ISOLATION AND CHARACTERISATION OF C60(CF3)2

ABSTRACT

From the products of reactions of [60]fullerene with either K₂PtF₆ at 470?°C or AgF at 520?°C, we have isolated C₆₀(CF₃)₂, the simplest trifluoromethylfullerene, which gives a single ¹⁹F NMR line at ?69.5?ppm. The HPLC retention time is less than that of C₆₀F₂ confirming the trend observed for other fluoro- vs. trifluoromethylfullerenes namely that the latter elute more rapidly. Other trifluoromethyl- containing species, C₆₀(CF₃)₄O, C₆₀F₅CF₃, C₆₀(CF₃)₄H₂, C₆₀(CF₃)₆H₂, and C₆₀(CF₃H)₃ were detected in the product mixture.     

掺杂C60的SiO2-PDMS有机-无机复合材料的光学性质

用溶胶-凝胶法制备了含有C60的二氧化硅-聚二甲基硅氧烷复合凝胶材料,研究了材料的制备机理及结构性质,及其在低温条件下的变温发光光谱,给出了发光强度与温度的变化关系曲线.拟合实验数据得到了C60/SiO2-PDMS热激活能为450cm-1.     

GROUP TRANSFER AND DIMERIZATION PROCESSES OF C60(CN)2 UNDER ATMOSPHERIC PRESSURE IONIZATION CONDITIONS

Neutral and anionic C₆₀(CN)₂ were investigated with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) mass spectrometry. It was observed that its anions underwent cyano- group and oxygen transfer, and dimerization processes in ESI conditions to form C₆₀(CN)₃H^-, C₆₀(CN)₂(OH₂)^-, [C₆₀(CN)₃H]^-₂, [C₆₀(CN)₂(OH₂)]^-₂ and [(C₆₀)₂(CN)₂(OH)]^-. Meanwhile, neutral C₆₀(CN)₂, for which no signal was observed in ESIMS, showed a base peak corresponding to C₆₀(CN)₂Cl^- in APCIMS spectra with CHCl₃ used as solvent, while only a molecular ion peak corresponding to C₆₀(CN)^-₂ was observed for the toluene solution of neutral C₆₀(CN)₂ in the same conditions. Possible mechanisms for group transfer and dimerization were proposed based on these observations.     

纳米C60/C70-丙烯酸(酯) 共聚物的合成及性能

将纳米C60／C70与丙烯酸(酯)单体在引发剂作用下共聚,合成得到C60／C70-丙烯酸(酯)共聚物。对该共聚物的结构进行了红外光谱和荧光光谱分析,探讨了有富勒烯参与的聚合反应机理和共聚物结构。将该共聚物用有机胺中和成盐,使其水性化,制得水溶性纳米C60／C70-丙烯酸(酯)高分子成膜材料,对其成膜性能进行了分析测试。发现C60／C70对丙烯酸(酯)聚合物具有独特的成膜改性功能。     

掺杂TiO2对C4A3(-S)形成及水化性能的影响

研究了掺杂TiO2对C4A3(S)矿物的形成及水化性能的影响在1300℃保温1 h,TiO2稳定过渡产物CA的作用使C4A3(S)的形成速度降低;在1300℃保温3 h,适量的TiO2增加C4A3(S)的形成量;TiO2的含量过高,使C4A3(S)的形成量减少并出现CT(CaTiO3).掺杂TiO2使C4A3(S)以四方晶系的结构存在.掺杂提高了C4A3(S)的水化反应活性,其原因是晶体结构的畸变.     

EXPERIMENTAL CHARACTERISATION OF DYNAMIC TENSILE AND FRACTURE TOUGHNESS PROPERTIES

Abstract— —An experimental procedure for obtaining material tensile and fracture toughness properties at rates applicable to shock loading is reported. A variant of the key curve approach to determine dynamic J -R curves is described and results are presented for a nickel aluminium bronze alloy for actuator loading rates in the range 0.75–7500 mm/s.     

Thermodynamic properties of seven gaseous halogenated hydrocarbons from acoustic measurements: CHClFCF3, CHF2 CF3, CF3 CH3, CHF2CH3, CF3CHFCHF2, CF3CH2CF3, and CHF2CF2CH2F

Measurements of the speed of sound in seven halogenated hydrocarbons are presented. The compounds in this study are 1-chloro-1,2,2,2-tetrafluoroethane (CHClFCF₃ or HCFC-124), pentafluoroethane (CHF₂ CF₃ or HFC-125), 1,1,1-trifluoroethane (CF₃CH₃ or HFC-143a), 1,1-difluoroethane (CHF₂CH₃ or HFC-152a), 1,1,1,2,3,3-hexafluoropropane (CF₃CHFCHF₂ or HFC-236ea), 1,1,1,3,3,3-hexafluoropropane (CF₃CH₂CF₃ or HFC-236fa), and 1,1,2,2,3-pentafluoropropane (CHF₂CF₂CH₂F or HFC-245ca). The measurements were performed with a cylindrical resonator at temperatures between 240 and 400 K and at pressures up to 1.0 MPa. Ideal-gas heat capacities and acoustic virial coefficients were directly deduced from the data. The ideal-gas heat capacity of HFC-125 from this work differs from spectroscopic calculations by less than 0.2% over the measurement range. The coefficients for virial equations of state were obtained from the acoustic data and hard-core square-well intermolecular potentials. Gas densities that were calculated from the virial equations of state for HCFC-124 and HFC-125 differ from independent density measurements by at most 0.15%, for the ranges of temperature and pressure over which both acoustic and Burnett data exist. The uncertainties in the derived properties for the other five compounds are comparable to those for HCFC-124 and HFC-125.     

Normal-incidence reflectance of crystalline K(6)C(60), Rb(6)C(60), and Cs(6)C(60)

The structure factors and normal-incidence reflectances of the alkali-metal-doped fulleride crystals M(6)C(60) (where M = K, Rb, or Cs) were calculated, and the peak reflectances are in the 2-20% range for incident wavelengths of 9-17 ?, which indicates that C(60) may be a promising transmissive (spacer) material for normal-incidence mirrors that have relatively high normal-incidence reflectance in the x-ray region.     

Modelling of C(2) addition route to the formation of C(60)

To understand the phenomenon of fullerene growth during its synthesis, an attempt is made to model a minimum energy growth route using a semi-empirical quantum mechanics code. C(2) addition leading to C(60) was modelled and three main routes, i.e.?cyclic ring growth, pentagon and fullerene road, were studied. The growth starts with linear chains and, at n = 10, ring structures begins to dominate. The rings continue to grow and, at some point n>30, they transform into close-cage fullerenes and the growth is shown to progress by the fullerene road until C(60) is formed. The computer simulations predict a transition from a C(38) ring to fullerene. Other growth mechanisms could also occur in the energetic environment commonly encountered in fullerene synthesis, but our purpose was to identify a minimal energy route which is the most probable structure. Our results also indicate that, at n = 20, the corannulene structure is energetically more stable than the corresponding fullerene and graphene sheet, however a ring structure has lower energy among all the structures up to n≤40. Additionally, we have also proved that the fullerene road is energetically more favoured than the pentagon road. The overall growth leading to cage closure for n = 60 may not occur by a single route but by a combination of more than one route.     

CHROMATOGRAPHIC SEPARATION OF N@C60/C60 AND N@C70/C70 MIXTURES

Since endohedral fullerenes exhibit unique features there is growing demand for their production and purification in high quality and quantity. This work shows how the chromatographic enrichment process can be optimized, for the separation of N@C₆₀ and N@C₇₀ from their respective empty parent compounds.     

TERNARY SYSTEM OF C60 AND C70 WITH 1,2-DIMETHYLBENZENE

Differential scanning calorimetry, X-ray, and solubility measurements were used to study phase equilibria in the ternary system C₆₀-C₇₀-1,2-dimethylbenzene up to the boiling point of the solvent. Formation of the two ternary phases was confirmed. Partial solubilities of C₆₀ and C₇₀ were measured and calculated.     

Experimental study ofPVT properties of HFC-125 (CHF2CF3)

Pressure-volume-temperature (PVT) properties and vapor pressures of HFC125 (pentafuoroethane; CHF₂CF₃) have been experimentally obtained. Vapor pressures of HFC-125 have been measured in the range of temperatures from 223 to 338 K and pressures up to 3.54 M Pa with uncertainties of 5 mK and 2.5 kPa, respectively. The vapor pressure equation for this substance was correlated based on the present data. PVT properties of HFC-125 have been determined with a constant-volume apparatus in the range of temperatures from 280 to 473 K, pressures up to 17 M Pa, and densities up to 1145 kg · m^–3 with uncertainties of 5 mK, 2.5 kPa, and 0.01%, respectively. All of the available experimentalPVT property data were compared with the equation of state correlated by Wilson et al.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

RADIATION CHEMICAL AND PHOTOPHYSICAL PROPERTIES OF C60(C4H8SO3Na)n IN AQUEOUS SOLUTION: A LASER FLASH PHOTOLYSIS AND PULSE RADIOLYSIS STUDY

Optical absorption studies on aqueous solutions of C₆₀(C₄H₈SO₃Na)_n (n = 4-6) revealed deviation from the Beer-Lambert law in the 250-350 nm region, which is assigned to the formation of solute aggregates at concentrations higher than 1 × 10^-3 mol dm^-3. Dynamic light scattering experiments showed aggregates with an average size of ∼100 nm. The solute has a broad weak fluorescence emission (ϕ_f = 1.8 × 10^-3) in the 450-650 nm region, which remained independent of solute concentration. The broad transient absorption band in the 450-900 nm region (ε₆₆₀ = 2170 dm³ mol^-1 cm^-1), which formed immediately on laser flash photolysis (λ_ex = 355 nm, 35 ps), is assigned to singlet-singlet transition. It decays to a triplet excited state whose absorption is observed to depend strongly on solute concentration. In dilute solutions, an absorption band with λ_max = 590 nm is seen, and at high solute concentration a broad absorption in the 500-900 nm region is observed. The e_aq^- reacts with the solute with a bimolecular rate constant of 1.7 × 10⁸ dm³ mol^-1 s^-1 and forms weak broad absorption bands at 440, 540, 620, 870, 940, and 1020 nm. Isopropanol radicals also react with the solute with a bimolecular rate constant of 2.3 × 10⁸ dm³ mol^-1 s^-1 with the formation of a transient optical absorption spectrum similar to that observed on reaction with e_aq^- and assigned to a solute radical anion. The ^•H and ^-OH radicals react with bimolecular rate constants of 3.2 × 10⁹ and 4.4 × 10⁹ dm³ mol^-1 s^-1, respectively, and form transient absorption bands at 440, 510, and 660 nm. Based on electron transfer studies with suitable electron donor/acceptor substrates, the ranges of the reduction and oxidation potentials of the solute an estimated.     

(2-羟基-3-丁氧基)丙基-羟丙基壳聚糖的合成及结构表征

将壳聚糖与环氧丙烷及丁氧基环氧丙烷在碱性条件下进行反应,生成水溶性的两亲性化合物（2-羟基-3-丁氧基）-丙基-羟丙基壳聚糖,用红外光谱、核磁共振和X射线衍射谱对产物进行了结构表征。实验表明,产物具有良好的表面活性,可以作为具有独特性能的高分子表面活性剂使用。     

SIMULTANEOUS DETERMINATION OF C60 AND C70 FULLERENES BY A SPECTROPHOTOMETRIC METHOD

In all fullerene-producing systems, reaction products were black soot extracts reported to contain a 5-25% fullerene mixture. Toluene extraction of the soot results in a solution of C₆₀, C₇₀, and higherc fullerenes. Without separation, absolute determination of the contents is not possible, leaving the researcher to comment only on the C₆₀/C₇₀ ratio of the solution. High-performance liquid chromatography, nuclear magnetic resonance, and scanning tunneling microscopy imaging techniques were reported in the literature for determining the C₆₀/C₇₀ ratio of the mixtures. These methods require tedious experiments and produce slightly differing results as well. In this communication, a new and relatively quick method is proposed for the simultaneous determination of the yields of C₆₀ and C₇₀ (not the ratio) in fullerene-containing solutions by ultraviolet-visible spectrophotometric analysis.     

Rb3C60单晶薄膜制备及Rb3C60/C60相界面稳定性研究

通过控制蒸发源电流、源和样品间距及扩散时间,室温下在C60单晶(111)解理面上制备出Rb3C60.用低温同步辐射角分辨光电子谱测量了样品的能带结构.观察到的能带色散表明样品为单晶薄膜.用X光电子谱首次研究了Rb3C60与C60相界面的稳定性.结果表明温度低于约420 K时界面是稳定的.     

Au电极作用下C60、2C60与4C60富勒烯分子的电子传输特性

采用扩展的Hückel方法与格林函数方法,研究了Au电极作用下,C60富勒烯、2C60和4C60聚合体分子的电子结构与导电性,并对它们的电子结构与电子输运特性进行了对比.研究结果表明,C60、2C60或4C60富勒烯分子与Au电极 "接触"后,其HOMO、LUMO间的能隙减小;C60、2C60或4C60分子与Au电极之间的结合既有共价键的成分,又有离子键的成分,其中,C60、4C60分子与Au电极结合的离子键特征更为明显;三种富勒烯分子的电子输运性能依次具有C60>2C60>4C60分子的顺序.     

Building Solids with Buckminsterfullerene (C60)

Solids built with C₆₀ or C₆₀ anions and structurally characterized are reviewed and specific trends identified in order to stimulate further synthetic work in fullerene material research.     

以BF3（CH3）2O/CF3COOH共引发剂合成端羟基聚环氧氯丙烷的探讨

通过改变传统的引发体系,采用BF3.(CH3)2O/CF3COOH合成了无色透明且分子量较高的端羟基聚环氧氯丙烷(PECH),利用核磁共振、红外光谱等手段对产物的化学结构进行了详细的分析,同时考察了BF3.(CH3)2O及CF3COOH用量对PECH相对黏度的影响,探讨了TCA提高产物透明度的作用。结果表明,合成了主链以头尾连接为主,头头及尾尾连接为辅的PECH。     

涂层成分对IrO_2（5）TiO_2（60）Co_3O_4（x）RuO_2（35

用电化学和Ｘ射线衍射方法研究了氧化物涂层成分对热分解法制备的ＩｒＯ２（５）ＴｉＯ２（６０）Ｃｏ３Ｏ４（ｘ）ＲｕＯ２（３５—ｘ）／Ｔｉ阳极材料析氯速率的影响．ｘ值为０－１３ｍ／ｏ时，氧化物涂层为单相金红石型固溶体，阳极析氯速率随ｘ值增加，ｘ值大于１３ｍ／ｏ时，涂层中出现尖晶石Ｃｏ３Ｏ４第二相，析氯速率随ｘ值下降．