Noncovalent interactions of amino acids with fullerene C60: A dispersion-corrected DFT study

By using the general gradient approximation functional PBE with Grimme's empirical dispersion correction in conjunction with the double numerical basis set DNP, we studied the noncovalent interaction of twenty proteinogenic l-amino acids (AAs) with fullerene C₆₀. The calculations were performed both under vacuum conditions and in aqueous medium. We analyzed the calculated geometries and binding energies for AA+C₆₀ complexes, the shape of HOMO and LUMO orbitals and the corresponding gap energies. Generally, we found a poor correlation between binding energies calculated for AA+C₆₀ complexes in aqueous medium and hydrophobicity scales proposed by other other authors. Despite of C₆₀ cage can be envisioned as a typical hydrophobic surface, the AA adsorption apparently takes place according to a mechanism different from classical hydrophobic interactions, or due to a combination of several types of interactions with a limited contribution of hydrophobic mechanism.     

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.     

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.     

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.     

Fullerenes C60 and C70: a model for solubility by applying the correlation intensity index

Abstract

Fullerenes are materials which have many applications as in the field of chemical technology as well as in the field of biochemistry and medicine. Solubility of fullerenes in different solvents has been studied many times in the field of computational chemistry. However, analysis of different approaches which able help to solve the task of prediction of solubility fullerenes remains attractive and very important direction of scientific activity. The correlation intensity index (CII) is a new criterion of the predictive potential of models. The applying of CII together with Index of Ideality Correlation (IIC) in modeling of fullerenes solubility in various solvents by the Monte Carlo method using the CORAL software (http://www.insilico.eu/coral) indicates that applying of the CII improves the predictive potential of these models. These models can be applied for systematization of ecological, biochemical, and medicinal knowledge related to applying of fullerenes. This systematization gradually becomes a factor of key importance, since the applying of the fullerenes expanded day by day.     

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.     

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.     

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.     

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.     

Reactions of microcrystalline fullerene C60 with amino and aza macrocyclic ligands under solvent-free conditions

We evaluated the reactivity under solvent-free conditions of 2-aminomethyl-15-crown-5 (AM15C5), 2-aminomethyl-18-crown-6 (AM18C6), 1,4,8,12-tetraazacyclopentadecane (TACPD) and rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (tet b) with microcrystalline fullerene C₆₀. The reactions of nucleophilic addition were carried out at temperatures of about 160°C for 5 h in the case of crown ethers and TACPD, and at 180–190°C for 24 h in the case of tet b. Characterization of the products obtained was performed by using Fourier-transform infrared (FTIR) and Raman spectroscopy, laser desorption/ionization time-of-flight (LDI-TOF) mass spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). To provide an additional insight into the reactivity of macrocyclic compounds with C₆₀ molecules, we employed theoretical calculations in the frame of density functional theory (DFT). According to the results of SEM imaging, macrocyclic reagents are generally unable to deeply penetrate into the bulk of fullerene microcrystals (with a possible exception of TACPD). According to TGA measurements, the reaction efficiency is very low for tet b, whereas the average content of organic fraction in C₆₀-AM15C5 and C₆₀-AM18C6 reaches about 29%, and in C₆₀-TACPD, almost 40%. According to LDI-TOF mass spectral analysis, the products of TACPD, tet b and AM15C5 reactions with fullerene have oligomeric or polymeric structure. By using DFT theoretical calculations, the latter observation was explained by enhanced reactivity of secondary amino groups toward nucleophilic addition onto fullerene cage.     

Structure and Thermophysical Properties of Fullerene C60 Aqueous Solutions

The structure and thermophysical properties of fullerene C₆₀aqueous solutions were investigated both experimentally and theoretically. The aggregation kinetics results indicated that the structure of fullerene C₆₀aggregates in water could be described as a fractal system. The IR and electronic absorption spectra obtained confirm the presence of the crystalline phase in aqueous solution. The numerical values of thermodynamic coefficients _P, _T, _S,c _P, andc _V, and sound velocity were determined from the measured (P–V–T) data. The vibrational spectrum of the crystalline structure (T_hsymmetry group) formed from the hydrated single fullerene C₆₀molecules in aqueous solutions was calculated using the molecular dynamics approach.     

Degradation of fullerene C60 by human myeloperoxidase and some reaction products

Abstract

The biodegradation of the fullerene molecule C₆₀ under the action of the human myeloperoxidase enzyme accompanied by a complete loss of the topology of the fullerene core. Analysis of this reaction mixture using UV and FTIR spectroscopy, chromatographic and mass spectrometry methods showed that the degradation proceeds without the formation of significant amounts of hydroxylated compounds. Among other intermediate compounds aromatic compounds were detected.     

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.     

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.     

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.     

Bromination of [60]Fullerene. II. Crystal and Molecular Structure of [60]Fullerene Bromides,C60Br6, C60Br8, and C60Br24

Abstract

The crystal and molecular structures of the bromofullerene solvates C₆₀Br₆·0.5C₆H₅Cl·0.5Br₂, C₆₀Br₈·1.5(o‐C₆H₄Cl₂), C₆₀Br₈·Br₂, C₆₀Br₈·0.5C₆H₅Br·0.5Br₂, and C₆₀Br₂₄·2Br₂ have been determined by single crystal X‐ray diffraction. The molecular species C₆₀Br₆, C₆₀Br₈, and C₆₀Br₂₄ which have idealized C _s , C _2v  , and T _h symmetries, respectively, have several different types of C?Br and C?C bonds. A comparison between different solvates of the same bromofullerenes revealed a larger stability of the packing modes for the C₆₀Br₆ and C₆₀Br₂₄ solvates, whereas the C₆₀Br₈ solvates showed different packing motifs dependent on the nature and amount of the solvent molecules.     

Infrared Spectra and Structure of C60 Heterocyclic Derivatives

Abstract

Infrared spectra of a number of C₆₀ cycloaddition products, namely, fullerenopyrroline and fullerenopyrazolines with the substituents in the heterocyclic fragments have been studied experimentally and employing DFT calculations. Complete vibrational assignment is proposed.     

Catalytic activity of hybrid platinum nanoparticle-[C60]fullerene nanowhisker composites for 4-nitrophenol reduction

Abstract

Composites comprising platinum nanoparticles loaded on [C₆₀]fullerene nanowhiskers were prepared by a liquid-liquid interfacial precipitation method. The synthesized platinum nanoparticle-[C₆₀]fullerene nanowhisker composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The catalytic activity of the platinum nanoparticle-[C₆₀]fullerene nanowhisker composites was confirmed for the reduction of 4-nitrophenol by UV–vis spectroscopy. The reduction of 4-nitrophenol catalyzed by the platinum nanoparticle-[C₆₀]fullerene nanowhisker composites followed the pseudo-first-order reaction rate law.     

Photo‐Induced Polymerization and Stress Effects in Fullerite C60

Abstract

Modifications of the structure and hardness of fullerite C₆₀ crystals under stresses generated during photo‐induced polymerization are investigated.     

Fullerene C60 Complexed with Poly(N-Vinyl-pyrrolidone) (C60/PVP) Prevents the Disturbance of Long-Term Memory Consolidation Induced by Cycloheximide

Abstract

It is shown that fullerene C₆₀/water‐soluble complex with PVP molecular mass of 10,000 injected in the dorsal hippocampus completely prevents the development of amnesia caused by cycloheximide, the inhibitor of protein synthesis. With the increased PVP molecular mass up to 25,000 the complex does not produce protective effect disturbance of learning.