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1.
N. I. Alekseev N. A. Charykov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(2):268-276
A joint analysis of fullerene assembly kinetics and gas flow dynamics in an arc chamber for the production of fullerenes showed
that the effective annealing of fullerenes and the evident dominance of “magic” fullerenes C60 and C70 were mainly explained by the difference between the thermal dissociation rates of these and less stable C62 and C68 fullerenes. The percent of “nonmagic” fullerenes was also shown to depend on the structure of the gas flows formed in the
arc discharge chamber. The majority of newly formed fullerenes were not immediately removed from the chamber, bur were trapped
by closed gas flows. Back in the hot region of the chamber, fullerenes were simultaneously annealed and dissociated under
the action of high temperature and, partially, UV radiation. The “nonmagic” fullerenes were most actively suppressed in a
non-pumpable discharge chamber. 相似文献
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Deza M Fowler PW Rassat A Rogers KM 《Journal of chemical information and computer sciences》2000,40(3):550-558
If a fullerene is defined as a finite trivalent graph made up solely of pentagons and hexagons, embedding in only four surfaces is possible: the sphere, torus, Klein bottle, and projective (elliptic) plane. The usual spherical fullerenes have 12 pentagons; elliptic fullerenes, 6; and toroidal and Klein-bottle fullerenes, none. Klein-bottle and elliptic fullerenes are the antipodal quotients of centrosymmetric toroidal and spherical fullerenes, respectively. Extensions to infinite systems (plane fullerenes, cylindrical fullerenes, and space fullerenes) are indicated. Eigenvalue spectra of all four classes of finite fullerenes, are reviewed. Leapfrog fullerenes have equal numbers of positive and negative eigenvalues, with 0, 0, 2, or 4 eigenvalues zero for spherical, elliptic, Klein-bottle, and toroidal cases, respectively. 相似文献
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采用二硫化碳重结晶富勒烯混合物或二硫化碳二次抽提烟灰以提取高富勒烯(higherfulerenes,Cn,n>70)。产物经高效液相色谱分析,高富勒烯的含量从1%分别提高到4%和6%;经激光飞行时间质谱证明,产物中除含主要成分C60和C70以外,还含有C76、C78、C82、C84以及更高碳原子的富勒烯。 相似文献
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Giorgio De Luca Marlon Basantes Valverde Matilde Morrone Lorenzo S. Caputi 《International journal of quantum chemistry》2019,119(10):e25890
Multi-shell fullerenes are widely studied for their interesting properties although comparative studies on single- and multi-shell structures remain scarce. In this work, important electronic features of single- and double-shell icosahedral fullerenes as a function of their sizes were calculated in the framework of the density functional theory. Fully optimized structures were used to get the gap between the highest occupied molecular and the lowest unoccupied molecular orbital (H-L gap), electronegativity, softness and density of the electronic states. This work shows that the H-L gap of the single-shell fullerenes decreases nonlinearly as the nanoparticles size increases, whereas for the double-shell fullerenes an opposite trend is obtained. A decrease of the H-L gap is found going from single- to double-shell fullerenes with similar external sizes, up to a diameter of 3.13 nm. The electron density of states revealed that isolated peaks give way to more dense electronic states for nanoparticles with diameters above 2 nm. 相似文献
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This paper is a tutorial review of the host-guest chemistry of fullerenes and metalloporphyrin. Among various host molecules for fullerenes, cyclic hosts composed of metalloporphyrin moieties possess one of the highest affinities toward fullerenes, which can be widely tuned simply by changing the central metal ions of the porphyrin moieties. Inclusion of fullerenes occurs not only by van der Waals interactions but also, in some cases, via pi-electronic charge-transfer from the host metalloporphyrin moieties to the guest fullerenes. Fullerenes such as C(120), upon inclusion with cyclic metalloporphyrin dimers, show an oscillatory motion within the host cavity, whose frequency reflects the solvation/desolvation dynamics of the fullerenes. A molecularly engineered metalloporphyrin host with a self-assembling capability allows a guest-directed formation of a supramolecular peapod, where included fullerenes, as peas, are aligned along the self-assembled metalloporphyrin nanotube, as a pod. Furthermore, certain metalloporphyrin hosts are applicable to the selective extraction of low-abundance higher fullerenes from an industrial production source and also allow spectroscopic discrimination of chiral fullerenes. 相似文献
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The aggregation behavior of C60 fullerenes and C60 fullerenes with six symmetrically tethered poly(ethylene oxide) oligomers [(PEO)-6-C60] in aqueous solutions has been studied using implicit solvent molecular dynamics simulations. Our simulations reveal that while the attraction between two (PEO)-6-C60 fullerenes in aqueous solution is stronger and longer range than that between two bare C60 fullerenes, the (PEO)-6-C60 fullerenes do not phase-separate in water but rather aggregate in chain-like clusters at concentrations where unmodified fullerenes completely phase-separate. 相似文献
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色谱法分离富勒烯的研究 总被引:3,自引:0,他引:3
研究了用活性炭作固定相,CS2作流动相柱色谱法分离富勒烯混合物的方法,考察了用溶剂浸泡活性炭减活的时间、活性炭与富勒烯混合物配比、活性炭的粒度等因素对分离结果的影响,采用了索氏抽提器,可以很快地将固定相中的C70等高级富勒烯提取出来,提高了回收率。 相似文献
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A series of novel transformations of [60]fullerene derivatives were found, starting from methano[60]fullerenes with an electron-donating group on the methano-bridge carbon. Aminomethano[60]fullerenes, in situ generated by the treatment of their trifluoromethanesulfonic acid salts with a base, were readily converted into 1-acyl-1,2-dihydro[60]fullerenes via the ring opening of the cyclopropane moiety. The aldehyde/ketones thus obtained were easily hydrolyzed to give 1,2-dihydro[60]fullerene in the presence of hydroxide anions. 相似文献
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Sadana AK Liang F Brinson B Arepalli S Farhat S Hauge RH Smalley RE Billups WE 《The journal of physical chemistry. B》2005,109(10):4416-4418
Large fullerenes and carbon-coated metal nanoparticles that are formed during the synthesis of carbon nanotubes have been functionalized by the addition of alkyl radicals and isolated by extraction into chloroform. The soluble, functionalized fullerenes have been isolated from raw single-wall carbon nanotube (SWNT) material prepared by laser oven, direct current arc, and high-pressure carbon monoxide production methods. Analyses of the extracted large fullerenes were carried out by thermogravimetric analysis, UV-vis-near-IR, laser desorption ionization mass spectrometry, and high-resolution transmission electron microscopy. 相似文献
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We present follow-up studies on the formation mechanism of fullerene molecules from random ensembles of C2 molecules using quantum chemical molecular dynamics. Two possible roadmaps are investigated as to how buckminsterfullerene C60 and higher fullerenes could be formed. In a "size-up" scenario, fullerenes of the cage size of C72-C96 were found to form directly from high concentrations of C2 molecules at 2000 K with periodic supply of batches of additional C2's. In a "size-down" approach, smaller fullerenes are sometimes formed by losing carbon fragments in "fall-off" or "pop-out" annealing processes under prolonged heating of giant fullerenes, which were self-assembled at initial stages from C2's with lower concentrations. Both roadmaps are found to provide explanations for the appearance of C60 and larger fullerenes in combustion and carbon arc experiments. 相似文献
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中性富勒烯分子的直接电喷雾质谱分析 总被引:1,自引:0,他引:1
电喷雾电离是新近发展的一种质谱技术, 适用于分析在溶液中呈离子状态的物质, 具有无碎片的特点。本文根据富勒烯分子的电子亲和性能, 将富勒烯混合物的甲苯溶液直接进行电喷雾质谱分析, 检出了C60, C70, C76, C80, C82, C84, C86,C88, C90, C92, C94和C96等的负离子峰。并用萘钾作还原剂,将富勒烯混合物预先还原, 制得富勒烯负离子溶液后再作电喷雾质谱分析, 得到相同的结果。表明各类富勒烯分子在电喷雾过程中俘获电子的能力与被萘钾还原的能力相一致。 相似文献
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K. Jinno H. Matsui H. Ohta Y. Saito K. Nakagawa H. Nagashima K. Itoh 《Chromatographia》1995,41(5-6):353-360
Summary Two-step liquid chromatographic separation (LC) has been applied to soot extract and the identification of higher fullerenes
has been accomplished by LC-MS measurements using an ESI interface. The first separation step is preparative-scale LC using
a 50 mm i.d. column packed with monomeric octadecylisilica (ODS) because elution is mainly controlled by relative molecular
mass. 39 batches of five fractions each were collected and then as the second separation step each fraction was analysed by
analytical-scale LC using a conventional column of a polymeric ODS phase which can elute fullerenes according to shape and
structure. This stationary phase can also separate many isomers of higher fullerenes, consequently the existence of several
higher fullerenes larger than C86 has been confirmed and their UV-Vis spectra were obtained by the photodiode array detection system coupled to the analytical
LC. 相似文献
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V. I. Sokolov 《Russian Journal of Coordination Chemistry》2007,33(10):711-724
Fullerenes are considered as ligands in transition metal π-complexes. The following aspects are discussed: metals able to form complexes with fullerenes; haptic numbers; homo-and heteroligand complexes; ligand compatibility with fullerenes for different metals, including fullerenes with a disturbed structure of conjugation. 相似文献
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Kuniko Nasu Tetsuya Taketsugu Takashi Nakano Umpei Nagashima Haruo Hosoya 《Theoretical chemistry accounts》1995,90(2-3):75-86
Summary By semi-empirical molecular orbital calculations stability of fullerenes was analyzed in terms of topological parameters, such as the number of special fragments and the number of three types of abutting bonds between two 5-membered rings. Relative stability was compared by AM1 method for all spectrally distinct closed-shell isomers of C36 and C40 fullerenes, and for some closed-shell isomers of C60 fullerene. Molecular geometries of these fullerenes were also optimized. Their relative stabilities were well explained by the instability of abutting bonds. 相似文献
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富勒烯合成化学研究进展 总被引:2,自引:0,他引:2
富勒烯是一类由12个五元环和若干六元环组成的笼状分子, 自20世纪80年代中期被发现以来就以其独特的结构和新奇的性质而成为科学界研究的热点, 25年来, 无论在基础研究还是在实际应用领域都有了长足的进步, 人们在发展富勒烯合成新方法和寻找富勒烯新结构方面做了大量的工作。本文对富勒烯的各种宏量合成方法进行了回顾, 并概述了迄今已发表的60余种富勒烯新结构,包括各种富勒烯空笼、内嵌富勒烯、富勒烯笼外修饰衍生物及氮杂富勒烯等结构。 相似文献