Effect of Substituents on the Redox Potentials of C60 Derivatives

The electrochemical properties of four C₆₀ derivatives (compounds 1∼4) were investigated with cyclic voltammetry (CV), and compared with that of C₆₀. The reduction potentials of compound 1∼3 shifted to more negative positions than C₆₀, and their oxidation peaks appeared at the lower potentials. Significantly, the reduction potentials of compound 4 shifted to more positive positions than C₆₀, which is advantageous to form charge-transfer complexes with more donors. So the reduction properties in different solvents and in situ NIR absorption spectra of compound 4 were studied in more details. In addition, the AM1 molecular orbital calculation was performed on C₆₀ and compound 1∼4 for the explanation of the potential shifts. The reduction potentials of these compounds exhibited good linear relationships with the calculation LUMO or LUMO+1 energy levels.     

Two Methods to Synthesize C60Nitroxide Derivatives

C₆₀derivatives covalently linked with the nitroxide radical of 2,2,6,6-tetramethylpiperidine-1-oxyl have been synthesized by two methods: C₆₀ reacts with 4-amino-4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TOAC) and aldehyde; And another new route: C₆₀ reacts with 4-oxo-2,2,6,6-tetramethyl-piperidinyloxy(4-oxo-TEMPO) and amino acid.     

Penetration of Fullerene C60 Derivatives Through Biological Membranes

Penetration of fullerene C₆₀ in hydrated molecular-colloidal form (FMC) and various C₆₀ water-soluble derivatives (FDs) through membranes of human erythrocytes, platelets and symbiosomes (subcellular organelles of plant origin) were tested. The FDs bearing amino acids induced pronounced depolarization of symbiosome membranes energized with Mg-ATP. In erythrocytes and platelets incubated in K⁺-free medium in the presence of FCCP, FDs with malonic acid pendants promoted acidification of the intracellular medium thereby simulating an effect of the K⁺ ionophore valinomycin. Dissipation of ΔpH artificially induced on the plasma membrane of these cells was observed in the presence of C₆₀-γ-aminobutiric acid which, in addition, strongly stimulated Mg-ATP-dependent generation of membrane potential on symbiosome membranes. C₆₀-Arg was shown to dissipate K⁺-diffusion potential on erythrocyte membranes induced by valinomycin. Fullerene C₆₀ used in hydrated molecular-colloidal form (FMC) also entered symbiosomes and platelets as evidenced by the quenching of the fluorescence of the Ca²⁺ indicator chlorotetracycline localized in the interior of these cells. These findings provide evidence for ease of permeation of these fullerene-based compounds through biological membranes from different type cells.     

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.     

Preparation of Two Novel C60 and C70 Fullerene Pyrrolidine Derivatives

C₆₀ reacted with paraformaldehyde and DL-valine in dry toluene under nitrogen to give a monoadduct. Under the similar conditions,C₇₀ gave a bisadduct. Both products were characterized by FT-IR,UV-Vis,EI-MS and NMR.The studies of the cyclic voltammetry showed that the abilities of donating electron of the products were increased compared to C₆₀ and C₇₀ respectively.     

Preparation of Two Novel C60 and C70 Fullerene Pyrrolidine Derivatives

Abstract

C₆₀ reacted with paraformaldehyde and DL-valine in dry toluene under nitrogen to give a monoadduct. Under the similar conditions,C₇₀ gave a bisadduct. Both products were characterized by FT-IR,UV-Vis,EI-MS and NMR.The studies of the cyclic voltammetry showed that the abilities of donating electron of the products were increased compared to C₆₀ and C₇₀ respectively.     

Structures, Stabilities and Strain in C60 and C70 Derivatives

The stabilities of a number of small adducts as well as larger hydrides of C₆₀ and C₇₀ are reported using semiempirical MO methods. The data are shown to be consistent with the nature of bond alternation in the parent fullerenes and strain effects in the cage systems.     

Evaluation of Effects of C60 Fullerene and Its Derivatives on Selected Microorganisms

The contribution deals with preparation of C50 fullerene derivatives （oxo derivative, bromo derivative, hydrolyzed bromoderivative, bromo-chloro derivative）, their identification and pilot testing of their biological effects on unicellular organisms. The contribution describes effects of C60 fullerene derivatives, both on prokaryotic organisms （bacteria, cyanobacteria） and eukaryotic organisms （algae） and assesses their potential use as biocides.     

On the Effect of the Rotational State of C60 Molecules on Electronic Transport in the C60 Fullerite

Abstract

A phenomenological scenario is suggested in an attempt to explain controversies in the published data concerning the effect of orientational order on electronic transport in solid C₆₀. The main factor of crucial importance is the dependence of the charge hop probability on the mutual orientation of the molecules. Magnitude and the sign of the conductivity response to the changes in the rotational state of C₆₀ across the orientational phase transition are the results of the interplay between the changes in dynamic and static disorder that accompany the transition and may vary in the samples with different structure perfection.     

Highly Water Soluble C60 Derivatives: A New Synthesis

Unprecedented protocol, consisting in reduction of Buckminsterfullerene with Na/K alloy and successive stirring in presence of O₂, affords polyhydroxylated fullerenols which are highly water soluble, from strongly basic to medium acidic conditions. The products have been characterized by means of cross polarization magic angle spinning (CPMAS) NMR, ¹H-NMR, electron, FT-IR, Raman and mass spectroscopies. Possible paths of reaction and the role of molecular oxygen in fullerene cage-oxidation are discussed.     

Highly Water Soluble C60 Derivatives: A New Synthesis

Abstract

Unprecedented protocol, consisting in reduction of Buckminsterfullerene with Na/K alloy and successive stirring in presence of O₂, affords polyhydroxylated fullerenols which are highly water soluble, from strongly basic to medium acidic conditions. The products have been characterized by means of cross polarization magic angle spinning (CPMAS) NMR, ¹H‐NMR, electron, FT‐IR, Raman and mass spectroscopies. Possible paths of reaction and the role of molecular oxygen in fullerene cage‐oxidation are discussed.     

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.     

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

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.     

Effect of C60 on solid supported lipid bilayers

We show that water-soluble fullerenes accumulate on the surface of zwitterionic and cationic supported bilayers to different extents. We propose on the basis of bilayer thicknesses, phase-transition temperatures, and fullerene movement that the water-soluble fullerenes do not penetrate into the hydrocarbon tails of supported bilayers. These findings are important to toxicity issues concerning fullerene materials and the development of decorated lipid bilayers for future drug delivery or sensor application.     

New Developments on the Photochlorination of C60 and C70 Fullerene and Preparation of Fullerene Derivatives: Polyfluorofullerenes and Polyfullerols.

Abstract

Improved methods for photochlorination of C₆₀ and C₇₀ are described. The photoproducts fit respectively the average formulae C₆₀ Cl₄₀ and C₇₀ Cl₄₇. It is also shown that these photoproducts can be easily fluorinated by means of KF to give fluorofullerenes.

Polyhydroxyfullerene (fullerol) can be easily produced by the action of a methanolic solution of alkali over C₆₀ Cl₄₀.     

New Developments on the Photochlorination of C60 and C70 Fullerene and Preparation of Fullerene Derivatives: Polyfluorofullerenes and Polyfullerols.

Improved methods for photochlorination of C₆₀ and C₇₀ are described. The photoproducts fit respectively the average formulae C₆₀ Cl₄₀ and C₇₀ Cl₄₇. It is also shown that these photoproducts can be easily fluorinated by means of KF to give fluorofullerenes.

Polyhydroxyfullerene (fullerol) can be easily produced by the action of a methanolic solution of alkali over C₆₀ Cl₄₀.     

取代基位置对羟基[60]富勒烯吡咯烷衍生物空间结构的影响

为进一步认识羟基[60]富勒烯吡咯烷衍生物的空间结构,借助密度泛函考察了羟基取代位置和取代基数量对羟基[60]富勒烯吡咯烷衍生物空间结构的影响。结果显示,5种羟基[60]富勒烯吡咯烷衍生物的LUMO均集中在[60]富勒烯上,羟基出现在邻位时其衍生物的LUMO和HOMO能量差ΔE最小,而羟基在间位时其ΔE最大。吡咯烷键长和键角并不随羟基数量的增加而呈规律性的变化,但羟基取代基位置对吡咯烷键长和键角的影响由大到小的顺序是:对位、间位、邻位。     

High-Pressure Diels-Alder Reaction of Buckminsterfullerene (C60) with Several Disubstituted Tropone Derivatives

The high-pressure Diels-Alder reaction of C₆₀ with disubstituted tropone derivatives gave the stable [4+2] cycloadducts in good yields. The site selectivity was controlled by the steric environment.     

Intramolecular Negative-Effect in the Alkali-Metal-Doped C60; A2C60 and A4C60

It is investigated theoretically why alkali-metal-doped C₆₀, A_xC₆₀, is a nonmagnetic semiconductor for x=2 and 4. We find that this is the consequence of the intramolecular negative- U effect due to the strong electron-phonon interaction and the weak Hund coupling between conduction electrons.     

Organosilicon Derivatives of Buckminsterfullerene (C60): First Preparation of A Fullerene Silirane

C₆₀ reacts with photochemically generated bis(2,6-diisopropylphenyl)silylene (1) to give adducts, 2-4, as the isolable products. Spectroscopic analysis and theoretical investigation strongly support the silirane structure 2a, and not the isomeric 1,6-silamethano[10]annulene 2b.