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1.
Two molecular Janus particles based on amphiphilic [60]fullerene (C60) derivatives were designed and synthesized by using the regioselective Bingel–Hirsh reaction and the click reaction. These particles contain carboxylic acid functional groups, a hydrophilic fullerene (AC60), and a hydrophobic C60 in different ratios and have distinct molecular architectures: 1:1 (AC60–C60) and 1:2 (AC60–2C60). These molecular Janus particles can self‐assemble in solution to form aggregates with various types of micellar morphology. Whereas vesicular morphology was observed for both AC60–C60 and AC60–2C60 in tetrahydrofuran, in a mixture of N,N‐dimethylformamide (DMF)/water, spherical micelles and cylindrical micelles were observed for AC60–C60 and AC60–2C60, respectively. A mechanism of formation was tentatively proposed based on the effects of molecular architecture and solvent polarity on self‐assembly.  相似文献   

2.
Methanofullerenes were directly synthesized under mild conditions by cycloaddition to fullerene C60 of diazoalkanes generated in situ by oxidation of ketone hydrazones containing a heterocyclic fragment with manganese(IV) oxide in the presence of the catalytic system Pd(acac)2-2 PPh3-4 Et3Al.  相似文献   

3.
Fullerene (C60), the third carbon allotrope, is a classical engineered material with the potential application in biomedicine. However, extremely high hydrophobicity of fullerene hampers its direct biomedical evaluation and application. In this work, we investigated the solubilization of fullerene using 9 different solubility enhancers: Tween 20, Tween 60, Tween 80, Triton X-100, PVP, polyoxyethylene (10) lauryl ether, n-dodecyl trimethylammonium chloride, myristyl trimethylammonium bromide and sodium dodecyl sulphate and evaluated its antioxidant activity in biorelevant media. The presence of C60 entrapped in surfactant micelles was confirmed by UV/VIS spectrometry. The efficacy of each modifier was evaluated by chemometric analysis using experimental data for investigating the relationship between solubilization and particle size distribution. Hierarchical clustering and principal component analysis was applied and showed that non-ionic surfactants provide better solubilization efficacy (>85%). A correlation was established (r = 0.975) between the degree of solubilization and the surfactant structure. This correlation may be used for prediction of C60 solubilization with non-tested solubility modifiers. Since the main potential biomedical applications of fullerene are based on its free radical quenching ability, we tested the antioxidant potential of fullerene micellar solutions. Lipid peroxidation tests showed that the micellar solutions of fullerene with Triton and polyoxyethylene lauryl ether kept high radical scavenging activity, comparable to that of aqueous suspension of fullerene and BHT. The results of this work provide a platform for further solubilization and testing of pristine fullerene and its hydrophobic derivatives in a biological benign environment.  相似文献   

4.
The collisional electron detachment process of carbon cluster anions containing from 2 to 72 atoms was investigated on the collision with a MoS2 surface. The detachment efficiency was classified into several groups and is most likely to reflect the structures or the isomer contents of the incident cluster anions. The cluster anions produced via laser-vaporization of graphite showed quite a larger detachment efficiency than the fullerene C 60 - and its fragment anions. The major isomers of these cluster anions were suggested to be chains or rings.  相似文献   

5.
《Chemical physics letters》1999,291(1-2):31-36
We report the discovery of elongated fullerene capsules contained within single-wall carbon nanotubes, as well as new findings pertaining to encapsulated, self-assembled chains of C60. The observed structures comprise a new, complete class of hybrid materials: hemispherically-capped graphene cylinders of various lengths within carbon nanotubes. Short capsules and chains comprised of only a few C60 molecules spontaneously jump nanometer distances along the axis of the containing tube. A model explaining this behavior is proposed.  相似文献   

6.
曾和平 《中国化学》2002,20(10):1007-1011
Photoinduced electron transfer(PET) processes between C60-C6H8SO and Tetrathiafulvalene(TTF) have been studied by nanosecond laser photolysis.Quantrm yiekds(φet) and rate constants of electron transfer(ket) from TTF to excited triplet state of[60] fullerene-containing cyclic sulphoxide in benzonitrile(BN) have been evaluated by observing the transient absorption bands in the NIR region.With the decay of excited triplet state of [60]fullerene-containing cyclic suplhoxide,the rise of radical anion of [60]fullerene-containing cyclic sulphoxinde is observed.  相似文献   

7.
Effect of fullerene C60 was investigated on thermal, mechanical and optical properties of polymethylmethacrylate (PMMA) under ionizing radiation. It was stated that fullerene C60 behaves as an effective antirad with respect to PMMA. Fullerene C60 addition raises temperature of destruction for polymer subjected to electron radiation by 20-25 °C, lowers the rate from 4 to 4.5 times and increases the activation barrier for radiated PMMA destruction reaction. Fullerene C60 addition promotes improvement of strength properties of PMMA: for films containing C60 addition and else subjected to electron radiation treatment a decrease in rupture strength is 10-15%, for samples containing no fullerene it equals ∼25%. Interaction of free radicals with fullerene at radiation treatment influences optical characteristics of PMMA films.  相似文献   

8.
The anionic methods for the synthesis of homo- and heteroarm (hybrid) star-shaped polymers using fullerene C60 aPre considered. The possibilities of fullerene C60 as an agent of combination of living polymer chains and the procedures of transformation of polymer derivatives of C60 (hexaadducts) into polyfunctional macroinitiators of anionic polymerization of vinyl monomers are shown. The methods for functionalization of polymer fullerene derivatives and their combinations into structures of complex controlled architecture are presented. The structural features and initiating properties of the living polymer fullerene derivatives and their role in the formation of heteroarm star-shaped macromolecules with the controlled number of branches and predetermined molecular weight characteristics of the arms are discussed. The hydrodynamic properties of the star-shaped fullerene-containing polymers are considered. The data on the small-angle neutron scattering study of self-organization of the stars in solutions are presented.  相似文献   

9.
Method of radiation polymerization of N-vinylpirrolidone (NVP) in the presence of fullerene C60 has been used to obtain water soluble compound containing fullerene C60. The yield of resulted product was ~10% in the case of low-temperature radiation polymerization of NVP—C60 mixture in ethanol and ~40% at 300 K. The content of C60 in obtained product was ~0.5 wt.%.  相似文献   

10.
The recent results of investigations involving the electrochemical formation of polymers containing fullerenes and studies of their properties and applications are critically reviewed. From a structural point of view, these polymers can be divided into four main categories including (1) polymers with fullerenes physically incorporated into the foreign polymeric network without forming covalent bonds, (2) fullerene homopolymers formed via [2+2] cycloaddition, (3) “pearl necklace” polymers with fullerenes mutually linked covalently to form polymer chains, and (4) “charm bracelet” polymers containing pendant fullerene substituents. The methods of electrochemical polymerization of these systems are described and assessed. The structural features and properties of the electrochemically prepared polymers and their chemically synthesized analogs are compared. Polymer films containing fullerenes are electroactive in the negative potential range due to electroreduction of the fullerene moieties. Related films made with fullerenes derivatized with electron-donating moieties as building blocks are electroactive in both the negative and positive potential range. These can be regarded as “double cables” as they exhibit both p- and n-doping properties. Fullerene-based polymers may find numerous applications. For instance, they can be used as charge-storage and energy-converting materials for batteries and photoactive units of photovoltaic cell devices, respectively. They can be also used as substrates for electrochemical sensors and biosensors. Films of the C60/Pt and C60/Pd polymers containing metallic nano-particles of platinum and palladium, respectively, effectively catalyze the hydrogenation of olefins and acetylenes. Laser ablation of electrochemically formed C60/M and C70/M polymer films (M=Pt or Ir) results in fragmentation of the fullerenes leading to the formation of hetero-fullerenes, such as [C59M]+ and [C69M]+.Dedicated to Professor Dr. Alan M. Bond on the occasion of his 60th birthday.  相似文献   

11.
The reduction of fullerene C60 by zinc dust in the presence of crystal violet cations (CV+) yielded a deep‐blue solution, from which crystals of (CV+)(C60.?) ? 0.5 C6H4Cl2 ( 1 ) were obtained by slow mixing with n‐hexane. The salt contained isolated, closely packed zigzagged chains that were composed of C60.? radical anions with a uniform interfullerene center‐to‐center distance of 9.98 Å. In spite of the close proximity of the fullerenes, they did not dimerize, owing to spatial separation by the phenyl substituents of CV+. The room‐temperature conductivity of compound 1 was 3×10?2 S cm?1 along the fullerene chains. The salt exhibited semiconducting behavior, with an activation energy of Ea=167 meV. Spins localized on C60.? were antiferromagnetically coupled within the fullerene chains, with a Weiss temperature of ?19 K without long‐range magnetic ordering down to 1.9 K.  相似文献   

12.
Star-shaped regular homopolystyrenes with 22 arms and heteroarm polymers with 12 PS arms and 10 poly(2-vinypyridine) arms have been synthesized by consecutive coupling-functionalization-coupling reactions. The synthesis includes the following stages: the exhaustive grafting of fullerene C60 by polystyryllithium chains (living hexaadducts); the coupling of hexaadducts with the use of dimethyldichlorosilane or 1,4-dibromobutane into twelve-arm macromolecules, where the branching center is composed of two covalently bonded fullerene C60 molecules; functionalization of twelve-arm double-core PS stars during the action of excess dihalides (the replacement of lithium atoms with groups containing chlorine or bromine atoms); and the coupling of living chains of PS or poly(2-vinylpyridine) via reactions with halogen-containing groups at the branching center of double-core PS stars. Linear living polymers used as arms have been prepared by anionic polymerization. Exclusion chromatography has been used to control the individual stages of synthesis. The molecular characteristics of the PS precursor and of star-shaped polymers have been studied in terms of hydrodynamics and light scattering.  相似文献   

13.
The quantum-chemical simulation of possible reactions occurring at the initial stage of the free-radical polymerizations of styrene and methyl methacrylate in the presence of fullerene C60 is performed. The reactions of interaction between initiating and model short-chain growing radicals containing from one to three monomer units with fullerene are considered. It is shown that, at the initial stage of styrene polymerization, the addition of short-chain growing radicals to fullerene predominates (with respect to the reaction of chain propagation). In the case of methyl methacrylate polymerization in the presence of fullerene C60, the induction period is absent because of a higher probability of the initiation and chain propagation reactions (compared with the chain-termination reaction of short growing poly(methyl methacrylate) chains on fullerene C60). The formation of bis- and trisadducts of fullerene C60 with short-chain styrene and methyl methacrylate growing radicals is analyzed. The quantum-chemical simulation results are confirmed by electron spectroscopy and ESR studies.  相似文献   

14.
The electrochemically active polymers have been formed during electro-reduction carried out in solution containing fullerenes, C60 or C70, and transition metal complexes of Pd(II), Pt(II), Rh(III), and Ir(I). In these films, fullerene moieties are covalently bounded to transition metal atoms (Pd and Pt) or their complexes (Rh and Ir) to form a polymeric network. All films exhibit electrochemical activity at negative potentials due to the fullerene cages reduction process. For all studied metal complexes, yields of formation of films containing C70 are higher than yields of electrodeposition of their C60 analogs. C70 /M films also exhibit higher porosity in comparison to C60/M layers. The differences in film morphology and efficiency of polymer formation are responsible for differences in electrochemical responses of these films in acetonitrile containing supporting electrolyte only. C70/M films shows more reversible voltammeric behavior in negative potential range. They also show higher potential range of electrochemical stability. Processes of film formation and electrochemical properties of polymers depend on the transition metal ions or atoms bonding fullerene cages into polymeric network. The highest efficiency of polymerization was observed for fullerene/Pd and fullerene/Rh films. In the case of fullerene/Pd films, the charge transfer processes related to the fullerene moieties reduction in negative potential range exhibit the best reversibility among all of the studied systems. Capacitance performances of C60/Pd and C70/Pd films deposited on the porous Au/quartz electrode were also compared. Capacitance properties of both films are significantly affected by the conditions of electropolymerization. Only a fraction of the film having a direct contact with solution contributes to pseudocapacitance. Capacitance properties of these films also depend on the size of cations of supporting electrolyte. The C70/Pd film exhibits much better capacitance performance comparison to C60/Pd polymer.  相似文献   

15.
Kinetics was studied of bulk polymerization of methyl methacrylate initiated by dicyclohexyl peroxydicarbonate in the presence of tri-n-butylborane and fullerene C60 (or C70) at variable ratio initiator: fullerene. The deceleration of the polymerization in the first stage of the reaction (below 10% conversion) was established by dilatometric method that depended on the fullerene concentration and the mode of its addition to the monomer. It was shown that at similar ratios initiator: fullerene the C60 inhibited the polymerization process considerably stronger than C70. The gel-permeation chromatography revealed the widening of the molecular weight distribution of the poly(methyl methacrylates) containing C60 or C70 compared to its analog synthesized under the same conditions without fullerene. It was established that in the fullerene-containing poly(methyl methacrylates) all the framework nanospecies are linked by covalent bonds and are mostly accumulated in the low-molecular fractions. The effect of the covalently bound fullerene on the molecular characteristics of polymers were investigated by translational isothermal diffusion, high-speed sedimentation, and viscometry  相似文献   

16.
Leading position among numerous methods for synthesis of star polymers is occupied, as regards their potential and diversity, by techniques based on the anionic polymerization. The review considers five basic approaches to application of the anionic polymerization mechanisms in relation to an agent used or procedure employed (methods with polyfunctional coupling agents, multifunctional initiators, polymerizing and nonpolymerizing divinyl agents; multistage methods, methods using C60 fullerene). All groups of syntheses are illustrated by examples, and advantages of methods for synthesis of various homo- and heteroarm star structures are demonstrated. Particular attention is given to syntheses with C60 fullerene. The potential of C60 fullerene as a coupling agent for “living” polymer chains and methods for conversion of polymeric derivatives of C60 (hexaadducts) to polyfunctional macroinitiators of anionic polymerization are described and techniques for functionalization of polymeric fullerene derivatives and their coupling into structures with a complex controllable architecture are presented.  相似文献   

17.
An effective computational strategy to describe the dispersion of C60 by surfactants is presented. The influence of parameters such as surfactant concentration and molecular length on the final morphology of the system is explored to explain the experimental results and to understand the incorporation of C60 inside micelles. Both neutral and charged amphiphilic molecules are simulated. The long‐discussed problem of the location of fullerenes in micelles is addressed and C60 is found in the hydrocarbon‐chain region of the micelles. If the available hydrophobic space increases, C60 is localized in the inner part of the micellar core. Short, charged amphiphilic stabilizers are more efficient at dispersing fullerenes monomolecularly. Two different phases of C60 are observed as the C60/surfactant ratio varies. In the first, aggregates of C60 are entrapped inside the micelles, whereas, in the second, colloidal nanoC60 is formed with surfactants adsorbed on the surface.  相似文献   

18.
Synthesis of fullerenes from graphite powders of different grade was studied in a radiofrequency (RF) plasma reactor. Dependence of fullerene yield on the properties and feed rate of precursors and on the helium content of plasma gas was studied in details. The fullerene yield was influenced by the mean size and the thermal conductivity of graphite particles on the one hand, and the helium content of the gas phase on the other. Soot containing fullerene mixture of 5.9% was produced in best conditions found in this work. The main component of the fullerene mixture was C60. In addition, it contained about 30% of C70 (corresponding to a C60/C70 mass ratio of 2.64). Higher fullerenes such as C84 were also detected by mass spectroscopy (MS) and high performance liquid chromatography (HPLC).  相似文献   

19.
The structure and conformational properties of star-shaped oligostyrenes containing fullerene C60 as a branching center and short arms with lengths at the level of the persistent length or a segment of a polystyrene chain are studied by small-angle neutron scattering in deuterotoluene. The gyration radii of linear precursor oligomers (~0.4 and 0.6 nm) and corresponding star-shaped molecules (~1.1 and 1.4 nm) are calculated under the Guinier approximation. The linear oligomer (4–5 units) is found to be a rodlike molecule; arms of star-shaped molecules based on it assume the straightened conformations as well. Linear oligomer chains composed of 6–7 units deviate from the rodlike shape and acquire a certain flexibility in solution, but oligomer chains grafted onto the C60 center preserve the extended conformations. There is no marked tendency toward screening of fullerene by radially extended arms. The number of branches in the star-shaped oligostyrenes corresponds to a functionality of f = 6 preset by the conditions of synthesis.  相似文献   

20.
Host–guest and supramolecular chemistry can produce water-solubilization of fullerenes such as C60, C70, and C60/70 derivatives by hydrophobic interactions, CH–π interactions, and/or π–π interactions. For materials and biomedical applications, these water-soluble host–fullerene complexes must have the following important properties: (i) high solubility, (ii) high stability, and (iii) functionalization of the host–fullerene complex. These objectives can be achieved by selection of appropriate host molecules, development of novel solubilizing methods, and synthesis of functionalized host molecules. This review describes the introduction of a variety of host molecules that can solubilize fullerenes in water. In addition, we describe applications of host–fullerene complexes, in particular using photoinduced energy- and electron-transfer processes in water.  相似文献   

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