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1.
The absorption feasibility of benzene molecule in the C24, Si@C24, Si-doped C24, and C20 fullerenes has been studied based on calculated electronic properties of these fullerenes using Density functional Theory (DFT). It is found that energy of benzene adsorption on C24, Si@C24, and Si-doped C24 fullerenes were in range of –2.93 and –51.19 kJ/mol with little changes in their electronic structure. The results demonstrated that the C24, Si@C24, and Si-doped C24 fullerenes cannot be employed as a chemical adsorbent or sensor for benzene. Silicon doping cannot significantly modify both the electronic properties and benzene adsorption energy of C24 fullerene. On the other hand, C20 fullerene exhibits a high sensitivity, so that the energy gap of the fullerene is changed almost 89.19% after the adsorption process. We concluded that the C20 fullerene can be employed as a reliable material for benzene detection.  相似文献   

2.
This review concerns assemblies of the main carbon nanostructures (fullerenes and nanotubes) generated by interactions between similar and dissimilar species. The two major families of these nanomaterials are reviewed: (1) assemblies with weak (van der Waals) bonds between fullerenes and/or nanotubes (fullerites, nanopeapods, nanotube bundles, and nanotubular crystals) and (2) assemblies formed by covalently bonded (polymerized) fullerenes and/or nanotubes (covalent crystals of small fullerenes C n < 60 , nanobuds, ropes of polymerized nanotubes, and covalent networks built of nanotubes). Data are systematized on their atomic structures, stability factors, electronic structures, chemical bonding, physical and chemical properties, and potential fields of application. Related heteronanomaterials (assemblies of boron-nitrogen fullerene-like molecules and/or nanotubes) are reviewed briefly.  相似文献   

3.
First‐principles DFT calculations are carried out to study the changes in structures and electronic properties of two‐dimensional single‐layer graphene in the presence of non‐covalent interactions induced by carbon and boron fullerenes (C60, C70, C80 and B80). Our study shows that larger carbon fullerene interacts more strongly than the smaller fullerene, and boron fullerene interacts more strongly than that of its carbon analogue with the same nuclearity. We find that van der Waals interactions play a major role in governing non‐covalent interactions between the adsorbed fullerenes and graphene. Moreover, a greater extent of van der Waals interactions found for the larger fullerenes, C80 and B80, relative to smaller C60, and consequently, results in higher stabilisation. We find a small amount of electron transfer from graphene to fullerene, which gives rise to a hole‐doped material. We also find changes in the graphene electronic band structures in the presence of these surface‐decorated fullerenes. The Dirac cone picture, such as that found in pristine graphene, is significantly modified due to the re‐hybridisation of graphene carbon orbitals with fullerenes orbitals near the Fermi energy. However, all of the composites exhibit perfect conducting behaviour. The simulated absorption spectra for all of the graphene–fullerene hybrids do not exhibit a significant change in the absorption peak positions with respect to the pristine graphene absorption spectrum. Additionally, we find that the hole‐transfer integral between graphene and C60 is larger than the electron‐transfer integrals and the extent of these transfer integrals can be significantly tuned by graphene edge functionalisation with carboxylic acid groups. Our understanding of the non‐covalent functionalisation of graphene with various fullerenes would promote experimentalists to explore these systems, for their possible applications in electronic and opto‐electronic devices.  相似文献   

4.
The chlorination of HPLC fractions with pristine giant fullerenes, C102 and C104, followed by X‐ray crystallographic study of chlorides, C102(603)Cl18/20 and C104(234)Cl16–22, confirmed the presence of the most stable IPR (IPR=Isolated Pentagon Rule) isomers, C102(603) and C104(234), in the fullerene soot. The discussion concerns the chlorination patterns of polychlorides and relative stability of pristine isomers of C102 and C104 fullerenes.  相似文献   

5.
Data concerning the isomeric composition of C98 and the chemistry of C98 derivatives are scarce due to very low abundance of C98 in the fullerene soot. Trifluoromethylation of C98-containing mixtures followed by HPLC separation of CF3 derivatives and single crystal X-ray diffraction study resulted in structural characterization of four compounds C98(248)(CF3)18/20, C98(116)(CF3)18, and C98(120)(CF3)20. To date, these compounds represent the largest fullerenes isolated as CF3 derivatives with experimentally determined molecular structures. The addition patterns of C98(CF3)18/20 are discussed in detail revealing the stabilizing factors, such as isolated double C=C bonds and benzenoid rings on C98 fullerene cages. A detailed comparison with the addition patterns of the known C98Cln allowed us to contribute to the better understanding the chemistry of elusive C98 fullerene.  相似文献   

6.
The formation of different 32 π‐electron systems derived from a prominent small fullerene given by C28, allows to evaluate several approaches ensuring an electronic shell closure in terms of the characteristic chemical shift anisotropy (CSA) and long‐range magnetic response properties for spherical aromatic compounds. Our results show that the inclusion of extra electrons and the doping of the cage, are able to sustain a long‐range shielding cone when an external field is oriented in a specific orientation. Such properties are inherent characteristics of spherical aromatic compounds, which are not obtained in the neutral C28 fullerene, and in the exo‐bonded approach leading to C28H4. Thus, the doping of the cage is suggested as the most suitable approach to modify the overall count of electrons, leading to the expected response properties for further design of highly aromatic fullerenes.  相似文献   

7.
The synthesis of (E)-hex-3-ene-l, 5-diynes and 3-methylidenepenta-1, 4-diynes with pendant methano[60]-fullerene moieties as precursors to C60-substituted poly(triacetylenes) (PTAs, Fig. 1) and expanded radialenes (Fig. 2) is described. The Bingel reaction of diethyl (E)-2, 3-dialkynylbut-2-ene-1, 4-diyl bis(2-bromopropane-dioates) 5 and 6 with two C60 molecules (Scheme 2) afforded the monomeric, silyl-protected PTA precursors 9 and 10 which, however, could not be effectively desilylated (Scheme 4). Also formed during the synthesis of 9 and 10 , as well as during the reaction of C60 with thedesilylated analogue 16 (Scheme 5 ), were the macrocyclic products 11, 12 , and 17 , respectively, resulting from double Bingel addition to one C-sphere. Rigorous analysis revealed that this novel macrocyclization reaction proceeds with complete regio- and diastereoselectivity. The second approach to a suitable PTA monomer attempted N, N′-dicyclohexylcarbodiimide(DCC)-mediated esterification of (E)-2, 3-diethynylbut-2-ene-l, 4-diol ( 18 , Scheme 6) with mono-esterified methanofullerene-dicarboxylic acid 23 ; however, this synthesis yielded only the corresponding decarboxylated methanofullerene-carboxylic ester 27 (Scheme 7). To prevent decarboxylation, a spacer was inserted between the reacting carboxylic-acid moiety and the methane C-atom in carboxymethyl ethyl 1, 2-methano[60]fullerene-61, 61-dicarboxylate ( 28 , Scheme 8), and DCC-mediated esterification with diol 18 afforded PTA monomer 32 in good yield. The formation of a suitable monomeric precursor 38 to C60-substituted expanded radialenes was achieved in 5 steps starting from dihydroxyacetone (Schemes 9 and 10), with the final step consisting of the DCC-mediated esterification of 28 with 2-[1-ethynyl(prop-2-ynylidene)]propane-1, 3-diol ( 33 ). The first mixed C60-C70 fullerene derivative 49 , consisting of two methano[60]fullerenes attached to a methano[70]fullerene, was also prepared and fully characterized (Scheme 13). The Cs-symmetrical hybrid compound was obtained by DCC-mediated esterification of bis[2-(2-hydroxy-ethoxy)ethyl] 1, 2-methano[70]fullerene-71, 71-dicarboxylate ( 46 ) with an excess of the C60-carboxylic acid 28 . The presence of two different fullerenes in the same molecule was reflected by its UV/VIS spectrum, which displayed the characteristic absorption bands of both the C70 and C60 mono-adducts, but at the same time indicated no electronic interaction between the different fullerene moieties. Cyclic voltammetry showed two reversible reduction steps for 49 , and comparison with the corresponding C70 and C60 mono-adducts 46 and 30 indicated that the three fullerenes in the composite fullerene compound behave as independent redox centers.  相似文献   

8.
The distribution of C60 and C70 fullerenes in the extraction system (C60 + C70)-α-pinene-ethanol-H2O was studied at constant C60 to C70 ratio and variable total fullerene concentration at 25°C. The relationship between the C60 and C70 content in ethanol (I) and α-pinene (II) phases is nonlinear over the entire fullerene concentration range.  相似文献   

9.
The single-crystal micro/nanostructures of fullerene species, namely C60 and C70, have been previously studied, but studies on the morphology and properties of higher fullerenes have rarely been reported due to the limited amount of samples and their ellipsoidal isomeric structures. Herein, we report the formation of three-dimensional (3D) micro-cubes and micro-dice of a higher fullerene (C78) via a facile liquid–liquid interfacial precipitation (LLIP) method. The micro-cubes were prepared by regulating the concentration of C78 in trimethylbenzene (TMB) and the volume ratio of TMB and isopropanol. Interestingly, the micro-cubes are transformed into micro-dice with an open-hole on each crystal face by simply shaking the solution. X-ray diffraction and Fourier-transform infrared spectroscopic studies revealed a simple cubic unit cell with a lattice constant of 10.6 Å and intercalated TMB molecules in both crystals. The C78 cubic and dice-like microstructures exhibited enhanced photoelectrochemical and photoluminescence properties compared with pristine C78 powder, indicating their potential applications as photodetectors and photoelectric devices.  相似文献   

10.
Chiral induction has been an important topic in chemistry, not only for its relevance in understanding the mysterious phenomenon of spontaneous symmetry breaking in nature but also due to its critical implications in medicine and the chiral industry. The induced chirality of fullerenes by host–guest interactions has been rarely reported, mainly attributed to their chiral resistance from high symmetry and challenges in their accessibility. Herein, we report two new pairs of chiral porous aromatic cages (PAC), R- PAC-2 , S- PAC-2 (with Br substituents) and R- PAC-3 , S- PAC-3 (with CH3 substituents) enantiomers. PAC-2 , rather than PAC-3 , achieves fullerene encapsulation and selective binding of C70 over C60 in fullerene carbon soot. More significantly, the occurrence of chiral induction between R- PAC-2 , S- PAC-2 and fullerenes is confirmed by single-crystal X-ray diffraction and the intense CD signal within the absorption region of fullerenes. DFT calculations reveal the contribution of electrostatic effects originating from face-to-face arene-fullerene interactions dominate C70 selectivity and elucidate the substituent effect on fullerene encapsulation. The disturbance from the differential interactions between fullerene and surrounding chiral cages on the intrinsic highly symmetric electronic structure of fullerene could be the primary reason accounting for the induced chirality of fullerene.  相似文献   

11.
12.
It is shown that fullerenes C20 of the $ \bar 5\bar 3 It is shown that fullerenes C20 of the m symmetry can form seven types of low-symmetry species of the initial “mother” fullerene molecule by means of continuous deformation. Possible routes of formation and continuous transformations of these species are presented on the adjacency graph of structural elements of fundamental regions of fullerenes C20. The approach used in this work can be applied for design of structural-geometrical models of all low-symmetry species of fullerene C20. Original Russian Text ? V.M. Talanov, N.V. Fedorova, V.V. Gusarov, 2009, published in Zhurnal Obshchei Khimii, 2009, Vol. 79, No. 2, pp. 285–288.  相似文献   

13.
Kekulé count is not as useful in predicting the thermodynamic stability of fullerenes as it is for benzenoid hydrocarbons. For example, the Kekulé count of the icosahedral C60, the most stable fullerene molecule, is surpassed by its 20 fullerene isomers (Austin et al. in Chem Phys Lett 228:478–484, 1994). This article investigates the role of Clar number in predicting the stability of fullerenes from Clar’s ideas in benzenoids. We find that the experimentally characterized fullerenes attain the maximum Clar numbers among their fullerene isomers. Our computations show that among the 18 fullerene isomers of C60 achieving the maximum Clar number (8), the icosahedral C60 has the largest Kekulé count. Hence, for fullerene isomers of C60, a combination of Clar number and Kekulé count predicts the most stable isomer.  相似文献   

14.
The polythermal solubility of fullerene C60 and a fullerene mixture (60 wt % C60 + 39 wt % C70 + 1 wt % higher fullerenes C n , n = 76, 78, 84, 90...) in valeric and caproic acids was studied in the temperature range 20–80°C. The solubility diagrams are presented and characterized.  相似文献   

15.
The adsorption of a variety of fullerenes (C60, C70, C86, Y@C82) on Au(111) electrode surfaces was comprehensively investigated in 0.1 M HClO4 by electrochemical scanning tunneling microscopy (ECSTM). In the ordered C60’s adlayer, C60 molecules formed either (2 $ \sqrt 3 $ ×2 $ \sqrt 3 $ ) or “in-phase” structure. The high resolution STM image shows that the C60 cage is not simply round but shows a bifurcated feature. The adsorption orientation of C60 on Au(111) is tentatively suggested. In the ordered C70’s adlayer, the perpendicular fullerene molecules are the main adsorption mode and form (2 $ \sqrt 3 $ ×2 $ \sqrt 3 $ ) structure. However, for C86 and Y@C82, the ordered adlayer could not be obtained on Au(111) under the present condition. These differences may be due to the different molecular shapes and sizes, and the encapsulated metal atom which affects the lattice matches with the substrate. The adsorption of fullerene molecules on Au(111) from disorder to order could be tuned simply by steering the dimensional sizes or shapes of the fullerenes used.  相似文献   

16.
17.
Solubility of light fullerenes (C60, C70, and the standard fullerene mixture containing (wt %): C60 65, C70 34, C n>70 1) in the oleic, linoleic and linolenic acids, respectively, at 20–80°C was studied and the corresponding solubility polytherms were reported.  相似文献   

18.
The results of the theoretical investigation of the behavior of fullerenes C20 and C60 inside the icosahedral external shell on example of carbon nanoclusters, C20240 and C60540, are presented in this article. The multiwell potential of interaction between fullerenes in investigated nanoclusters is calculated to reveal the regularities of moving for internal fullerene in the field of holding potential of the external shell. The possible variants of fullerenes C20 and C60 moving between the potential wells are predicted on base of topology data of the fullerenes relative positioning in nanoparticle and analysis of relief of the energy surface of interaction between fullerenes. The formulated prediction is confirmed by the data of the numerical experiment. The investigation of two‐shell fullerenes allows to conclude that the light fullerene С20 will probably jump between the potential wells already at small temperatures (139–400 K) if the external shell is slightly bigger. © 2014 Wiley Periodicals, Inc.  相似文献   

19.
High‐temperature chlorination of fullerene C88 (isomer 33) with VCl4 gives rise to skeletal transformations affording several nonclassical (NC) fullerene chlorides, C86(NC1)Cl24/26 and C84(NC2)Cl26, with one and two heptagons, respectively, in the carbon cages. The branched skeletal transformation including C2 losses as well as a Stone–Wales rearrangement has been comprehensively characterized by the structure determination of two intermediates and three final chlorination products. Quantum‐chemical calculations demonstrate that the average energy of the C?Cl bond is significantly increased in chlorides of nonclassical fullerenes with a large number of chlorinated sites of pentagon–pentagon adjacency.  相似文献   

20.
A technique for improving the sensitivity of high mass molecular analysis is described. Three carbon species, fullerenes, single walled carbon nanotubes, and highly ordered pyrolytic graphite are introduced as matrices for the secondary ion mass spectrometry analysis of cyclodextrin (C42H70O35, 1134 u). The fullerene and nanotubes are deposited as single deposition, and 10, 20, or 30 deposition films and cyclodextrin is deposited on top. The cyclodextrin parent-like ions and two fragments were analyzed. A 30 deposition fullerene film enhanced the intensity of cationized cyclodextrin with Na by a factor of 37. While the C6H11O5 fragment, corresponding to one glucopyranose unit, increased by a factor of 16. Although fragmentation on fullerene is not suppressed, the intensity is twice as low as the parent-like ion. Deprotonated cyclodextrin increases by 100× and its C8H7O fragment by 10×. While the fullerene matrix enhances secondary ion emission, the nanotubes matrix film generates a basically constant yield. Graphite gives rise to lower intensity peaks than either fullerene or nanotubes. Scanning electron microscopy and atomic force microscopy provide images of the fullerene and nanotubes deposition films revealing flat and web structured surfaces, respectively. A “colliding ball” model is presented to provide a plausible physical mechanism of parent-like ion enhancement using the fullerene matrix.  相似文献   

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