Fullerene Solutions Research Articles

New insights into nonlinear optical effects in fullerene solutions—a detailed analysis of self-diffraction of continuous wave laser radiation

Spatial self-phase modulation (SSPM), i.e. the formation, temporal evolution and subsequent distortion of self-diffraction ring patterns, generated by transmitting a continuous wave 532 nm laser beam through solutions containing C60 or C70 has been investigated. The nonlinear optical response regarding SSPM of such systems was studied, to our knowledge for the first time, in dependence of various solvents, different sample temperatures and viscosities. The SSPM patterns consisted of a number of concentric rings, generated due to induced refractive index changes and start with a central spot, expanding into a series of concentric rings. The number of rings increases steadily and the ring pattern becomes larger with time until a maximum is reached. Thereafter, thermal convection leads to a distortion of the upper part of the ring system, while the lower part keeps its shape. The dependence of temporal and spatial evolution of self-diffraction ring pattern on different sample parameters and not only the functional material itself, leading to our conclusion that thermal effects are responsible for the observed SSPM. For further substantiation, measurements of C60 in toluene at a wavelength of 1070 nm have been carried out. At this wavelength no absorption occurs and no SSPM patterns were observed. Knowing that for ultashort pulses no significant thermal effects take place, we performed additional measurements at a pulse length of 8 ps and a wavelength of 527 nm. Also in this case no SSPM patterns were generated. In order to gain a deeper understanding of the involved physical processes, we developed a thermal blooming simulation: Thermally-induced refractive index changes and convection caused by locally heating of the solution by the laser beam were taken into account, any other nonlinear phenomena were left aside. A laser beam propagating through an absorbing solution generates similar ring structures under these conditions, what is in fully agreement with our experimental results. Additionally, as a practical application of SSPM a laser protection device is presented.

Current-voltage and spectral characteristics of heterostructures of fullerene-water system – N-isoamylisatin 4-methylphenylhydrazone

The paper presents the transmission and absorption spectra of electromagnetic radiation for thin films obtained by pouring from solutions of fullerene-water system and N-isoamylisatin 
 4-methylphenylhydrazone in chloroform. The method of obtaining, synthesis, microscopy of carbon and organic films is described. Shown are the spectra of the interaction of electro-magnetic radiation with thin films in the vision (400–920 nm) and IR (650–4000 cm-1) ranges. 
 The optimal thicknesses of the active layers of the heterostructure based on aqueous solutions of fullerene and N-isoamylisatin 4-methylphenylhydrazone were determined, which made it possible to obtain the maximum increase in conductivity.

Aqueous C60 Fullerene Solution Effects on Cell Viability

Abstract Fullerenes are carbon nanoparticles with the ability to quench reactive oxygen species. The biomedical potential of fullerenes is diminished by their low solubility in water, but many approaches have been developed to bypass this problem, like chemical modification of the carbon cage and the use of the solvent exchange method to transfer fullerenes from one solvent to the other. These two approaches were used in this study. Carboxylated fullerene aqueous solution was acquired using solvent exchange method transferring fullerene nanoparticles (C60) from toluene to water. Effects of varying concentration (0.5, 1, 1.5, 2, 2.5, 3, 5, 10 µM) of aqueous fullerene solution on cell viability and their antioxidative capabilities were evaluated on PC-3 and on monocytes isolated from a blood donor using Resazurin Cell Viability Assay. PC-3 cell viability was drastically affected by the 10 µM fullerene solution but remained relatively stable when treated with other concentrations even after longer periods of incubation with resazurin dye. Elevated cell viability was observed in monocytes treated with various fullerene concentrations, possibly indicative of fullerene protective activity against oxidative stress.

Peculiarities of the Physicochemical Properties of Hydrated C60 Fullerene Solutions in a Wide Range of Dilutions

Hydrated fullerene C60 (HyFn) is a supramolecular object in which the nanosized fullerene molecule is enclosed in a multilayer shell of water molecules. Despite the fact that fullerene C60 is chemically rather inert, aqueous solutions of HyFn exhibit a wide spectrum of biological activity in particular in low and ultra-low concentrations. Thus, physical and chemical properties of aqueous solutions of HyFn in a wide range of its dilutions are of interest. Here we compared some physical and chemical properties of aqueous systems prepared by successive 100-fold dilutions of HyFn (10–7 M) with deionized water, with their intensive shaking at each stage up to the calculated HyFn concentration of 10–31 M and of the corresponding “dilutions” of deionized water prepared in the same manner (controls). We studied the character of рН changes in dilutions when titrating them with HCl and NaOH. It turned out that HyFn dilutions had significantly higher buffering capacity against acidification with HCl than control water “dilutions.” At the highest acidity reached pH in all HyFn dilutions was almost 0.3 units higher than in the respective controls. Average buffering capacity of HyFn dilutions and water controls when titrated with NaOH did not differ. However, differences in buffering capacity could be seen between consecutive dilutions of HyFn at their titration either with NaOH or with HCl. Most prominent differences were observed between consecutive HyFn dilutions in the range of calculated concentrations 10–17–10–31 M titrated with NaOH while no significant differences in pH between equivalent “dilutions” of control water were observed. Similar though less prominent variations in buffering capacity between consecutive HyFn dilutions titrated with HCl were also noticed. Thus, titration with an acid and especially with an alkali made it possible to reveal differences between individual dilutions of HyFn, as well as differences between HyFn dilutions and corresponding dilutions of water. These features may be due to complexity in the structural properties of aqueous systems, which, supposedly, can arise due to the emergence of heterogenous aqueous regions (“clouds”) in the course of their dilutions with intensive mixing at each stage. In order to find out if such heterogeneity is a characteristic for HyFn dilutions we used the method of drying microsphere-containing droplets, whose aqueous base were either HyFn dilutions in the range of calculated HyFn concentration 10–7–10–31 M or respective water controls. It was found that a significant part of HyFn dilutions is characterized by mesoscopic heterogeneity. It showed up by the tendency of microspheres to concentrate in a specific way resembling ornaments once the droplets had dried. As the degree of HyFn dilution increased, the number of dried droplets with an ornament-like microsphere distribution increased. Same was also observed in water control drops. However, for the dilutions of HyFn equivalent to concentrations 10–19–10–31 M the percentage of complexly structured dried up droplets reached 60–80%, while for dried out drops of respective water controls it did not exceed 15–20%. Thus, the physicochemical properties of high dilutions of hydrated fullerene differ not only from each other dependently on the dilution level, but also from those of high dilutions of water, which can be explained by the structuredness and heterogeneity of these aqueous systems. Therefore, upon dilution process the properties of the solutions change according to complex and non-linear laws so that final dilutions cannot be identical in their properties and features to those of the initial solutions (before dilutions process) and to the untreated water. Dilution process, in view of the aforementioned, should not be underestimated when analyzing properties of the solutions, having shown to be able to affect dramatically properties of the solutions.

Kinetic Processes in Fullerene Solutions

In solutions, fullerenes, carbon nanoparticles with size of the order of one nanometer, exhibit a number of interesting properties and kinetic effects. A large part of these effects is connected with the ability of these macromolecules to form aggregates (or clusters), in which the nanoparticles are bound together by dispersion interactions. In this review, we present results of modeling of the kinetics of clusters formation and growth in fullerene C60 solutions of different polarity. The basic approach is the numerical solution of a system of kinetic equations of nucleation theory, applied here for the description of aggregation of fullerenes and accompanying effects. The non-monotonous time dependence of fullerene concentration during dissolution was investigated. A molecular-colloidal solution transition in polar systems is described. In addition, a model description of the critical effect of cluster decomposition after water addition to certain fullerene solutions is presented.

Fabrication of Mesoporous C60/Carbon Hybrids with 3D Porous Structure for Energy Storage Applications.

We report on the synthesis of 3D mesoporous fullerene/carbon hybrid materials with ordered porous structure and high surface area by mixing the solution of fullerene and sucrose molecules in the nanochannels of 3D mesoporous silica, KIT-6 via nanotemplating approach. The addition of sucrose molecules in the synthesis offers a thin layer of carbon between the fullerene molecules which enhances not only the specific surface area and the specific pore volume but also the conductivity of the hybrid materials. The prepared hybrids exhibit 3D mesoporous structure and show a much higher specific surface area than that of the pure mesoporous fullerene. The hybrids materials are used as the electrodes for supercapacitor and Li-ion battery applications. The optimised hybrid sample shows an excellent rate capability and a high specific capacitance of 254 F/g at the current density of 0.5 A/g, which is much higher than that of the pure mesoporous fullerene, mesoporous carbon, activated carbon and multiwalled carbon nanotubes. When used as the electrode for Li-ion battery, the sample delivers the largest specific capacity of 1067 mAh/g upon 50 cycles at the current density of 0.1 A/g with stability. These results reveal that the addition of carbon in the mesoporous fullerene with 3D structure makes a significant impact on the electrochemical properties of the hybrid samples, demonstrating their potential for applications in Li-ion battery and supercapacitor devices.

Atomically Precise Insights into Metal–Metal Bonds Using Comparable Endo-Units of Sc 2 and Sc 2 C 2

The precise identification of metal–metal bonds is critical to fully understanding the nature of metal–metal bonding but remains a fundamental challenge. Herein, we show the essence of Sc–Sc bonds ...

3,6-Fluoren[5]arenes: synthesis, structure and complexation with fullerenes C60 and C70.

A new class of macrocyclic arenes, 3,6-fluoren[5]arenes, were conveniently synthesized in good yields by one-step reaction. The 3,6-fluoren[5]arenes had symmetric pentagon structures with big and rich-electron cavities, which made them form 1 : 1 complexes with fullerenes C60 and C70. The association constants of the complexes were all greater than 105 M-1.

The Influence of the Sequence of Application of Modifying Components on the Protective Properties of a Chemical Ammonia Absorber

In this work, a universal sorbent has been obtained that works according to the mechanisms of chemisorption and adsorption by impregnating AG-5 activated carbon with copper sulfate and modifying it with a fullerene solution. The influence of the sequence of technological operations on the properties of the obtained sorbent is shown. The main porous and sorption characteristics of materials have been determined at various moisture levels of gas–air flow.

Simulation of the oil film thickness on a friction surface in the presence of fullerene compositions in the lubricant

The paper contains theoretical studies of the oil film formation on a friction surface in the presence of fullerene solutions in a lubricant. The mathematical model is developed on the basis of the interaction between electrically active heterogeneous finely dispersed systems at the interface between the friction surface and the lubricating medium and is described by the Poisson differential equation. The role of the friction surface on the formation of clusters and micelles in an adsorbed film of the lubricant near the friction surface is established. It is shown that in the stress-strain state of triboelement material surface layers, the friction surface acts as an “electrostatic field generator”. Expressions are obtained for the simulation of the oil film thickness in the presence of fullerenes in the base lubricant. Based on the simulation results, the most significant factors in the formation of the oil film thickness have been established: these are the electric field strengths of the friction surface and the base lubricating medium; the load on the tribosystem; the temperature, and dynamic viscosity of the lubricating medium.

Tuning the electrochemical and catalytic ORR performance of C60by its encapsulation in ZIF-8: a solid-state analogue of dilute fullerene solution

Hassle-free encapsulation of fullerene C60in ZIF-8 has been performed to preserve the molecularity and solution-like properties of C60in solid-state. The resulting composite shows efficient heterogeneous electrocatalytic oxygen reduction reaction.

Influence of cryopreserved piglets skin fragments or aqueous colloidal solution of C60 fullerene on destruction and inflammation severity after skin cryodestruction

Influence of cryopreserved piglets skin fragments or aqueous colloidal solution of C60 fullerene on destruction and inflammation severity after skin cryodestruction

Density, specific heat capacity and viscosity of fullerene C60 solutions in tetralin

By combination of thermophysical and optical properties the solutions of tetralin with nanoparticles such as fullerene C60 can be considered as promising heat transfer agents for solar energy. The paper presents the results of experimental investigation for the density, viscosity and specific heat capacity of tetralin / fullerene C60 solutions. The study was performed in the temperature range 237…434 (K) and concentrations of fullerene C60 up to 1.043 (wt.%). The obtained results have shown an increase in the density and viscosity, as well as a decrease in the specific heat capacity of tetralin after adding C60. The obtained temperature dependences for the thermophysical properties of tetralin / C60 solutions are equidistant to theirs for tetralin. Obtained data on the density and viscosity were accurately fitted by a few-constant correlations for non-associated substances. The experimental data on the specific heat capacity of both tetralin and tetralin / C60 solutions indicate to significant effect of supramolecular structures in a liquid phase of aromatic hydrocarbons on this property. This effect is most significant in the temperature region close to the triple point. A new correlation for predicting the specific heat capacity of aromatic hydrocarbons containing fullerene C60 on the boiling line using a limited initial empirical data is proposed.

Diluted and concentrated organosols of fullerene C60 in the toluene–acetonitrile solvent system as studied by diverse experimental methods

In this article, we examined the state of fullerene C60 in toluene and its mixtures with acetonitrile in both diluted, (4.0 to 6.3)×10−6 M, and concentrated, (0.23 to 1.9)×10−3 М solutions, prepared by either equilibrium or non-equilibrium procedures. Typically, the working solutions were prepared by diluting stock solutions of fullerene in toluene. Some specific features of solid fullerene interaction with atmospheric oxygen were revealed using the LDI mass-spectrometry. A combination of electron absorption spectra of the fullerene in C6H5CH3–CH3CN mixtures with the analysis of the particle size distribution using the DLS method demonstrated that even in acetonitrile-rich media, where diluted C60 exists in colloidal state, some features of the molecular absorption spectra are still present. Such effect is in line with the formation of the large solvation shells of an aromatic solvent around fullerenes. The TEM images of the dried colloidal solutions demonstrate a loose floc configuration of the aggregates, contrary to the crystal structure of the species in a toluene-free C60 dispersion obtained by hand-grinding. In solution, the spectrum of the last-named is a monotonous curve increasing toward ultraviolet. The LDI measurements proved the tendency of C60 toward forming negative species under contact with acetonitrile. Electrophoretic studies state that a universal property of the negatively charged colloidal species is their expressed ability to overcharging in the presence of inorganic cations, which are poorly solvated by acetonitrile. In concentrated (oversaturated) fullerene solutions, where the SAXS and SANS methods are applicable, fractal-type aggregates of fullerenes were revealed in solutions. The analysis of aggregates structure indicates that their packing density is increased with growth of fullerene concentration and/or amount of acetonitrile in the mixture. Thus, branched aggregates were observed in toluene solution, while fullerenes form dense clusters with diffusive surface in mixtures with acetonitrile.

Volume Properties of Aqueous Solutions of Light Fullerene С60 and Its Association in Binary C60(OH)24–H2O System at 25°С

The density of aqueous solutions of light fullerene С60 in binary system C60(OH)24–H2O is studied via pycnometry. The concentration dependences of the molar volumes and partial molar volumes of the components (Н2О and corresponding fullerenol) are calculated for the binary C60(OH)24–H2O system at 25°С. The linear sizes and the electrokinetic potentials and mobilities of the associates in the given system are studied via dynamic light scattering.

Liquid Systems with Fullerenes in Organic Solvents and Aqueous Media

The unique properties of nanocarbon materials – in particular, fullerenes – has led in recent years to the expansion of the spectrum of their application in various fields of the industry, including the chemical, energy, and pharmaceutical ones. The use of fullerenes in new industries poses new challenges to the scientific and research community. Thus, new methods of obtaining biocompatible liquid systems with small-sized monodisperse fullerene aggregates are still being sought. The paper focuses on the properties of fullerene solutions in mixtures of organic solvents, which serve as a basis for the development of new methods for synthesizing the aqueous liquid systems with fullerenes.

Penta(zinc porphyrin)[60]fullerenes: Strong reverse saturable absorption for optical limiting applications

Penta(zinc porphyrin)[60]fullerene, in which a fullerene (C60) with attached five electron donating zinc porphyrin moieties was synthesized. The nonlinear optical response was studied together with reference penta(trimethylsilyl)C60 and triazole-zinc porphyrin compounds. The second and third harmonic generation in both guest-host polymeric films deposited by means of spin coating technique and films obtained by physical vapor deposition technique was investigated via Maker fringe technique employing 30 ps laser pulses at 1064 nm. The second and third order susceptibilities as well as second hyperpolarizabilities were determined. Penta(zinc porphyrin)[60]fullerene in solutions and PMMA films demonstrated strong reverse saturable absorption in Z-scan measurements employing the laser double frequency. The nonlinear absorption coefficient and imaginary part of cubic susceptibility were obtained for solutions and films. The second hyperpolarizability and nonlinear absorption cross section were extracted as well. Penta(zinc porphyrin)[60]fullerene shows attractive optical limiting response property suitable for photonic applications.

Effect of Colloidal Aqueous Solution of Fullerene (C60) in the Presence of a P-Glycoprotein Inhibitor (Verapamil) on Spatial Memory and Hippocampal Expression of Sirtuin6, SELADIN1, and AQP1 Genes in a Rat Model of Alzheimer's Disease.

Alzheimer's disease (AD) is one of the most common types of neurodegenerative diseases which is accompanied by irreversible neuronal damage, learning difficulties, memory impairments, and cognitive disorders. The cholinergic system is destroyed during AD pathogenesis, leading to the major symptoms of the disease. Although in severe stages AD is life threatening, to date no absolute treatment has been found for this illness and some palliative options are available. The aim of this study was to investigate the effect of fullerene (C60) aqueous suspension (FAS) on improving spatial memory in amnesic male Wistar rats (weighing 200 ± 20 g) and to further compare the results with that of donepezil (DNPZL) as a standard drug. FAS was prepared via a solvent exchange method. The particle size was in the 119.14 ± 3.38 nm range with polydispersity index of 0.15 ± 0.02 and zeta potential of -12.22 ± 5.98 mV. A simple and high sensitive reversed phase high performance liquid chromatography (HPLC) method was developed to identify the C60 concentration in FAS (21 μg/mL). Efficiencies of drugs were examined in both pretreatment and post-treatment groups of animals to better understand how they participate in affecting AD symptoms. Seeing that previous studies have presented antithetical declarations about whether C60 is a P-glycoprotein (P-gp) substrate, we studied FAS effects in both conditions of the presence and absence of a P-gp inhibitor (verapamil HCl, 25 mg/kg). In order to clarify the molecular mechanisms of action of two drugs, their effects on the expression of three principal genes involved in AD, including Sirtuin6, SELADIN1, and AQP1, and as well as their total antioxidant capacities (TACs) were studied. In order to induce memory impairment, scopolamine HBr (SCOP) was administered for 10 days (2 mg/kg/i.p.). FAS and DNPZL administration regimens were 21 μg/mL, BID (i.p.) and 10 mg/kg (p.o.) for 10 days, respectively. Our results introduce FAS as a promising nanoformulation for improving AD symptoms, especially memory impairment, and further assert that more studies are needed to elucidate C60 and P-gp interaction type.

Vortex-Aligned Ordered Film of Crystalline Fullerene C70 Microtubes with Enhanced Photoluminescence and Photovoltaics Properties

Crystalline fullerene C70 microtubes (FMTs) were produced employing ultrasound-assisted liquid- liquid interfacial precipitation (ULLIP) technique at the interface between fullerene C70 solution in 1,2 dichlorobenzene (DCB) and isopropanol (IPA) at 15 °C. Using the vortex-flow motion of the subphase water (also called Vortex-Langmuir-Blodgett technique), the FMTs were aligned and homogeneous films were prepared at the air-water interface. The aligned FMTs film exhibited enhanced photoluminescence (PL) with PL intensity ~5 times higher than that of the pristine C70. Moreover, the aligned FMT film showed better photovoltaics properties compared with randomly oriented FMTs and pristine C70 film obtained from the spin coating. The compact, directional orientation and proper surface coverage of the FMT film enhanced the charge transport properties in the photovoltaic device.

MORPHOLOGICAL ASSESSMENT OF WOUND HEALING AFTER CRYODESTRUCTION OF SKIN USING AN AQUEOUS COLLOIDAL SOLUTION OF C60 FULLERENES

The aim is to assess the morphological state of a cold skin wound in an experiment, using an aqueous colloidal solution of C60 fullerenes. Materials and methods: An experimental study was conducted in 30 six-month-old male rats divided into three groups, 10 individuals in each group: group I included rats that did not undergo any manipulations; group II was represented by rats which underwent a cold wound simulation on the lateral thigh surface; group III was represented by rats who had a simulated cold wound followed by introduction of an aqueous colloidal solution of C60 fullerenes at a dose of 0.1 mg/kg for 5 days into the abdominal cavity, starting from the cryodamage day. Animals of all groups were removed from the experiment on days 7, 14 and 21. The material for the morphological study was skin with underlying soft tissues. The resulting sample was studied, using histological, histochemical, morphometric and statistical research methods. Results: C60 fullerenes stimulate proliferative activity in the epidermis, located in the wound marginal regions or covering the regenerate surface, which leads to an increase in epithelial layer thickness by 2.6, 2.6, 2.5 times on 7, 14 and 21 days; promotes faster cleansing of the wound from necrotic tissue, reducing the thickness of the zone of primary necrosis on days 7, 14 and 21 by 1.3 times by increasing the demarcation zone on days 7, 14 and 21 by 1.4, 1.4 and 2, 2 times; reduces the thickness of the secondary necrosis area on 7, 14 and 21 days by 1.4, 1.5 and 1.3 times; accelerates filling of the wound defect with granulation tissue, the layer thickness of which increases by 2.3, 2.2 and 1.4 times on the 7th, 14th and 21st days, respectively; reduces the severity of hemodynamic disorders and cell infiltration in the wound defect adjacent tissues of the dermis, hypodermis with the underlying muscle tissue. Conclusions: A comprehensive morphological study of the experimental material indicates that the injection into the abdominal cavity of an aqueous colloidal solution of C60 fullerenes activates reparative processes in the skin cold wounds, which go through all the classical stages.