153 resultados para C_(60)


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Ion/molecule reactions of C-60 with vinyl acetate under chemical ionization conditions have been studied here. Compared with C2H3O+ from acetone, C2H3O+ from vinyl acetate undergoes the reactions more easily, a new heterocycle between C-60 and the studied ion is formed The generation of two sigma-bonds and little angle tensile force of pentatomic ring make it more stable.

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Gas-phase ion-molecule reactions of buckminsterfullerene (C-60) with the acetyl cation CH3-C-+=O (m/z 43) and formylmethyl cation (CH2)-C-+-CH=O (m/z 43, or oxiranyl cation), generated from the self-chemical ionization of acetone and vinyl acetate, respectively, were studied in the ion source of a mass spectrometer. Adduct cations [C60C2H3O](+) (m/z 763) and protonated C-60, [C60H](+) (m/z 721), were observed as the major products. AM1 semiempirical molecular orbital calculations on the possible structures, stabilities and charge locations of the isomers of the adducts [C60C2H3O](+) were carried out at the restricted Hartree-Fock level. The results indicated that the sigma-addition product [C-60-COCH3](+) is the most stable adduct for the reaction of C-60 with CH3-C-+=O rather than that resulting from the [2+2] cycloaddition. The [2+3] cycloadduct and the sigma-adduct [C60CH2CHO](+) might be the most possible coexisting products for the reactions of C-60 with (CH2)-C-+-CH=O or oxiranyl cation. Other [C60C2H3O](+) isomers are also discussed. (C) 1997 by John Wiley & Sons, Ltd.

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C-60 films, prepared by solution casting, were studied by means of in situ probe beam deflection (PBD) combined with cyclic voltammetry (CV). PBD is a powerful technique for investigation of phenomena at the electrode/electrolyte interface in acetonitrile with quaternary ammonium and alkali metal salts as supporting electrolytes. In tetra-n-butylammonium (TBA(+)) salt solution, a stable CV can be obtained during the first two reduction/reoxidation waves. On reduction, injection of cations to maintain charge balance and dissolution of small amount of C-60(-) (TEA(+)) and/or C-60(2-) (TBA(+))(2) are detected. During the reoxidation process ejection of cations and injection of anions occur simultaneously, especially for the second reoxidation wave. In the case where TBABr is the supporting electrolyte, the accompanied behavior is more complicated than in TBABF(4), TBAClO(4), and TBAPF(6) solutions. A small pair of prewaves in CV are proposed due to oxidation/reduction of C-60 domains but not dissolution/redeposition of C-60 film. Extending the potential scan range to the third reduction wave, no apparent corresponding reoxidation wave is related to the third reduction wave, the electroactivity of the film disappears rapidly and dissolution of C-60 film is observed. In tetraethylammonium (TEA(+)) and NAClO(4) solutions, the electrochemistry of the C-60 films is unstable, and potential scans lead to dissolution of flaking of the film.

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A new method for the preparation of polyalkyl and polyarenefullerene derivatives C-60(RH)(n)(R=Bu,n=1-3; R=Ph,n=1-10) by the reaction of C-60 with organotin hydride in toluene is described. Another series of products of stannanes R(a)Sn(b)H(c) (R=Bu, a=3-8, b=1-4, c=0-3 R=Ph, a=3-11, b=1-5, c=0-4) were also obtained, which shows that C-60 can catalyze polymerization of organic-tin. These products were determined by mass and infrared spectrometry. And the possible reaction mechanisms are discussed.

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The reaction of buckministerfullerene (C-60) with tri-n-blltyltin hydride(n-Bu(3)SnH) in toluene solution has been investigated. According to mass spectrometry analysis, the products of above reaction are C-60(BuH)(n)(n = 1 similar to 3) and Bu(x)Sn(y)H(x) (x = 3 similar to 8, y = 1 similar to 4,approximate to = 0 similar to 3). The reaction maybe provide a new method for the synthesis of alkylated fullerene derivatives. Where C-60 also takes a role of a catalysis of organtic-tin polymerization. The radical reaction mechanism has been discussed.

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In this paper, we introduce a very convenient method to produce water soluble C-60 derivatives- fullerols by the reaction of C-60 with potassium in toluene solution, FT-IR, H-1 NMR and FABMS proved the multi-hydroxyl and C-60 cage structures of the products, The properties of unstability to light, heat, basicity of aqueous solution and the solubility in some common polar solvents were also described.

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采用对掺入La_2O_3的石墨棒原位活化并结合交换电极回放方法制备了产率较高的金属富勒烯,并用甲苯高温热提取的方法有效地提取出La@C_(2n),其中La@C_(74)为可溶性金属富勒烯增加了新成员.同时,首次采用解吸电子轰击质谱对提取物进行了表征,讨论了提取物的ESR谱.

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研究了交联XE-60和PEG-20M极性固定相非晶硅膜改性弹性玻璃毛细管柱,在适当的温度下,用过氧化二异丙苯(DCUP)游离基引发交联,成功地制备了XE-60和PEG-20M极性柱,它们均具有柱效高、惰性好、化学稳定性好和耐溶剂、抗腐蚀、耐高温等性能,是一种新型的极性交联柱。

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The DCI MS of C-60 with the reactions of gaseous cyclohexane and cyclohexene have been studied. Several kinds reactions of C-60 have been observed. The results show that the gasphase C-60 has very active chemical properties. The adduct ions of [C60C4H7](+) and [C60C5H7](+) may be formed by [2+4] cycloaddition where one of double bonds of C-60 acted as a dienophilic unit.

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Gas phase ion-molecular reactions of C-60 with the ion system of CS2 have been studied in the ion source of mass spectrometer. It was found for the first time that the sulfuric derivative of C-60-C60S+ was the main ions in the ion source, they did not react with C-60 to form adduct ions due to their highly saturated structures. According to the dynamic analysis, the product ion came from the reaction of C-60 with the fragment ion S+. The adduct ion may have the structure of epsulfide that is advantageous in energy.

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In chemical ionization mass spectrometry (CIMS) gas phase C-60(+) or C-60 can react with fragment ions from three chloromethane and four multichloroethane molecular ions via ion-molecule reactions. A dozen of gas-phase adduct ions of C-60 are observed, and most of them contain chlorine atoms. The results of the comparison and analysis show that the relative intensities of adductions are not directly proportional to the corresponding fragment ions in the MS of reagents,which implies that some fragment ions containing radicals are more reactive with C-60(+) or C-60. This indicates that the alkene-like C-60(+) or C-60 can act as a radical sponge in addition reactions.

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Gas phase reactions of C-60 and C-70 with the ion system of acetone under chemical ionization conditions have been studied. C-60 and C-70 can react with acetyl and oxonium ions, which come from self-chemical ionization of acetone, to form adduct ions. In addition, C-60 and C-70 can accept protons to produce protonated ions. C-70 is more active in the above reactions than C-60 because of its stronger gas-phase basicity. A sigma-bond between C-60 and an acyl carbon atom can be formed to produce stable acetylated C-60 ions. The above results may be relevant to the acetylation reactions of C-60 in the condensed phase.