Fullerene Research in Poland

Abstract

Main results of the investigations of fullerene and its derivatives are briefly reviewed. Such topics as plasma spectroscopy, fullerenes and nanotubes formation, C₆₀ carbyne knots, fullerene reduction and doping, charge transfer states and electroabsorption of C₆₀, electrical conductivity, superconductivity, ESR properties, fullerene clathrates, C₆₀/C₇₀ complexes with organic donors, fullerene adducts, hydrogenated fullerenes, metallofullerenes and carbon nanotubes are discussed.     

Addition of “Living” Polymers onto C60.

Abstract

Various “living” polymers were grafted onto C₆₀ The number of arms of the so obtained “star” molecules can be controlled by stoechiometry and/or by varying the reactivity of the carbanion on the “living” chain against a double bond on the C₆₀. Even the oxanion of “living” polyethylenoxide is able to add onto the reactive double bonds on C₆₀. In some conditions, the carbanions present on these alkaline salts of grafted fullerenes becomes able to initiate anionic polymerization of vinyl monomers. Using “living” poly(phenylvinylsulfoxide) as a precursor polymer for PA, polyacetylene chains could be attached to the fullerene.     

The New Method for the Synthesis of Fullerols Based on Radical Reaction

Abstract

The method for the synthesis of fullerols C₆₀(OH) _x was developed, allowing to obtain products with low number of hydroxy groups attached to fullerene molecule. At the first stage, product C₆₀(tert‐BuO) _x was obtained by the radical reaction of C₆₀ with tert‐butyl‐peroxide under heating or UV‐irradiation. At the second stage, fullerol C₆₀(OH) _x was synthesized after the elimination of tert‐butyl groups by acid treatment. Several samples C₆₀(OH) _x containing different numbers (x = 2–5) of hydroxy groups were obtained, the main product had x = 2. The structure of the fullerols was confirmed by UV‐ and Fourier‐transform infrared (FTIR)‐spectroscopy and MALDI‐TOF mass‐spectrometry.     

[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.     

On Some Complexes of Allyl Derivatives of C60 Fullerene: Simulation of Molecular and Electron Structure by DFT

Abstract

The problem of existence of η³–π‐complexes of transition metal atoms with the allyl type derivatives C₆₀X₃ of C₆₀ fullerene is discussed. It is shown that complexes C₆₀X₃Co(CO)₃ (X = H, F, Cl, Br), C₆₀H₃NiC₅H₅, C₆₀H₃Fe(CO)C₅H₅, where three atoms X are bound to the C atoms of fullerene in the α‐positions relative to the same five‐membered ring in the C₆₀ fullerene, must be sufficiently stable. In these complexes the metal atoms are η³–π‐bound to the fullerene cage. In contrast to this, the metal atoms with the same allyl type C₆₀H₃ derivative of C₆₀ fullerene in the C₆₀H₃Li and C₆₀H₃FeC₅H₅ complexes are η⁵–π‐coordinated to the carbon cage. Calculations were carried out by the DFT with the exchange‐correlation potential by Perdew–Burke–Ernzerhow.     

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).     

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.     

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.     

Crystal Structure of C60 and C70 Compounds

Abstract

Fullerene intercalated compounds are the most intensively examined molecular materials to exhibit superconducting, ferromagnetic, optical non-linear and other properties. the fullerene C₆₀ or C₇₀ serve usually as electron acceptors in these materials. Although the electron acceptor properties of the fullerene are similar to those of the weak organic acceptors, the fullerene forms various C₆₀-based materials, namely clathrates, charge-transfer complexes and weak, molecular complexes. the search for cation species for fullerene-based materials is one of the routes towards progress in the design of materials with interesting physical properties.

Physical properties of the fullerene-derived molecular compounds are determined mainly by their crystal structure packing. Relatively large cavities in the fullerene solid can easily accommodate small units like solvent molecules or electron-donor organic compounds. An intercalation with these species is usually accompanied either by a lowering in crystal symmetry or by a change in the stacking arrangement of the C₆₀ spheres. These factors influence the interactions between fullerene (host) and an organic molecule (guest). Charge transfer between the electron donor molecule and the fullerene is usually weak and is hindered by unfavourable steric factors; it does not correlate with the ionization potential of the donor.

In this paper we present characteristic structures of one-, two-, and three-component fullerene compounds or else the structures of fullerene clathrates, neutral (van der Waals) complexes and ionic charge-transfer complexes. One can conclude that the stability and properties of the fullerene-based derivatives are defined by the steric compatibility between the three-dimensional donor and the spherical or elongated fullerene.     

Effect of C60 on the thermal stability of polyethylene glycol grafted to it

The thermal degradation of regular polymer networks, cross-linked by C₆₀ molecules along the end groups of polyethylene glycol, has been investigated by mass-spectrometric thermal analysis for the example of polyethylene glycol grafted to fullerene C₆₀. The character of the thermal degradation of the networks is substantially different from that of free polyethylene glycol and other polymer systems investigated earlier. The grafting to C₆₀ increases the thermal stability of polyethylene glycol. Pis’ma Zh. Tekh. Fiz. 23, 19–24 (September 26, 1997)     

Positional isomerism,stability, and polarizability of C20(CH2)n (n = 1–10), the cyclopropane adducts of the smallest fullerene: General formula for calculation of mean polarizability of fullerene derivatives C20XnYm and C60XnYm with fixed (n + m) number of different addends

All regioisomers of fullerene adducts C₂₀(CH₂)_n have been found and their stability and polarizability have been studied by the PBE/3ζ method. As in the case of the C₆₀ and C₇₀ adducts, mean polarizability of C₂₀(CH₂)_n quadratically depends on the number of addends and demonstrates the depression, viz. negative deviation of polarizability from the linear additive scheme. Another, linear formula is proposed for calculating mean polarizability of the C₂₀ and C₆₀ fullerene adducts with mixed functionalization C₂₀(CH₂)_nO_m and C₆₀(CH₂)_nO_m and fixed number of addends. The obtained results will be further used to work out the algorithm for counting all possible C₆₀X_n cycloadducts and searching a general formula for calculation of the C₆₀X_nY_m polarizability with variable (n + m) number of addends.     

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.     

Synthesis of novel ultraviolet stabilizers based on [60]fullerene and their effects on photo-oxidative degradation of polystyrene

Abstract

Two N-benzyl fulleropyrrolidines were synthesized via Prato reaction. The polystyrene (PS) films containing 0.5?wt% fullerene and N-benzyl fulleropyrrolidines were prepared from toluene via the solvent evaporation method. The photo-oxidative activities and thermostability of these films were determined by monitoring the average molecular weight and thermogravimetric curve. The changes in weight loss (%) and tensile strength with irradiation time were also tracked. After 480?h of illumination, the weight loss of PS films was 6.8%, while the corresponding index of PS with C₆₀ was 6.1%. The weight loss of PS with two fulleropyrrolidines was significantly lower than that before (3.8% and 2.7%). The results manifested the good ultraviolet (UV) stabilizing effect and thermostability of these complex films compared with PS. A probable mechanism was proposed to account for the stabilizing action of the [60]fullerene derivatives as multifunctional UV stabilizers.     

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.     

Superstructures of Polymeric Stars with Fullerene Core in Solutions

Abstract

Poly(styrene) stars (PS)₆C₆₀, twin‐cores (PS)₆C₆₀‐[Si‐(CH₃)₂]‐C₆₀(PS)₆ and hybrids (PS)₆C₆₀(PTBMA)₆ with paired arms of PS + poly(tertbutylmethacrylate) have been studied in toluene (20°C, concentration C = 1–6 wt.%) by small‐angle neutron scattering (SANS) at momentum transfer q = 0.001–5 nm^?1. The C₆₀ stabilize arms' stretched conformation and intensify stars' ordering. While the (PS)₆C₆₀ and hybrids formed tiny clusters (particles' number N ～ 10–80, size R _C ～ 50–100 nm), the dimers created massive structures (N ～ 1 · 10³–2 · 10³, R _C ～ 300 nm) that can be induced by dipolar interaction of C₆₀ twin‐cores.     

Langmuir-Blodgett films made from C60 fullerene with grafted macromolecules

Langmuir-Blodgett films made from C₆₀ fullerene with grafted polymer chains —polystyrene and polyethylene oxide — are obtained for the first time. The Langmuir-Blodgett films are obtained by the transfer of Langmuir films onto substrates of single-crystal silicon. The Langmuir films and the single-layer Langmuir-Blodgett films of C₆₀ with grafted polystyrene are nonuniform over their thickness and form a network consisting of aggregates with a size of ≤6 μm. The Langmuir films of C₆₀ with grafted polyethylene oxide are much more uniform. They can easily be used to obtain Langmuir-Blodgett films containing up to 20 layers and having a surface that appears smooth under an optical microscope. Pis’ma Zh. Tekh. Fiz. 24, 88–94 (June 26, 1998)     

Two Alternative Ways for Formation of Mono‐atomic Carbon Layer on Ni(1 1 1): Organic‐Gas Cracking and Thermal Decomposition of Fullerenes in Thin Film

Abstract

Formation of graphite mono‐atomic layers (monolayer of graphite, MG) on Ni(1 1 1) single‐crystal surface by cracking of propylene C₃H₆ as well as by decomposition of fullerene molecules C₆₀ was investigated. Comparative analysis of carbon films was made in both cases by means of auger electron spectroscopy (AES), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM) techniques. It was shown with the LEED measurements, that quality of graphite mono‐atomic layer obtained in the two different ways is similar and high enough. For the system prepared by fullerene fragmentation some fullerene‐similar topography features were found in STM images. These observations are explained as a result of arrangement of single C₆₀ molecules underneath the MG on Ni(1 1 1).     

Carbon Clusters Formation by Laser Irradiation of Carbonaceous Solids

Abstract

A laser ablation/Fourier‐transform ion cyclotron resonance mass spectrometry was used to generate fullerenes clusters from targets of carbonaceous material containing carbyne, C₆₀ photopolymer, graphite, diamond, C₆₀ fullerene crystals.     

Chemically Driven Microstructure Evolution in Cobalt–Fullerene Mixed System

Abstract

We report on the formation of Co–C₆₀ nano‐composite prepared by simultaneous deposition of cobalt and C₆₀ fullerene on sapphire or NaCl at room temperature. The composite includes fcc‐Co single‐crystals with size of order 10 nm separated by C₆₀‐based matrix. Detailed characterization of the composite by electron diffraction and Raman spectrometry revealed the existence of small amount of diamond and cobalt carbides (orthorhombic Co₂C and Co₃C) in the composite matrix. According to electron diffraction analysis diamond nucleates epitaxialy on facets of fcc‐Co crystals. The proposed model shows the role of chemical interaction in Co–C₆₀ mixture in the nano‐composite structure formation.