Intermolecular Interaction of [60]Fullerene with Tröger's Base Analogues

Tröger's base (TB, 1) and its analogues were synthesized and were subject to the titration experiments to evaluate their ability of supramolecular complexation with C₆₀. Results demonstrate clearly that the fluorene-based TB analogue (2) and the bioctylfluorene-based TB analogue (3) show 1:1 binding with C₆₀ to form the corresponding complexes while TB 1 does not. Titration experiments exhibited that the association constant (K_ass) of 3/C₆₀ (48.1 ± 7.9 M ^?1) was larger than that of 2/C₆₀ (13.7 ± 1.4 M ^?1)_. The formation of the 1:1 binding complexes 2/C₆₀ and 3/C₆₀ was also confirmed by MALDI-TOF mass spectrometry. Theoretical calculations suggest that 2 and 3 have appropriate cavities to embrace C₆₀. These findings indicate that not only the π/π interaction between the fluorene moieties and the C₆₀ surface but also the CH/π interaction between the octyl groups and the C₆₀ surface serve efficiently in the supramolecular complexation with C₆₀.     

Direct and Catalytic Hydrogenation of Buckminsterfullerene C60

Abstract

C₆₀H₁₈ was obtained by direct hydrogenation of C₆₀ at 400 C and 80 atm C₆₀ was hydrogenated to C₆₀H₃₆ as a main product in the presence of Pd/C catalyst at 180C and 30–70 atm. C₆₀H₃₆ is unstable in dichloromethane and some other organic solvents.     

Thermal Reactions of C60 with Siliranes: Carbosilylation and Silylene Addition of Fullerenes

Thermal reactions of C₆₀ with siliranes (1a, b) afforded carbosilylated C₆₀ derivatives. When a bicyclic fused silirane (1c) was employed instead of 1a and 1b, a silylene adduct and its hydrolyzed compound were obtained through thermal extrusion of silylenes from 1c. These products were determined to be 1,2-adducts at 6,6-junctions of C₆₀ by MS, UV, and NMR analyses. These results provide a complementary method to the photochemical addition of reactive silicon compounds, which have been long employed for silylation of C₆₀. Electrochemical analyses revealed the redox properties of the silylated products, indicating the perturbation caused by silyl groups introduced on the C₆₀ cage. Theoretical calculations were also conducted for understanding of the electronic property of the silylated product.     

Quantitative Determination of C60 and C70 in Soot Extracts by High Performance Liquid Chromatography and Mass Spectrometric Characterization

Abstract

A quantitative HPLC method was applied to determine the amounts of C₆₀ and C₇₀ present in extracts of soot produced in the electric arc reactor and in flames. The combustion method was found to yield a higher C₇₀/C₆₀ ratio (0.67) compared with the evaporation experiment where the C₇₀/C₆₀ ratio amounts to 0.27.     

Search for C60 Fullerene in Char Produced on a Norway Spruce by Lightning

Abstract

A search was made for C₆₀ fullerene by High Performance Liquid Chromatography in char formed on a Norway Spruce struck by lightning. Firm proof that C₆₀ occurs in the char was not obtained. However, the evidence showed the possible presence of 1 ppb C₆₀.     

Synthesis of Radiolabeled Fullerenes C60 and C70

Abstract

The synthesis of radiolabeled C₆₀/C₇₀ for potential biochemical tracer studies was carried out. Vaporization under plasma are conditions (~3000C) of graphite rods impregnated with the ¹⁴C labeled steroid progesterone generates the expected C₆₀/C₇₀ mixture. Isolation and characterization of the ¹⁴C-C₆₀ is reported. Interestingly, the C₇₀ had more radioactivity than the C₆₀.     

Singlet‐Triplet Transition in the C60 2− Dianion

Abstract

The C₆₀ complexes with decamethylcobaltocene: (Cp*₂Co)₂C₆₀(C₆H₄Cl₂, C₆H₅CN)₂ (1) and [K · (18‐crown‐6)]₂ · C₆₀ · (DMF)₄ (2) have been obtained as single crystals by the diffusion method. The IR‐ and UV‐VIS‐NIR‐spectra justify the formation of the C₆₀ ^2? dianions in these salts. EPR measurements show that the low temperature signals of 1 in the 4–140 K range and 2 in the 4–60 K range have intensity corresponding only to 0.4% and 3.5% from total C₆₀. Because of this, most of the complexes are EPR silent, and, consequently, C₆₀ ^2? has a diamagnetic singlet (S = 0) state in these temperature ranges. The appearance of a broad EPR signal in the spectum of 1 above 140 K and 2 above ～60 K is assigned to a thermal population of a close lying excited triplet (S = 1) state. The singlet–triplet energy gap for C₆₀ ^2? in solid 1 and 2 was estimated to be 730 ± 10 and 300 ± 10 cm^?1.     

Laser Photolysis Study on Mechanism and Efficiency of Electron Transfer Between Fullerenes (C60 and C70) and Tetraselenafulvalenes

Abstract

Efficient electron-transfer reactions from three kind of tetraselenafulvalenes (TSeF's) to photoexcited triplet state of C₆₀ or C₇₀ in polar solvents have been confirmed by transient absorption spectroscopy observing the decay of ³C₆₀*/³C₇₀* and rise of C₆₀ ^??/C₇₀ ^??. Growth of single crystal seems to be stimulated by laser irradiation of the solution containing C₆₀ and bis(ethylenedithio)tetraselena-fulvalene (BEDT-TSeF), in which C₆₀ ^?? was effectively formed.     

The Solid-State Mechanochemical Reaction of Fullerene C60

Abstract

The solid-state mechanochemical reaction of fullerene C₆₀ by the use of a high-speed vibration milling technique has been applied to the nucleophilic addition of an organozinc reagent to C₆₀, [4+2] cycloaddition of C₆₀ with condensed aromatic hydrocarbons, 1,3-dipolar addition of C₆₀ with organic azides, and dimerization of C₆₀.     

Early effects of C60 Administration in Swiss Mice: A Preliminary Account for In Vivo C60 Toxicity.

Abstract

High amounts of micronized C₆₀ have been injected intraperitoneally into Swiss mice. Until the fourteenth day, they were still alive without any behaviour trouble. C₆₀ was well absorbed, and found localized in spleen and liver. Inside the liver, C₆₀ was     

[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.     

Bromination of [60]Fullerene. I. High‐Yield Synthesis of C60Br x (x=6, 8, 24)

Abstract

The systematic study of the bromination of C₆₀ was performed under various experimental conditions. Application of some chloroarenes as reaction media resulted in the high‐yield (70–96%) selective synthesis of C₆₀Br₆ and C₆₀Br₈. Direct bromination of fullerene yielded either C₆₀Br₈, C₆₀Br₁₄, or C₆₀Br₂₄ depending on the reaction time. Possible pathways of bromination of C₆₀Br₈ were analyzed using semiempirical (AM1) calculations, two most probable molecular structures are conjectured for the first isolated C₆₀Br₁₄.     

Transport Properties of Fullerene–Polyphenylene Oxide Homogeneous Membranes

Abstract

Fullerene–polyphenylene oxide (C₆₀–PPO) compositions containing up to 2 wt% C₆₀ were obtained and used for homogeneous membranes formation. Gas separation properties were estimated by measuring the permeability of individual gases H₂, O₂, N₂, CH₄, and CO₂. A correlation between gas permeability and free volume was established. The pervaporation of water/ethanol mixtures through fullerene‐containing membranes showed that C₆₀–PPO membranes exhibit dehydration properties. The degree of equilibrium sorption for PPO and C₆₀–PPO membranes in a water/ethanol system was estimated in the liquid phase. Gas separation and pervaporation properties were treated as a reflection of molecular interactions between PPO and C₆₀ molecules in compositions.     

The Form of Sulfur Impurity in Neutron Irradiated Commercial C60

Abstract

By using SEM, SAED, HRTEM and XPD it was found that the unexpectedly high sulphur impurity in some commercial C₆₀ product readily reacts with C₆₀, during neutron irradiation producing the compound C₆₀S₁₆ ⁽³⁾ that can be regarded as a stable collecting form of the original undefined sulphur impurities.     

Catalytic Preparation and Characterization of C60Br24

Abstract

In this paper the procedure for catalytical bromination of C₆₀ with elementary bromine with FeBr₃ as a catalyst is described. In this procedures only one reaction product - C₆₀ Br₂₄ is obtained. The twenty four bromine atoms are symmetrically distributed over the C₆₀ sphere, which was confirmed by thermogravimetric analysis. The yield of bromine derivative in this reaction is 98%.     

Synthesis,Spectral Investigations,and Thermal Stability of [60]Fullerene Complexes with TMTSF: 2(C60) · 2(TMTSF) · (C6H6), C60 · TMTSF · 2(CS2), and 2(C60) · 2(TMTSF) · (C6H5Cl)

Abstract

Molecular complexes of [60]fullerene with tetramethyltetraselenafulvalene (TMTSF): C₆₀ · (TMTSF) · 2(CS₂) (1), 2(C₆₀) · (2(TMTSF) · (C₆H₆) (2), and 2(C₆₀) · (2(TMTSF) · (C₆H₅Cl) (3) have been synthesized and their thermal stability and IR spectra vs. light polarization and temperature have been performed.     

Visible Light Irradiation of [60]Fullerene Causes Killing and Initiation of Transformation in Balb/3T3 Cells

Abstract

Cell transformation in vitro is a model of carcinogenesis in vivo. Two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. [60]Fullerene (C₆₀) was cytotoxic in BALB/3T3 cells when it was irradiated by visible light, but not without light irradiation. Under conditions when C₆₀ was cytotoxic, it acted as an initiating agent for cell transformation, but it did not act as a complete transforming agent. the initiating activity of visible-light-irradiated C₆₀ was statistically significant in a modified two-stage transformation assay including a procedure for replating cells treated by C₆₀ and light, but it was equivocal in the standard two-stage transformation assay.     

Effects of γ Radiation on C60 Fullerene in CCI4 Solution

Abstract

By treating a CCI₄ solution of C₆₀ in a sealed ampoule under argon with γ radiation generated by a ⁶⁰Co source, chlorinated and trichloromethylated C₆₀ oligomers (dimers, trimers) are produced. A total radiation dose of 122 kGy was used.     

Non-Rigid Treatment of Interactions Between C60 Molecules

Abstract

Atom-atom van der Waals interaction energies are compared between bimolecular clusters of C₆₀ and circumcoronene, a model of graphite, with the aid of molecular mechanics. The minimum in the potential energy curve of the former is shallower and higher than the latter. Average equilibrium distance (3.08 Å) in the bimolecular cluster C₆₀–C₆₀ agrees well with the experimental value (2.96 Å). Equilibrium configurations of the C₆₀–C₆₀ cluster contain quite a few inter-cage atom-pairs in the repulsive region. Analysis of molecular as well as electronic structure in the closest possible approach under stringent conditions indicate that C₆₀ molecule is highly resilient ball.     

Esr Study of C60 N- Anion Radicals in DMSO Solution

Abstract

With the aim to stabilize reduced C₆₀ molecules of solid fulleride as free anion radicals in solution, Na_xC₆₀ (x=l, 10) was dissolved in DMSO. The Na_xC₆₀ was chosen among the other alkali-metal fullerides due to the possibility to increase a number of intercalated Na atoms in a fee. lattice of C₆₀ A sufficiently high concentration of C₆₀ anion radicals of an order of magnitude larger than that usually achieved in solution by an electrochemical reduction was obtained. The sharp resonances with the linewidths of order of 0.1 G and with g=2.0004(6) ?2.0012(8) of the room temperature ESR spectra of fluid solution were assigned from mono- to pentaanions of C₆₀. An appearance of additional sharp peaks at g=2.0016–2.0019 in the spectra of solution of nominal Na₁₀C₆₀, but Na₁C₆₀, tentatively related to C₆₀ ^n- with n>6. The results of this study showed a simple approach in an accomplishment of highly concentrated solutions of free anion radicals C₆₀ ^n-, as well as in stabilization of the anion radicals with increased n. In this way a homogeneity of alkali metal intercalation and characteristics of the solvent will be important.