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Fullerenes salts

Figure 14.1 Possible derivatizations of Qq- ( ) fullerene salts, (b) exohedral adducts, (c) open cage fullerenes, (d) quos/Tullerenes, (e) heterofullerenes, (f) endohedral fullerenes. Figure 14.1 Possible derivatizations of Qq- ( ) fullerene salts, (b) exohedral adducts, (c) open cage fullerenes, (d) quos/Tullerenes, (e) heterofullerenes, (f) endohedral fullerenes.
The endohedral fullerene salts thus formed exhibit different interstitial sites upon K intercalation and show signs of phase separation, as was the case in fullerene salts of C60 and C70. [Pg.214]

The electrochemical method is also used for the synthesis of fullerene derivatives, among them C6o fullerene salts with alkali metals crystallized at the cathode [11, 12]. No evidence on the electrochemical deposition of fullerenes on the electrodes from organic solvents is available although this method for producing fullerene coatings on metals is of indubitable practical interest. [Pg.288]

As for the ability of C60 to function as an electron donor, it would be difficult to obtain acceptor-type fullerene salts or charge transfer complexes because of the higher ionization potential 7p of 7.6 eV [10] for the molecule. In fact, the electrochemical oxidation of C60 in solutions is irreversible [11,12], in contrast to the reversible, six one-electron cathodic reduction in solutions [13,14]. [Pg.556]

One can debate whether is an organic molecule, or just a molecular allotrope of elemental carbon in fact it is the largest molecule ever synthesized by astrophysicists [31]. The critical temperatures of ET salts seem to be stuck at about 13 K, while the fullerene salts have reached 40 K, and the ceramic superconductors are way ahead, at 150 K. [Pg.337]

The alkali metals act here as donors, which make a metal of the semiconductor Ceo as acceptor, with an energy band gap of ca. 2.3 eV via half-filling of the conduction band. The system behaves similarly to the radical-anion salts which we have already treated (Sects. 9.2 and 9.3). Ceo is a good electron acceptor. It consists entirely of carbon atoms and is thus not actually an organic molecule. Superconducting Fullerene salts however have properties which are like those of the organic molecular salts. These are above all the important role played by the Jt electrons in charge transport, and the existence of relatively narrow bands with a low electron density. [Pg.362]

Proc. 2nd Inti. Conf. Optical Probes of Conjugated Polymers and Fullerenes, Salt Lake City, Utah, USA, Mol. Cryst. Liq. Cryst., 256, (1994). [Pg.456]

Kuhn s carbanion analogues, [44 ], [45 ] and [46 ], have recently been synthesized, and the precursor hydrocarbons [44]-H, [45]-H and [46J-H dissociate into the respective anions in DMSO to show deep blue colours without any added base (Kinoshita et al., 1994). A fullerene anion, Bu Qb [47 ], has also been obtained as a stable carbanion (Fagan et al., 1992) its lithium salt has been isolated in the form Li [47 ]-4MeCN or Li [47"]-3-4THF. Several stable all-hydrocarbon anions of precursor hydrocarbons with low pKa values ( 7) are listed in Table 2, along with their oxidation potentials, ox-... [Pg.183]

Dendritic polymers, fullerene, 12 252 Dendritic salt, 22 805 Dendritic siloxanes, synthesis of, 22 554 Dendrobine, 2 102... [Pg.251]

In other cases fullerene antibacterial action takes place after photoirradiation of fulleropyrrolidinium salts. It is not yet clear if the photodynamic action implies the participation of superoxide and hydroxyl radicals (type I mechanism) or singlet oxygen (type II mechanism) but the efficacy is really interesting with the death of more than 99.9% of bacterial and fungal cells and a special selectivity for microbes over mammalian cells (Tegos et al., 2005). Also a sulfobutyl fullerene derivative is able to inhibit environmental bacteria after photoirradiation and it exerts its action on E. coli even if incorporated in coated polymer (Yu et al., 2005). [Pg.10]

The work that paved the way toward enzymatic inhibition was published in the early 1990s by Wudl and coworkers (Schinazietal., 1993 Friedmanetal., 1993 Sijbesma et al., 1993) and since then studies regarding antiviral activity, mainly HIV-protease inhibition, have been carried out to find active compounds. Up to now, the most effective fullerene derivatives are the trans-2, -dimethy 1-bis-fulleropyrrolidin-ium salt (Fig. 1.4) (Marchesan et al., 2005) and the dendrofullerene reported by Hirsch (Schuster et al., 2000) both of them present an ECJ0 of 0.2pM. Also HIV reverse transcriptase can be inhibited by, -dimcthyl-bis-fulleropyrrolidinium salts (Mashino et al., 2005). The same compounds are also active against acetylcholine esterase (AChE), an enzyme that hydrolyzes a very important neurotransmitter. [Pg.10]

A comparable addition pattern with as many as five attached groups allowing further functionalization is represented in pentaaryl-fullerenes like 25-27 (Troshina et al., 2007 Zhong et al., 2006). Whereas the free acids are virtually insoluble in pure water, the use of basic water in the case of 25 (Zhong et al., 2006) and conversion of the polyacids 26 and 27 to the corresponding potassium salts leads to stable aqueous solutions with high fullerene concentrations. [Pg.62]

Li H, Hao J (2007) Phase behavior of salt-free catanionic surfactant aqueous solutions with fullerene C60 solubilized. J Phys Chem B. Ill 7719-7724. [Pg.154]

Depending on the synthesis technique, CNTs may contain various impurities, including fullerenes and irregular carbon structures on the surface (i.e. amorphous) as well as residual salts and metal catalysts often encapsulated within a carbon shell. [Pg.16]

Coulter CV, Smith RAJ, Murphy MP. Synthesis, characterization, and biological properties of a fullerene triphenylphosphonium salt. Fullerene Sci Technol 2001 9 339-350. [Pg.337]

It was found that the intercalation of Cgo fullerene by an alkali metal in stoichiometric ratio (1 1) gives rise to the formation of anion-radical salts, namely, KC50, RbCgg, and CsCgo (Bommeli et al. 1995, Btouet et al. 1996). On slow cooling of the intercalation products, [2 + 2] cycloaddition of the fullerene species that is neighboring a crystal lattice occurs. Linear chain fullerenic polymers are formed. These polymers are stable in air, insoluble in THF, and possess metallic conductivity. They depolymerize only on heating above 320°C. [Pg.359]

Interestingly, if the C50 fullerene doped by alkali metals is rapidly cooled down to the liquid nitrogen temperature, polymerization does not occur. Only monomeric anion-radical salts are obtained. Warming up these monomers to 80-160 K results in dimerization polymerization does not take place. The dimer (KCgo)2 is dielectric (Pekker et al. 1995). It has been shown that the tris(anion)-radical Cgo can polymerize too. Particularly, Na2CsCgo forms a polymer that maintains superconducting properties (Mizuki et al. 1994). [Pg.359]

The first chemical transformations carried out with Cjq were reductions. After the pronounced electrophilicity of the fullerenes was recognized, electron transfer reactions with electropositive metals, organometallic compounds, strong organic donor molecules as well as electrochemical and photochemical reductions have been used to prepare fulleride salts respectively fulleride anions. Functionalized fulleride anions and salts have been mostly prepared by reactions with carbanions or by removing the proton from hydrofullerenes. Some of these systems, either functionalized or derived from pristine Cjq, exhibit extraordinary solid-state properties such as superconductivity and molecular ferromagnetism. Fullerides are promising candidates for nonlinear optical materials and may be used for enhanced photoluminescence material. [Pg.49]

Reductive transformations of fullerenes have not only been carried out to prepare fulleride salts. The fulleride ions themselves are reactive species and easily undergo subsequent reactions, for example, with electrophiles. Therefore, the anions provide a valuable synthetic potential for fullerene chemistry. [Pg.49]


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See also in sourсe #XX -- [ Pg.195 ]




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Fullerene alkali metal salt

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