Synthesis and Complex Study of Water‐Soluble Polymer Derivatives of C60 Fullerene

Abstract

The water‐soluble composites with fullerene content up to 5 wt% based on poly‐(N‐vinylpyrrolydone) (PVP) were obtained. The higher fullerene content is achieved by means of introducing tetraphenylporphyrine (TPP) and KBr into composites. The synthesis includes the formation of C₆₀–TPP complex and its further interaction with polymer. The formation of C₆₀–TPP complex was confirmed by ¹³C NMR, SANS, and translational diffusion. The hydrodynamic and electrooptical studies of C₆₀–TPP–PVP complexes indicate the higher symmetry of the polymer coil in the complex as compared to PVP. The C₆₀–PVP–KBr composites were also obtained by the solid state interaction under vacuum, KBr promoting the destruction of fullerene aggregates.     

He+ Ion Bombardment of C70 Fullerene: An FT‐IR and Raman Study

Abstract

C₇₀ fullerene films deposited on a silicon substrate have been bombarded with He⁺ ions at 30 keV at room temperature in vacuum. The structural changes undergone by C₇₀ have been followed by both FT‐IR and Raman spectroscopy. The results have been compared to the behavior of C₆₀ fullerene and discussed in an astrochemical context. The main conclusion is that C₇₀, contrary to C₆₀, does not form oligomers at low radiation dose but it is directly and gradually degraded to amorphous carbon (carbon black).     

Structure and Photoluminescence of Single‐Emulsion C60 and Cu‐C60 Films

Abstract

The phase composition of single‐emulsion C₆₀ and Cu‐C₆₀ films and their photoluminescence were studied and analyzed in detail.     

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.     

Light Scattering Study of Aqueous Poly(Vinyl)pyrrolidone–Fullerene C70 Solutions

Abstract

It was shown by static and dynamic light scattering that poly(vinyl)pyrrolidone (PVP) molecules form large intermolecular complexes (clusters) with C₇₀ in aqueous solutions. The molecular weights and dimensions of PVP–C₇₀ clusters increase both with the increase of fullerene content and the molecular weight of the matrix PVP. However, two different diffusion coefficients were detected by dynamic light scattering. The slow mode was explained as diffusion of large PVP–C₇₀ clusters. The fast mode represents free PVP molecules in solution. Dimensions of clusters revealed in aqueous PVP–C₇₀ solutions are less than that for PVP–C₆₀ by factor of 2.5–3.     

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.     

About the iron carbonyl complex with C60 and C70 fullerene: [Fe(CO)4(η2C60)] and [Fe(CO)4(η2C70)]

The iron carbonyl complexes with C₆₀ and C₇₀ fullerenes were synthesized in high yield by photochemical irradiation of solutions of C₆₀ and C₇₀ in presence of Fe(CO)₅. The resulting complexes were studied by FT-IR, Raman and electronic absorption spectroscopy. All the data are consistent with the structures [Fe(CO)₄(η²C₆₀)] and [Fe(CO)₄(η²C₇₀)]. The thermal stability and decomposition reaction of the two complexes were studied by TGA-FTIR and Differential Scanning Calorimetry (DSC). Both complexes decompose at moderate temperatures releasing CO and Fe(CO)₅ in the vapor phase leaving a residue of metallic iron and free C₆₀ or C₇₀ fullerenes that can be recovered by solvent extraction of the decomposition residue.     

Structural and Vibrational Properties of Li‐ and Na‐Doped Fullerene Polymers

Abstract

We have studied tetragonal C₆₀ and C₆₀‐based polymers doped with Lithium and Sodium. We show that the intercalated phases Li₄C₆₀ and Na₄C₆₀ both form two‐dimensional polymers. X‐ray diffraction diagrams for Li₄C₆₀ and tetragonal C₆₀ can be accurately indexed assuming tetragonal structures, but for Na₄C₆₀ a monoclinic quasi‐tetragonal structure is found. We conclude that in Li₄C₆₀ the covalent bonds are formed by (2 + 2) cycloadditions, in the same way as in the tetragonal polymer produced by treating pure C₆₀ at high temperature and high pressure, while single C–C bonds connect the fullerene molecules in Na₄C₆₀.     

Computer Simulation of Molecular and Electron Structure of C60 Fullerene Complexes with Twelve Half‐Sandwich Groups MC5H5 (M = Fe,Ru, Os)

Abstract

The C₆₀(MCp)₁₂ complexes of I _h ‐C₆₀ fullerene in which each of 12 MCp groups (M = Fe, Ru, Os; Cp = C₅H₅) is coordinated to one of the five‐membered cycles of C₆₀ via formation of η⁵–π‐bond are considered. Geometry and electron structure of these complexes are simulated by using of the PBE–DFT approach. Stability of complexes considered is evaluated. It is shown that energies of the M–C₆₀ bonds are increased in the sequence C₆₀(FeCp)₁₂, C₆₀(RuCp)₁₂, C₆₀(OsCp)₁₂.     

Photosensitization of Nanocrystalline SnO2 Films with a tris(2,2′‐Bipyridine) Ruthenium(II)‐Fullerene Dyad

Abstract

A photoelectrochemical study of a tris(2,2′‐bipyridine)ruthenium(II)‐C₆₀ donor–acceptor dyad adsorbed on nanocrystalline semiconductor SnO₂ electrodes has been carried out. The results show that the incident photon‐to‐current conversion efficiency of dyad‐based photoelectrochemical cells is ～10%.     

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.     

The Voltage–Current Characteristics and Photoelectric Effect of Fullerene C60–N-Isoamylisatin 4-Methylphenylhydrazone Heterostructures

Technical Physics Letters - The results of using N-isoamylisatin 4-methylphenylhydrazone for the optimization of fullerene-based heterostructures are presented. The synthesis and microscopy of thin...     

Synthesis and Properties of Layered Oxides LiCo_(1-x)Ni_xO_2

The mechanism of LiCo1-xNixO2(x=0, 0.5, 1) synthesis from carbonates or hydrates was studied by thermogravimetric analysis and X-ray diffraction to identify the medium and final products. The synthesis process from carbonates can be divided into two steps. Below 300℃cobalt carbonate and/or nickel carbonate decompose forming oxides. Over 300℃ Li2CO3 decomposes and reacts with Co and/or Ni oxides gradually, as a result Co++ and/or Ni++ areoxidized to Co+++ and/or Ni+++, finally LiCo1-xNixO2 forms. The proportion of cobalt tonickel in the starting mixture and atmosphere during synthesis affects the structure of products.LiCo1-xNixO2(x≤0.5) can be synthesized in air or oxygen and characterized by solid solutionof LiCoO2 and LiNiO2. LiNiO2 can be obtained only from hydrates and in oxygen atmosphere.LiNiOz and LiCo0.5Ni0.5O2 have higher first charge capacity than that of LiCoO2. Their discharge capacity reaches a level with that of LiCoO2 and has reasonable reversibility.     

Calculation of Ionization Energy and Electron Affinity of Molecule of Hydro‐ and Fluorinefullerenes C60H(F) n (0 ≤ n ≤ 60)

Abstract

Vertical and adiabatic electron affinities (EA) and ionization energies (IE) of C₆₀H(F) _n (0 ≤ n ≤ 60) have been determined using semiempirical calculations with AM1 Hamiltonian. Comparison of the thermo‐chemical characteristics of the fluorinated and hydrogenated fullerene positive and negative ions has been carried out on the basis of these calculations.     

Photoluminescence Study of the Two‐Dimensional Tetragonal and Rhombohedral Polymers of C60 at High Pressure

Abstract

The pressure behavior of the photoluminescence (PL) spectra of the planar polymeric phases of C₆₀ have been studied at pressure up to 4 GPa. The PL spectra and the pressure‐induced shift of the principal bands differ considerably for the pristine C₆₀, two‐dimensional tetragonal (2D‐T) and rhombohedral (2D‐R) polymers of C₆₀. The changes in the PL spectra may be related with the transformation of the electron energy spectrum of polymers.     

Raman Modes and Stability at High Pressure of the Two‐Dimensional Rhombohedral Polymer of C60

Abstract

Phonon modes and stability of the planar rhombohedral polymer of C₆₀ have been studied at pressure up to ～30 GPa by means of in situ Raman scattering. At P ～ 15 GPa the phonon frequencies show an irreversible transition to a new phase related with random covalent bonding between the molecules in adjacent polymeric sheets.     

纳米C60/C70-丙烯酸(酯) 共聚物的合成及性能

将纳米C60／C70与丙烯酸(酯)单体在引发剂作用下共聚，合成得到C60／C70-丙烯酸(酯)共聚物。对该共聚物的结构进行了红外光谱和荧光光谱分析，探讨了有富勒烯参与的聚合反应机理和共聚物结构。将该共聚物用有机胺中和成盐，使其水性化，制得水溶性纳米C60／C70-丙烯酸(酯)高分子成膜材料，对其成膜性能进行了分析测试。发现C60／C70对丙烯酸(酯)聚合物具有独特的成膜改性功能。     

Star‐like Fullerene Containing Poly(Vinylpyrrolydone) Derivatives: Chloroform Solution Properties

Abstract

Star‐like fullerene C₆₀ derivatives with different branch number, synthesized by the reaction of fullerene with poly(vinylpyrrolydone) (PVP) macromolecules bearing the terminal amino‐groups, were investigated in solution by the viscometry, dielectric, and electrooptical Kerr‐effect methods in comparison with the ordinary linear PVPs of the same molecular mass. It was shown that covalent linkage of branches to fullerene through amino‐groups leads to appearance of a polar and optically anisotropic nanoparticle (amine‐substituted C₆₀) in the center of the coil of star‐like polymers that radically changes dielectric and electrooptical properties of the initial polymer. Effect of fullerene on the dimension of polymer coil had been detected also.