Soluble Fullerene Research Articles

Synthesis of 1,6‐didecylnaphtho[1,2‐b:5,6‐b']difuran‐based copolymers by direct heteroarylation polymerization

AbstractThe use of direct CH arylation cross‐coupling polymerization was evaluated for the synthesis of donor–acceptor conjugated co‐polymers using the novel donor 1,6‐didecylnaphtho[1,2‐b:5,6‐b']difuran and either thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) or 1,4‐diketopyrrolo[3,4‐c]pyrrole (DPP) as the acceptor. Thiophene and furan moieties were used to flank the DPP group and the impact of these heterocycles on the polymers' properties was evaluated. The alkyl chains on the diketopyrrolopyrrole monomers were varied to engineer the solubility and morphology of the materials. All of the polymers have similar optoelectronic properties with narrow optical band gaps around 1.3 eV, which is ideal for solar energy harvesting. Unfortunately, these polymers also had high‐lying highest occupied molecular orbital levels of −4.8 to −5.1, and as a result bulk‐heterojunction photovoltaic cells fabricated using the soluble fullerene derivative PC71BM as the electron‐acceptor and these polymers as donor materials exhibited poor performance due to limited Voc values. An examination of the films from these blends indicates that film‐thickness and morphology were also a major hindrance to performance and a potential point of improvement for future materials.

Bicontinuous network of electron donor-acceptor composites achieved by additive-free sequential deposition for efficient polymer solar cells

We report that sequential deposition of a highly crystalline polymer donor and a soluble fullerene acceptor leads to a well-defined interpenetrating network and enhanced power conversion efficiencies in bilayer polymer solar cells. Even without the use of solvent additives, layered thin films of poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2’; 5′,2’’; 5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) and [6,6]-phenyl C71-butyric acid methyl ester (PC71BM), as electron donor and acceptor materials, respectively, showed bicontinuous networks similar to those of a PffBT4T-2OD:PC71BM bulk-heterojunction (BHJ) thin film processed with 1,8-diiodooctane (DIO) as a solvent additive. Transmission electron microscopy results confirmed the BHJ-like morphology of the bilayered PffBT4T-2OD/PC71BM thin films. Bilayer solar cells fabricated without the DIO additive produced a power conversion efficiency of η ≈ 7.65%, which is even higher than that of a BHJ solar cell fabricated with the DIO additive (η ≈ 7.04%). These results demonstrate that a highly crystalline polymer donor and an electron-accepting small molecule can be a good combination for efficient bilayer polymer solar cells.

C70-based aqueous-soluble fullerene for the water composition-tolerant performance of eco-friendly polymer solar cells

Our work highlights the development of eco-PSCs based on newly developed C70-based water/alcohol soluble fullerene with enhanced light absorption, aggregation properties and highly solvent composition-tolerant eco-friendly solvent processes.

Catechol amide derivatized polyhydroxylated fullerene as potential chelating agents of radionuclides: Synthesis, reactive oxygen species scavenging, and cytotoxic studies

Radionuclide internal contamination can induce chemical and radioactive intoxication and produce harmful free radicals in vivo. At present, administration of chelating agents is the most effective treatment against nuclide contamination. However, traditional studies on chelating agents have ignored the damage caused by free radicals to the body. The present study aimed to develop a type of a bifunctional sequestering agent that can chelates nuclides and scavenges free radicals simultaneously. Therefore, a novel catechol amide-derivatized polyhydroxylated fullerene was designed and prepared. The poor water solubility of fullerene was ameliorated by chemically modifying hydrophilic catechol amide and multiple hydroxyl groups, and obtaining high water-soluble fullerene derivatives. The affinities of chelators were investigated via sulfochlorophenol competitive complexing method and antioxidant capacities were examined by electron paramagnetic resonance. The results revealed the good complexation of the designed and synthesized chelating agent with uranyl ions; and its efficiency in scavenging hydroxyl radicals. This chelating agent showed extremely low toxicity and notable protective effect against oxidative stress on A549 cells. Besides, in U(VI)-exposed A549 cells, immediate treatment with catechol amide-derivatized polyhydroxylated fullerene significantly decreased the lactate dehydrogenase (LDH) release by inhibiting the cellular U(VI) intake, promoting the intracellular U(VI) release and inhibiting the production of intracellular reactive oxygen species (ROS). These results suggest that this fullerene derivative may be a valuable in vivo antioxidant and radionuclide decorporation agent.

Critical Comparison of the Superoxide Dismutase-like Activity of Carbon Antioxidant Nanozymes by Direct Superoxide Consumption Kinetic Measurements

The superoxide dismutase-like activity of poly(ethylene glycolated) hydrophilic carbon clusters (PEG-HCCs), anthracite and bituminous graphene quantum dots (PEG-aGQDs and PEG-bGQDs, respectively), and two fullerene carbon nanozymes, tris malonyl-C60 fullerene (C3) and polyhydroxylated-C60 fullerene (C60-OHn), were compared using direct optical stopped-flow kinetic measurements, together with three native superoxide dismutases (SODs), CuZnSOD, MnSOD, and FeSOD, at both pH 12.7 and 8.5. Computer modeling including both SOD catalytic steps and superoxide self-dismutation enabled the best choice of catalyst concentration with minimal contribution to the observed kinetic change from the substrate self-dismutation. Biexponential fitting to the kinetic data ranks the rate constant (M-1 s-1) in the order of PEG-HCCs > CuZnSOD ≈ MnSOD ≈ PEG-aGQDs ≈ PEG-bGQDs > FeSOD ≫ C3 > C60-OHn at pH 12.7 and MnSOD > CuZnSOD ≈ PEG-HCCs > FeSOD > PEG-aGQDs ≈ PEG-bGQDs ≫ C3 ≈ C60-OHn at pH 8.5. Nonlinear regression of the kinetic model above yielded the same ranking as the biexponential fit, but provided better mechanistic insight. The data obtained by freeze-quench EPR direct assay at pH 12.7 also yield the same ranking as stopped-flow data. This is a necessary assessment of a panel of proclaimed carbon nano SOD mimetics using the same two direct methods, revealing a dramatic, 3-4 orders of magnitude difference in SOD activity between PEG-HCCs/PEG-GQDs from soluble fullerenes.

Water-Soluble Fullerenol C60(OH)36 toward Effective Anti-Air Pollution Induced by Urban Particulate Matter in HaCaT Cell.

Particulate matter (PM), a widespread air pollutant, consists of a complex mixture of solid and liquid particles suspended in air. Many diseases have been linked to PM exposure, which induces an imbalance in reactive oxygen species (ROS) generated in cells, and might result in skin diseases (such as aging and atopic dermatitis). New techniques involving nanomedicine and nano-delivery systems are being rapidly developed in the medicinal field. Fullerene, a kind of nanomaterial, acts as a super radical scavenger. Lower water solubility levels limit the bio-applications of fullerene. Hence, to improve the water solubility of fullerene, while retaining its radical scavenger functions, a fullerene derivative, fullerenol C60(OH)36, was synthesized, to examine its biofunctions in PM-exposed human keratinocyte (HaCaT) cells. The PM-induced increase in ROS levels and expression of phosphorylated mitogen-activated protein kinase and Akt could be inhibited via fullerenol pre-treatment. Furthermore, the expression of inflammation-related proteins, cyclooxygenase-2, heme oxygenase-1, and prostaglandin E2 was also suppressed. Fullerenol could preserve the impaired state of skin barrier proteins (filaggrin, involucrin, repetin, and loricrin), which was attributable to PM exposure. These results suggest that fullerenol could act against PM-induced cytotoxicity via ROS scavenging and anti-inflammatory mechanisms, and the maintenance of expression of barrier proteins, and is a potential candidate compound for the treatment of skin diseases.

QSPR as a random event: solubility of fullerenes C[60] and C[70

Correlations of criteria of predictive potential of models for solubility of fullerenes C[60] and C[70] observed for the calibration (visible) set with the determination coefficient of corresponding models for validation sets (external, invisible). The Index of Ideality of Correlation (IIC) gave the best correlation with the determination coefficient for the validation set. The IIC was involved in the Monte Carlo optimization used to build up one-variable quantitative structure-property relationships (QSPR) to predict the solubility of fullerenes C[60] and C[70]. This considerably improved the predictive potential of models for this solubility. According to principle “QSPR is a random event”, corresponding computational experiments, which are aimed to build up model, were carried out for group of ten random splits into the training and validation sets. These calculations are source of usual data related to assessment of predictive models, such as the statistical quality for the training and validation sets and mechanistic interpretation of models in terms of structural alerts which are promoter of increase (or decrease) for an endpoint.

Application of the Consonance Solvent Concept for Accurate Prediction of Buckminster Solubility in 180 Net Solvents using COSMO-RS Approach

The default COSMO-RS (Conductor like Screening Model for Real Solvents) approach is incapable of accurate computation of C60 solubility in net solvents. Additionally, there is no adequate selection of single or multiple reference solvent, which can be applied to the whole population of 180 solvents for improving prediction of mole fraction at saturated conditions. This failure cannot be addressed to inaccurate data of the Buckminster fusion, although they pose a challenge for experimental measurement due to intense sublimation of C60 at elevated temperatures and the possibility of solvates precipitation. However, taking advantage of the richness of experimental data of fullerene solubility, it is possible to identify the source of errors expressed in terms of fluidization affinity. Classification of solvents according to the value of this fluidization term allowed for formulation of a consonance solvents approach, which enables accurate prediction of C60 solubility using the single reference solvent method.

Modeling the Solubility of C70 Fullerenes in Diverse Solvents: Role of Quantum-mechanical Descriptors.

Solubility of fullerenes in diverse solvents is difficult to model owing to the involvement of inherent quantum-mechanical interactions. This work proposes pure quantum mechanical models for predicting the solubility of C70 fullerenes. The models are developed using single-molecule quantum mechanical properties of solvents,which includes electron-correlation based descriptors accounting for the instantaneous inter-electronic interactions responsible for the origin of these properties. The external predictivity of the models was validated using an external prediction set of compounds not exposed to the model during its development. The most influential factor affecting the solubility was found to be electron-correlation contribution to the energy of highest occupied molecular orbital of solvents, which in fact, has been analyzed to suppress the solubility of fullerenes. However, the polarizability of the solvents, particularly that due to the quantum-mechanical exchange interactions between the electrons, is observed to drive the solubility of C70 fullerenes. The present work also found several other quantum mechanical properties affecting the solubility of fullerenes, which pay valuable insights towards the origin of the solubility of carbon-based nano-materials.

Flexible All-Organic Photorefractive Devices

The objective of the present study is to demonstrate and evaluate the photorefractive (PR) performance of an all-organic PR device with a self-assembled monolayer (SAM)-modified organic conductive electrode of PEDOT:PSS coated on polyethylene terephthalate (PET). The PR composite consisted of a triphenylamine-based photoconductive polymer: poly(4-(diphenylamino)benzyl acrylate) (PDAA), a triphenylamine photoconductive plasticizer: (4-(diphenylamino)phenyl)methanol (TPAOH), a nonlinear optical dye based on aminocyanostyrene: (4-asacycloheptylbenzylidenemalononitrile) (7-DCST), and soluble fullerene: [6,6]-phenyl C61 butyric acid-methyl ester (PCBM). For comparison with the all-organic PR device, the PR performances using PET/ITO, glass/ITO, and glass/PEDOT:PSS substrates were also evaluated. At an applied electric field of 40 V μm–1, the diffraction efficiency and the response time of the PR device using the PET/PEDOT:PSS-SAM substrate were 21.9%, and 390 ms, respectively. As a result of repeating bending ...

Zn Phthalocyanine Derivatives for Solution‐Processed Small Molecule Organic Solar Cells

AbstractZinc phthalocyanine derivatives, 1 and 2, having either electron donating octyl‐thiol group or electron accepting octyl‐sulfonyl groups have been synthesized to serve as new electron donor components for bulk heterojunction (BHJ) solar cells. BHJ solar cells, in which the active layer consist of zinc phthalocyanine (ZnPc) as an electron donor and a soluble fullerene derivative, namely PCBM, as an electron acceptor component were produced and characterized. The device consisting of octylthiol‐ZnPc:PCBM (1:4) gave power‐conversion efficiencies of 0.42%. On the other hand, the device having octyl‐sulfonyl substituted ZnPc gave very low efficiency due to both low Voc and Jsc values.

Exploring the Inhibitory and Antioxidant Effects of Fullerene and Fullerenol on Ribonuclease A.

Fullerene–protein interaction studies have been a key topic of investigation in recent times, but the lower water solubility of fullerene somewhat limits its application in the biological system. In this work, we have compared the activities of fullerene and its water-soluble hydrated form, that is fullerenol, on ribonuclease A (RNase A) under physiological conditions (pH 7.4). The interaction studies of fullerene and fullerenol with protein suggest that the binding depends on the hydrophobic interactions between the protein and the ligand. In addition, fullerene and fullerenol slow down the ribonucleolytic activity of RNase A through noncompetitive and mixed types of inhibition, respectively. This precisely gives the idea about the ligand-binding sites in RNase A, which has further been explored using docking studies. Both these nanoparticles show a reduction in dityrosine formation in RNase A caused due to oxidative stress and also prevent RNase A dimer formation to different extents depending on their concentration.

Salvaging Reactive Fullerenes from Soot by Exohedral Derivatization.

The awesome allotropy of carbon yields innumerable topologically possible cage structures of molecular carbon. This field is also related to endohedral metallofullerenes constructed by metal-atom encapsulation. Stable and soluble empty fullerenes and endohedral metallofullerenes are available in pure form in macroscopic amounts from carbon arc production or other physical processes followed by extraction and subsequent chromatographic separation. However, many other unidentified fullerene species, which must be reactive and insoluble in their pristine forms, remain in soot. These "missing" species must have extremely small HOMO-LUMO gaps and may have unconventional cage structures. Recent progress in this field has demonstrated that reactive fullerenes can be salvaged by exohedral derivatization, which can stabilize the reactive carbon cages. This concept provides a means of preparing macroscopic amounts of unconventional fullerenes as their derivatives.

Fullerol C60(OH)24 nanoparticles modulate aflatoxin B1 biosynthesis in Aspergillus flavus

The water soluble fullerene C60 daughter product - fullerols C60(OH)24 (FNP) possesses a great potential of modifying secondary metabolites biosynthesis. In order to clarify the extent of interaction, the impact of FNP (10, 100 and 1000 ng mL−1) on aflatoxin production and the available precursors of biosynthesis pathway from Aspergillus flavus NRRL 3251 was determined, in both the mycelia and yeast extract sucrose (YES) medium, during a 168-hour growth period at 29 °C in the dark. The FNP of 8 nm in diameter, and with a zeta potential of −33 mV affected mycelial growth at 1000 ng mL−1 while conidia production was slightly affected at 10 ng mL−1. The FNP effect on aflatoxin and it biosynthetic precursors was concentration dependent and alteration of the sterigmatocystin (ST) export from the cell was observed. Most of the monitored aflatoxin precursors, except norsolorinic acid, were detected in both mycelia and YES medium. However, observed precursor concentrations were much higher in mycelia, with exception of ST. The study shows the loss of FNP antioxidative effect after 120 hours of growth, and strong concentration dependent aflatoxigenic effect after that time. Thus, this data is relevant to guide future considerations on FNP-fungal interactions in the environments and on risk assessment.

Ordered Mesoporous C70 with Highly Crystalline Pore Walls for Energy Applications

AbstractMesoporous materials with carbon framework structure can offer distinctive functionalities with tunable electronic or catalytic properties. Many synthetic routes including hard or soft templating approaches are developed for the fabrication of various ordered mesoporous carbon based materials which have demonstrated unique catalytic and energy storage properties. So far, most of these techniques deliver only mesoporous carbon with amorphous wall structures which limit their performance in many applications. Fullerenes exhibit unique structure and significant properties including superconductivity, electrochemical stability, and heat resistance. Herein, for the first time, the preparation of highly ordered mesoporous fullerene C70 materials with tunable porous structure and controlled rod‐shaped morphology through the thermal oligomerization of fullerene C70 molecules inside the mesopore channels of SBA‐15 silica as a hard template with the help of chlorinated aromatics, wherein the solubility of fullerenes is high, is reported. It is demonstrated that these metal‐free mesoporous fullerene C70 framework with a high surface area and bimodal pores with multifunctionality exhibit excellent performance in the oxygen reduction reaction for fuel cells and supercapacitors. This simple strategy can also be extended to other fullerene nanostructures with different carbon atoms which can exhibit interesting physicochemical properties and find applications in catalysis and energy storage.

Water Soluble Nanocarbon Materials:A Panacea for All?

The low solubility of nanocarbon materials (fullerenes, CNTs and graphene) has restricted their widespread commercial use. Functionalization, however, helps overcome this major limitation. Much work has been documented recently on water soluble fullerenes (FWS) in treating cancer (e.g. breast cancer), tumours, arthritis, Parkinson’s, influenzas and HIV-AIDS. Even an aqueous nasal spray to combat Alzheimer’s has been advocated. A recent US patent shows that FWS, based on its anti-oxidant activity, is a powerful Radical Oxygen Scavenger. FWS have been used in X-ray imaging, as MRI Contrast Agents (MRI-CA), to make solar cells and could help produce nanodevices and biosensors. This review examines this emerging field.

Predictive modeling: Solubility of C60 and C70 fullerenes in diverse solvents

Solubility of fullerenes imposes a major limitation to further advanced research and technological development using these novel materials. There have been continued efforts to discover better solvents and their properties that influence the solubility of fullerenes. Here, we have developed QSPR (quantitative structure-property relationship) models based on structural features of diverse solvents and large experimental data for predicting the solubility of C60 and C70 fullerenes. The developed models identified most relevant features of the solvents that encode the polarizability, polarity and lipophilicity properties which largely influence the solubilizing potential of the solvent for the fullerenes. We also established Inter-moieties solubility correlations (IMSC) based quantitative property-property relationship (QPPR) models for predicting solubility of C60 and C70 fullerenes. The QSPR and QPPR models were internally and externally validated deriving the most stringent statistical criteria and predicted C60 and C70 solubility values in different solvents were in close agreement with the experimental values. In test sets, the QSPR models yielded high correlations (R2 > 0.964) and low root mean squared error of prediction errors (RMSEP< 0.25). Results of comparison with other studies indicated that the proposed models could effectively improve the accuracy and ability for predicting solubility of C60 and C70 fullerenes in solvents with diverse structures and would be useful in development of more effective solvents.

Excess thermodynamic functions in aqueous systems containing soluble fullerene derivatives

Using a Beckman thermometer, the concentration dependence of water crystallization temperatures was investigated for C60(OH)22–24 – H2O, C70(OH)12 – H2O, C70[C(COOH)2]3 – H2O, С60(C5H9NO3)2 - H2O, С60(C6H14N2O2)2 – H2O binary systems. The semi-empirical Virial Decomposition Asymmetric Model of virial expansion of the excess Gibbs energy of the light fullerene derivatives solutions was applied. On the basis of the proposed model, partial and average molar thermodynamic functions of binary solutions as well as the conditions of stability against phase separation were determined.

Electrolyte-gated transistors based on phenyl-C61-butyric acid methyl ester (PCBM) films: bridging redox properties, charge carrier transport and device performance.

The n-type organic semiconductor phenyl-C61-butyric acid methyl ester (PCBM), a soluble fullerene derivative well investigated for organic solar cells and transistors, can undergo several successive reversible, diffusion-controlled, one-electron reduction processes. We exploited such processes to shed light on the correlation between electron transfer properties, ionic and electronic transport as well as device performance in ionic liquid (IL)-gated transistors. Two ILs were considered, based on bis(trifluoromethylsulfonyl)imide [TFSI] as the anion and 1-ethyl-3-methylimidazolium [EMIM] or 1-butyl-1-methylpyrrolidinium [PYR14] as the cation. The aromatic structure of [EMIM] and its lower steric hindrance with respect to [PYR14] favor a 3D (bulk) electrochemical doping. As opposed to this, for [PYR14] the doping seems to be 2D (surface-confined). If the n-doping of the PCBM is pursued beyond the first electrochemical process, the transistor current vs. gate-source voltage plots in [PYR14][TFSI] feature a maximum that points to the presence of finite windows of high conductivity in IL-gated PCBM transistors.

Chlorofullerene C60Cl6: A Precursor for Straightforward Preparation of Highly Water‐Soluble Poly‐hydroxypyridinone Fullerene Derivatives as Potential Radionuclide Chelators

AbstractRadionuclide internal contamination can induce chemical and radiological intoxication and produce harmful free radicals in vivo. Conventional studies on chelating agents have disregarded the damage of free radicals to the body. Therefore, novel poly‐hydroxypyridinone fullerene derivatives were designed and prepared by using chlorofullerene as precursor. The poor water solubility of fullerene was ameliorated by chemically modifying of hydrophilic hydroxypyridinone, and obtaining high Water‐soluble fullerene derivatives. The radical scavenging reaction kinetics of target products were studied. They all exhibited much higher rate constants than other fullerene polymer system. The CeIII ion was used as a simulated radionuclide for evaluating the binding ability of target products, and the values of conditional stability constants were about 5.15‐6.11. Thus, the bifunctional, Water‐soluble fullerene derivatives were successfully generated. The results provided basis for further study on the potential application of poly‐hydroxypyridinone fullerene derivatives as radionuclide chelators.