Synthesis of Various Water-Soluble C60 Derivatives and Their Superoxide-Quenching Activity

Abstract

In order to examine the utility of fullerene as a medicinal application, we evaluated the reaction between fullerene derivatives and active oxygen species in vitro. This paper describes the synthesis of various water-soluble C₆₀ derivatives (cationic and anionic) and evaluation of their superoxide (O₂ ^?) quenching activity. Cationic C₆₀ derivatives showed fairly high efficiency.     

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.     

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.     

On η5 -π-Complexes of C70 and Some of its Cyclopentadienyl Derivatives with Li Atoms: MNDO Simulation

Abstract

The molecular and electronic structure of hypothetical η⁵ -complexes of C₇₀ and its cyclopentadienyl derivatives such as C₇₀R₅, C₇₀R₁₀ and C₆₀X₁₀ (R = H, Cl, Br; X = B, N, Al, P) with Li are discussed. It was proposed that atoms R were attached to the α-positions of one (two) polar pentagon(s) of prolated shape fullerene (D_5n)-C₇₀, and atoms X substituted atoms C in same sites. It was established that the complexes under consideration were more stable systems in comparison with unsubstituted C₇₀. The MNDO method was used. The results obtained are generalizing theoretical studies of electron stucture of similar complexes of fullerene C₆₀ and its derivatives such as C₆₀R₅ and C₅₅X₅.     

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.     

Ion–Ion Collisions Involving Fullerene Ions

Abstract

Fullerenes are a direct link between atoms with discrete electronic energy levels and solids with a band structure and a well defined surface. In collision experiments, both between energetic ions or electrons and neutral C₆₀ molecules [Walch, B.; Cocke, C.L.; Voelpel, R.; Salzborn, E. Electron capture from C₆₀ by slow multiply charged ions. Phys. Rev. Lett. 1994, 72, 1439–1442; Scheier, P.; Hathiramani, D.; Arnold, W.; Huber, K.; Salzborn, E. Multiple ionization and fragmentation of negatively charged fullerene ions by electron impact. Phys. Rev. Lett. 2000, 84, 55–58; Hathiramani, D.; Aichele, K.; Arnold, W.; Huber, K.; Salzborn, E.; Scheier, P. Electron‐impact induced fragmentation of fullerene ions. Phys. Rev. Lett. 2000, 85, 3604–3607], as well as between charged fullerene ions and neutral targets [Hvelplund, P.; Andersen, L.; Haugen, H.; Lindhard, L.; Lorents, D.C.; Malhotra, R.; Rouff, R. Dynamical fragmentation of C₆₀ ions. Phys. Rev. Lett. 1992, 69, 1915–1918; Hvelplund, P.; Andersen, L.; Brink, C.; Yu, D.; Lorents, D.C.; Rouff, R. Charge transfer in collisions involving multiply charged C₆₀ molecules. Z. Phys. D 1994, 30, 323; Rohmund, F.; Campbell, E.E.B. Resonant and non‐resonant charge transfer in C₆₀ ⁺ + C₆₀ and C₇₀ ⁺ and C₆₀ collisions. J. Phys. B: At. Mol. Opt. Phys. 1997, 30, 5293–5304; Shen, H.; Hvelplund, P.; Mathur, D.; Barany, A.; Cederquist, H.; Selberg, N.; Lorents, D.C. Fullerene–fullerene collisions: fragmentation and electron capture. Phys. Rev. A 1995, 52, 3847–3851], the fundamental processes of electron transfer, ionization, and fragmentation have been studied extensively. Here we report on our experiments on electron transfer in the collision systems C₆₀ ⁺ + ³He²⁺ → C₆₀ ²⁺ + ³He⁺ and C₆₀ ⁺ + C₆₀ ²⁺ → C₆₀ ²⁺ + C₆₀ ⁺. For the latter system we also report on an upper level for the fragmentation probability.     

INHIBITORY EFFECTS OF FULLERENE C60 DERIVATIVES ON ENDOTHELIUM-DERIVED RELAXATION IN RABBIT THORACIC AORTA

Inhibitory effects of newly synthesized fullerene C₆₀ derivatives 1 (C₆₀-bis(N,N-dimethylpyrrolidinium iodide)), 2 (C₆₀-proline-N-acetic acid) and 3 (C₆₀-ethylenediamine-N, N′-diacetic acid) on acetylcholine-induced relaxation in endothelium-intact rabbit thoracic aorta precontracted by phenylephrine (10^?6 M) were studied. Fullerene C₆₀ derivative 1 (3 × 10^?6 M), 2 (10^?5 M) and 3 (10^?5 M) reduced the maximum amplitude of the acetylcholine-induced relaxation without significantly changing the pD₂ values obtained from the concentration - response curves. In the presence of fullerene C₆₀ derivative 1 (10^?5 M) the acetylcholine-induced relaxation was eliminated and an acetylcholine-induced contraction was observed. These results suggest that fullerene C₆₀ derivative 1 strongly inhibits endothelium (nitric oxide)-dependent acetylcholine-induced relaxation in thoracic aorta of rabbit.     

Light scattering in water solutions of fullerene-containing polymers: Part 2. Effect of the molecular weight of the carrier polymer

The effect of the molecular mass M _PVP of linear polyvinylpyrrolidone macromolecules on the structures of domains formed in water solutions of PVP/fullerene (C₆₀) complexes is investigated. For constant C₆₀ concentration in a complex, the values of M _dom, starting at M _PVP=20×10³, increase as M _PVP ^1.7 , attesting to the formation of a fluctuation network whose nodes are C₆₀ molecules. Pis’ma Zh. Tekh. Fiz. 25, 45–49 (October 12, 1999)     

Aqueous fullerene C60 solution suppresses herpes simplex virus and cytomegalovirus infections

Abstract

Fullerene C₆₀ is known as a promising therapeutic agent due to its antioxidant, anti-inflammatory and other properties, along with the lack of noticeable toxicity. In this article, we describe antiviral properties of aqueous fullerene C₆₀ dispersion (ndC₆₀) produced by biocompatible diafiltration technology and C₆₀ amino derivatives against Herpes simplex virus type 1 (HSV-1) and Human cytomegalovirus (HCMV) infections. Their activity in vitro was evaluated by a plaque reduction assay using Vero and HF cells in pre- and post-treatment modes. Therapeutic efficacy of dnC₆₀ and C₆₀ derivatives was studied in DBA mice using cutaneous model of HSV-1 infection. Data obtained indicated low cytotoxicity of all used compounds for both cell lines (CC₅₀ > 1?mg/ml). The antiviral activity of dnC₆₀ in most tests exceeded the activity of both C₆₀ amino adducts and acyclovir (ACV), and it demonstrated significant therapeutic effect against HSV-1 skin infection in mice.     

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.     

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).     

Synthesis of fullerene nanowhiskers using the liquid–liquid interfacial precipitation method and their mechanical,electrical and superconducting properties

Abstract

Fullerene nanowhiskers (FNWs) are thin crystalline fibers composed of fullerene molecules, including C₆₀, C₇₀, endohedral, or functionalized fullerenes. FNWs display n-type semiconducting behavior and are used in a diverse range of applications, including field-effect transistors, solar cells, chemical sensors, and photocatalysts. Alkali metal-doped C₆₀ (fullerene) nanowhiskers (C₆₀NWs) exhibit superconducting behavior. Potassium-doped C₆₀NWs have realized the highest superconducting volume fraction of the alkali metal-doped C₆₀ crystals and display a high critical current density (J_c) under a high magnetic field of 50 kOe. The growth control of FNWs is important for their success in practical applications. This paper reviews recent FNWs research focusing on their mechanical, electrical and superconducting properties and growth mechanisms in the liquid–liquid interfacial precipitation method.     

Synthesis of Novel Supramolecular Complexes from Fullerene C60 and Two New Cavitands

Abstract

Two new cavitands were prepared, their reactions with fullerene C₆₀ afford novel complexes, hosting one and two C₆₀ molecules. The cavitands were studied by solution NMR and solid‐state ¹³C, ²⁹Si CP‐MAS NMR. The complexes obtained were characterized by elemental analysis, ¹³C and ²⁹Si CP‐MAS NMR, UV and FTIR. In the complexes π–π, CH–π and n–π interactions were observed.     

He+ ION BOMBARDMENT OF C60 FULLERENE: AN FT-IR AND RAMAN STUDY

ABSTRACT

C₆₀ fullerene films have been bombarded with He⁺ ions at 30?keV at room temperature in vacuum. The structural changes undergone by C₆₀ have been followed by both FT-IR and Raman spectroscopy. Raman spectroscopy was the most useful tool for this scope. It has been clearly discovered that at low radiation dose C₆₀ forms oligomers but at higher radiation doses it is converted into an amorphous carbonaceous matter. The implications of these results on the possible survival of C₆₀ fullerene in the interstellar space have been discussed briefly in connection with the previous results on the effects of various types of electromagnetic radiation over C₆₀.     

First synthesis of a new fullerene oximes bis(9-[hydroxo]-1-[1′-hydroxymino-2′-oxo-2′-alkyl-ethyl])1,9-dihydro-[C60-Ih][5,6]fullerenes via reaction of C60 with ketones and NaNO2 promoted by HCl

A mixture of cis-2 and cis-3 isomers of new fullerene derivatives bis(9-[hydroxo]-1-[1′-hydroxymino-2′-oxo-2′-alkyl-ethyl])-1,9-dihydro-[C₆₀-I_h][5,6]fullerenes have been selectively synthesized with high yields at the reaction of C₆₀ fullerene with ketones Me₂CO, EtMeCO, i-PrMeCO, PhMeCO in the presence of NaNO₂ and HCl.     

New Polymeric Phase in Low‐Doped Lithium Intercalated Fullerides

Abstract

The low‐doped Li _x C₆₀ compounds (x≤6) were investigated using laboratory X‐ray and synchrotron radiation diffraction, ¹³C NMR and Raman spectroscopy. Li₄C₆₀ shows an unusual 2D polymerisation in which the C₆₀ units are connected both by [2+2] cycloaddition and by single carbon–carbon bonds, a unique feature among the known polymerised fullerene compounds. This picture is fully supported also by static NMR and Raman measurements. The charge transfer to C₆₀ in the polymeric phase was evaluated from the shift of the A_g(2) mode. The depolymerisation process was investigated as well; despite the presence of two different bonds, the polymer‐to‐monomer transition induced by thermal treatments is a single‐step phenomenon.     

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.     

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.     

Complexation of free-base and 3d transition metal(II) phthalocyanines with fullerene C60: A dispersion-corrected DFT study

We performed a systematic comparative theoretical study of noncovalent interactions of free-base H₂Pc and a series of 3d transition metal(II) phthalocyanines (where the transition metals included manganese, iron, cobalt, nickel, copper and zinc) with fullerene C₆₀, by employing a DFT technique accounting for vdW interactions (PBE GGA functional with a dispersion correction by Grimme). We observed four different types of Pc interaction with fullerene cage, depending on central metal atom. Upon complexation with C₆₀, the macrocyclic plane undergoes distortion in all cases, to a different degree. Some correlation was observed between the calculated formation energies for Pc–fullerene complexes and intermolecular separations in them, where stronger binding is generally associated with shorter M^…C_C60 and N^…C_C60 distances. Despite of considerable differences in the structure of Pc–fullerene complexes, the latter do not exhibit notable variations in the distribution of electrostatic potential, contrary to spin density plots for open-shell species. Similarly, HOMO and LUMO distribution can vary within some limits.     

High-pressure behavior of the crystal structure of the fullerene molecular complex with ferrocene C60·{Fe(C5H5)2}2

Abstract

The crystal structure of the molecular complex C₆₀·{Fe(C₅H₅)₂}₂ was studied by single crystal X-ray diffraction (XRD) analysis at pressures up to 5?GPa using the diamond anvil cell (DAC) technique. The XRD data and subsequent structural analysis clearly show that there is no pressure-induced polymerization in fullerene layers in pressure range studied. The reciprocal unit cell volume V₀/V is a smooth and monotonous function of pressure and fits well to the Murnaghan equation of state (V₀/V) ^B'=?{1?+?P·(B'/B₀)}, where V₀ is the volume at ambient pressure, B₀=8.7?GPa and B'=10.5 are the bulk modulus and its derivative, respectively. Pressure dependence of the shortest distance between the C₅H₅ ring of the ferrocene molecule and the center of the nearest fullerene molecule is linear, while the slope changes at 2.2?GPa indicating on the intermolecular interactions crossover. Other relevant parameter, the Fe-C bond lengths of ferrocene, sensitive to iron charge state, gradually increases. This peculiarity can a sign of pressure-induced partial charge transfer between the donor ferrocene and acceptor fullerene molecules.