Effect of fullerene C<Subscript>60</Subscript> on copolymerization parameters of methyl methacrylate with compounds containing allyl bond

The effect of fullerene C₆₀ on copolymerization of methyl methacrylate with compounds, one of which is a typical allyl monomer and the other is a vinyl monomer with a side allyl bond, was examined. The kinetic parameters of the reactions and the copolymerization constants of monomers in the absence and in the presence of fullerens were determined. Based on the UV spectrometric data, the material balance was calculated and a variation of the molar extinction coefficient of fullerene was revealed.     

Preparation of Aqueous Colloidal Dispersion of C<Subscript>60</Subscript> Fullerene

A method for preparing aqueous colloidal dispersions of C₆₀ fullerene free of organic solvents is proposed. The size of dispersed particles is determined using the turbidity spectra. A solvatochromic effect is observed upon the addition of a C₆₀ solution in toluene to a water-acetone mixture.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 4, 2005, pp. 575–576.Original Russian Text Copyright © 2005 by Tseluikin, Tolstova, Gun’kin, Pankst’yanov.     

Endohedral Complex of Fullerene C<Subscript>60</Subscript> with Tetrahedral N<Subscript>4</Subscript>, N<Subscript>4</Subscript>@C<Subscript>60</Subscript>

B3LYP/6-31G(d) hybrid HF/DFT and BLYP/6-31G(d, p) DFT calculations were carried out to determine the structural and electronic properties of the endohedral complex of C₆₀ with Tetrahedral N₄ (T_d N₄), N₄@C₆₀. It was demonstrated that N₄ was seated in the center of the fullerene cage and the tetrahedral structure of N₄ is remained in the cage. The formation of this complex is endothermic with inclusion energy of 37.92 kcal/mol. N₄ endohedral doping perturbs the molecular orbitals of C₆₀ not so much, the calculated HOMO–LUMO gaps, the electron affinity (EA) and the ionizational potential (IP) of N₄@C₆₀ are similar to that of C₆₀.     

Inhibiting effect of fullerenes C<Subscript>60</Subscript> and C<Subscript>70</Subscript> on high-temperature oxidative degradation of copolymers of methyl methacrylate with methacrylic acid and methacrylamide

The inhibiting effect of fullerenes on thermal oxidative degradation of copolymers of methyl methacrylate with methacrylic acid and methacrylamide at 340°C was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 12, 2004, pp. 2047–2049.Original Russian Text Copyright © 2004 by Troitskii, Khokhlova, Konev, Denisova, Novikova.     

Synthesis of fullerene C<Subscript>60</Subscript> monoadducts. Cyclopropanation of C<Subscript>60</Subscript> with sulfonium ylides

3′H-Cyclopropa[1,9](C₆₀-I_h)[5,6]fullerene-3′-carboxylic acid can be synthesized in a good yield by cyclopropanation of fullerene C₆₀ with 2-(dimethyl-λ⁴-sulfanylidene)acetates provided that the ester residue is readily hydrolyzable in acid medium.     

Influence of UV Pretreatment on Thermooxidative Degradation of Poly(Methyl Methacrylate) Films with Fullerene C<Subscript>60</Subscript> or C<Subscript>70</Subscript>

Wariation of the concentration of fullerenes C₆₀ and C₇₀ in poly(methyl methacrylate) films under UV exposure in atmospheric oxygen was studied. The mechanism of the influence exerted by addition of some photostabilizing polymers and xanthene dyes on the photooxidative degradation of fullerene in the polymer matrix was analyzed.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 1038–1042.Original Russian Text Copyright © 2005 by Troitskii, Khokhlova, Konev, Denisova, Novikova, Lopatin.     

The standard enthalpy of formation of fullerene chloride C<Subscript>60</Subscript>Cl<Subscript>30</Subscript>

A rotating-bomb calorimeter was used to measure the energy of combustion of crystalline fullerene chloride C₆₀Cl₃₀ · 0.09Cl₂, Δ_c U° = (?24474 ± 135 kJ/mol). The result was used to calculate the standard enthalpy of formation, Δ_f H° (C₆₀Cl₃₀, cr) = 135 ± 135 kJ/mol, and the C-Cl bond energy, 195 ± 5 kJ/mol. The C-X (X = F, F, Cl, and Br) bond energies in fullerene C₆₀ derivatives and other organic compounds are compared.     

Reactivity of fullerene C<Subscript>60</Subscript>

The results of a quantum-chemical study of the reactivity of fullerene C₆₀ in such reactions as polymerization (dimerization), cycloaddition, addition of valence-saturated molecules are presented. The mechanisms of these reactions are also discussed.     

A Quantum Chemical Study of C<Subscript>60</Subscript>Cl<Subscript>30</Subscript>, C<Subscript>60</Subscript>(OH)<Subscript>30</Subscript> Molecules and Fe@C<Subscript>60</Subscript>(OH)<Subscript>30</Subscript> Endocomplex

(U)PBE0/cc-pVDZ method is used to study the structure of C₆₀Cl₃₀, C₆₀(OH)₃₀ molecules and Fe@C₆₀(OH)₃₀ endocomplex. The triplet state of the endocomplex is shown to be the lowest in energy among its four states corresponding to different spin multiplicities and positions of Fe nucleus within the fullerene cavity. This state is characterized by bonding between the iron atom and one of two benzenoid cycles of the carbon cage, six internuclear Fe–C distances (208 pm), and 1s²2s²2p⁶3s²3p⁶3d^7.24s^0.14p^0.3 electron configuration of iron with spin population of 2.36.     

Molecular Characteristics of Star-Like Polyvinylpyrrolidone with Fullerene C<Subscript>60</Subscript> as the Branching Site in Dilute Solutions

Star-like water-soluble macromolecules with fullerene as the branching site were synthesized by the reaction of fullerene C₆₀ with polyvinylpyrrolidone whose molecules contain one terminal primary amino group. The initial and C₆₀-containing polymers were studied by UV spectroscopy, thin-layer chromatography, centrifugal sedimentation, translation diffusion, and viscometry in aqueous buffer solutions. Diffusion-sedimentation and sedimentation two-detector analyses of the initial and fullerene-containing samples were performed. The molecular weights of the polymers were estimated by the Svedberg equation. The proportion of the fullerene-containing segment in the samples synthesized was determined, and the number of the branches in the fullerene-containing macromolecules was estimated.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 132–138.Original Russian Text Copyright © 2005 by Pavlov, Nazarova, Ebel, Mikhailova, Zaitseva, Bokov, Litvinova, Afanas’eva, Korneeva, Panarin.     

Synthesis and Polar and Electrooptical Properties of a Butylamine Derivative of Fullerene C<Subscript>60</Subscript>

A butylamine derivative of fullerene was prepared by the reaction of butylamine with fullerene C₆₀. The experimental electrooptical and dipole characteristics of the derivative were compared with the corresponding calculated PM3 data. The reaction product proved to be inhomogeneous in the number of the amine molecules added; it contains polar multiadducts of C₆₀ with noncentrosymmetric distribution of covalently bound amino groups over the fullerene core.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 5, 2005, pp. 795–802.Original Russian Text Copyright © 2005 by Evlampieva, Yakimanskii, Dobrodumov, Nazarova, Pashkov, Panarin, Ryumtsev.     

Sorption of light fullerenes C<Subscript>60</Subscript> and C<Subscript>70</Subscript> on NORIT-AZO carbon

Sorption of fullerenes C₆₀ and C₇₀ from o-xylene, toluene, and dichlorobenzene solutions on NORIT-AZO carbons was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1638–1642.Original Russian Text Copyright © 2004 by Semenov, Seregin, Arapov, Charykov.     

Aqueous dispersions of C<Subscript>60</Subscript> fullerene

Stable aqueous colloidal dispersions of C₆₀ fullerene are prepared. A solvatochromic effect is revealed upon the addition of C₆₀ solution in chlorobenzene to a water-acetone mixture.     

Direct phosphorylation of fullerene C<Subscript>60</Subscript> with phosphine

Fullerene C₆₀ reacts with phosphine (PH3) under free radical initiation conditions (azobis(isobutyronitrile), xylene, 65°C, 6–11 h) to give in the presence of air oxygen functional oligofullerenes (yield up to 32%) containing functional groups of phosphinic and phosphonic acids.     

Synthesis and structure of allylated derivatives of fullerenes C<Subscript>60</Subscript> and C<Subscript>70</Subscript>

New chromatographically pure monoand hexamethanofullerenes C₆₀ and C₇₀ containing active allylic groups were synthesized by Bingel—Hirsch reaction. These compounds are promising for the studies of biological activity, as well as for obtaining on their basis new fullerenecontaining materials. The purity and composition of the synthesized compounds were confirmed by MALDI-TOF mass spectrometry and HPLC, their structure was established by ¹H and ¹³C NMR spectroscopy and X-ray diffraction.     

On the initial stage of the free-radical polymerizations of styrene and methyl methacrylate in the presence of fullerene C<Subscript>60</Subscript>

It has been demonstrated experimentally and theoretically that the essentially different inhibiting effects of fullerene C₆₀ on the initial stage of the polymerizations of styrene and methyl methacrylate (including complete hampering of styrene polymerization throughout a long induction period) are of common kinetic nature. The difference arises from the competition between C₆₀ and the monomer not for initiating radicals but for radicals originating from the monomer; that is, the difference stems from the competition between the chain propagation reactions and the termination reactions on fullerene molecules. As a consequence, the further development of the process is determined by the relative reactivities of the radicals toward C₆₀ and towards their parent monomers.     

Mass spectrometric determination of the electron affinity of C<Subscript>60</Subscript>(CF<Subscript>3</Subscript>)<Subscript>10</Subscript> and C<Subscript>60</Subscript>(CF<Subscript>3</Subscript>)<Subscript>12</Subscript> molecules

Knudsen cell mass spectrometry was used to study ion-molecular electron exchange reactions between some trifluoromethyl derivatives of C₆₀ fullerene. Electron affinity values were experimentally determined for C₆₀(CF₃)₁₀ and the S ₆ isomer of C₆₀(CF₃)₁₂ and compared with the results of calculations and the data in the literature.     

Self-assembling of fullerene C<Subscript>60</Subscript> into (C<Subscript>60</Subscript>)<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> clasters in aromatic solvents

Self-assembling of fullerene C₆₀ into (C₆₀) _n clusters in aromatic solvents was studied. The role of the π-π interactions and dispersion forces in the (C₆₀) _n cluster formation in these media is demonstrated using the data on the solubility of fullerene C₆₀ in these solvents and their ionization potentials and also spectral characteristics of fullerene C₆₀ in the range of 326–340 nm in different solvents.     

Fullerene C<Subscript>60</Subscript> as a superefficient quencher of singlet exited states of polycyclic aromatic hydrocarbons

Quenching of fluorescence of polycyclic aromatic hydrocarbons (PAH), namely, naphthalene, anthracene, 9,10-diphenylanthracene, 9,10-dibromoanthracene by C₆₀ fullerene in ethylbenzene at 293 K was found and investigated. The phenomenon is characterized by abnormally high values of bimolecular rate constants for quenching (k _bim = (0.18–6.78)·10¹² L mol⁻¹ s⁻¹) determined from the Stern—Volmer dependence of the PAH fluorescence intensity on the C₆₀ concentration and occurs through the inductive-resonance (dominant channel) and exchange-resonance (minor channel) energy transfer from ¹PAH* to C₆₀. The overlap integrals of the PAH fluorescence spectra with the C₆₀ absorption spectrum and the critical energy transfer distances were calculated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 432–436, March, 2007.