Synthesis of endohedral di-and monometallofullerenes Y<Subscript>2</Subscript>@C<Subscript>84</Subscript>, Ce<Subscript>2</Subscript>@C<Subscript>78</Subscript>, and M@C<Subscript>82</Subscript> (M = Y,Ce)

Endohedral metallofullerenes Y₂@C₈₄, Ce₂@C₇₈, and M@C₈₂ (M = Y, Ce) were synthesized by the electric arc method and isolated from the soot using extraction with o-dichlorobenzene. Pure (98%) endohedral dimetallofullerenes Y₂@C₈₄ and Ce₂@C₇₈ were isolated for the first time from o-dichlorobenzene extracts using HPLC and characterized by mass spectrometry and spectrophotometry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2067–2071, November, 2007.     

Theoretical study of the structure of the C<Subscript>60</Subscript>@C<Subscript>450</Subscript> nanoparticle and relative motion of the encapsulated C<Subscript>60</Subscript> molecule

The equilibrium state of the C₆₀@C₄₅₀ nanoparticle was studied. The compound was found to be stable during the encapsulation of C₆₀ tubelene. The motions of tubelene in the confinement potential field of a closed C₄₅₀ nanotube, namely, the translational motion along the tubule axis and the rotational motion were investigated in detail. It is predicted that there is a nanogyroscope inside C₄₅₀, rotating in the field of the C₆₀ capsule. Its quantized rotational states were calculated. The nanoparticle structure and energy were investigated by the tight binding method using modified parameters.     

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.     

Fullerene C<Subscript>60</Subscript> in copolymerization of allyl chloride with methyl methacrylate

The effect of fullerence C₆₀ on the copolymerization of allyl chloride and methyl methacrylate has been studied. With the use of UV spectroscopy, it has been shown that, with an increase in the conversion, the redistribution of optical densities of two π-π* absorption maxima due to fullerene at λ_max = 407 and 330 nm is observed. A difference in the kinetics of copolymer’s formation in the absence and presence of fullerene has been found.     

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.     

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.     

Molecular modeling of hydration properties of hydrophobic ions Li<Superscript>+</Superscript>@C<Subscript>60</Subscript> and K<Superscript>+</Superscript>@C<Subscript>60</Subscript>

The Gibbs free energies of solvation (ΔG _s) and the electronic structures of endohedral metallofullerenes M⁺@C₆₀ (M⁺= Li⁺, K⁺) were calculated within the framework of the density functional theory and the polarizable continuum model. In water environment, the equilibrium position of K⁺ is at the center of the fullerene cavity whereas that of Li⁺ is shifted by 0.14 nm toward the fullerene cage. The Li⁺ cation is stabilized by interactions with both the fullerene and solvent. The equilibrium structures of both endohedral metallofullerenes are characterized by very close ΔG _s values. In particular, the calculated ΔG _s values for K⁺@C₆₀ are in the range from −124 to −149 kJ mol⁻¹ depending on the basis set and on the type of the density functional. Molecular dynamics simulations (TIP3P H₂O, OPLS force field, water sphere of radius 1.9 nm) showed that the radial distribution functions of water density around C₆₀ and M⁺@C₆₀ are very similar, whereas orientations of water dipoles around the endohedral metallofullerenes resemble the hydration pattern of isolated metal ions.     

Conductivity of molten LiF-ZrF<Subscript>4</Subscript>, NaF-ZrF<Subscript>4</Subscript>, KF-ZrF<Subscript>4</Subscript>, RbF-ZrF<Subscript>4</Subscript>, and CsF-ZrF<Subscript>4</Subscript> systems

Specific conductivity of molten salt mixtures of the LiF-ZrF₄, NaF-ZrF₄, KF-ZrF₄, RbF-ZrF₄, and CsF-ZrF₄ systems is measured in the whole concentration range using the reference capillary technique. The results are presented in the form of equations of the χ = a + bT + cT ² [S m^?1] type. The concentration dependences of molar conductivity are calculated on the basis of the density data. The obtained regularities are explained in the terms of the complex model of ion melt structures.     

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.     

Thermochemistry of Complex Formation of Endofullerene Li<Superscript>+</Superscript>@C<Subscript>60</Subscript> with the Triflate Ion

The density functional theory method at the M06-2X/6-31G(d,p) level was used to calculate the optimal geometry and thermodynamic parameters of formation of the Li⁺CF₃SO₃^? and Li⁺@C₆₀(CF₃SO₃^?) ion pairs, as well as topological characteristics of the electron density distribution in the critical point (3,?1) of bonds between lithium cation endofullerene Li⁺@C₆₀, and the triflate anion in a vacuum and in chlorobenzene.     

Molecular structure of NiO<Subscript>2</Subscript>N<Subscript>2</Subscript>C<Subscript>16</Subscript>H<Subscript>14</Subscript> from gas-phase electron diffraction and quantum chemical data

Gas-phase electron diffractometry was used to study the molecular structure of N,N′-ethylenebis(salicylaldiminato)nickel(II), NiO₂N₂C₁₆H₁₄, [hereinafter Ni(salen)] at 583(5) K. The molecule has C ₂ symmetry with a practically planar structure of the NiN₂O₂ coordination unit and with internuclear distances r _α (Ni-O) = 1.882(21) Å and r _α (Ni-N) = 1.889(22) Å. The results of B3LYP/CEP-31G molecular structure calculations are in good agreement with experimental data, whereas the RHF/CEP-31G method significantly overestimates the Ni-N internuclear distance and gives worse results for other structural parameters. According to 3LYP/CEP-31G calculations, the ¹ A low-spin state is 28 kJ/mole lower in energy than the ³ B high-spin state.     

Relative Raman Intensities in C<Subscript>6</Subscript>H<Subscript>6</Subscript>, C<Subscript>6</Subscript>D<Subscript>6</Subscript>, and C<Subscript>6</Subscript>F<Subscript>6</Subscript>: A Comparison of Different Computational Methods

The accuracy of various computational methods (Hartree–Fock, MP2, CCSD, CAS-SCF, and several types of DFT) for predicting relative intensities in Raman spectra for C₆H₆, C₆D₆, and C₆F₆ was compared. The predicted relative intensities for ν₁ and ν₂ were compared with relative intensities measured by an FT-Raman spectrometer. While none of these methods excelled at this prediction, Hartree–Fock with a large basis set was most successful for C₆H₆ and C₆D₆, while PW91PW91 was the most successful for C₆F₆.     

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.     

Synthesis and structures of C<Subscript>60</Subscript> fullerene chlorides

Systematic study of chlorination of fullerene C₆₀ with inorganic chlorides SbCl₅, VCl₄, MoCl₅, and KICl₄ was carried out. Higher chlorofullerenes, viz., T _h -C₆₀Cl₂₄, C₆₀Cl₂₈, C ₂-C₆₀Cl₃₀, and D _3d -C₆₀Cl₃₀, can be prepared depending on the temperature and time of chlorination. The molecular and crystal structures of C₆₀Cl₂₄⋅VOCl₃, C₆₀Cl₃₀⋅2CS₂, and C₆₀Cl₃₀O_1.22 were determined by single-crystal X-ray diffraction. Fullerenes C₆₀Cl₂₈ and C ₂-C₆₀Cl₃₀ were shown to be only kinetically stable, whereas D _3d -C₆₀Cl₃₀ is a thermodynamically stable product. Transformations of less chlorinated fullerenes into more chlorinated products are accompanied by substantial changes in the addition patterns. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1608–1618, July, 2005.     

Voltammetric studies on microcrystalline C<Subscript>60</Subscript> adhered to an electrode surface by solvent casting and mechanical transfer methods

Voltammetric studies on C₆₀ fullerene particles adhered to an electrode surface by solvent casting or mechanical transfer exhibit evidence of nucleation and growth controlled processes for the C₆₀ ^0/– and C₆₀ ^–/2– solid state when the modified electrode is in contact with acetonitrile solutions containing NBu₄ ⁺ electrolyte. Although peak potentials and peak separations are dependent on scan rate as well as the amount of deposit and temperature, potentials obtained using a zero-current extrapolation method are almost independent of all these parameters. These data enable reversible potentials of –816 and –1168 mV vs. Ag/Ag⁺ to be obtained in acetonitrile (0.1 M NBu₄PF₆) respectively for the processes: and . Images obtained by scanning electron microscopy reveal that both the crystalline and particle size is enhanced by 60 s of reductive electrolysis, with the detected (NBu₄)₂C₆₀ crystals being slightly larger than those of (NBu₄)C₆₀. After a short period of potential cycling or controlled potential electrolysis, it is concluded that the data obtained by either method of surface adherence are almost indistinguishable, as are their morphologies. Electronic Publication     

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.     

Experimental Studies on Isonicotinato Cadmium(II) Complex [Cd(C<Subscript>6</Subscript>H<Subscript>4</Subscript>NO<Subscript>2</Subscript>)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>] and Density Functional Calculations

Isonicotinato cadmium(II) complex [Cd(C₆H₄NO₂)₂(H₂O)₄] has been synthesized by hydrothermal method and characterized by elemental analysis, electronic-spectra and thermogravimetric analysis. Density functional theory (DFT) method calculations of the structure, atomic charges distribution, electronic spectra, natural population analysis and the thermodynamic properties at different temperatures have been performed. The calculated results show the electronic transitions are mainly derived from the contribution of bands π → π^* and the decomposition of the title compound should first occur at the bond of Cd—O, then at the bond of Cd—N, which agrees very well with the experimental data.     

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.