C120On from C60Br24
TL;DR: In this paper, a microcrystalline mixture of fullerene dimer oxides (C120On; na 1, 2, 3,..) was extracted from decomposed C60Br24.
About: This article is published in Chemical Physics Letters.The article was published on 2001-01-26. It has received 10 citations till now. The article focuses on the topics: Dimer & Cycloaddition.
Citations
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TL;DR: In this paper, the optical properties of layers of C60 fullerene on a silicon substrate are studied before and after a reducing annealing at 900-1050°C in a hydrogen atmosphere in order to detect the formation of silicon-carbide clusters.
Abstract: The optical properties of layers of C60 fullerene on a silicon substrate are studied before and after a reducing annealing at 900–1050°;C in a hydrogen atmosphere in order to detect the formation of silicon-carbide clusters. It is shown, on the basis of Raman scattering, infrared absorption, time-resolved photoluminescence spectra, and ellipsometric measurements, that the SiC clusters are not detected at the accuracy of the methods used. After annealing, the layer is in the form of a porous hydrogen-rich film of disordered graphite, possibly with a small amount of fullerene molecules.
1 citations
05 Dec 2022
TL;DR: In this article , the formation of an interconnected, three-dimensional, mesoporous polymeric fullerene oxide framework via thermal [3 + 2] cyclo-additions of monomeric C60 and Fullerene oxides (C60On) was reported.
Abstract: We report the formation of an interconnected, three-dimensional, mesoporous polymeric fullerene oxide framework via thermal [3 + 2] cyclo-additions of monomeric C60 and fullerene oxides (C60On), formed upon thermal decomposition of C60Br24, causing the eliminations of bromine atoms in an oxygen atmosphere at an elevated temperature of 200 °C. The newly formed mesoporous fullerene oxide framework is found to be a low bandgap semiconductor capable of acting as a photocatalyst similar to graphitic C3N4. The sunlight-assisted photocatalytic degradation of the methylene blue dye is demonstrated. To have a better understanding of the mechanism of the [3 + 2] cyclo-additions of monomeric C60 and fullerene oxides, a theoretical investigation has been carried out and the energetics of the reaction C60O + C60 → C120O is calculated.
DOI•
TL;DR: In this paper , the thermal decomposition of C60Br24•2Br2 has been studied by Differential Scanning Calorimetry (DSC) at different heating rates.
Abstract: Abstract The thermal decomposition of C60Br24•2Br2 has been studied by Differential Scanning Calorimetry (DSC) at different heating rates. Depending from the heating rate, the thermal decomposition peak occurred between 163 °C and 201 °C with an activation energy E# = 108.6 kJ/mol. The decomposition products are C60 (assessed by FT-IR) and molecular bromine. From the decomposition enthalpy measured by DSC, the enthalpy of formation ΔHf°(C60Br24(c)) = 2114 ± 34 kJ/mol has been determined. By group increment or group additivity method ΔHf°(C60Br24 (g)) = 2184 kJ/mol has been calculated, in fair agreement with the experimental value. Furthermore, through the group increment method ΔGf°(C60Br24 (g)) = 3264 kJ/mol has been estimated. The enthalpy of the C-Br bond in the C60Br24 molecule was found comprised between 108 and 120 kJ/mol.
DOI•
TL;DR: In this article , the formation of an interconnected, three-dimensional, mesoporous polymeric fullerene oxide framework via thermal cyclo-additions of monomeric C60 and Fullerene oxides (C60On) was reported.
Abstract: Abstract We report the formation of an interconnected, three-dimensional, mesoporous polymeric fullerene oxide framework via thermal [3 + 2] cyclo-additions of monomeric C60 and fullerene oxides (C60On), formed upon thermal decomposition of C60Br24, causing the eliminations of bromine atoms in an oxygen atmosphere at an elevated temperature of 200 °C. The newly formed mesoporous fullerene oxide framework is found to be a low bandgap semiconductor capable of acting as a photocatalyst similar to graphitic C3N4. The sunlight-assisted photocatalytic degradation of the methylene blue dye is demonstrated. To have a better understanding of the mechanism of the [3 + 2] cyclo-additions of monomeric C60 and fullerene oxides, a theoretical investigation has been carried out and the energetics of the reaction C60O + C60 → C120O is calculated. Graphical Abstract
Dissertation•
04 Apr 2014
TL;DR: In this article, an aerosolization technique that produces nano-scale aerosols without using solvents, which can alter the surface chemistry of the aerosols, is presented.
Abstract: While research on the environmental impacts of engineered nanoparticles (ENPs) is growing, the potential for them to be chemically transformed in the atmosphere has been largely ignored. The overall objective of this work was to assess the atmospheric transformation of carbonaceous nanoparticles (CNPs). The research focuses on C60 fullerene because it is an important member of the carbonaceous nanoparticle (CNP) family and is used in a wide variety of applications. The first specific objective was to review the potential of atmospheric transformations to alter the environmental impacts of CNPs. We described atmospheric processes that were likely to physically or chemically alter aerosolized CNPs and demonstrated their relevance to CNP behavior and toxicity in the aqueous and terrestrial environment. In order to investigate the transformations of CNP aerosols under controlled conditions, we developed an aerosolization technique that produces nano-scale aerosols without using solvents, which can alter the surface chemistry of the aerosols. We demonstrated the technique with carbonaceous (C60) and metal oxide (TiO2, CeO2) nanoparticle powders. All resulting aerosols exhibited unimodal size distributions and mode particle diameters below 100 nm. We used the new aerosolization technique to investigate the reaction between aerosolized C60 and atmospherically realistic levels of ozone (O3) in terms of reaction products, reaction rate, and oxidative stress potential. We identified C60O, C60O2, and C60O3 as products of the C60-O3 reaction. We demonstrated that the oxidative stress potential of C60 may be enhanced by exposure to O3. We found the pseudo-first order reaction rate to be 9 × 10 to 2 × 10 s, which is several orders of magnitude lower than the rate for several PAH species under comparable conditions. This research has demonstrated that a thorough understanding of atmospheric chemistry of ENPs is critical for accurate prediction of their environmental impacts. It has also enabled future research in that vein by developing a novel technique to produce nanoscale aerosols from nanoparticle powders. Results of this research will help guide the formulation of appropriate environmental policy concerning the regulation of ENPs.
References
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NEC1
TL;DR: In this paper, it was shown that the oxidation of carbon nanotubes in air for short durations above about 700 °C results in the etching away of the tube caps and the thinning of tubes through layer-by-layer peeling of the outer layers, starting from the cap region.
Abstract: CAPPED hollow carbon nanotubes1,2 can be modified into nanocomposite fibres by simultaneous opening of the caps (by heating in the presence of air and lead metal) and filling of the interior with an inorganic phase3. To generalize this approach, greater understanding is needed of the reaction mechanism between the tube caps and oxygen. Here we report that the oxidation of carbon nanotubes in air for short durations above about 700 °C results in the etching away of the tube caps and the thinning of tubes through layer-by-layer peeling of the outer layers, starting from the cap region. The oxidation reaction follows an Arrhenius-type relation with an activation energy barrier of about 225 kJ mol−1 in air. Heating of closed nanotubes with an oxide (Pb3O4) in an inert atmosphere lowers the activation barrier for the reaction and opening of the tubes occurs at lower temperatures. Contrary to intuition, however, open tubes are much more difficult to fill with inorganic materials than in the one-step filling of tubes reported previously3. But various other experiments might be possible in the inner nano-cavities of the open tubes such as studies of catalysis and of low-dimensional chemistry and physics.
1,026 citations
01 Jan 1976
TL;DR: Spin coating is demonstrated to be a promising technique for depositing magnetic transition metal complexes as discussed by the authors, which shows nano-crystalline formations with random orientations, indicating the preservation of the molecular structure upon the deposition process.
Abstract: Spin coating is demonstrated to be a promising technique for depositing magnetic transition metal complexes. The thin films show nano-crystalline formations with random orientations. The optical properties determined using spectroscopic ellipsometry compare well to those of single molecules in solution indicating the preservation of the molecular structure upon the deposition process. © 2006 Elsevier B.V. All rights reserved.
879 citations
Book•
01 Aug 1995TL;DR: The fullerenes instead undergo a wide variety of reactions characteristic of alkenes as mentioned in this paper, and the many derivatives of C60 and C70 have been reported to offer new directions for organic chemistry.
Abstract: Initially envisaged as rather unreactive, aromatic-like molecules, the fullerenes instead undergo a wide variety of reactions characteristic of alkenes. The many derivatives of C60, and the few of C70, that have now been reported offer new directions for organic chemistry.
614 citations
"C120On from C60Br24" refers background in this paper
...From the low-temperature FTIR study, it is evident that the C60 balls in these dimers are not free to rotate unlike the case of pristine C60 and C60 derivatives such as C60O [28] and C60Br24 [29] which also show the orientational ordering transition....
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...The low-temperature FTIR study of the fullerene dimer oxides (Fig....
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...FTIR studies were performed with a Perkin Elmer Spectrum RXI FTIR spectrometer....
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...Purity of the product was checked with the FTIR spectroscopy....
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...A Leybold commercial cryostat was used for low-temperature FTIR measurements....
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TL;DR: The toluene extract of the fluffy carbon material produced by resistive heating of graphite contains a variety of molecules larger than C60 and C70 in a total amount of 3 to 4% by weight that are identified as higher fullerenes.
Abstract: The toluene extract of the fluffy carbon material produced by resistive heating of graphite contains a variety of molecules larger than C(60) and C(70) in a total amount of 3 to 4% by weight. Repeated chromatography of this material on neutral alumina has led to the isolation of stable solid samples of C(76), C(84), C(90), and C(94). The characterization, which includes mass spectrometry, (13)C nuclear magnetic resonance, electronic absorption (ultraviolet/visible) and vibrational (infrared) spectroscopy identifies these all-carbon molecules as higher fullerenes. In addition, C(70)O, a stable oxide, has been isolated that is structurally and electronically closely related to D5h-C(70). This compound forms during the resistive heating process and probably has an oxygen atom inserted between two carbon atoms on the convex external surface of the C(70) skeleton.
598 citations
TL;DR: In this paper, it was shown that photooxidation of C{sub 60} in benzene furnishes a single monooxide, C{ sub 60}O, as the sole isolable product.
Abstract: The isolation of C{sub 60} in preparatively useful quantities has stimulated intensive efforts to generate and characterize functional derivatives. Many reactions of C{sub 60} furnish complex, inseparable mixtures of products, and only a few discrete, monofunctional congeners have been described to date. We now report that photooxidation of C{sub 60} in benzene furnishes a single monooxide, C{sub 60}O, as the sole isolable product. Moreover, we have obtained the same species as a byproduct of the synthesis of C{sub 60}. Spectroscopic analysis strongly supports the epoxide structure. It is demonstrated that C{sub 60}O is efficiently converted to C{sub 60} in a 91% yield during chromatography of neutral alumina. The widespread use of alumina for purification of the fullerenes may explain why the fullerene oxide was not isolated before.
447 citations