Molecular dynamics study on oscillation dynamics of a C60 fullerene encapsulated in a vibrating carbon-nanotube-resonator

We investigated the oscillation dynamics of a C₆₀ fullerene encapsulated in a single-walled carbon-nanotube-resonator via classical molecular dynamics simulations. The C₆₀ fullerene positions in a single-walled carbon-nanotube-resonator could be controlled by vibrating the resonator. The C₆₀-fullerene’s oscillations along the tube axis in a vibrating carbon-nanotube-resonator were originated by centrifugal forces exerted at the central position of the vibrating carbon-nanotube, and thus property was very different from its oscillation due to van der Waals forces in the fixed carbon-nanotube. These properties suggest that a carbon-nanotube-resonator encapsulating a C₆₀ fullerene has a potential application for programmable multiple-position devices controlled by the resonance frequency.     

Cucurbit[8]uril‐Regulated Colloidal Dispersions Exhibiting Photocontrolled Rheological Behavior

In situ photocontrol over shear‐thickening of condensed colloidal dispersions is of paramount importance in a wide range of applications including process technology and photorheological fluids. Its development and practicability, however, are hampered by the lack of well‐designed photoresponsive systems. Here, a colloidal suspension whose rheological behavior is readily switchable between shear‐thinning and shear‐thickening using an external light stimulus is reported. This smart colloidal solution contains hybrid raspberry‐like colloids prepared by employing cucurbit[8]uril as a supramolecular linker to assemble functional Fe₃O₄ nanoparticles onto a silica core. The formed raspberry colloids are photoresponsive and can be reversibly disassembled under UV irradiation.     

Catalytic activity of hybrid platinum nanoparticle-[C60]fullerene nanowhisker composites for 4-nitrophenol reduction

Abstract

Composites comprising platinum nanoparticles loaded on [C₆₀]fullerene nanowhiskers were prepared by a liquid-liquid interfacial precipitation method. The synthesized platinum nanoparticle-[C₆₀]fullerene nanowhisker composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The catalytic activity of the platinum nanoparticle-[C₆₀]fullerene nanowhisker composites was confirmed for the reduction of 4-nitrophenol by UV–vis spectroscopy. The reduction of 4-nitrophenol catalyzed by the platinum nanoparticle-[C₆₀]fullerene nanowhisker composites followed the pseudo-first-order reaction rate law.     

The Next Generation of Colloidal Probes: A Universal Approach for Soft and Ultra‐Small Particles

The colloidal probe technique, which is based on the atomic force microscope, revolutionizes direct force measurements in many fields, such as interface science or biomechanics. It allows for the first time to determine interaction forces on the single particle or cell level. However, for many applications, important “blind spots” remain, namely, the possibility to probe interaction potentials for nanoparticles or complex colloids with a soft outer shell. Definitely, these are colloidal systems that are currently of major industrial importance and interest from theory. The here‐presented novel approach allows for overcome the aforementioned limitations. Its applicability has been demonstrated for 300 nm sized carboxylate‐modified latex particles as well as sub‐micron core–shell particles with a soft poly‐N‐isopropylacrylamide hydrogel shell and a rigid silica core. For the latter, which until now cannot be studied by the colloidal probe technique, determined is the temperature dependency of electrosteric and adhesion forces has been determined on the single particle level.     

Controlling the Number of Arms of Polymer Stars with a Fullerene C60 Core

Abstract

Pure di‐ and tetra‐adducts can be obtained by grafting polystyrene (PS) chains onto C₆₀ via an atom transfer radical addition. Stars with a C₆₀ core and exactly six PS arms of molar mass ranging from 1000 to several 100,000 are easily produced by adding an excess of PSLi to the fullerene. Tri‐ to penta‐adducts can be prepared by controlling the stoichiometry PSLi/C₆₀. The number of grafts on the fullerene can be extended to seven or eight by initiation of the anionic polymerization of an adequate monomer with a “living” hexa‐adduct or by grafting onto this latter an halogen terminated polymer.     

Size control for fullerene C60 nanocrystals during the high temperature and high pressure fluid crystallization process

The preparation and size control for mono-dispersed fullerene C₆₀ fine particles was successfully achieved during the high temperature and high pressure fluid (HTPL) crystallization process, in which acetone was used as the HTPL solvent and pure water or the mixture of acetone and water as the cooling solvent. The prepared fullerene C₆₀ particles had spherical shape and narrow size distribution with the average size ranging from 44 nm to 110 nm depending on the various experimental conditions, such as fluid temperature, solvent flow rate, system pressure and the ratio of acetone and water in cooling solvent. The products were characterized by using X-ray powder diffraction (XRD), scan electron microscopy (SEM), dynamic light scattering technique (DLS) and UV–VIS spectrum, respectively. And the size effect of such fullerene C₆₀ nanocrystals was confirmed.     

Two Alternative Ways for Formation of Mono‐atomic Carbon Layer on Ni(1 1 1): Organic‐Gas Cracking and Thermal Decomposition of Fullerenes in Thin Film

Abstract

Formation of graphite mono‐atomic layers (monolayer of graphite, MG) on Ni(1 1 1) single‐crystal surface by cracking of propylene C₃H₆ as well as by decomposition of fullerene molecules C₆₀ was investigated. Comparative analysis of carbon films was made in both cases by means of auger electron spectroscopy (AES), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM) techniques. It was shown with the LEED measurements, that quality of graphite mono‐atomic layer obtained in the two different ways is similar and high enough. For the system prepared by fullerene fragmentation some fullerene‐similar topography features were found in STM images. These observations are explained as a result of arrangement of single C₆₀ molecules underneath the MG on Ni(1 1 1).     

Optical and photoelectrical studies of gold nanoparticle-decorated C60 films

Optical and photoelectrical studies were performed on octane-1,8-dithiol cross-linked fullerene films, with supported gold nanoparticles (C₆₀-DT-Au). According to high-resolution transmission electron microscopy observations, the average size of obtained gold nanoparticles was about 5 nm, and the shape was spherical. The comparative investigation of optical properties of pristine and cross-linked with octane-1,8-dithiol C₆₀ films, decorated with gold nanoparticles, found the difference in the extinction coefficient spectra, which was observed also in the photocurrent spectra of barrier heterostructure Au/C₆₀/Si. The analysis of dark current-voltage characteristics for Au/C₆₀/Si heterostructures showed that the model for them includes the barrier at the C₆₀/Si interface and internal barriers in the C₆₀ layer, caused by the trapping centers. The hopping mechanism of the current transport in the C₆₀ layer was supplemented with the Poole-Frenkel emission process on these centers, with the barrier height greater for the fullerene C₆₀ film cross-linked with octane-1,8-dithiol.     

In Vitro Effects of Fullerene C60 and Fullerene Black on Immuno-Functions of Macrophages

Abstract

Bovine alveolar macrophages and HL-60-macrophages were incubated with fullerene C₆₀ and fullerene black particles in native form. No cytotoxic effects were observed. Both types of particles induced the production of Tumor-Necrosis-Factor and interleukin-8 at which fullerene black is more effective. Superoxide anions (O₂) are not released.     

On Some Complexes of Allyl Derivatives of C60 Fullerene: Simulation of Molecular and Electron Structure by DFT

Abstract

The problem of existence of η³–π‐complexes of transition metal atoms with the allyl type derivatives C₆₀X₃ of C₆₀ fullerene is discussed. It is shown that complexes C₆₀X₃Co(CO)₃ (X = H, F, Cl, Br), C₆₀H₃NiC₅H₅, C₆₀H₃Fe(CO)C₅H₅, where three atoms X are bound to the C atoms of fullerene in the α‐positions relative to the same five‐membered ring in the C₆₀ fullerene, must be sufficiently stable. In these complexes the metal atoms are η³–π‐bound to the fullerene cage. In contrast to this, the metal atoms with the same allyl type C₆₀H₃ derivative of C₆₀ fullerene in the C₆₀H₃Li and C₆₀H₃FeC₅H₅ complexes are η⁵–π‐coordinated to the carbon cage. Calculations were carried out by the DFT with the exchange‐correlation potential by Perdew–Burke–Ernzerhow.     

Size-controlled recrystallization of fullerene by gas–antisolvent process

Gas–antisolvent (GAS) process using CO₂ successfully prepared crystals of fullerene (C₆₀) from a toluene solution through a precipitation. Particle sizes of precipitated C₆₀ could be easily controlled by changing the initial pressurization rate of CO₂, the temperature at the initial pressurization, and the quantity of C₆₀. Fullerene particles obtained by GAS method had regular octahedral shapes, whereas the particles obtained by adding liquid ethanol as an antisolvent to C₆₀ solution did not have such shape. Particle sizes could be changed in a range of 1.0–8.5 μm by GAS method; they were wider than the range of particles obtained by ethanol addition (0.7–1.8 μm).     

Chemically Driven Microstructure Evolution in Cobalt–Fullerene Mixed System

Abstract

We report on the formation of Co–C₆₀ nano‐composite prepared by simultaneous deposition of cobalt and C₆₀ fullerene on sapphire or NaCl at room temperature. The composite includes fcc‐Co single‐crystals with size of order 10 nm separated by C₆₀‐based matrix. Detailed characterization of the composite by electron diffraction and Raman spectrometry revealed the existence of small amount of diamond and cobalt carbides (orthorhombic Co₂C and Co₃C) in the composite matrix. According to electron diffraction analysis diamond nucleates epitaxialy on facets of fcc‐Co crystals. The proposed model shows the role of chemical interaction in Co–C₆₀ mixture in the nano‐composite structure formation.     

THE SINGLE CRYSTAL X-RAY STRUCTURE OF C70Me8; THE ORIGIN OF THE FULLERENE ADDITION PATTERNS FOR BULKY GROUPS

ABSTRACT

The first complete proof of the equatorial addition pattern in [70]fullerene is provided by a single crystal x-ray structure of C₇₀Me₈. Compared to the bonds in the parent fullerene, those having a methyl group attached are lengthened, those having two methyl groups adjacent at each end are shortened due to compression by these groups, and some hexagonal rings show greater delocalisation (more aromaticity) than the corresponding rings in the precursor fullerene. In contrast to the 1,2-addition of sterically undemanding groups, bulky groups generally undergo 1,4-addition, but only give 1,2-addition if there is a need to quench an intermediate radical. The manner in which this gives rise to the patterns seen in C₆₀ X ₆, C₆₀ X ₈ and C₇₀ X ₁₀, where X is bulky, is proposed.     

HPLC Diode‐Array Analysis of C60 and C70 Polymeric Fullerene Oxides (Fullerene Polymeric Ozonides)

Abstract

It is shown by HPLC diode‐array analysis that the C₆₀ and C₇₀ polymeric fullerene oxides ([C₆₀]‐PFOs and [C₇₀]‐PFOs) which are polymeric ozonides, are composed by nine different components. The ozonide derivatives of C₆₀ and C₇₀ have been proved to be practically analogous in chemical structure and composition. The most important component of both [C₆₀]‐PFOs and [C₇₀]‐PFOs accounts for about 3/4 of each sample. The overozonation of [C₆₀]‐PFOs in methanol has been studied and shown to not produce any significant changes.     

Synthesis of bipyramidal gold nanoparticle-[C60]fullerene nanowhisker composites and catalytic reduction of 4-nitrophenol

The seed solution was prepared by dissolving hydrogen tetrachloroaurate(III) trihydrate (HAuCl₄·3H₂O), trisodium citrate dihydrate (C₆H₅Na₃O₇·2H₂O), and sodium borohydride (NaBH₄) in distilled water. The resulting reddish-purple seed solution was stirred for 3 h at room temperature. The growth solution was prepared by mixing hydrogen tetrachloroaurate(III) trihydrate (HAuCl₄·3H₂O), cetyltrimethylammonium bromide (CTAB, (C₁₆H₃₃)N(CH₃)₃Br), silver nitrate (AgNO₃), hydrochloric acid (HCl), and ascorbic acid (C₆H₈O₆) in distilled water. Subsequently, 100 μL of this seed solution was transferred into 10 mL of the growth solution. The mixed solution was maintained at 30 °C for 3 h to obtain a solution of bipyramidal gold nanoparticles. The bipyramidal gold nanoparticle-[C₆₀] fullerene nanowhisker composites were synthesized by applying the liquid-liquid interfacial precipitation (LLIP) method to a saturated solution of C₆₀ in toluene, the solution of bipyramidal gold nanoparticles, and isopropyl alcohol. The prepared bipyramidal gold nanoparticle-[C₆₀] fullerene nanowhisker composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The catalytic activity of these composites was confirmed in the reduction of 4-nitrophenol by UV-Vis spectroscopy.     

Synthesis and Complex Study of Water‐Soluble Polymer Derivatives of C60 Fullerene

Abstract

The water‐soluble composites with fullerene content up to 5 wt% based on poly‐(N‐vinylpyrrolydone) (PVP) were obtained. The higher fullerene content is achieved by means of introducing tetraphenylporphyrine (TPP) and KBr into composites. The synthesis includes the formation of C₆₀–TPP complex and its further interaction with polymer. The formation of C₆₀–TPP complex was confirmed by ¹³C NMR, SANS, and translational diffusion. The hydrodynamic and electrooptical studies of C₆₀–TPP–PVP complexes indicate the higher symmetry of the polymer coil in the complex as compared to PVP. The C₆₀–PVP–KBr composites were also obtained by the solid state interaction under vacuum, KBr promoting the destruction of fullerene aggregates.     

[60]Fullerene as a Novel Photoinduced Antibiotic

Abstract

The antibacterial activity of [60]fullerene (C₆₀), dissolved with poly(vinylpyrrolidone) K30 (PVP), was studied. Under photo‐irradiation, C₆₀/PVP aqueous solutions showed antibacterial activity, whereas PVP solution alone or fullerene solutions in the absence of light showed no activity. These results reveal that C₆₀ is a potentially good device as a photoinduced antibacterial agent.     

Mechanisms of increased wear resistance of composites based on PTFE doped with fullerene soot

We have studied the effect of small additives of a fullerene soot (FS) on the linear wear intensity I _h of poly(tetrafluoroethylele) (PTFE) in sliding friction on steel with water lubrication. The introduction of only 1% FS into PTFE leads to a sharp drop in I _h . The investigation of FS samples by means of small-and wide-angle X-ray scattering showed that FS contains C₆₀ fullerene and graphite nanocrystals with an average size of 20–25 nm and ultrafine carbon particles 2–3 nm in size. The presence of dispersed nanoscopic particles probably imparts the FS-doped PTFE samples the properties of nanocomposites. The possible mechanism of microcrack healing in PTFE by nanoparticles representing fullerene fragments is considered.     

Electrochemical Synthesis and Transformations of Substituted Methano[60]fullerenes

Abstract

61‐(Dimethoxyphosphoryl)‐61‐(methoxycarbonyl)methano[60]fullerene was produced by using the joint electrochemical reduction of fullerene C₆₀ and (dimethoxyphosphoryl)methoxycarbonyldibromomethane. A few steps of reduction were detected for phosphorylated methano[60]fullerenes. When two electrons per molecule are transferred, the methano fragment is rapidly eliminated (retro‐Bingel reaction). This process involves the step‐by‐step cleavage of two C–C bonds of exo‐carbon with the fullerene shell in combination with the stepwise transfer of other two electrons and a proton to form finally the carbanion of the methano fragment and fullerene dianion.     

FORMATION OF FULLERENES AND CARBON CLUSTERS BY LASER IRRADIATION OF POLYMERIC FULLERENE OXIDE (FULLERENE OZOPOLYMER)

ABSTRACT

Polymeric fullerene oxide (PFO) prepared by prolonged ozonation of C₆₀ fullerene has been laser irradiated and the resulting products formed have been studied by ion cyclotron resonance mass spectrometry. It has been found that PFO produces a complete set of carbon clusters from C₆₀ up to C₁₆₄. The mechanism of formation of this set of fullerenic clusters implies necessarily a laser-induced carbonization step of the PFO substrate. Once the PFO target has been changed into the opportune carbon nanostructure by the laser radiation, the sequence of fullerene carbon clusters has been produced.