Nanoencapsulation of [60]Fullerene with the Cavitand Cucurbit[7]uril

Novel supramolecular nanocapsules consisting of [60]fullerene and the macrocycle cucurbit[7]uril via self-assembly are reported. The nanocapsules, which were synthesized in a two-phase reaction at room temperature, were obtained in good yields. The stoichiometry of the product was found to be 1:2.     

Reaction of [60]fullerene With Triethylamine

[60]Fullerene reacts with neat triethylamine via an electron transfer involving an intermediate C60-radical-anion, to give a salt-like product. This decomposes to [60]fullerene upon either heating, or treatment with ultrasound. EI mass fragmentation of the product indicates an intramolecular abstraction of H from C₂H₅ by the [60]fullerene moiety.     

Chromatographic separation and identification of a water-soluble dendritic methano[60]fullerene octadecaacid

The chromatographic separation of a highly water-soluble dendritic monoadduct methano[60]fullerene octadecaacid (dendrofullerene) with octadecylsilica bonded phases has been studied. It has been found that the RP-HPLC behavior of this dendrofullerene obeys the general rules of stationary-phase and mobile-phase selection for controlling the separation of usually acidic compounds. An RP-HPLC-ESI-MS analysis confirms the identity of the dendrofullerene and allows characterization of the molecular weights of the main impurities contained in the sample. The described methods can control the synthesis and efficiently purify this fullerene derivative, which has been previously shown to be active against mutant infectious clones of HIV-1, which are resistant to AZT and 3TC, drugs that are widely used in AIDS therapy.     

Radical reactions of [60]fullerene mediated by manganese(III) acetate dihydrate

Mn(OAc)3 x 2H2O is an excellent reagent to promote free radical reactions of C60. C60 reacted with various methylene active compounds, methyl ketones, beta-enamino carbonyl compounds, carboxylic acid derivatives, and diallylamines in the presence of Mn(OAc)3 x 2H2O to afford singly-bonded fullerene dimers, 1,4-bisadducts and 1,16-bisadducts of C60, C60-fused dihydrofuran derivatives, methanofullerenes, C60-fused pyrroline derivatives, C60-fused lactone derivatives, and C60-fused pyrrolidine derivatives. Mn(OAc)3 x 2H2O was successfully employed to transform ArC60-H into ArC60-OAc.     

Synthesis of novel ultraviolet stabilizers based on [60]fullerene and their effects on photo-oxidative degradation of polystyrene

Abstract

Two N-benzyl fulleropyrrolidines were synthesized via Prato reaction. The polystyrene (PS) films containing 0.5?wt% fullerene and N-benzyl fulleropyrrolidines were prepared from toluene via the solvent evaporation method. The photo-oxidative activities and thermostability of these films were determined by monitoring the average molecular weight and thermogravimetric curve. The changes in weight loss (%) and tensile strength with irradiation time were also tracked. After 480?h of illumination, the weight loss of PS films was 6.8%, while the corresponding index of PS with C₆₀ was 6.1%. The weight loss of PS with two fulleropyrrolidines was significantly lower than that before (3.8% and 2.7%). The results manifested the good ultraviolet (UV) stabilizing effect and thermostability of these complex films compared with PS. A probable mechanism was proposed to account for the stabilizing action of the [60]fullerene derivatives as multifunctional UV stabilizers.     

Sonochemical reaction of fullerene[C60] with several 2'-azidoethyl per-O-acetyl glycosides

Cycloadditive reaction of fullerene[C60] with various 2'-azidoethyl per-O-acetyl glycopyranoside of D-mannose, D-galactose, D-glucose, D-xylose and D-maltose, respectively gave the glycosyl fullerene[C60] derivatives 2a-2e such as alpha-D-mannosyl fullerene[C60] under ultrasonication. Based on analyses using 1H- and 13C-NMR, UV-vis, FT-IR, and FAB-MS spectroscopies of the glycosyl fullerene[C60] derivatives, the products were composed of a mixture of [5,6]- and [6,6]-junction isomers which were predominantly the closed [5,6]-junction isomer.     

Trapping of solvent by a C60 fullerene film

Mass spectrometry was used over a wide temperature range to compare processes of solvent (toluene) release and desorption of C₆₀ fullerene molecules from a fullerite film formed from solution on an oxidized metal substrate. It is shown that toluene is strongly retained in the fullerite film and that it is almost impossible to remove the toluene from the film without damaging its structure. Quantitative characteristics of the toluene retention and trapping effect are determined. Pis’ma Zh. Tekh. Fiz. 24, 23–29 (December 12, 1998)     

Water-soluble [60] fullerene derivatives as potential chelating agents of radionuclides via chlorofullerene (C60Cl6) as a precursor

The reactions of catecholamide ligands with hexachlorofullerene via O-nucleophiles yielded new water-soluble [60] fullerene derivatives as chelators for radionuclides decorporation. The derivatives were characterized through ¹H NMR spectroscopy, FT-IR spectroscopy, and X-ray photoelectron spectroscopy. The affinities of the chelators were investigated through the fluorescence quenching of simulated nuclide Ce(III) via a linear Stern–Volmer plot method. Conditional stability constant (K) could also be estimated with this method. The antioxidant capacities of the chelators with a solubility of more than 150 mg/mL in water were examined through UV-vis spectroscopy by determining their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities. Results revealed that these chelators may be used for complexation, antioxidant activity, and radionuclide decorporation.     

Construction of long-wavelength-light photocurrent generation system based on self-assembled monolayer of cobaltadithiolene [60]fullerene complex

[60]Fullerene pentaester and pentaacid derivatives bearing cobaltadithiolene dyes were successfully synthesized under mild reaction conditions. Self-assembled monolayers (SAMs) of the pentaacid derivative were prepared by an immersion method and the photocurrent generation properties of the SAMs were measured. Due to the introduction of the light-absorbing cobaltadithiolene moiety, the range of available wavelengths for photoelectric conversion was extended to lambda = 700 nm, which is longer than that of conventional penta(organo)[60]fullerene carboxylic acids.     

Thermal desorption of fullerene C60 from polymer matrices

The data on thermally stimulated desorption (TSD) study of fullerene C₆₀ molecules from different polymer matrices are compared in view of the temperature positions and relative intensities of resolved thermal desorption stages. An increase of the low temperature C₆₀ desorption stages is observed for polydimethylsiloxane (PDMS) and polystyrene (PS) contrary to polyimide (PI). This is in agreement with the difference in glass transition temperatures (T_g) of these polymers. The TSD data allow us to conclude that above T_g of the polymer the solubility of fullerene C₆₀ in PDMS and PS is up to the order of magnitude higher compared with C₆₀ solubility in low molecular weight solvents.     

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.     

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.     

[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.     

[60]Fullerene as a Novel Photoinduced Antibiotic

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.     

Synthesis of High-Molecular-Weight [60]Fullerene Pearl-Necklace Polyamides Derived from Equatorial [60]fullerenobisacetic Acid

Abstract

A series of [60]fullerene pearl-necklace polyamides, consisting of equatorial-[60]fullerenobisacetic acid and various chromophoric aromatic diamines, were synthesized by a phosphorylation route using large amounts of triphenyl phosphite and pyridine as condensing reagents with stepwise addition of the condensing reagents. In the present polymers, [60]fullerene pearls and diamine linkers were attached to one another by cyclopropane connectors. The polyamides had weight-average molecular weights (M_w)of 4.5-5.0×10⁴ g/mol and inherent viscosities (n _inh) of 0.3-0.4 dL/g in N, N-dimethylacetamide (DMAc) at 30 °C. They had glass transition temperatures at 30-125 °C and decomposition temperatures at 300-310 °C. The UV-VIS spectra in DMAc exhibited broad absorption with λ_max at 310-390 nm tailing to longer wavelengths.     

TETHER-LINKED [60]FULLERENE-DONOR DYADS

A series of [60]fullerene bis-adducts having a π-electron-rich aromatic ring as a donor in a face-to-face arrangement were synthesized by the bis-cyclopropanation of [60]fullerene with tether-linked bis-malonates. One of the bis-adducts showed a photoinduced intramolecular electron transfer which caused the dramatic quenching of its fluorescence in a polar solvent.     

TETHER-LINKED [60]FULLERENE-DONOR DYADS

A series of [60]fullerene bis-adducts having a π-electron-rich aromatic ring as a donor in a face-to-face arrangement were synthesized by the bis-cyclopropanation of [60]fullerene with tether-linked bis-malonates. One of the bis-adducts showed a photoinduced intramolecular electron transfer which caused the dramatic quenching of its fluorescence in a polar solvent.     

Synthesis of High-Molecular-Weight [60]Fullerene Pearl-Necklace Polyamides Derived from Equatorial [60]fullerenobisacetic Acid

A series of [60]fullerene pearl-necklace polyamides, consisting of equatorial-[60]fullerenobisacetic acid and various chromophoric aromatic diamines, were synthesized by a phosphorylation route using large amounts of triphenyl phosphite and pyridine as condensing reagents with stepwise addition of the condensing reagents. In the present polymers, [60]fullerene pearls and diamine linkers were attached to one another by cyclopropane connectors. The polyamides had weight-average molecular weights (M_w)of 4.5-5.0×10⁴ g/mol and inherent viscosities (n_inh) of 0.3-0.4 dL/g in N, N-dimethylacetamide (DMAc) at 30 °C. They had glass transition temperatures at 30-125 °C and decomposition temperatures at 300-310 °C. The UV-VIS spectra in DMAc exhibited broad absorption with λ_max at 310-390 nm tailing to longer wavelengths.     

60]fullerene is a powerful antioxidant in vivo with no acute or subacute toxicity

In the present work, we report the effects of C(60)-pretreatments on acute carbon tetrachloride intoxication in rats, a classical model for studying free-radical-mediated liver injury. Our results show that aqueous C(60) suspensions prepared without using any polar organic solvent not only have no acute or subacute toxicity in rodents but they also protect their livers in a dose-dependent manner against free-radical damage. To be sure, according to histopathological examinations and biological tests, pristine C(60) can be considered as a powerful liver-protective agent.