆｕｌｌｅｒｅｎｅ的含量增加。     

Determination of the Electron Density Distribution in the Bonds of a Fullerene Derivative by High-Resolution X-Ray Structure Analysis

Bent bonds in the strained fullerene system , restricted to the [5,6] bonds, were detected by high-resolution X-ray structure analysis of the 1,2-dihydro[60]fullerene derivative 1 . In addition the maxima of electron densities are higher in the [6,6] bonds than in the [5,6] bonds—an important finding with respect to the question of the extent of electron delocalization in fullerenes.     

More spherical large fullerenes and multi-layer fullerene cages

According to the experimental investigation, the carbon nano-particles have spherical multi-layer structure (also called onion-like carbon structure). Theoretically, the optimum structures of these large fullerenes contain highly faceted shapes with icosahedral symmetry. This discrepancy in structure may be attributed to the formation mechanism. Thus, a method is devised to construct spherical large fullerenes (C₂₄₀, C₅₄₀, C₉₆₀, C₂₁₆₀, C₂₉₄₀, C₃₈₄₀, C₄₈₆₀) by using the triangular motif. The 5–7–5–7 shape defect is applied in this method for assembling the large spherical fullerenes which could transform the graphene sheet to a spherical motif via SW rearrangement. The geometry-optimized structures of large spherical fullerenes have been generated by molecular mechanics calculation. Then, the average radius and standard deviation of these large fullerenes were obtained to verify the spherical shape. The multi-layer fullerene with spherical shape was confirmed by the TEM observation. According to the structure analysis, the distance between two neighboring encapsulating carbons is about 3.5 Å, which approximately coincides with the distance between two layers of graphite. The van der Waals force per carbon atom and of multi-layer fullerene with the spherical shape generated by force field calculation, predict their relative stability.     

C60与叠氮化合物的单加成反应

本文从实验以及理论研究两方面介绍了C60与叠氧化合物的单加成反应。依照叠氮化合物的不同,C60与叠氮合物的单加成反应可分为烷基叠氮化物与C60的反应,酰基叠氧化物与C60的反应以及苯基叠氮化与C60的反应三类,而反应产物则为C60亚氨基[6,6]闭环衍生物和C60亚氨基[5,6]开环衍生物两类,不同类型的反应具有不同的反应机理,某些C60亚氨基[5,6]开环衍生物可以转化为C60亚氨基[6,6]闭环衍生物。本文还介绍了碳纳米管与叠氮化合物的加成反应。     

Technology for manufacture of pure fullerenes C60, C70 and a concentrate of higher fullerenes

An integrated technology for manufacture of fullerenes was developed. It includes the following stages: synthesis of a fullerene black, extraction of a mixture of fullerenes from the black, preliminary separation of the mixture into concentrates enriched in C₆₀ and C₇₀ fullerenes, and production of C₆₀ and C₇₀ fullerenes of purity exceeding 99.5 and 98.0 wt %, respectively, from the concentrates.     

Exohedral silicon fullerenes: SiNPtN/2 (20<or=N<or=60)

Using density functional theory method we show that hollow silicon fullerene cages, SiN (20相似文献   

富勒烯硫化反应进展

富勒烯官能化研究是富勒烯化学的重要组成部分。 近年来,随着富勒烯化学研究的深入发展,许多新颖富勒烯衍生物被陆续合成出来,并在生物医学和有机太阳能电池方面显示出良好的应用潜力。 与快速发展的富勒烯化学相比,富勒烯硫化反应研究进展较慢,近年来逐步引起广泛兴趣。 在此,我们结合本课题组开展的工作,对富勒烯硫化反应的最新进展进行总结。     

新型碳材料在催化领域中的应用及进展

碳材料以其优异的性能和独特的结构,已成为国内外研究的热点,在催化领域中常被用作催化剂和催化剂载体,有效提高了贵金属的利用效率.同时,新型碳材料的兴起也不断吸引着人们的目光.我们综述了普通活性炭、富勒烯、碳纳米管和石墨烯在工业催化反应中的一些应用情况,综述了它们作为催化剂和载体在催化反应中的实际应用和研究进展,最后展望了碳材料在催化领域中的未来发展前景.     

A C78 fullerene precursor: toward the direct synthesis of higher fullerenes

A C78 fullerene related structure (of C78:1 and C78:4, the last undiscovered C78 IPR isomer) has been synthesized and investigated as a pyrolytic precursor. The pyrolysis of precursor containing all 78 carbon atoms in the required positions and 93 of the 117 C-C bonds, needed for fullerene formation, showed selectivity for C78 fullerene formation. In independent experiments it has been shown that the flash pyrolysis of C78 fullerene is not affected by Stone-Wales rearrangement and loss of C2 fragments and, thus, is very promising for the synthesis of individual isomers of higher fullerenes.     

氢氧根和烷氧基负离子含氧亲核试剂在富勒烯衍生化中的应用

富勒烯衍生化合物在有机光电、生物医学等领域表现出良好应用前景,相关的富勒烯衍生化方法研究引起了广泛关注,近年来发展迅速。富勒烯由于具有较强的缺电子性质,容易与亲核试剂反应。但相比于碳亲核试剂,含氧亲核试剂与富勒烯的反应发展缓慢,长期被忽略。我们结合本课题组最近开展的工作,对OH~-与MeO~-含氧亲核试剂参与的富勒烯衍生化反应的最新进展进行了总结,并对反应机理进行了较为详尽的阐述,为进一步扩展富勒烯衍生化方法提供参考。     

The influence of an intramolecular H-bond on the adsorption of sulfur-containing amino acids on graphitized thermal carbon black

The thermodynamic characteristics of adsorption of sulfur-containing amino acids and their derivatives on the surface of graphitized thermal carbon black were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the S atom in amino acids and the graphite C atom were determined. It was shown that an intramolecular H-bond influenced the adsorption of amino acids on the surface of graphitized thermal carbon black.     

Reactivity Differences between Carbon Nano Onions (CNOs) Prepared by Different Methods

The carbon nanoparticles obtained from either arcing of graphite under water or thermal annealing of nanodiamonds are commonly called carbon nano onions (CNOs), or spherical graphite, as they are made of concentric fullerene cages separated by the same distance as the shells of graphite. A more careful analysis reveals some dramatic differences between the particles obtained by these two synthetic methods. Physicochemical methods indicate that the CNOs obtained from nanodiamonds (N‐CNOs) are smaller and contain more defects than the CNOs obtained from arcing (A‐CNOs). These properties explain the enhanced reactivity of the N‐CNOs in cycloaddition and oxidation reactions, as well as in reactions involving radicals. Given the easier functionalization of the N‐CNOs, they are the most obvious choice for studying the potential applications of these multi‐shelled fullerenes.     

氮气氛中合成杂氮球烯,碳纳米管及纳米晶体的研究

氮气氛中合成杂氮球烯、碳纳米管及纳米晶体的研究詹梦熊，余荣清，王育煌，杨士姚，程大典，刘朝阳，郑兰荪（厦门大学化学系，厦门，３６１００５）关键词杂氮球烯，碳纳米管，纳米晶体，氮气氛自球烯及碳纳米管常规制备方法问世以来［１，２］，制备方法的改进一直成为...     

Thermal decomposition of ammonium perchlorate based mixture with fullerenes

The effects of fullerenes, including fellerene soot (FS), extracted fullerene soot (EFS) and pure C₆₀ on the thermal decomposition of ammonium perchlorate (AP) compared with traditional carbon black (CB) catalyst has been studied by employing thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR) and ignition temperature experiments. The results showed that the addition of CB and FS to AP reduced the activation energy as well as the temperature at maximum decomposition rate, but that of EFS and pure C₆₀ had little effect on the thermal decomposition of AP, and among all catalysts, FS was the best one.     

Qualitatively graph-theoretical study on stability and formation of fullerenes and nanotubes

Kekule structures of different carbon species have been determined. On the basis of Kekule structure and C-C bond counts as well as the surface curvature, stability of diverse carbon species, driving force for curling of graphite fragments and formation of fullerenes and nanotubes, have been discussed. Curling of graphite flat fragments, end-capping of nanotubes, and closure of curved structures are driven by a tremendous increase in Kekule structures as terminal carbon atoms couple their dangling bonds into C-C o bonds. The increasing tendency becomes particularly striking for large cages and nanotubes. Resonance among numerous Kekule structures will stabilize the curved structure and dominate formation of closed carbon species. For similar carbon cages with comparable Kekule structure counts in magnitude, the surface curvature of carbon cages, as a measure for the strain energy, also plays an important role in determining their most stable forms.     

A new calix[5]arene-based container: selective extraction of higher fullerenes

[reaction: see text] A new double calix[5]arene successfully extracts higher fullerenes from fullerene mixtures. The syn isomer of the double calix[5]arene selectively captures higher fullerenes from fullerene mixtures. The elevation of the temperature more than 100 degrees C stimulates its conformational change to the anti isomer, bringing liberation of the captured higher fullerenes.     

Extraction of fullerene mixture from fullerene soot with organic solvents

Investigation of extraction of fullerene mixture from the fullerene soot obtained by plasma erosion of graphite rod in helium atmosphere with different solvents such as α-chloronaphthalene, o-dichlorobenzene, o-xylene, toluene, benzene, carbon tetrachloride, and n-hexane at 25°C was carried out. Completeness and effectiveness of extraction as well as relative content of light (C₆₀, C₇₀) and heavy (C₇₆, C₇₈, C₈₄) fullerenes in the extract were evaluated.     

Synthesis of carbon-polyacrylate nanocomposite materials by crosslinking polymerization

Nanocomposite materials made of carbon nanoparticles dispersed in a crosslinked polymer have been produced by light-induced polymerization of a multifunctional acrylic resin containing graphite, oxidized graphite or acetylene black. Exfoliation of graphite was achieved by sonication of the filled resin, and confirmed by sedimentation analysis. Under intense illumination the solvent-free resin was transformed within a fraction of a second into a hard and tough material, at ambient temperature. The photopolymerization was followed by infrared spectroscopy and shown to proceed effectively up to 85% conversion of the acrylate double bonds. The slowing down effect of the carbon particles by screening of the UV-radiation is becoming increasingly important as the sample thickness and the filler content are increased. A redox initiator consisting of benzoyl peroxide and a tertiary amine was used to achieve a deep through-cure of thick samples, a process which was markedly accelerated in presence of acetylene black. These carbon nanocomposite materials proved to be more flexible and resistant to shocks than the neat acrylic polymer. Electrical conductivity was found in nanocomposites containing acetylene black at concentrations above 1 wt.%.