Reactions of fullerene C60 with organometallic azides

Reactions of fullerene C₆₀ with organometallic azides [Et₂AlN₃, EtAl(N₃)₂ and Bu₃SnN₃] led to novel 1-azido-2-alkylfullerenes. The structures of the products were confirmed by IR, ¹Н and ¹³C NMR spectroscopy and MALDI TOF mass spectrometry.     

Separation of aromatic hydrocarbons from alkanes using ammonium ionic liquid C2NTf2 at T = 298.15 K

(Liquid + liquid) equilibrium data are presented for four ternary systems of an alkane, or aromatic compound and ethyl(2-hydroxyethyl)dimethylammonium bis{(trifluomethyl)sulfonyl}imide (C₂NTf₂) at 298.15 K: [hexane + benzene + C₂NTf₂], [hexane + p-xylene + C₂NTf₂], and [hexane, or octane + m-xylene + C₂NTf₂]. The separation of aromatic hydrocarbons (benzene, or p-xylene, or m-xylene) from aliphatic hydrocarbons (hexane, or octane) is investigated by extraction with the ammonium ionic liquid. Selectivities and distribution ratios are discussed for these mixtures at constant temperature. The data were analysed and compared to those previously reported for other ionic liquids and especially for the system {hexane + benzene + [EMIM][NTf₂]}. The nonrandom two liquid NRTL model was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems.     

载有C60的TiO2纳米粒子光催化活性

以水溶性C₆₀和TiO₂粒子为前驱体,采用水热法制备了载有C₆₀的锐钛矿型TiO₂纳米粒子。应用X射线衍射、透射电子显微镜、红外光谱、紫外-可见漫反射光谱、荧光光谱对产物进行了表征。以对-硝基苯酚为模型污染物研究了产物的光催化活性,结果表明适量负载C₆₀可以提高TiO₂纳米粒子的光催化活性,C₆₀起着传输电子、促进TiO₂光生载流子分离的作用,且经7次循环使用后对-硝基苯酚的降解效率仍能达到74%。讨论了载有C₆₀的TiO₂纳米粒子光催化降解对-硝基苯酚的机理。     

High-temperature and photochemical syntheses of C60 and C70 fullerene derivatives with linear perfluoroalkyl chains

New experimental results on perfluoroalkylation of C₆₀ and C₇₀ with the use of R_fI (R_f = CF₃, C₂F₅, n-C₃F₇, n-C₄F₉, and n-C₆F₁₃), along with a critical overview of the existing synthetic methods, are presented. For the selected new fullerene (R_f)_n compounds we report spectroscopic, electrochemical and structural data, including improved crystallographic data for the isomers of C₇₀(C₂F₅)₁₀ and C₆₀(C₂F₅)₁₀, and the first X-ray structural data for the dodecasubstituted perfluoethylated C₇₀ fullerene, C₇₀(C₂F₅)₁₂, which possesses unprecedented addition pattern.     

One-pot three-component reaction of C60, amino acid and fluorinated benzaldehyde to C60-pyrrolidine derivatives

A series of fluorinated 2,5-disubstituted C₆₀-pyrrolidine derivatives were synthesized via one-pot three-component reaction of C₆₀, amino acid and fluorinated benzaldehyde under reflux in toluene or microwave irradiation. The cis- and trans-isomers could be isolated by chromatography and fully confirmed by ¹H NMR.     

Investigation of fullerene C60 effect on properties of polymethylmethacrylate exposed to ionizing radiation

Effect of fullerene C₆₀ was investigated on thermal, mechanical and optical properties of polymethylmethacrylate (PMMA) under ionizing radiation. It was stated that fullerene C₆₀ behaves as an effective antirad with respect to PMMA. Fullerene C₆₀ addition raises temperature of destruction for polymer subjected to electron radiation by 20-25 °C, lowers the rate from 4 to 4.5 times and increases the activation barrier for radiated PMMA destruction reaction. Fullerene C₆₀ addition promotes improvement of strength properties of PMMA: for films containing C₆₀ addition and else subjected to electron radiation treatment a decrease in rupture strength is 10-15%, for samples containing no fullerene it equals ∼25%. Interaction of free radicals with fullerene at radiation treatment influences optical characteristics of PMMA films.     

Easily characterized systems of C60 grafted on SiO2

Fullerenes grafted on silica with cleavable anchors give materials that can be easily characterized after thermal/chemical treatment or use as catalysts. Transesterification of an ester linkage leads to detachment of the fullerene moiety from the silica and permits study with standard spectroscopic methods. In particular, UV-vis spectroscopy was proved to be a valuable tool permitting structure analysis and quantitative determination at the same time.     

He+C60↔(He@C60)的反应势垒研究

The reaction barriers of (He+C60(He＠60)) have been calculated by the quantum-chemical method EHMO/ASED in the following four paths: (1) penetrate through the pentagon on the C60 cage; (2) penetrate through the hexagon on the C60 cage,(3) penetrate through the short bond; (4) penetrate through the long bond. Corresponding to each path, there are two choices: (a) while He penetrate C60 cage, the distances of the C’s which are the most adjacent to He are changed with a planar extension and a concerned window is formed; (b) while He penetrate C60 cage, the distances of the C’s which are the most adjacent to He are changed with a spherical extension and a concerned window is formed. The results are given in Figs. 1-2 and Tables 1-2. It is shown that the reaction through path(4) with choice (a) has the least reaction barrier, being optimum. At that case, a window of 9-membered ring is formed. Because the window extension of C6H6 is more free than that of C60, the barrier of He penetrating through C6H6 will be lower than that of He penetrating through C60.     

Determination of thermodynamic properties of aqueous mixtures of MgCl2 and Mg(NO3)2 by the potentiometric method at T = 298.15

In this research, thermodynamic properties of the ternary electrolyte system (MgCl₂ + Mg(NO₃)₂ + H₂O) were investigated using a potentiometric method. The galvanic cell used had no liquid junction of type: Mg-ISE|MgCl₂ (m_A), Mg(NO₃)₂ (m_B), H₂O|Ag/AgCl. The measurements were performed at T = 298.15 K and at total ionic strengths from 0.001 to 8.000 mol/kg for different series of salt ratios r=mMgCl₂/mMg₂(NO₃) =1.00, 2.50, 5.00, 7.50, 10.00 and 15.00. The PVC based magnesium ion-selective electrode (Mg-ISE) and the Ag/AgCl electrode used in this work were prepared in our laboratory and showed a reasonably good Nernst response. The Pitzer ion interaction model and Harned rule were used to illustrate the ternary electrolyte system investigated. The experimental results showed that both Pitzer model and Harned rule were suitable to be used satisfactorily to describe this ternary system.     

Thermodynamics of dimethylene urethane and poly(dimethylene urethane) in the range from T → 0 to 490 K at standard pressure

By high-precision dynamic calorimetry the temperature dependences of heat capacity of dimethylene urethane (DMU) between 320 and 370 K and partially crystalline poly(dimethylene urethane) (PDMU) in the range 326-490 K at standard pressure have been determined within ±1.5%. The thermodynamic characteristics of fusion of the substances, namely the temperature interval of melting, temperature, enthalpy and entropy of fusion, as well as the characteristics of devitrification and glassy state for poly(dimethylene urethane) have been estimated. The first and the second cryoscopic constants have been calculated for dimethylene urethane. The experimental data obtained in the present work and literature findings on the heat capacity of the substances were used to calculate their thermodynamic functions: the heat capacity C°_p (T), enthalpy H°(T)−H°(0), entropy S°(T) and Gibbs function G°(T)−H°(0) over the range from T→0 to (370-480) K. Based on the data, the thermodynamic characteristics of polymerization process with five-membered ring opening Δ_polH°, Δ_polS° and Δ_polG° of dimethylene urethane with the formation of linear partially crystalline poly(dimethylene urethane) have been evaluated.     

Novel solvent-free reaction of C60 with active methylene compounds in the presence of Na2CO3 under high-speed vibration milling

Inorganic base, Na₂CO₃, was utilized to replace organic base, DBU, in the Bingel reaction employing diethyl bromomalonate under the mechanochemical ‘high-speed vibration milling’ conditions to give the cyclopropanated C₆₀1 in high yield. In contrast, reactions of C₆₀ with diethyl malonate and ethyl acetoacetate in the presence of Na₂CO₃ under HSVM conditions afforded 1,4-bisadduct 2 and dihydrofuran-fused C₆₀ derivative 3, respectively.     

复合催化剂上CO2加氢合成C2烃类

介绍了由CO₂+H₂合成C2⁺烃的几种复合催化剂体系的研究进展，比较和评价了复合催化剂体系的活性和选择性及对C2⁺烃类生成的影响。着重于复合催化剂体系对C4⁺烃的生成及产物分布的影响并简述反应机理。     

H2O + Fe(NO3)3 + Ni(NO3)2 ternary system isotherms at 0 °C and 30 °C

H₂O + Ni(NO₃)₂ binary system were investigated in the temperature range from −25 °C to 55 °C. The solid-liquid equilibria of the ternary system H₂O + Fe(NO₃)₃ + Ni(NO₃)₂ were studied using a synthetic method based on conductivity measurements. Tow isotherms were established at 0 °C and 30 °C, and the appearing stable solid phases are iron nitrate nonahydrate (Fe(NO₃)₃·9H₂O), iron nitrate hexahydrate (Fe(NO₃)₃·6H₂O), nickel nitrate hexahydrate (Ni(NO₃)₂·6H₂O) and nickel nitrate tetrahydrate (Ni(NO₃)₂·4H₂O).     

Base-promoted reaction of C60Cl6 with thioamides: an access to [60]fullereno[1,9-d] thiazoles

Regioselective reaction of C₆₀Cl₆ with thioamides via a radical annulation to form fullereno thiazole derivatives is reported. The reaction is promoted by K₂CO₃, which might deprotonate thioamide to initiate a single electron transfer from thioamide anion to C₆₀Cl₆. The experiments with various thioamides establish the proposed base-promoted reaction as a facile route for synthesis of fullereno fused thiazole derivatives starting from C₆₀Cl₆, a prevalent synthon in fullerene chemistry. In addition, the tunable electrochemical properties of the fullereno thiazole products have been investigated for their potential photovoltaic application.     

Switching of global minima of novel germylenic reactive intermediates via halogens (X): C2GeH2 vs. C2GeHX at ab initio and DFT levels

For 30 C₂GeHX germylenic isomers, one cyclic structure, X-germacyclopropenylidene, and three acyclics are considered, which include: ethynyl-X-germylene, X-vinylidenegermylene, and (X-ethynyl)germylene (X = H, F, Cl, and Br). The global minimum among six isomeric C₂GeH₂ (where X = H), is found to be cyclic, aromatic, singlet germacyclopropenylidene. In contrast, among the 24 corresponding halogermylenes, C₂GeHX (where X = F, Cl, and Br), the global minima switch to acyclic, singlet ethynylhalogermylenes, at eight reasonably high ab initio and DFT levels. The direct resonance interaction between X and the divalent center Ge in the singlet acyclic ethynylhalogermylene structures, is claimed to justify switching of the calculated global minima in the halo derivatives. GIAO-NICS calculations indicate that the X-germacyclopropenylidene isomer is more aromatic for X = H than X = F, Cl, or Br. The angle ∠XGeC bending potential energy curves show the singlet and triplet ethynylgermylene crossing at ≈146°, for X = H.     

Thermodynamics of linear polyurethanes on basis of 1,4-diisocyanatobutane with 1,4-butanediol and 1,6-hexanediol in the range from T → 0 to 490 K

The temperature dependence of heat capacity and characteristics of physical transformations of partially crystalline linear aliphatic polyurethanes based on 1,4-diisocyanatobutane with 1,4-butanediol and 1,6-hexanediol have been studied over the range 6.5-490 K by precision adiabatic vacuum and dynamic calorimetry. The calorimetric data were used to determine the thermodynamic quantities of devitrification and fusion and to calculate the standard thermodynamic functions , H⁰(T) − H⁰(0), S⁰(T) and G⁰(T) − H⁰(0) of linear polyurethanes in totally crystalline and amorphous states. The values of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids were estimated and the character of heterodynamics of their structures was detected. The energies of combustion of the substances were measured in a calorimeter with an isothermal shield and a static bomb. The enthalpies of combustion and the standard thermodynamic characteristics of formation of the polymers at T = 298.15 K were calculated too. The standard thermodynamic characteristics of polycondensation processes in bulk of 1,4-diisocyanatobutane with 1,4-butanediol and 1,6-hexanediol followed by the formation of linear polyurethanes were determined in the range from 0 to 350 K. A comparative analysis of the corresponding standard thermodynamic properties of the polymers under consideration and polyurethanes of isomeric structure was made and some dependences of their change on various conditions were found.     

Thermodynamic properties of some polymeric forms of fullerite C<Subscript>60</Subscript> at temperatures ranging from 0 to 320 K

The temperature dependences of the heat capacityC ⁰ _p of fullerites C₆₀ were studied at temperatures ranging from 5 to 320 K in an adiabatic vacuum calorimeter with an accuracy of 0.4–0.2%. The fullerite C₆₀ samples were prepared by treating the starting fullerite C₆₀ under 8 GPa at 920 and 1270 K and “quenched” by a sharp decrease in pressure to −10⁵ Pa and in temperature to ∼300 K. Fullerite C₆₀(8 GPa, 920 K), a crystalline polymer with layered structure formed by polymerized fullerene C₆₀ molecules, was obtained at 920 K and 8 GPa. Fullerite C₆₀(8 GPa, 1270 K), a three-dimensional polymer with a graphite-like structure formed by fragments of decomposed C₆₀ molecules and containing many C(sp³)−C(sp³) bonds, was obtained at 1270 K and 8 GPa. Both polymers are metastable polymeric phases. The anomalous character of the temperature dependence of the heat capacity was revealed in the 49–66 K range for the polymer formed at 1270 K. The thermodynamic functions of the substances under study were calculated for the 0–320 K region along with entropies of their formation from graphite. The entropies of transformation of the starting fullerite C₆₀ into metastable phases and that of intertransformation of phases were estimated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 277–281, February, 2000.     

(p, ρ, T) properties, and apparent molar volumes V? of ZnBr2 in methanol at T = (298.15 to 398.15) K and pressures up to p = 40 MPa

The (p, ρ, T) properties of pure methanol, the (p, ρ, T) properties and apparent molar volumes V_? of ZnBr₂ in methanol at T = (298.15 to 398.15) K and pressures up to p = 40 MPa are reported, and apparent molar volumes have been evaluated. The experimental (p, ρ, T, m) values were described by an equation of state. For the solutions the experiments were carried out at molalities m = (0.05772, 0.37852, 0.71585 and 1.95061) mol · kg⁻¹ of zinc bromide.     

Structures of LiCaAlF6 and LiSrAlF6 at 120 and 300 K by synchrotron X-ray single-crystal diffraction

The low-temperature structures of the colquiriite-type fluorides LiCaAlF₆ and LiSrAlF₆ have been investigated by single crystal X-ray diffraction. Molecular orbital calculations were also carried out using cluster models based on the obtained structures. The crystallographic c-axis at 120 K in LiSrAlF₆ became slightly elongated with respect to the 300 K lattice and the structure became more distorted. In contrast, there was uniform lattice parameter contraction in LiCaAlF₆ and the structure changed minimally between 300 and 120 K. These structural variations support other studies of temperature dependent optical properties reported in the literature.