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.     

Synthesis,Spectral Investigations,and Thermal Stability of [60]Fullerene Complexes with TMTSF: 2(C60) · 2(TMTSF) · (C6H6), C60 · TMTSF · 2(CS2), and 2(C60) · 2(TMTSF) · (C6H5Cl)

Abstract

Molecular complexes of [60]fullerene with tetramethyltetraselenafulvalene (TMTSF): C₆₀ · (TMTSF) · 2(CS₂) (1), 2(C₆₀) · (2(TMTSF) · (C₆H₆) (2), and 2(C₆₀) · (2(TMTSF) · (C₆H₅Cl) (3) have been synthesized and their thermal stability and IR spectra vs. light polarization and temperature have been performed.     

Intermolecular vibrations in pure and doped C60: An inelastic neutron scattering study

We discuss results of neutron time-of-flight spectroscopy on powder samples of C₆₀, K₃C₆₀, and Rb₃C₆₀. Model calculations show that the excitation spectra can be well understood within the framework of lattice dynamics of a molecular crystal. Indications for a weak anomalous temperature dependence of low-energy phonons are observed for K₃C₆₀.     

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.     

Inelastic neutron scattering results on pure and doped fullerenes

Via inelastic neutron scattering (INS) generalized phonon densities of states are obtained for C₆₀ and superconducting A₃C₆₀ (A=K, Rb). Changes in the intramolecular modes agree with and augment recent Raman (RA), infrared (IR), and INS measurements, i.e., in the vicinity of the high-frequency modes of C₆₀ [H _g (8),A _g (2),H _g (7)] we find a pronounced shift of about 10 meV toward smaller energy transfers upon intercalating with potassium. Separated from these vibrations by a gap are the intermolecular spectra which for the doped samples display well-defined optic modes at 11 and 14 meV due to the vibrations of Rb and K ions. Indications of a weak anomalous temperature dependence of low-energy phonons ( <3 meV) nearT _c are observed for K₃C₆₀.     

Initial Stage of Condensation of C60 Films on Semiconducting Substrates of Different Chemical Nature

Abstract

Conditions of growing C₆₀ films deposited from the gas‐dynamic vapor flow on different substrates [layered GaSe substrates with inactive surface, A^IIB^VI (CdS, CdSe) crystals, silicon substrates of (1 1 1) orientations, porous Si substrate] are studied. The condensate structure and growth mechanisms for different substrate are compared. It is shown that the high‐quality epitaxial films of the fullerenes can be prepared by using GaSe layered crystals as substrates.     

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.     

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.     

ON THE ABSORPTION SPECTRUM OF C60 IN THE VISIBLE SPECTRAL REGION

ABSTRACT

A complete (720–380?nm), strong visible absorption spectrum (OD₅₉₈=1.6) for C₆₀ in a decalin/methylcyclohexane inert matrix at 77?K is reported for the first time. The structure of this spectrum allows one to construct an acceptable approximation to the gas-phase spectrum for this substance at a low temperature. The 0–0 component of the S₀→S₁ transition in the gas phase at a low temperature was estimated to be at about 635?nm.     

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.     

In the Chase of Mixed Halofullerenes: Remarkable Transformation of C60Cl n (n = 6, 8, 12, 14) to C60Br24

Abstract

Chlorofullerenes C₆₀Cl _n (n = 6, 8, 12, 14) were found to react with bromine yielding C₆₀Br₂₄ as a single product. No intermediates containing both bromine and chlorine atoms attached to the cage were detected in the course of transformation.     

Structural and morphological properties of Fe2O3/TiO2 nanocrystals in silica matrix

We report on structural, morphological and ordering properties of Fe₂O₃/TiO₂ nanoparticles embedded in SiO₂-based multilayers. We investigated the structure of these systems by X-ray diffraction and grazing incidence small angle X-ray scattering after post-growth annealing. We found that the presence of TiO₂ promotes the growth and crystallization of the nanocrystals of Fe₂O₃. In multilayers containing both Fe₂O₃ and TiO₂, crystalline nanoparticles create partially ordered three-dimensional arrays.     

Low-frequency dielectric permittivity of C60

Complex dielectric response measurements have been made on a C₆₀/C₇₀ mixture pellet. The frequency and temperature ranges cover from 20 Hz to 1 MHz and from 30 to 300 K. Results show that the real part of the dielectric constant is 5 with a weak thermally activated polarization contribution. This thermal polarization is believed to be related to reorientation of C₆₀ molecules recently observed by many techniques such as NMR, sound velocity, thermal conductivity, and others. Our data yield relaxation frequencies for reorientation, indicating that the presence of an additional electric dipole moment of the orientationally ordered C₆₀ molecules at low temperature contributes 0.2–0.3 to the static dielectric constant.We wish to thank William Jenks and Chris Rey for their assistance and advice in performing the measurements. We appreciate helpful discussions with E. Manousakis and J. Cioslowski. One of us (G.C.) acknowledges the support by the National Science Council of R.O.C. under grant No. NSC82-0208-M-194-030.     

Fullerane,the Hydrogenated C60 Fullerene: Properties and Astrochemical Considerations

Abstract

Hydrogenated C₆₀ fullerene, C₆₀H₃₆ was prepared in different solvents using Zn/HCl as reducing agents. The structure of C₆₀H₃₆ was confirmed both by electronic and FT‐IR spectroscopy and the purity of the reaction product was checked by HPLC analysis. It has been confirmed that C₆₀H₃₆ is not stable in air, especially in presence of light which enhances the oxidation. The oxidation of C₆₀H₃₆ was studied by FT‐IR spectroscopy and by differential scanning calorimetry (DSC) in air; the formation of hydroxyl groups on the fullerene cage and ketonic groups (involving cage breakdown) have been detected. Furthermore, the action of O₃ on C₆₀H₃₆ was investigated and it has been found that O₃ exerts practically the same effect of air but causing an enhanced cage breakdown. The thermal stability of C₆₀H₃₆ was checked by a thermogravimetric analysis (TGA) coupled with a differential thermal analysis (DTA) under N₂ flow. The vaporization of C₆₀H₃₆ occurs at very high temperature: the DTA trace has shown an endothermic peak at 540°C (at a heating rate of 20°C/min). C₆₀H₃₆ shows an electronic absorption spectrum with a maximum at about 217 nm and it is able to match both in position and in half width the peak at 217.5 nm observed in the spectrum of the interstellar extinction of light which was attributed to hydrogenated, radiation processed and thermally annealed carbon dust. Similarly, the absorption spectrum of C₆₀H₃₆ is able to match several infrared emission bands (called UIBs) detected from certain astrophysical objects like the protoplanetary nebulae (PPNe). It is proposed that hydrogenated fullerenes can be used as model compounds in the laboratory simulation studies of interstellar carbon dust.     

Synthesis of bipyramidal gold nanoparticle-[C60]fullerene nanowhisker composites and catalytic reduction of 4-nitrophenol

The seed solution was prepared by dissolving hydrogen tetrachloroaurate(III) trihydrate (HAuCl₄·3H₂O), trisodium citrate dihydrate (C₆H₅Na₃O₇·2H₂O), and sodium borohydride (NaBH₄) in distilled water. The resulting reddish-purple seed solution was stirred for 3 h at room temperature. The growth solution was prepared by mixing hydrogen tetrachloroaurate(III) trihydrate (HAuCl₄·3H₂O), cetyltrimethylammonium bromide (CTAB, (C₁₆H₃₃)N(CH₃)₃Br), silver nitrate (AgNO₃), hydrochloric acid (HCl), and ascorbic acid (C₆H₈O₆) in distilled water. Subsequently, 100 μL of this seed solution was transferred into 10 mL of the growth solution. The mixed solution was maintained at 30 °C for 3 h to obtain a solution of bipyramidal gold nanoparticles. The bipyramidal gold nanoparticle-[C₆₀] fullerene nanowhisker composites were synthesized by applying the liquid-liquid interfacial precipitation (LLIP) method to a saturated solution of C₆₀ in toluene, the solution of bipyramidal gold nanoparticles, and isopropyl alcohol. The prepared bipyramidal gold nanoparticle-[C₆₀] fullerene nanowhisker composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The catalytic activity of these composites was confirmed in the reduction of 4-nitrophenol by UV-Vis spectroscopy.     

C60H18, C60H36 and C70H36 Fullerene Hydrides: Study by Methods of IR,NMR, XPS,EELS and Magnetochemistry

Abstract

Fullerene hydrides of C₆₀H₁₈, C₆₀H₃₆ and C₇₀H₃₆ are studied by using IR, ¹H and ¹³C NMR, X-ray photoelectron and electron energy loss spectroscopies, and magnetochemistry. The comparison of IR and solid state ¹H and ¹³C NMR data for C₆₀H₃₆ with the theoretical ones allows the suggestion that fullerene hydride has a T symmetric structure and contains 4 isolated benzenoid rings located at tetrahedral positions on the surface of a closed skeleton of the molecule. The EELS revealed that the transition from fullerene to the hydride is accompanied by the decrease of the density of valence electrons. Magnetization measurements showed C₆₀H₃₆ to be a ferromagnet. The hydrogenated fullerenes were prepared by transfer hydrogenation procedures involving 9,10-dihydroanthracene. The compositions of the hydrides are determined by field desorption mass-spectral analysis.