Regiochemistry of Azide Additions to [70]Fullerene

In this paper we report for the first time on the reaction of C₇₀ with alkyl azides and show that the [3+2]-cycloaddition occurs preferably at bond 7 followed by bond 5 to give two regioisomeric A/B-triazolines and one C/C-triazoline Thermal extrusion of N₂ from these triazolines leads to open [5,6]-bridged iminofullerenes as A/A- and B/C-isomers as well as to the ring closed [6,6]-bridged analogues as A/B- and C/C-isomers. These results are in line with the corresponding thermal reaction of C₇₀ with diazomethane.     

Trifluoromethylation of [60]- and [70]Fullerene in the Ionization Chamber of a Mass Spectrometer

Abstract

Both [60]- and [70]fullerene react with either the Scherer radical (perfluorodiisopropylethylmethyl, C₉F₁₉), a mixture of branched perfluorononenes (C₉F₁₈, the product of hexafluoropropene trimerization), or β-fluorosulphatotetrafluoroethyldiheptafluoroisopropylmethyl radical (C₉F₁₈OSO₂F) in the ionization chamber of a mass spectrometer to give the positive parent ions of trifluoromethylation products, the reaction being accompanied by hydrogen addition. The reaction occurs at least partly on the walls of the ionization chamber, by a radical mechanism employing CF₃ radicals formed from the radical reactants both thermally and under electron impact; only the latter route occurs with the perfluorononenes.     

Chlorosulphonyl Group as a New Functionality on Fullerenes: [2+2]-Cycloaddition of Chlorosulphonylisocyanate to C60

Abstract

The chlorosulphonylisocyanate reacts smoothly with C₆₀ in xylene under thermal conditions in a [2+2]-cycloaddition fashion to yield the bisadduct as one of the products in the inseparable reaction mixture. The reaction product is analysed by FAB-MS, ¹³C NMR, FT-IR and HPLC techniques. Results show the formation of imino-lactone as one of the favourable products.     

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.     

Molecular Complex of [60]Fullerene with 2-(4-thione-l,3-dithiolan-5-yliden)-4,5-dimethyl-1,3-diselenol [C60·2(DTDS)]: Synthesis,Crystal Structure and Properties

Abstract

New molecular complexes of [60]fullerene with 2-(4-thione-l,3-dithiolan-5-yliden)-4,5-dimethyl-l,3-diselenol [C₆₀·2(DTDS)] have been synthesized, crystal structure, IR spectral and electrochemical properties have been studied. Partial charge transfer has been found. An unusual shortening of the endocyclic S-C(sp²) bond in the DTDS molecule has been found to be stipulated by conformational vibrations of the >CH₂ group. A comparative analysis of the X-ray data for the [C₆₀·2(DTDS)] crystals and the quantum chemical calculations (SCF MO, 6-31G? basis) for the DTDS molecules and its radical ions showed charge transfer not to be the cause for the shortening of the exocyclic C=S bonds.     

Synthesis and Characterization of Dialkyl-C61 +

Abstract

Three-step synthesis from dialkyl ketone (R₂C=O) with C₆₀ gave C₆₀(CR₂)_n [R = Me, Et, Pr, Bu, (CH₂)₅.; n = 1, 2]. The adducts were isolated by means of gel permeation chromatography, and the monoadducts were characterized by ¹H and/or ¹³C NMR spectroscopies as a mixture of major [5, 6] and minor [6, 6] isomers. Their solubility and electrochemical properties were reported.

     

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.     

Crystal and Molecular Structure of a New Complex of [60]Fullerene, 2(C60)·2(TMTSF)·(C6H6)

Abstract

A new molecular complex of [60]fullerene with composition 2(C₆₀)·2(TMTSF)·(C₆H₆) was synthesized. The structure and composition of the complex were found by an x-ray study. Crystal data: 2(C₆₀)2(C₁₀H₁₂Se₄)(C₆H₆), M = 2415.4, monoclinic, a = 19.388(4), b = 13.410(2), c = 32.467(6) A, β = 92.71(2)°, V = 8432(3) [Adot]³, space group P2₁/n, Z = 4, d_calc = 1.903 g/cm³, R = 0.0606. The crystal structure was shown to be layered with the alternating layers of three types. Two of them have the same composition (C₆₀, TMTSF) but different interorientation of molecules in a layer and different number of shortened contacts C…C and C…Se. The third layer consists of benzene molecules. The energy of intermolecular interactions C₆₀…. TMTSF was estimated by ab initio calculations. The TMTSF molecule has a “boat” conformation.     

Some New Aspects of Chlorination of Fullerenes

Abstract

The effect of the reagent ratio, reaction time and power of the reagent on the product composition in chlorination of [60]fullerene was studied. Chlorofullerenes C₆₀Cl₆, C₆₀Cl₈, C₆₀Cl₁₀, C₆₀Cl₁₂, C₆₀Cl₁₄, and C₆₀Cl₂₆ were synthesized and characterized by chemical analysis, FTIR, ¹³C NMR, and MALDI TOF mass spectrometry. The experimental data supported the coexistence of several isomers of C₆₀Cl _n (n = 8, 10, 12, 14, 26); the mixtures were not separated so far. Semiempirical calculations (AM1, PM3) were used to analyze the addition patterns and resulted in the most favorable structures of C₆₀Cl_8–26. Chlorination of C₇₀ under various conditions invariably yielded C₇₀Cl₁₀.     

Use of 1-alkyl-3-methylimidazolium l-lactates as both ligand and reaction media for AGET ATRP of acrylonitrile

Chiral ionic liquids, [C₂mim][LLA], [C₄mim][LLA] and [C₆mim][LLA] were firstly applied as both ligand and reaction media for atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) with ascorbic acid (VC) as reducing agent in the presence of air. A small but clear increase of polyacrylonitrile (PAN) isotacticity was observed for AGET ATRP of AN in [C₆mim][LLA] than in [C₆mim][BF₄]. PAN isotacticity markedly increased with the content of [C₆mim][LLA]. Compared with in [C₂mim][LLA] and [C₄mim][LLA], the rate of AGET ATRP of AN in [C₆mim][LLA] was fastest and the polymerization was best controlled. Well-defined PAN with molecular weight at 76,590, relatively narrower distribution at 1.27 and higher isotacticity at 0.37 was successfully prepared in [C₆mim][LLA].     

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.     

Reaction of [60]Fullerene with Terbium(IV) Fluoride

Abstract

A reaction between [60]fullerene and terbium(IV) fluoride is shown to be a new example of the thermally induced disruption of the fullerene skeleton. “Hyperfluorination” occurs at the elevated temperature (350° C) thereby producing species C₆₀ Fx (x > 60). The fluorination products were characterized by mass spectrometry and IR spectroscopy methods.     

Synthesis and Electrochemical Behavior of Regioisomeric Bismethanofullerene Derivatives

Abstract

A series of regioisomeric bis-methanofullerenes (diethyl [60]fullerenobisacetate) were prepared by reaction of the sulfonium ylide with C₆₀. Seven stable resultant regioisomers were completely isolated on a preparative HPLC and identified by FT-IR, UV-vis, TOF-MS, and ¹H and ¹³C NMR measurements. The structures of these bisadducts were assigned based on 1) the relationship of the polarities of the regioisomers with the elution order from HPLC; 2) a comparison of their UV-vis spectra with those of corresponding Bingel-Hirsch bisadducts; and 3) the identification of their molecular symmetries by their ¹H and ¹³C NMR spectra. The electrochemical properties of the resultant regioisomeric bismethanofullerene, derivatives were investigated through cyclic voltammetry (CV). The bisadducts exhibited more negative reduction potential than the pristine C₆₀. Trans-2- and cis-3- bisadducts had the least negative potential E¹ _1/2 of all the other bisadducts.     

A STUDY ON THE THERMAL STABILITY TO 1000°C OF VARIOUS CARBON ALLOTROPES AND CARBONACEOUS MATTER BOTH UNDER NITROGEN AND IN AIR

ABSTRACT

The thermal behavior of graphite, C₆₀ fullerene, fullerene black (carbon soot containing fullerenes), extracted fullerene black and diamond has been analyzed to 1000°C by TGA–DTA (thermogravimetric analysis and differential thermal analysis) under a nitrogen flow at a heating rate of 20°C/min. Very small weight losses have been recorded in the case of graphite and diamond. Furthermore no diamond graphitization has been observed. The sublimation of pure C₆₀ and the fullerene fraction of fullerene black (both pristine and extracted) has been observed and discussed.

The combustion reaction in air flow of graphite, C₆₀ and C₇₀ fullerenes, fullerene black (both unextracted and extracted), carbon nanotubes and diamond has been studied by TGA–DTA at a heating rate of 20°C/min. C₇₀ fullerene and fullerene black have been found to be the most reactive carbon materials with O₂. The role played by C₇₀ in the degradation of fullerites has been discussed. Among the carbon materials examined, the best resistance to O₂ attack has been shown by diamond and carbon nanotubes. The behavior of graphite is intermediate between diamond and fullerene blacks. The behavior of C₆₀ fullerene appears closer to that of graphite although it appears to be more reactive with O₂. Samples of graphite and carbon blacks N375 and N234 have been studied by TGA–DTA in air flow before and after a radiation treatment with neutrons or γ radiation. The effect of the radiation damage in the combustion reaction of these carbon materials has been discussed.     

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.     

Cyclopentadiene—iron—naphthalene tetrafluoroborate salt as a cationic photoinitiator for preparing photosensitive materials

Abstract

A novel cationic photoinitiator, cyclopentadiene-iron-naphthalene tetrafluoroborate ([Cp-Fe-Naph]BF₄) salt, was synthesized, characterized and used for preparing photosensitive materials. The purification process and the reaction conditions were optimized. The highest yield can reach 82 per cent. Compared with the mono-arene iron complexes, [Cp-Fe-Naph]BF₄ possesses a higher molar extinction coefficient (ε = 893 M^?1 cm^?1) at 373 nm in CH₂C1₂ and is more efficient for the polymerization of epoxide when a high-pressure mercury lamp is used as an ultraviolet light source. The photosensitivity S can reach 78.1 mJ/cm2 when [Cp-Fe-Naph]BF₄ is used to initiate the epoxide E44. When the photosensitizer benzoyl peroxide (BPO) is employed, [Cp-Fe-Naph]BF₄ is rendered much more efficient as a photoinitiator. The best molar ratio of BPO to [Cp-Fe-Naph]BF₄ is 1:1 to 1:2. In the photopolymerization of epoxide initiated by [Cp-Fe-Naph]BF₄, the temperature is very important with respect to the polymerization rate. At 60°C, the polymerization can be completed in a short time.     

Synthesis of Calix[4, 5, 6] Resorcinarenes Using Fullerene C60 as Template

Abstract

We present a new use of fullerene C₆₀ as a template for the synthesis of cyclic resorcinarenes, The cyclocondensation of 2‐methyl‐resorcinol with benzaldehyde and hexanal in THF, catalyzed by AlCl₃, in the presence of 1%, 5%, and 10% fullerene C₆₀, produces calix[4], [5], and [6] resorcinarenes, with the pentamer and hexamer as the major products. The resorcinarenes were characterized by ¹H, ¹³C NMR, FTIR, FAB⁺ mass spectrometry, and elemental analysis.     

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.     

Synthesis and Characterization of Some Organic Cations Buckminsterfulleride Salts

Abstract

Six new organic cations (Triphenylmethane dye, Hemicyanine dyes, calix[4]arene derivative) buckminsterfulleride salts were prepared by metathetical reaction. the products were characterized by UV-NIR, ESI-MS, ESR and FT-IR. the ESR spectra show a typical C₆₀ anion radical signal and dependence on countercations and temperature, the linewidth has an abrupt increasing at about the THF melting point and the ESR signal diminishes gradually when the temperature below 170K. the possible explanation is that the THF crystallization results in exclusion of solute from the lattice and leads to C₆₀ anion aggregation, which promotes line broadening and diamagnetic dimer of (C₆₀)₂ ^2? forming.     

Solubility of Fullerenes C60 and C70 in Seven Normal Alcohols and Their Deduced Solubility in Water

Abstract

The solubilities of C₆₀ and C₇₀ at 25°C in seven normal alcohols obey the relationship InY = a + bX + cX², where Y is solubility and X is the Hildebrand solubility parameter of the solvent. Extrapolation to the solubility parameter of water yields solubilities in water of 1.3′10^?11 (C₆₀) and 1.3′10^?10(C₇₀) ng/ml with an uncertainty of one order of magnitude.