共查询到20条相似文献,搜索用时 0 毫秒
1.
The performance of Fourier transform infrared spectroscopy (FT-IR) detection coupled to high-performance liquid chromatography for the analysis of C60 and C70 fullerenes was investigated. The isocratic separation method involved an octadecylsilane (ODS) column and an acetonitrile–toluene (1:1) mobile phase. The hyphenated system was designed with a split valve to control eluent volume leading to the FT-IR detector; this allowed for additional coupling of the liquid chromatograph to ultraviolet–visible detection. On-line FT-IR spectra of C60 and C70 were matched with standard off-line FT-IR spectra from the literature. In addition, with band chromatograms individual fullerenes can be identified using FT-IR active modes known specifically for each fullerene. Few changes to a pre-existing HPLC–UV method were necessary for the HPLC–FT-IR method, and there was no need for fraction collection to identify the fullerenes C60 and C70. 相似文献
2.
Yihua Zhang Run Liu Yumei Teng Erti Fang Zhengyu Huang Xiankang Zeng 《Reaction Kinetics and Catalysis Letters》1996,58(1):91-96
A new type of catalyst from supporting C60 on MoO3 and Al2O3 has been prepared. The effect of different order of impregnation and calcination atmosphere on catalyst are investigated by the solution test in toluene, UV-VIS spectroscopy and temperature programmed reduction (TPR). The results show that when the catalyst was prepared by supporting MoO3 on C60/Al2O3 and calcined in N2, there is a stronger interaction between C60, MoO3 and Al2O3, but when supporting C60 on MoO3/Al2O3, the interaction is relatively weak. We consider that in the former method a new complex, Mo–C60–O–Al, is formed. 相似文献
3.
Abby R O'Connor Chip Nataro James A Golen Arnold L Rheingold 《Journal of organometallic chemistry》2004,689(14):2411-2414
A new chemical oxidant [N(4-C6H4Br)3][B(C6F5)4], was prepared and used to synthesize [Fe(C5H5)2][B(C6F5)4]. The crystal structure of [Fe(C5H5)2][B(C6F5)4] was determined. 相似文献
4.
From C72 to C78, the top 20 low-energy isomers screened out from all isomers of each fullerene are optimized and computed by tight-binding Monte Carlo (TBMC), semi-empirical PM3, and ab initio B3LYP/6-31G*//HF/3-21G methods. The comparison results show that the TBMC method can efficiently optimize the structures and correctly predicate the low energy isomers. The relative energies computed by TBMC are in good agreement with the high-lever B3LYP calculation results. Our TBMC and B3LYP results show that the most energetically favorable structure of C72 is not an isomer satisfying the isolated pentagon rule (IPR), which is different with the result by PM3. The symmetry of the most stable IPR isomer tends to low as the fullerene becomes large and several non-isolated-pentagon structures are found to have low symmetries and low energies close to the most stable isomer. 相似文献
5.
C60 reacts thermally with 1,3-dipoles, formed in situ, from sulfide-bearing imines of glycine esters, and affords dihydro-pyrrolo [60]fullerene derivatives containing a vinylic sulfide group, which were isolated in good yields, and characterized with 1H and 13C NMR, FTIR, UV-vis spectroscopies, and with FAB, ESI mass spectrometries. The new derivatives contain a sulfide, an imine, and an ester functionality for further chemical transformations. Mechanistic considerations with regard to the loss of a mercaptan molecule in the course of the cycloaddition are deployed. 相似文献
6.
One isomer of C60(i-C3F7)8, three isomers of C60(i-C3F7)6, and the first mixed perfluoroalkylated fullerene, C60(CF3)2(i-C3F7)2, have been isolated by HPLC from a mixture prepared by reaction of C60 with heptafluoroisopropyl iodide in a glass ampoule at 260-290 °C. The molecular structures of the four new compounds have been determined by means of X-ray single crystal diffraction partially also by use of synchrotron radiation. Theoretical calculations at the DFT level of theory have been employed to rationalize the energetics of isomers and of C60-Rf binding. 相似文献
7.
The discovery of the fullerenes and nanotubes has completely changed our perspective on various aspects of carbon chemistry and materials science in quite fundamental ways. The experiments, which uncovered C60, occurred between 1985 and 1990 and there are lessons to be learned of various kinds over the way scientific advances occur and more importantly the way misconceptions can propagate. For instance much of our received wisdom over the behaviour of carbon, in particular graphite on a microscopic scale, was really quite ill-conceived and certainly misleading. Questions might be asked as to why it took almost till the end of the 20th century for the fact to be uncovered that the elegant C60 molecule had been lurking in the dark shadows of soot chemistry all the time. After all, mass spectrometric techniques were sufficiently advanced for the discovery to have been made in the 1960’s—perhaps even earlier. Some of these issues are addressed here and the discussion gives an insight into the curiously unpredictable way fundamental scientific advances sometimes occur and also highlights the limitations of applied research in this case. 相似文献
8.
N. V. Avramenko E. B. Stukalin M. V. Korobov I. S. Neretin Yu. L. Slovokhotov 《Thermochimica Acta》2001,370(1-2):21-28
Thermodynamic properties of binary systems of C60 with 1,2- and 1,3-dibromobenzenes have been studied by means of differential scanning calorimetry (DSC). Solid solvates with the compositions C603(1,2-C6H4Br2); C602(1,3-C6H4Br2) and C600.6(1,3-C6H4Br2) have been found. The solvates have been characterised by their enthalpies and temperatures of incongruent melting transition and in part by X-ray powder data. It has been shown that positional isomers 1,2- and 1,3- of the substituted benzenes formed two series of “typical” phase diagrams. Solubility behaviour of C60 in positional isomers has been discussed. 相似文献
9.
D. V. Konarev N. V. Drichko R. N. Lyubovskaya Yu. M. Shul''ga A. L. Litvinov V. N. Semkin Yu. A. Dubitsky A. Zaopo 《Journal of Molecular Structure》2000,526(1-3):25-29
A molecular complex of fullerene C60 with triptycene, TPC·C60 is obtained. The complex has a three-dimensional packing of C60 molecules. According to the IR spectra, the freezing of free rotation of C60 molecules in the complex is maintained up to 360 K. The XP-spectra of TPC·C60 show the suppression of π–π* transitions of TPC phenylene rings. The separation of C60 molecules by TPC ones in TPC·C60 results in low intensity of the C60 transitions in the 420–500 nm range in an optical spectrum. This absorption is assumed as that attributed to intermolecular transitions between adjacent C60 molecules. 相似文献
10.
Heterogeneous electrocatalytic reduction of hydrogen peroxide (H2O2) by C60 is reported for the first time. C60 is embedded in tetraoctylammonium bromide (TOAB) film and is characterized by scanning electron microscopy and cyclic voltammetry. Electrocatalytic studies show that the trianion of C60 mediates the electrocatalytic reduction of H2O2 in aqueous solution containing 0.1 M KCl. Application of such film modified electrode as an amperometric sensor for H2O2 determination is also examined. The sensor shows a fast response within 1 s and a linear response is obtained (R = 0.9986) in the concentration range from 3.33 × 10−5 to 2.05 × 10−3 mol L−1 for H2O2, with the detection limit of 2 × 10−5 mol L−1 and the sensitivity of 1.65 μA mM−1. A good repeatability and stability is shown for the sensor during the experiment. 相似文献
11.
The observation of the surface-enhanced vibrational Raman spectra of vapor-deposited C60 and C70 on rough silver films is reported. Both near-monolayer and multilayer films of pure C60 and of C60/C70 mixtures are studied. The films are obtained by evaporating fullerene samples at temperatures of 683–875 K in ultra-high vacuum. Mixed fullerene samples were greatly enriched in C70 by making use of the slightly different vapor pressures of the two major components at the low end of this temperature range. The spectra contain all the lines of the normal Raman spectra as well as several additional lines caused by a reduction in the stringency of the normal Raman selection rules. These results demonstrate the potential of this technique for detecting small quantities of fullerenes and obtaining their vibrational spectra. 相似文献
12.
C60Co(Pph3)2的合成和表征 总被引:1,自引:0,他引:1
The fullerene complexe C60Co(Pph3)2 has been prepared by the reaction of C60 with CoCl2(Pph3)2 under a nitrogen atmosphere and refluxing, and characterized by elemental analyses, FT-IR, XPS, NMR, which appove that C60 coordinates to Co(Pph3)2 group in σ-π pattern and the electron is super conjugate over whole molecule. The result of redox property study show that the reduction potentiel of C60Co(Pph3)2 is more negative than that of C60, the reason may be the π electron dentensity of C60 in C60Co(Pph3)2 increases, which lead to it′s electron affinity decreasing. The thermostability experiment indicates that the oxidation decomposition temperature of C60Co(Pph3)2 is lower than that of pure C60. 相似文献
13.
From the reaction of C60F18 with benzene in the presence of SbCl5 we have isolated a compound of 1252 amu indicated to be C60F14OFPh3, a fluoroxyfullerene. Temperature-variable 1H NMR shows that one phenyl group suffers restricted rotation on cooling to 218 K, attributed to the presence of the OF group which, as in the case of the recently characterised C60F17OF, fails to give a signal for this group in the 19F NMR. We have isolated also, C60F14O2FPh3 (1268 amu) a mixture of oxahomo derivatives of C60F14OFPh3 arising from oxygen insertion into FCCF bonds. Theoretical calculations for C60F14OFPh3 indicate that the phenyl group nearest to the OF group is twisted out of the plane containing the other two. 相似文献
14.
Ampoule reactions of C70 with n- and i-C3F7I were carried out at 250-310 °C. Two step HPLC separations allowed the isolation of several C70(n-C3F7)4-8 and C70(i-C3F7)4 compounds. Crystal and molecular structures of C70(n-C3F7)8-V, C70(n-C3F7)6O, C70(n-C3F7)4, and three isomers of C70(i-C3F7)4 have been determined by X-ray crystallography using synchrotron radiation. Molecular structures of the new compounds were compared with the known examples and discussed in terms of addition patterns and relative energies of their formation. 相似文献
15.
A series of fluorinated fullerene-fused 1,3-dioxolanes have been facilely and efficiently synthesized in the presence of easily available LiClO4·3H2O. The influences of the number of fluoro-substituents and their positions linked to the phenyl ring on the isolated yield of fullerene-fused 1,3-dioxolanes have been studied in detail. Based on reaction facts, a possible reaction mechanism for the formation of fluorinated fullerene-fused 1,3-dioxolanes has been proposed. Furthermore, detailed ultraviolet absorption spectra, fluorescence emission spectra, and cyclic voltammogram further explain the optical properties and electronic transmission capabilities of the products. 相似文献
16.
The first fluoroxyfluorofullerene C60F17OF (A) has been isolated from the fluorination of [60]fullerene with a mixture of MnF3 and K2NiF6 at 480 °C. This compound has a shorter HPLC retention time than the isomeric fluorofullerene ethers (oxahomofullerenes) and is less stable towards EI mass spectrometry. It fragments by losing OF as a single entity and shows no formation of C60O as a fragment ion. By contrast, the ethers fragment by first losing a number of F atoms and then CO, and ultimately show also the presence of C60O, whilst epoxides lose CO as a main fragmentation step and do not give C60O. The first oxahomofluorofullerenol C60F17O.OH (B) has been isolated from the UV-irradiation of a toluene solution of C60F18 in air during 65 h and readily eliminates HF due to adjacent F and OH groups during EI mass spectrometry. The structures of both the compounds have been deduced from 1D and 2D NMR spectroscopy. Just as oxygen inserts into FCCF bonds of C60F18 to give ethers, so insertion into a CF bond gives A. The oxahomofluorofullerenol B is produced by SN2′ substitution of F by OH, followed by oxygen insertion into a 6:5-bond (αβ to the OH group) giving a motif not seen previously in fluorofullerenes. 相似文献
17.
Eiji Okada Yuka Komazawa Masaaki Kurihara Naoki Miyata Toshie Tsuchiya 《Tetrahedron letters》2004,45(3):527-529
In order to study the interaction of fullerenes with biological molecules, a novel photoaffinity labeling agent derived from C60 was designed and synthesized. As photosensitive functional groups, azide group, and aziridine group are utilized. A convenient synthetic route via fulleropyrrolidine 2 was employed to obtain compounds labeling agents 5 and 9. 相似文献
18.
K. Balasubramanian 《Chemical physics letters》1992,200(6):649-650
The nuclear spin statistical weights obtained in a Letter by Harter and Reimer differ from the values obtained by the author a year earlier. However, the corrected numbers reported in the Erratum by Harter and Reimer agree with our values. 相似文献
19.
Bo-Cheng Wang Likey Chen Kuei-Jen Lee Chang-Yuan Cheng 《Journal of Molecular Structure》1999,469(1-3):127-134
The spectral analysis indicates that all isomers of C60O, C70O and C60O2 have an epoxide-like structure (an oxygen atom bridging across a C–C bond). According to the geometrical structure analysis, there are two isomers of fullerene monoxide C60O (the 5,6 bond and the 6,6 bond), eight isomers of fullerene monoxide C70O and eight isomers of fullerene dioxide C60O2. In order to simulate the real reaction conditions at 300 K, the calculation of the different isomers of C60O, C60O2 and C70O fullerene oxides was carried out using the semiempirical molecular dynamics method with two different approaches: (a) consideration of the geometries and thermodynamic stabilities, and (b) consideration of the ozonolysis mechanism. According to the semiempirical molecular dynamic calculation analysis, the probable product of this ozonolysis reaction is C60O with oxygen bridging over the 6–6 bond (C2v). The most probable product in this reaction contains oxygen bridging across in the upper part of C70 (6–6 bond in C70O-2 or C70O-4) an epoxide-like structure. C60O2-1, C60O2-3 and C60O2-5 are the most probable products for the fullerene dioxides. All of these reaction products are consistent with the experimental results. It is confirmed that the calculation results with the semiempirical molecular dynamics method are close to the experimental work. The semiempirical molecular dynamics method can offer both the reaction temperature effect by molecular dynamics and electronic structure, dipole moment by quantum chemistry calculation. 相似文献
20.
Ashley R. Seibert Author Vitae Author Vitae David S. Glueck Author Vitae Author Vitae 《Journal of organometallic chemistry》2011,696(10):2259-2262
The oxidative electrochemistry of P(CH2Fc)3 and three of its derivatives was examined. The electrochemistry of these compounds is sensitive to the functionality added to the phosphorus lone pair and the supporting electrolyte used. 相似文献