Sample records for bf4 clo4 pf6

  1. Thermopower studies of a series of salts of tetramethyltetrathiafulvalene [(TMTTF)2X, X=Br, ClO4, NO3, SCN, BF4, AsF6, and PF6

    Mortensen, Kell; Conwell, E. M.; Fabre, J. M.


    Thermoelectric power measurements on a group of tetramethyltetrathiafulvalene (TMTTF)2X salts show a wide variety of behavior. In the range of temperatures 300≥T≳100 K several of the salts (X=BF4, ClO4, NO3, SCN) have a constant thermopower S≃35 μV/K, while the PF6 and AsF6 salts have S∝1 / T, and...... the Br salt has S increasing with T. Below ∼100 K, S shows a steep increase or decrease with decreasing temperature for each salt which, with the exception of the SCN salt, is not associated with a phase transition. These materials had been identified as semiconductors below the maximum in...

  2. The Properties of Binary Composite Ionic Liquids BMimBF4 and BMimPF6 Mixtures%BMimBF_4和BMimPF_6二元复合离子液体的特性

    张冰; 陈松; 陈亮


    The kinematic viscosity, electrochemical window and electric conductivity of BMimBF4and BMimPF6 and their binary composite ionic liquids mixtures were studied. The results indicated that, physical and chemical properties of binary composite ionic liquids mixtures were changed by way of simply regulating volume of BMimBF4 and BMimPF6, which brought designing ionic liquids into full play and opened a new way for the application of "green solvent" - ionic liauids.%研究了BMimBF4、BMimPF6及其二者不同体积比复合离子液体的运动粘度、电化学窗口及电导率。结果表明,通过简单地调节BMimBF4和BMimPF6的复合体积比,可以改变BMimBF4和BMimPF6二元复合离子液体的物理化学性质,充分发挥离子液体的"可设计"性,为"绿色溶剂"离子液体的应用开辟了新的道路。

  3. Comparative X ray diffuse scattering studies of some superconducting and non superconducting 1 : 2 salts (TMTSF)2X and (TMTTF)2X; with x = PF6, AsF6, ClO4, NO3

    X-ray diffuse scattering experiments performed on the highly conducting (TMTSF)2X compounds (X = PF6, AsF6, ClO4, NO3) reveal no charge density wave instabilities, whether they display superconducting properties or not. Instead, another type of phase transition, not observed for the superconducting members (PF6, AsF6, ClO4), takes place in the non-superconducting (TMTSF)2NO3, and involves an ordering of the counter ions, which doubles the lattice constant in chain direction. Similar experiments performed on the less conducting (TMTSF)2X compounds (X = ClO4, PF6), which do not present a superconducting state, either reveal the ordering transition of the counter ion (ClO4) or the quasi 1-D 2ksub(F) scattering characteristic of a charge density wave instability (PF6). Consequences on the dimensionality of the Fermi surface and on the superconducting instability are discussed. (orig.)

  4. Organic metal (EDO-TTF2PF6 with multi-instability

    Hideki Yamochi and Shin-ya Koshihara


    Full Text Available The multi-instability of the electronic structure of (EDO-TTF2PF6, where EDO-TTF means ethylene-dioxytetrathiafulvalene, is reviewed. This complex showed the metal–insulator transition at 280 K associated with distinct molecular deformations. The mechanism is interpreted as the cooperation of Peierls transition, charge ordering, and the order–disorder transition of the countercomponent. The charge ordering pattern in the low-temperature phase is of the novel [0, 0, 1, 1] type. The sensitivity of the electronic state to external perturbations is demonstrated applying not only static but also instantaneous stimuli. In the latter case, the photo-induced phase transition is ultrafast and highly efficient. One photon causes the transition of several hundreds of donor molecules in the low-temperature phase to relax into a highly conducting metastable state within about 1.5 ps. In the early stage of the transient state, the charge ordering of the [1, 0, 1, 0] type occurs. As for the chemical modifications of this material, the partial deuteration of this complex increases the metal–insulator transition temperature. The introduction of a methyl group greatly modulates the electronic structure of the complex, i.e. (methyl-EDO-TTF2X (X=BF4, ClO4 shows a two-dimensional electronic structure. The working hypotheses for developing the systems with multi-instability are described.

  5. Dehumidification performance of [EMIM]BF4

    Some ionic liquids have dehumidification capacity and are non-corrosive to metals. Based on the Finite Difference Method, the heat and moisture transfer model of the counter-flow dehumidifier was established. Using this model, the dehumidification capacity of one kind of ionic liquids 1-Ethyl-3-methylimidazolium Tetrafluoroborate ([EMIM]BF4) and traditional desiccant lithium bromide (LiBr) was compared in equivalent conditions. The results show that the dehumidification performances of the two solutions both improve with the increase of air flow rate, solution flow rate and air humidity. Even though the dehumidification rate of [EMIM]BF4 is a little lower than that of LiBr, such difference could be reduced by increasing the mass concentration of [EMIM]BF4. Meanwhile, compared with traditional desiccants, [EMIM]BF4 solution has significantly lower corrosion to metals and does not crystallize at high mass concentration, which render it a possible substitute of existed desiccants in liquid desiccant air conditioning systems. - Highlights: → The paper researched on using [EMIM]BF4 solution as desiccant in the liquid desiccant air conditioning system by simulation. → By comparing the dehumidification performance of [EMIM]BF4 solution with traditional desiccant LiBr solution, it confirms the feasibility of using [EMIM]BF4 as desiccant. → [EMIM]BF4 solution has significantly lower corrosion of metals and does not crystallize at high mass concentration, which make it a possible substitute of existed desiccants.

  6. Transformations of Organic Molecules with F-TEDA-BF4 in Ionic Liquid Media

    Stojan Stavber


    Full Text Available The transformations of organic molecules with F-TEDA-BF4 (1 were investigated in the hydrophilic ionic liquid (IL 1-butyl-3-methyl-imidazolium tetrafluoroborate ([bmim][BF4], 2 and the hydrophobic IL 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6], 3. The range of substrates included alkyl substituted phenols 4a-c, 9, 13, 1,1-diphenylethene (15, alkyl aryl ketones 19-22, aldehydes 23-25 and methoxy-substituted benzene derivatives 26-30. The evaluation of the outcome of reactions performed in IL media in comparison to those of the corresponding reactions in conventional organic solvents revealed that the transformations in IL are less efficient and selective. The effect of the presence of a nucleophile (MeOH, H2O, MeCN on the course of reaction was also studied.

  7. Densities and viscosities for ionic liquids mixtures containing [eOHmim][BF4], [bmim][BF4] and [bpy][BF4

    Highlights: • Targets of this research are ILs mixtures. • Densities and viscosities were measured for three ILs mixtures. • Excess molar properties were deduced from the experiments. • Viscosities were discussed by the ideal Grunberg and Nissan mixing law. - Abstract: Densities and viscosities of binary ionic liquids mixtures, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF4]) + 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF4]) + N-butylpyridinium tetrafluoroborate ([bpy][BF4]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) + N-butylpyridinium tetrafluoroborate ([bpy][BF4]) were measured over the entire mole fraction from T = (298.15 to 343.15) K. The excess molar volumes were calculated and correlated by Redlich–Kiser polynomial expansions. The viscosities for pure ionic liquids were analyzed by means of the Vogel–Tammann–Fulcher equation and ideal mixing rules were applied for the ILs mixtures

  8. Thermal stability of LiPF 6 salt and Li-ion battery electrolytes containing LiPF 6

    Yang, Hui; Zhuang, Guorong V.; Ross, Philip N.

    The thermal stability of the neat lithium hexafluorophosphate (LiPF 6) salt and of 1 molal (m) solutions of LiPF 6 in prototypical Li-ion battery solvents was studied with thermogravimetric analysis (TGA) and on-line Fourier transform infrared (FTIR). Pure LiPF 6 salt is thermally stable up to 107 °C in a dry inert atmosphere, and its decomposition path is a simple dissociation producing lithium fluoride (LiF) as solid and PF 5 as gaseous products. In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct thermal reaction between LiPF 6 and water vapor to form phosphorous oxyfluoride (POF 3) and hydrofluoric acid (HF). No new products were observed in 1 m solutions of LiPF 6 in ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) by on-line TGA-FTIR analysis. The storage of the same solutions in sealed containers at 85 °C for 300-420 h did not produce any significant quantity of new products as well. In particular, no alkylflurophosphates were found in the solutions after storage at elevated temperature. In the absence of either an impurity like alcohol or cathode active material that may (or may not) act as a catalyst, there is no evidence of thermally induced reaction between LiPF 6 and the prototypical Li-ion battery solvents EC, PC, DMC or EMC.

  9. Proton irradiation defects in (fluoranthene)2PF6

    Electron spin resonance and electron-proton double resonance (Overhauser shift method) are used for the comparison of proton radiation damaged and as-grown (fluoranthene)2PF6 single crystals. Chemical modification and various consequences of the nonuniform distribution of radiation induced defects in this quasi-one-dimensional organic conductor with defect dependent Peierls transition are worked out

  10. Optimization of a NH4PF6-enhanced, non-organic solvent, dual microextraction method for determination of phthalate metabolites in urine by high performance liquid chromatography.

    Wu, Jia; Ye, Zhihan; Li, Xiaolong; Wang, Xuedong; Luo, Fangjun; Sheng, Bo; Li, Yiwei; Lyu, Jianxin


    In conventional ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) procedures, most of the IL disperser remains in the aqueous phase resulting in low recovery for moderately and weakly polar analytes due to the "carry-over effect". Herein, we successfully developed a "NH4PF6-enhanced, non-organic solvent, dual microextraction" method (ANSDM) for pretreatment of phthalate (PAE) metabolites with weak to moderate polarity. This method utilized in situ reaction of NH4PF6 as an ion-exchange reagent and disperser to realize two microextractions after using [C8MIM]PF6 as an extraction solvent and [C4MIM]BF4 as a disperser for conventional DLLME. Single-factor experiments, a two-level full factorial experimental design and central composite design were applied for optimizing operational parameters using 3D response surfaces and contour lines. Under optimized conditions, the newly developed method provided high extraction recoveries (93.8-99.1%) and low LODs (ca. 0.3μgL(-1)) for three phthalate metabolites in human urine. The primary advantages of the ANSDM method include: (1) integration of in situ reaction and conventional DLLME techniques to effectively extract both weak and moderately polar pollutants simultaneously; (2) non-organic solvent use in the microextraction procedure making the process safer and more environmental friendly; and (3) a time-saving, simple operation that is fully compatibility with HPLC analysis. To the best of our knowledge, our group is the first to develop the "non-organic solvent, dual microextraction" method and it has great potential as a sample pre-treatment technique for organic pollutants with weak to moderate polarity in biological and environmental matrices. PMID:26852090

  11. Study of the Ion Channel Behavior of Didodecyldimethylammonium Bromide Formed Bilayer Lipid Membrane Stimulated by PF-6

    TONG,Yue-Hong; HAN,Xiao-Jun; WANG,Er-Kang


    Bilayer lipid membranes ( BLM ) formed from didodecyldimethylammonium bromide were made on the freshly exposed surface ofa glassy carbon (GC) ani were demonstrated by the ac impedance spectroscopy. The ion channels of membrane properties induced by PF6- were studied by the cyclic voltammetric methods.Experimental results indicated that the ion channel of BLM was open in the presence of the PF6- due to the interaction of PF6- with the BLM, while it was switched offin the absence of PF6-. Because the ion channel behavior was affected by the concentration of PF6-,a sensor for PF6- can be developed.

  12. Structure, phase transitions, dielectric and spectroscopic studies of the 2-aminopyrimidinium salts: [(2-NH 2C 4N 2H 3) 2H][ClO 4] and [2-NH 2C 4N 2H 4][BF 4

    Czupiński, O.; Wojtaś, M.; Ciunik, Z.; Jakubas, R.


    Crystal structure of the 2-aminopyrimidinium derivatives: [(2-NH 2C 4N 2H 3) 2H][ClO 4] (I) and [2-NH 2C 4N 2H 4][BF 4] (II) has been determined at 100 K (I) and 293 K (II) by means of single crystal X-ray diffraction as monoclinic space group, P2/c and P2/n, respectively. The asymmetric part of the unit cell of (I) contains two symmetry independent 2-aminopyrimidine forming one dimeric cation and one disordered perchlorate anion. The structure of (II) consists of 2-aminopyrimidinium cation, [2-NH 2C 4N 2H 4] +, protonated at a pyrimidine ring-N atom and [BF 4] - anion. Differential scanning calorimetry (DSC) on perchlorate derivative ( 1:1), [2-NH 2C 4N 2H 3][ClO 4] (III)—being isomorphic to tetrafluoroborate one (I) at room temperature, reveals two phase transitions of first order: at 250/275 K and 390/410 K (cooling-heating, respectively), whereas the analog (II) only one transition at high temperatures—343/385 K. The dielectric studies in the frequency range 75 kHz - 10 MHz disclose relaxation process at high temperatures in salt (I). Infrared spectra of polycrystalline [2-NH 2C 4N 2H 4][BF 4] have been studied in the temperature range 300-420 K. Substantial changes in the temperature evolution of frequencies of internal modes of the 2-aminopyrimidinium cations and [BF 4] - anions near 390 K are due to the variations in the motion of both moieties and hydrogen bond configuration. The experimental studies indicate that all phase transitions taking place in studied 2-aminopyrimidinium derivatives are classified as an order-disorder.

  13. Thermal stability of LiPF6/EC+DMC+EMC electrolyte for lithium ion batteries

    WANG Qingsong; SUN Jinhua; CHEN Chunhua


    The thermal stability of lithium-ion battery electrolyte could substantially affect the safety of lithium-ion battery. In order to disclose the thermal stability of 1.0 mol·L-1 LiPF6/ethylene carbonate (EC)+dimethyl carbonate (DMC)+ethylmethyl carbonate (EMC) electrolyte, a micro calorimeter C80 micro calorimeter was used in this paper. The electrolyte samples were heated in argon atmosphere, and the heat flow and pressure performances were detected. It is found that LiPF6 influences the thermal behavior remarkably, with more heat generation and lower onset temperature. LiPF6/EC shows an exothermic peak at 212 ℃ with a heat of reaction -355.4J·g-1.DMC based LiPF6 solution shows two endothermic peak temperatures at 68.5 and 187 ℃ in argon filled vessel at elevated temperature. EMC based LiPF 6 solution shows two endothermic peak temperatures at 191 and 258 ℃ in argon filled vessel.1.0mol·L-1LiPF6/EC+DMC+ EMC electrolyte shows an endothermic and exothermic process one after the other at elevated temperature. By comparing with the thermal behavior of single solvent based LiPF6 solution, it can be speculated that LiPF6 may react with EC, DMC and EMC separately in 1.0 mol·L-1LiPF6/EC+DMC+EMC electrolyte, but the exothermic peak is lower than that of 1.0 mol·L-1LiPF6/EC solution. Furthermore, The 1.0 mol·L-1 LiPF6 /EC+DMC+EMC electrolyte decomposition reaction order was calculated based on the pressure data, its value is n =1.83, and the pressure rate constants kp=6.49×10-2k Pa·-0.83·min-1 .

  14. Cooperative phenomena in (TMTSF)2ClO4 : an NMR evidence

    Bourbonnais, C.; Creuzet, F.; Jérome, D.; Bechgaard, K.; Moradpour, A.


    We present 1H and 77Se NMR relaxation data on oriented (TMTSF)2ClO4 single crystals in the relaxed state. The data show the existence of three distinct regimes for the nuclear relaxation rate T-11. In the high temperature part (T > 25 K) the Korringa law seems to be well satisfied whereas in the lower temperature part we have strong deviations down to 8 K or so. At T ≲ 6 K, a different and enhanced Korringa regime appears to be restored. Preliminary results on (TMTSF)2FSO3 under pressure also...

  15. Investigation of toxic effects of imidazolium ionic liquids, [bmim][BF4] and [omim][BF4], on marine mussel Mytilus galloprovincialis with or without the presence of conventional solvents, such as acetone

    Highlights: • The toxic effects of [bmim][BF4] and [omim][BF4] on mussels were investigated. • Both ILs could induce lethal and nonlethal effects on Mytilus galloprovincialis. • Different extent of IL-mediated adverse effects was observed in mussel hemocytes. • The alkyl chain length and lipophilicity of ILs are crucial for their toxicity. • Acetone influences the oxidative and genotoxic effects of [omim][BF4]. - Abstract: This study investigated the cytotoxic, oxidative and genotoxic effects of two commonly used imidazolium ionic liquids (ILs), [bmim][BF4] (1-butyl-3-methylimidazolium) and [omim][BF4] (1-methyl-3-octylimidazolium tetrafluoroborate), on the marine mussel Mytilus galloprovincialis, as well as whether acetone could mediate their toxic profile. In this context, mussels were firstly exposed to different concentrations of [bmim][BF4] or [omim][BF4], with or without the presence of acetone (at a final concentration of 0.06% v/v), for a period of 96 h, in order to determine the concentration that causes 50% mussel mortality (LC50 values) in each case. Thereafter, mussels were exposed to sub- and non-lethal concentrations of ILs for investigating their ability to cause lysosomal membrane impairment (with the use of neutral red retention assay/NRRT), superoxide anion and lipid peroxidation byproduct (malondialdehyde/MDA) formation, as well as DNA damage and formation of nuclear abnormalities in hemocytes. The results showed that [omim][BF4] was more toxic than [bmim][BF4] in all cases, while the presence of acetone resulted in a slight attenuation of its toxicity. The different toxic behavior of ILs was further revealed by the significantly lower levels of NRRT values observed in [omim][BF4]-treated mussels, compared to those occurring in [bmim][BF4] in all cases. Similarly, [bmim][BF4]-mediated oxidative and genotoxic effects were observed only in the highest concentration tested (10 mg L−1), while [omim][BF4]-mediated effects were enhanced at

  16. Structural, spectroscopic and magnetic properties of [Cu(1-meim)4].2(PF6)

    Yıldırım, Ilkay; Karabulut, Bünyamin


    [Cu(1-meim)4].2(PF6) (1-meim: 1-methylimidazole) complex has been synthesized and characterized by EPR, FT-IR, and XRD techniques. The Cu(II) complex crystallizes in the monoclinic system with the space group P21/c. EPR spectrum of [Cu(1-meim)4].2(PF6) powder has been studied at room temperature. The spin Hamiltonian parameters (g and hyperfine values) have been calculated. The results indicate the axial symmetry around the paramagnetic Cu2+ center. 2 2 The ground state wave function of Cu2+ ion has been constructed. The unpaired electron spends most of its time in dx2-y2 orbital.

  17. Characterization of plasticized PMMA–LiBF4 based solid polymer electrolytes

    S Rajendran; T Uma


    Polymer electrolyte films prepared from poly(methyl methacrylate) and LiBF4 with different concentrations of plasticizer (DBP) are described. The formation of polymer–salt complex has been confirmed by FTIR spectral studies. The temperature dependence of conductivity of polymer films seems to obey the VTF relation. Values of conductivities of the polymer complexes are presented and discussed.

  18. Electrocrystallization and structures of perylene radical salts: hexaperylene perchlorate, (C20H12)6+ClO4-, triperylene perchlorate, (C20H12)3+ClO4-, and diperylene hexafluorophosphate-tetrahydrofuran (3/2), (C20H12)2+PF6-.2/3C4H8O

    Endres, Helmut; Keller, Heimo J.; Müller, Barbara; Schweitzer, Dieter


    Crystals grown by electrocrystallization, species obtained depending on perylene concentration. Room-temperature data collect ions, Mo Kat λ = 0·71069 A. 6:1 salt: Mr= 1613·3, triclinic. pl, a = 12·57 1 (7), b = 13·699(5). c = 13.835(II)A, α = 110·43 (4), β= 107·13 (7), γ= 107·09 (4)°, V = 1913A3, Z = 1, Dx = 1.40gcm-3, μ= 1.1 cm- ', F(OOO) = 841, final R = 0·077 for 3171 observed reflections. The structure contains three independent perylene π dimers arranged ne...

  19. Positron 2D-ACAR study of the quasi-one-dimensional organic superconductor (TMTSF)2ClO4

    We have measured electron-positron momentum density in (TMTSF)2ClO4 by the positron two-dimensional angular correlation of annihilation radiation (2D-ACAR) technique. In order to interpret the experimental results, the electronic structure of (TMTSF)2ClO4 as well as the positron state therein has been investigated by ab initio theoretical calculations. 2D-ACAR spectra have been also calculated and compared with the experimental ones through their anisotropies and Lock-Crisp-West remapped spectra. The Fermi-surface-related structure is discussed. (orig.)

  20. Electrodeposition of tin from EMI⋅BF4⋅Cl room temperature molten salts

    Morimitsu M.


    Full Text Available The electrochemistry of Sn(II was investigated with cyclic voltammetry and chronoamperometry in the 1-ethyl-3-methylimidazolium tetrafluoroborate molten salt containing free chloride ions (EMI ⋅BF4 ⋅Cl originated from the mixture of EMIC and NaBF4 (60:40 mol%. The well defined redox waves for the electro deposition and dissolution of tin were observed on a platinum electrode at 303 K. The deposition of tin proceeded through a quasi-reversible step with two electron transfer, and the deposited tin was sufficiently recovered during oxidation. The experimental current-time transient coincided with the theory based on one-dimensional diffusion control.

  1. Synthesis and characterization of ionic liquid (EMImBF4)/Li+ - chitosan membranes for ion battery

    Lithium ion battery has been currently developed and produced because it has a longer life time, high energycapacity, and the efficient use of lithium ion battery that is suitable for storing electrical energy. However, this battery has some drawbacks such as use liquid electrolytes that are prone to leakage and flammability during the battery charging process in high temperature. In this study, an ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) containing Li+ ions was synthesized and combined with chitosan polymer host as a polymer electrolyte membrane for lithium-ion batteries to solve this problems. This ionic liquid was obtained from the anion metathesis reaction between EMImBr and LiBF4 salt, while EMImBr was synthesized from the reaction between 1-methylimidazole and ethyl bromide utilizing Microwave Assisted Organic Synthesis (MAOS) method. The ionic liquid obtained was characterized by microstructure analysis with using NMR and FTIR spectroscopy. The polymer electrolyte membrane was characterized by analysis functional groups (FTIR), ionic conductivity (EIS), and surface morphology (SEM). The analysis results of ion conductivity by the EIS method showed the increase the ionic conductivity value of membranes from 1.30 × 10−2 S cm−1 for chitosan to 1.30 × 10−2 S cm−1 for chitosan with EMImBF4/Li+, and this result was supported by analysis the surface morphology (SEM)

  2. Synthesis and characterization of ionic liquid (EMImBF4)/Li+ - chitosan membranes for ion battery

    Pasaribu, Marvin H.; Arcana, I. Made; Wahyuningrum, Deana


    Lithium ion battery has been currently developed and produced because it has a longer life time, high energycapacity, and the efficient use of lithium ion battery that is suitable for storing electrical energy. However, this battery has some drawbacks such as use liquid electrolytes that are prone to leakage and flammability during the battery charging process in high temperature. In this study, an ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) containing Li+ ions was synthesized and combined with chitosan polymer host as a polymer electrolyte membrane for lithium-ion batteries to solve this problems. This ionic liquid was obtained from the anion metathesis reaction between EMImBr and LiBF4 salt, while EMImBr was synthesized from the reaction between 1-methylimidazole and ethyl bromide utilizing Microwave Assisted Organic Synthesis (MAOS) method. The ionic liquid obtained was characterized by microstructure analysis with using NMR and FTIR spectroscopy. The polymer electrolyte membrane was characterized by analysis functional groups (FTIR), ionic conductivity (EIS), and surface morphology (SEM). The analysis results of ion conductivity by the EIS method showed the increase the ionic conductivity value of membranes from 1.30 × 10-2 S cm- 1 for chitosan to 1.30 × 10-2 S cm-1 for chitosan with EMImBF4/Li+, and this result was supported by analysis the surface morphology (SEM).

  3. Solvent relaxation of a room-temperature ionic liquid [bmim][PF6] confined in a ternary microemulsion

    Debabrata Seth; Palash Setua; Anjan Chakraborty; Nilmoni Sarkar


    In this paper we have reported the solvent and rotational relaxation of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) confined in tween 20/([bmim][PF6]/water microemulsion using coumarin 153 (C-153) as probe. The most interesting feature of our experiment was that we observed an increase in solvent relaxation time with increase in ( = tween 20-to-[bmim][PF6] molar ratio). This is due to the fact that with increase in [bmim][PF6] content of the microemulsions, the microviscosity of the pool of the microemulsions increases, and motion of ions of [bmim][PF6] is hindered in the pool of microemulsions. Since motion of ions is responsible for solvation in room-temperature ionic liquids (RTILs), solvent-relaxation time increases with increase in .

  4. Anisotropy of the upper critical field in ultrahigh-pressure-induced superconductor (TMTTF)2PF6

    We have measured the temperature dependence of resistivity of (TMTTF)2PF6 under high pressures up to 7 GPa by using a turnbuckle DAC (diamond anvil cell) for pressurization, also in magnetic field up to 5 T. In superconducting transition, zero-resistivity was successfully observed even there are not many cases that zero-resistivity has been observed from measurements of organics under high pressures. Superconductivity was observed at P=4.18-6.03 GPa and showed the highest TC of 2.25 K at 4.58 GPa. The temperature dependence of the upper critical magnetic field HC2(T) was determined via resistivity at P=4.58 GPa, for the intrachain (a), interchain (b'), and interlayer (c*). Also, the values of GL coherence lengths for three different axis which obtained from this work show that (TMTTF)2PF6 is anisotropic three-dimensional superconductor.

  5. Thermodynamics of Imidazolium-Based Ionic Liquids Containing PF6 Anions.

    Zaitsau, Dzmitry H; Yermalayeu, Andrei V; Emel'yanenko, Vladimir N; Butler, Simon; Schubert, Thomas; Verevkin, Sergey P


    Imidazolium-based ionic liquids (ILs) with PF6(-) anions are considered as low-cost solvents for separation processes, but they exhibit restricted thermal stabilities. Reliable measurements of vaporization thermodynamics by conventional methods have failed. In this work, we applied a quartz-crystal microbalance method to determine for the first time the absolute vapor pressures for the [Cnmim][PF6] family, with n = 2, 4, 6, 8, and 10, in the temperature range 403-461 K. An absence of decomposition of ILs in experimental conditions was determined by the attenuated total reflection-infrared spectroscopy. The consistency of the experimental results within the homologous series was established through enthalpy and entropy analyses of the liquid and gas phases as well as by molecular dynamics simulations. PMID:27462931

  6. Studies on the thermal decomposition kinetics of LiPF6 and LiBC4O8

    Li Shi-You; Ma Pei-Hua; Cui Xiao-Ling; Ren Qi-Du; Li Fa-Qiang


    Thermal decomposition of LiPF6 and LiBC4O8 (lithium bis(oxalate)borate, abbreviated as LiBOB) were studied using TG (thermogravimetry)-DTG (derivative thermogravimetry) method with different heating rate of 5, 10, 20 and 40°C min-1 or at different constant temperature C (109.80, 118.79, 148.41, 176.86 °C for LiPF6 and 278.51, 298.13, 317.65, 336.13 for LiBOB). From the nonisothermal kinetics we calculate that LiPF6 is 1.01, LiBOB is 1.04, LiPF6 is 91907.61 J/mol, and LiBOB is 205179.88 J/mol; from the isothermal kinetics we calculate that n for both LiPF6 and LiBOB are 1, LiPF6 is 91907.61 J/mol, LiBOB is 205179.88 J/mol, lnALiPF6 is 16.89 s-1, and lnALiBOB is 31.96 s-1. The results obtained from the two ways have minor differences and can validate each other.

  7. Crystal structure, properties and phase transitions of morpholinium tetrafluoroborate [C 4H 10NO][BF 4

    Szklarz, P.; Owczarek, M.; Bator, G.; Lis, T.; Gatner, K.; Jakubas, R.


    The crystal structure of [C 4H 10NO][BF 4] is determined in the phase I at 160, 180, 240 and 290 K. At room temperature the compound crystallizes in the orthorhombic space group: Pnam. The structure is composed of the morpholinium cations, [C 4H 10NO] +, which form one-dimensional hydrogen bonded chains, and [BF 4] - anions. [C 4H 10NO][BF 4] undergoes two structural phase transformations: second-order at 153 K and first-order at 117/118 K (cooling/heating). The phase transitions are characterized with the differential scanning calorimetry, dilatometric and dielectric techniques. The possible mechanism of the phase transitions in [C 4H 10NO][BF 4] is discussed on the basis of the presented results.

  8. Di-ureasil hybrids doped with LiBF4: Spectroscopic study of the ionic interactions and hydrogen bonding

    Highlights: → FT-IR and FT-Raman spectroscopy were used to characterize cation interactions in two LiBF4-doped di-ureasil networks incorporating POE chains with different length. → Over the range of salt content analyzed the cations bond to amorphous POE chains and form ion contact pairs with BF4-. → A crystalline POE/LiBF4 complex of unknown stoichiometry emerges at high salt concentration. - Abstract: In the present work Fourier transform infrared and Raman spectroscopy were used to characterize the cation/polymer, cation/cross-link, cation/anion and hydrogen bonding interactions in hybrid electrolytes composed of lithium tetrafluoroborate (LiBF4) and di-urea cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks (di-ureasils) designated as d-U(2000) and d-U(600) and incorporating polyether chains with ca. 40.5 and 8.5 oxyethylene repeat units, respectively. Samples with ∞ > n ≥ 2.5 (where n, composition, is the molar ratio of CH2CH2O units per Li+ ion) were analyzed. In both di-ureasil systems over the whole range of salt content examined the Li+ ions bond to the ether oxygen atoms of amorphous POE chains and to BF4- ions forming ion contact pairs. Spectroscopic evidences and SEM images confirm the presence of a crystalline POE/LiBF4 complex of unknown stoichiometry at n +/urea carbonyl oxygen atom interactions.

  9. Synthesis of Aryl Allyl Ether in the Recyclable Ionic Liquid [bmim]PF6

    Zhou Mei-Yun; Li Yi-Qun; Xu Xin-Ming


    Ionic liquids, especially imidazonium salts, have recently gained recognition as possible environmentally benign alternative chemical process solvents. This is mainly due to their nonvolatile nature, insolubility in some solvents as well as their ability to dissolve a wide range of organic and inorganic materials, allowing the ionic liquids easy recovery and recycling. Examples of their application in organic reactions have been summarized in a number of recent review articles.1Aryl allyl ether is very useful intermediate in organic synthesis. The Williamson reaction is a well knows method for the preparation ethers. However, the reaction of alkylating agents with the phenoxide ions was conventionally carried out in the organic solvents. The usual solvents for this type of reaction are DCM, 2 DMSO, 3 DMF, 4 CH3CN5 etc. With the current desire to avoid the use of organic molecular solvents in organic synthesis, we decide to investigate the use of the ionic liquid for the alternative solvent for the Williamson reaction to prepare the aryl allyl ethers. The ionic liquid employed here was the moisture stable 1-butyl-3-methylimidazolium hexafluorophosphate [bmim]PF6.6 The ionic liquid is non-volatile, thermally stable, and depending on the anion, can present low immiscible with water,alkanes and dialky ethers. We have now found that aryl allyl ethers can have been obtained from various phenols and allyl bromide in the presence of potassium hydroxide in [bmim]PF6 as a replacement for classical organic solvents in the ambient temperature. The results are shown in Scheme 1.The reaction were carried out by simple mixing the phenolwith the ally bromide and potassium hydroxide in [bmim]PF6 and stirred at room temperature for 4h. The results are summarized in Table 1.In conclusion, Williamson reaction can be successfully conducted in ionic liquid [bmim]PF6 with a number of advantages: the procedure is simple, the reaction condition is mild and the yields are excellent

  10. Optimization of performances of gelatin/LiBF4-based polymer electrolytes by plasticizing effects

    Gelatin is a cheap and abundant natural product with very good biodegradation properties and can be used to obtain acetic acid or LiClO4-based gel polymer electrolytes (GPEs) with high ionic conductivity and good stability. This article presents results of GPEs obtained by the plasticization of gelatin and addition of LiBF4, where the optimization of the system was achieved by using a factorial design type 22 with two variables: glycerol and LiBF4. From this analysis it was stated that the effect of glycerol as a plasticizer on the ionic conductivity results is much more important than the effect obtained by varying the lithium salt content or the effect of the interaction of both variables. Also all the samples were characterized by X-ray diffraction measurements, UV-vis-NIR spectroscopy and scanning electron microscopy (SEM) and impedance spectroscopy. The ionic conductivity results of all analyzed samples as a function of temperature obey predominantly an Arrhenius relationship and the samples are stable up to 160 deg. C. Good conductivity results combined with transparency and good adhesion to the electrodes have shown that gelatin-based GPEs are very promising materials to be used as solid electrolytes in electrochromic devices.

  11. Assembly of a Cyclic Dimer Silver(I) Complex Encapsulating Two BF4 - Ions

    Unusual twenty-membered cyclic dimer encapsulating two BF4- anions was obtained by the self-assembly of the tridentate N2S donor ligand and silver ion. We are currently investigating the subtle factors influencing the formation of discrete or continuous complexes using dipicolyl sulfide derivatives including. It is a challenging work to capture ionic species or small molecules as guests. Thus, the construction of self-assembled cyclic oligomer complexes composed of metal centres connected by acyclic organic ligands has been a subject of great interest together with the inclusion phenomena of macrocyclic ligands in the supramolecular chemistry. The majority of the organic-inorgaic hybrid macrocyclic structures reported so far have been based on bis-monodentate ligands such as 4,4'-bipyridine and its derivatives interconnected by rigid or flexible spacers. The same type of ligands has been also used for the formation of coordination network

  12. Pitting corrosion of Al and Al-Cu alloys by ClO4- ions in neutral sulphate solutions

    The influence of various concentrations of NaClO4, as a pitting corrosion agent, on the corrosion behaviour of pure Al, and two Al-Cu alloys, namely (Al + 2.5 wt% Cu) and (Al + 7 wt% Cu) alloys in 1.0 M Na2SO4 solution was investigated by potentiodynamic polarization and potentiostatic techniques at 25 deg. C. Measurements were conducted under the influence of various experimental conditions, complemented by ex situ energy dispersive X-ray (EDX) and scanning electron microscopy (SEM) examinations of the electrode surface. In free perchlorate sulphate solutions, for the three Al samples, the anodic polarization exhibits an active/passive transition. The active dissolution region involves an anodic peak (peak A) which is assigned to the formation of Al2O3 passive film on the electrode surface. The passive region extends up to 1500 mV with almost constant current density (jpass) without exhibiting a critical breakdown potential or showing any evidence of pitting attack. For the three Al samples, addition of ClO4- ions to the sulphate solution stimulates their active anodic dissolution and tends to induce pitting corrosion within the oxide passive region. Pitting corrosion was confirmed by SEM examination of the electrode surface. The pitting potential decreases with increasing ClO4- ion concentration indicating a decrease in pitting corrosion resistance. The susceptibility of the three Al samples towards pitting corrosion decreases in the order: Al > (Al + 2.5 wt% Cu) alloy > (Al + 7 wt% Cu) alloy. Potentiostatic measurements showed that the rate of pitting initiation increases with increasing ClO4- ion concentration and applied step anodic potential, while it decreases with increasing %Cu in the Al samples. The inhibitive effect of SO42- ions was also discussed

  13. Electropolymerization of 3-Methylthiophene in [BMIM]PF6 Ionic Liquid, Characterization and Application

    ZHANG Ai-Jian; QI Xi-Min; DU Yan-Fang; LUO Yi-Wen; FANG Hui-Jue; LU Jia-Xing


    Poly-3-methylthiophene (P3MT) was synthesized in the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) by constant potential and constant current respectively. The structure and morphology of P3MT films were characterized by FTIR spectrum and SEM. The undoped (reduction) and doped (oxidation) forms of P3MT film prepared in ionic liquid were reversible and stable. The P3MT film has strong characteristics of electrocatalytic oxidation of ascorbic acid and can separate the oxidation peaks of ascorbic acid and dopamine. Two methods of potential steps were used to observe the response time of the film and the film was found to have perfect electrochromic response.

  14. Thermal reactions of mesocarbon microbead (MCMB) particles in LiPF 6-based electrolyte

    Xiao, Ang; Li, Wentao; Lucht, Brett L.

    The thermal reaction of ternary electrolyte (1.0 M LiPF 6 in 1:1:1 ethylene carbonate/dimethyl carbonate/diethyl carbonate) with mesocarbon microbeads (MCMB) particles was investigated by the combined use of NMR, GC-MS, FTIR-ATR, TGA, XPS and SEM/EDS-element map. The thermal decomposition of ternary electrolyte is not inhibited by the presence of MCMB particles. The chemical composition and morphology of the surface of MCMB particles changes significantly upon storage in the presence of ternary electrolyte. Electrolyte decomposition products including oligocarbonates, oligoethylene oxides, polyethylene oxide (PEO), lithium fluorophosphates (Li xPO yF z), and lithium fluoride are deposited on the surface of MCMB particles. The concentration of decomposition products on the surface of MCMB increases with increased storage time and temperature. The addition of dimethyl acetamide (DMAc) impedes the thermal decomposition of the electrolyte and deposition of electrolyte decomposition products on the surface of MCMB.

  15. Structure and Dynamics of [PF$_6$][P$_{1,2,2,4}$] from Molecular Dynamics Simulations

    Carignano, Marcelo A


    Diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate, [PF$_6$][P$_{1,2,2,4}$], is an organic ionic plastic crystal with potential uses as a solid electrolyte in storage and light harvesting devices. In this work we present a molecular dynamics simulation study for this material covering an extended temperature range, from 175 K to 500 K. The simulations predicts a transition from the crystalline to a {\\em semi} plastic phase at 197 K, the onset of cation jump-like rotations at 280 K, a third transition at 340 K to a {\\em full} plastic phase and melting to 450 K. Overall, the simulations show a good agreement with the experimental findings providing a wealth of detail in the structural and dynamic properties of the system.

  16. Enhanced Performance of Li|LiFePO4 Cells Using CsPF6 as an Electrolyte Additive

    Xiao, Liang; Chen, Xilin; Cao, Ruiguo; Qian, Jiangfeng; Xiang, Hongfa; Zheng, Jianming; Zhang, Jiguang; Xu, Wu


    The practical application of lithium (Li) metal anode in rechargeable Li batteries is hindered by both the growth of Li dendrites and the low Coulombic efficiency (CE) during repeated charge/discharge cycles. Recently, we have discovered that CsPF6 as an electrolyte additive can significantly suppress Li dendrite growth and lead to highly compacted and well aligned Li nanorod structure during Li deposition on copper substrates. In this paper, the effect of CsPF6 additive on the performance of rechargeable Li metal batteries with lithium iron phosphate (LFP) cathode was further studied. Li|LFP coin cells with CsPF6 additive in electrolytes show well protected Li anode surface, decreased resistance, enhanced rate capability and extended cycling stability. In Li|LFP cells, the electrolyte with CsPF6 additive shows excellent long-term cycling stability (at least 500 cycles) at a charge current density of 0.5 mA cm-2 without internal short circuit. At high charge current densities, the effect of CsPF6 additive becomes less significant. Future work needs to be done to protect Li metal anode, especially at high charge current densities and for long cycle life.

  17. Enhanced performance of Li|LiFePO4 cells using CsPF6 as an electrolyte additive

    Xiao, Liang; Chen, Xilin; Cao, Ruiguo; Qian, Jiangfeng; Xiang, Hongfa; Zheng, Jianming; Zhang, Ji-Guang; Xu, Wu


    The practical application of lithium (Li) metal anode in rechargeable Li batteries is hindered by both the growth of Li dendrites and the low Coulombic efficiency (CE) during repeated charge/discharge cycles. Recently, we have discovered that CsPF6 as an electrolyte additive can significantly suppress Li dendrite growth and lead to highly compacted and well aligned Li nanorod structures during Li deposition on copper substrates. In this paper, the effect of CsPF6 additive on the performance of rechargeable Li metal batteries with lithium iron phosphate (LFP) cathode is further studied. Li|LFP coin cells with CsPF6 additive in electrolytes show well protected Li anode surface, decreased resistance, enhanced rate capability and extended cycling stability. In Li|LFP cells, the electrolyte with CsPF6 additive shows excellent long-term cycling stability (at least 500 cycles) at a charge current density of 0.5 mA cm-2 without internal short circuit. At high charge current densities, the effect of CsPF6 additive becomes less significant. Future work needs to be done to protect Li metal anode, especially at high charge current densities and for long cycle life.

  18. Biosorption of BF-4B Reactive Red Dye by using Leaves of Macrophytes Eichhornia crassipes

    Aparecido Nivaldo Módenes


    Full Text Available The removal potential on BF-4B reactive red dye by Eichhornia crassipes dried leaves has been investigated. Furthermore, the influence of process parameters such as solution pH, agitation, and particle size on the dye adsorption efficiency was assessed. Both kinetic and equilibrium experiments were performed in batch operation of the system. Kinetic results demonstrated that the equilibrium state was achieved after 45 min process time. The kinetic experimental data were best described by applying a pseudo-second order model that evaluated the value of rate constant 0.22 g/mg/min and an equilibrium dye concentration 8.20 mg/g. A set of isotherm models, taken from knowledge database, was tested in order to represent the equilibrium adsorption data. The Langmuir model performed the best when fitting experimental data where the maximum adsorption capacity of 20.38 mg/g was achieved. The results demonstrated that the E. crassipes has good potential to be used as a biosorbent in industrial treatment systems to remove reactive dyes from textile effluents.

  19. Time-dependent effects of [apyr]BF4 and key contributors to their mixture stimulation on Vibrio qinghaiensis sp.-Q67 at apical and biochemical levels.

    Yu, ZhenYang; Zhang, Jing


    Earlier reports studied the time-dependent effects of imidazolium-based ionic liquids ([amim]X) in the aspect of biochemical explanation and that of key contributor in mixture effects. Presently, the effects of N-alkylpyridinium-based ILs ([apyr]BF4) were studied combining the above two aspects, i.e., the time-dependent effects of [bpyr]BF4, [hpyr]BF4 and [opyr]BF4 on luminescence and biochemical indicators in Vibrio qinghaiensis sp.-Q67, and those of the mixtures. In individual results, the inhibition on luminescence increased over concentrations and the side chain length, showing concentration- and side chain-dependence. Moreover, the inhibition of [apyr]BF4 decreased from 0.25 to 24h, showing a time-dependence. Notably, [hpyr]BF4 stimulated the luminescence at 24h. The biochemical effects, including inhibition and stimulation, were well correlated to those on luminescence. In mixture results, the inhibition on luminescence was lower than the predicted effects by concentration addition model which was based on individual results. Moreover, the mixture stimulation on luminescence was significantly higher than individual ones, and the mixture stimulation on biochemical indicators was even greater than that on luminescence. In mixture effects, [bpyr]BF4 was the positive contributor, and [hpyr]BF4 was the negative contributor. Similarities and differences between [amim]X and [apyr]BF4 indicated underlying mechanisms of the commonly observed hormetic effects of ionic liquids. PMID:27017397

  20. Direct measurement of the chemical reactivity of silicon electrodes with LiPF6-based battery electrolytes

    Veith, Gabriel M [ORNL; Baggetto, Loic [ORNL; Sacci, Robert L [ORNL; Unocic, Raymond R [ORNL; Tenhaeff, Wyatt E [ORNL; Browning, Jim [ORNL


    We report the first direct measurement of the chemistry and extent of reactivity between a lithium ion battery electrode surface (Si) and a liquid electrolyte (1.2M LiPF6-3:7 wt% ethylene carbonate:dimethyl carbonate). This layer is estimated to be 3.6 nm thick and partially originates from the consumption of the silicon surface.

  1. Graphene-Polypyrrole Nanocomposite as a Highly Efficient and Low Cost Electrically Switched Ion Exchanger for Removing ClO4- from Wastewater

    Zhang, Sheng; Shao, Yuyan; Liu, Jun; Aksay, Iihan A.; Lin, Yuehe


    Perchlorate (ClO4-) contamination is now recognized as a widespread concern affecting many water utilities. In this report, graphene is employed as the scaffold to synthesize novel graphene-polypyrrole nanocomposite, which is demonstrated as excellent electrically switched ion exchanger for perchlorate removal. Scanning electron microscopy (SEM) and electrochemical measurements showed that the 3D nanostructured graphene/Ppy nanocomposite exhibited the significantly improved uptake capacity for ClO4- compared with Ppy film. X-ray photoelectron spectroscopy (XPS) confirmed the uptake and release process of ClO4- in graphene/Ppy nanocomposite. In addition, the presence of graphene substrate resulted in high stability of graphene/Ppy nanocomposite during potential cycling. The present work provides a promising method for large scale water treatment.

  2. Comparison of the local binding motifs in the imidazolium-based ionic liquids [EMIM][BF4] and [EMMIM][BF4] through cryogenic ion vibrational predissociation spectroscopy: Unraveling the roles of anharmonicity and intermolecular interactions

    We clarify the role of the critical imidazolium C(2)H position (the central C between N atoms in the heterocycle) in the assembly motif of the [EMIM][BF4] ionic liquid by analyzing the vibrational spectra of the bare EMIM+ ion as well as that of the cationic [EMIM]2[BF4]+ (EMIM+ = 1-ethyl-3-methylimidazolium, C6H11N2+) cluster. Vibrational spectra of the cold, mass-selected ions are obtained using cryogenic ion vibrational predissociation of weakly bound D2 molecules formed in a 10 K ion trap. The C(2)H behavior is isolated by following the evolution of key vibrational features when the C(2) hydrogen, the proposed binding location of the anion to the imidazolium ring, is replaced by either deuterium or a methyl group (i.e., in the EMMIM+ analogue). Strong features in the ring CH stretching region of the bare ion are traced to Fermi resonances with overtones of lower frequency modes. Upon incorporation into the EMIM+ ⋅ ⋅ ⋅ BF4− ⋅ ⋅ ⋅ EMIM+ ternary complex, the C(2)H oscillator strength is dramatically increased, accounting for the much more complicated patterns derived from the EMIM+ ring CH stretches in the light isotopomer, which are strongly suppressed in the deuterated analogue. Further changes in the spectra that occur when the C(2)H is replaced by a methyl group are consistent with BF4− attachment directly to the imidazolium ring in an arrangement that maximizes the electrostatic interaction between the molecular ions


    王成俊; 郭爱红; 王凤花; 韩晓丽; 张宝贵



  4. Photoinduced electron and energy transfer from coumarin 153 to perylenetetracarboxylic diimide in bmimPF6/TX-100/water microemulsions.

    Wu, Haixia; Wang, Haixia; Xue, Lin; Li, Xiyou


    A perylenetetracarboxylic diimide (PDI) compound with an attached hydrophilic polyoxyethylene group at the imide nitrogen position was designed and synthesized. Photoinduced electron and energy transfer between coumarin 153 (C-153) and PDI in a ternary microemulsion with an ionic liquid (bmimPF(6)/TX-100/H(2)O) were investigated by steady state electronic absorption and fluorescence spectroscopy. The results revealed that both PDI and C-153 resided at the interface between the surfactant TX-100 and the ionic liquid bmimPF(6) in the ternary microemulsions. The absorption spectra suggested no interactions between C-153 and PDI in the ground states, but the fluorescence spectra revealed the presence of an efficient electron transfer and a less efficient energy transfer from C-153 to PDI. Moreover, the electron transfer was much more efficient in microemulsions than that in homogeneous conventional organic solvents due to the unique micro-environment of the microemulsion. PMID:20965513

  5. Overhauser effect experiments on the one-dimensional conductor (perylene)2+PF6-·2/3THF

    Brunner, Hermann; Hausser, Karl H.; Keller, Heimo J.; Schweitzer, Dieter


    We have measured the Overhauser enhancement of the protons and the 19F-nuclei of the one-dimensional conductor (perylene)2+PF6-·2/3THF in its metallic phase at room temperature. The enhancement factor V was found to be VP=+320±20 for the protons and VF=+175±40 for the 19F-nuclei indicating a predominantly scalar interaction with the conduction electrons in both cases.

  6. Direct measurement of the chemical reactivity of silicon electrodes with LiPF6-based battery electrolytes.

    Veith, Gabriel M; Baggetto, Loïc; Sacci, Robert L; Unocic, Raymond R; Tenhaeff, Wyatt E; Browning, James F


    We report the first direct measurement of the extent of the spontaneous non-electrochemically driven reaction between a lithium ion battery electrode surface (Si) and a liquid electrolyte (1.2 M LiPF6-3 : 7 wt% ethylene carbonate : dimethyl carbonate). This layer is estimated to be 35 Å thick with a SLD of ∼ 4 × 10(-6) Å(-2) and likely originates from the consumption of the silicon surface. PMID:24513965

  7. TEMPO-catalyzed aerobic oxidation of alcohols to aldehydes and ketones in ionic liquid [bmim][PF6].

    Ansari, Imtiaz A; Gree, Rene


    [reaction: see text]. A simple and mild TEMPO-CuCl catalyzed aerobic oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones in ionic liquid [bmim][PF6] with no trace of overoxidation to carboxylic acids has been developed. The product can be isolated by a simple extraction with organic solvent, and the ionic liquid can be recycled or reused. PMID:11975615

  8. Dielectric spectroscopy study on ionic liquid microemulsion composed of water, TX-100, and BmimPF6

    Chen, Zhen; Nozaki, Ryusuke


    We report here a broadband dielectric spectroscopy study on an ionic liquid microemulsion (ILM) composed of water, Triton X-100 (TX-100), and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6). It is found that the phase behavior of this ILM can be easily identified by its dielectric response. The dielectric behavior of the ILM in the GHz range is consistent with that of TX-100/water mixtures with comparable water-to-TX-100 weight ratio. It consists of the relaxations due to ethylene oxide (EO) unit relaxation, hydration water dynamics, and/or free water dynamics. The water content dependence of the EO unit relaxation suggests that this relaxation involves dynamics of hydration water molecules. In the IL-in-water microemulsion phase, it is found that bmimPF6 molecules are preferentially dissolved in water when their concentration in water is lower than the solubility. An additional dielectric relaxation that is absent in the TX-100/water mixtures is observed in the frequency range of 107-108 Hz for this ILM. This low-frequency relaxation is found closely related to the bmimPF6 molecule and could be attributed to the hopping of its cations/anions between the anionic/cationic sites.

  9. Electrochemical investigation of Li-Al anodes in oligo(ethylene glycol) dimethyl ether/LiPF6

    LiPF6 dissolved in oligo(ethylene glycol) dimethyl ether with a molecular weight 5 g mol-1 was investigated as a new electrolyte (OEGDME5, 1 M LiPF6) for metal deposition and battery applications. At 25 C a conductivity of .48 x 1-3 S cm-1 was obtained and at 85 C, 3.78 x 1-3 S cm-1. The apparent activation barrier for ionic transport was evaluated to be 3.7 kJ mol-1. OEGDME5, 1 M LiPF6 allows operating temperature above 1 C with very attractive conductivity. The electrolyte shows excellent performance at negative and positive potentials. With this investigation, we report experimental results obtained with aluminum electrodes using this electrolyte. At low current densities lithium ion reduction and re-oxidation can be achieved on aluminum electrodes at potentials about 28 mV more positive than on lithium electrodes. In situ X-ray diffraction measurements collected during electrochemical lithium deposition on aluminum electrodes show that the shift to positive potentials is due to the negative Gibbs free energy change of the Li-Al alloy formation reaction.

  10. A laser flash photolysis study on duroquinone in binary mixtures of ionic liquid [bmim]+[PF6]- and acetonitrile

    Room temperature ionic liquids (RTILs) are entirely composed of special organic cations and anions, which are liquid near room temperature. Owing to their desirable properties including nonvolatility, high polarity, high selectivity and ease of recycling, RTILs are regarded as suitable solvents for green chemistry,which have been used as reaction media for a number of organic synthesis reactions, catalysis, separation processes and polymerization. As a prototype of RTIL, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] has been used as medium in which some representative photochemical reactions have been previously studied in comparison with volatile organic compounds. It was found that molecular diffusion of solute was significantly retarded and lifetime of transient species was longer in the neat [bmim][PF6]. Laser flash photolysis experiments were carried out using a Nd:YAG laser that provides 266 and 355 nm laser pulse with a duration of 5 ns and a maximum energy of 80 mJ per pulse. Using duroquinone (DQ) as a probe molecule photochemical properties of the ionic liquid [bmim][PF6] and its binary mixed solutions with acetonitrile (MeCN) were investigated at an excitation wavelength of 355 nm by laser flash photolysis technique. Along with the increasing of the fraction of [bmim][PF6] in the mixture, the characteristic absorption peak of triplet excited state 3DQ* showed a blue shift of ca. 20 nm. It was found that the decay of 3DQ* under N2 atmosphere followed a mono-exponential kinetics. Its rate constant increased with xRTIL (VRTIL/VMeCN) before the critical point at xRTIL = 0.3; however, it decreased obviously with xRTIL after the critical point. The experimental results indicate that RTIL didn't react with 3DQ*, which is different from our previous study on anthraquinone in binary solutions of [bmim][PF6] and acetonitrile. In view of the experimental data, it can be concluded that the viscosity and phase transformation are dominant for the effects

  11. Moessbauer study and magnetic properties of bis (ethanol) tetraphenylporphinatoiron (III) tetrafluoroborate [Fe(EtOH)2(tpp)]+BF4-

    Moessbauer experiments and magnetic measurements have been performed at various temperatures between 1.8 and 300 K on a six-coordinated iron porphyrin [Fe(EtOH)2(tpp)]+BF4-. All the results are consistent with the presence of high-spin iron (III) with an unambiguous S = 5/2 ground state. A marked reversal of the asymmetric broadening of the quadrupole doublet lines has been observed between 1.8 and 300 K. This asymmetric broadening of the lines arising from relaxation effects depends on the directions along which the hyperfine magnetic field fluctuates relative to the principal axes of the e.f.g. tensor. (Auth.)

  12. Theoretical study on reaction of [(Ind ∗)Rh(CO) 2Me]BF 4 with nbd

    Bi, Siwei; Wang, Bin; Zhao, Yi; Zhang, Zhenwei; Zhu, Shufen


    The mechanisms on the model reaction of [(Ind)Rh(CO) 2Me]BF 4 with nbd have been studied using density functional theory. Two pathways are proposed due to the rotation of indenyl group. Our results of calculations predict that the methyl migration is the rate-determining step, and that the rotation of indenyl group around the Rh-indenyl axis plays an important role in lowering the reaction barrier. Theoretical studies also reveal that this kind of reaction is favorable thermodynamically as a result of the relief of ring strain as nbd coordinating to the metal center and the chelation effect arisen from the cyclometallation.

  13. Effect of ZrO2 on conductivity of PVC–PMMA–LiBF4–DBP polymer electrolytes

    S Rajendran; T Uma


    The preparation and characterization of composite polymer electrolytes of PVC–PMMA–LiBF4–DBP for different concentrations of ZrO2 have been investigated. FTIR studies indicate complex formation between the polymers, salt and plasticizer. The electrical conductivity values measured by a.c. impedance spectroscopy is found to depend upon the ZrO2 concentration. The temperature dependence of the conductivity of the polymer films seems to obey the VTF relation. The conductivity values are presented and results discussed.

  14. Dielectric spectroscopy study on ionic liquid microemulsion composed of water, TX-100, and BmimPF6

    Chen, Zhen; Nozaki, Ryusuke


    We report here a broadband dielectric spectroscopy study on an ionic liquid microemulsion (ILM) composed of water, Triton X-100 (TX-100), and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6). It is found that the phase behavior of this ILM can be easily identified by its dielectric response. The dielectric behavior of the ILM in the GHz range is consistent with that of TX-100/water mixtures with comparable water-to-TX-100 weight ratio. It consists of the relaxations due to ethylene o...

  15. Nonlinear Hall effect in the field-induced spin-density wave states of (TMTSF)2PF6

    The resistivity along the conducting chains, ρxx, and the Hall resistivity ρxy are investigated as a function of the electric field in the magnetic-field-induced spin-density wave (FISDW) states of (TMTSF)2PF6 under hydrostatic pressure. Both resistivities decrease with increasing electric field above the same well-defined threshold electric field in the order of 100 μV/cm. We interpret the nonlinearity by the depinning and sliding of the FISDW. The nonlinearity in ρxy is much stronger than in ρxx what we attribute to an unusually strong coupling between the FISDW and single-particle excitations. (orig.)

  16. Glass transition in the spin density wave phase of (TMTSF)2PF6 investigated by calorimetric measurements

    We report on detailed kinetic investigation of the specific heat anomaly of the spin density wave phase of (TMTSF)2PF6 in the temperature range 2.5-5K. We point out the crucial role of kinetic conditions and of previous thermal history, such as isothermal annealing, which causes large hysteretic phenomena. This gives strong support to the origin of the anomaly in a glass transition which can be described in the general framework of freezing of supercooled liquids. For the unannealed system, Tg = 3.45 K. (orig.)

  17. Experiments and model for the surface tension of (MDEA + [Bmim][BF4]) and (MDEA + [Bmim][Br]) aqueous solutions

    Highlights: • The surface tensions of (MDEA + ionic liquids) aqueous solutions were measured. • The experiments were modeled satisfactorily by using a thermodynamic equation. • The temperature dependence of the surface tension was illustrated. • The effects of the mass fractions of MDEA and ionic liquids were demonstrated. -- Abstract: The surface tension (γ) of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), 1-butyl-3-methylimidazolium bromide ([Bmim][Br]), (N-methyldiethanolamine(MDEA) + [Bmim][BF4]) and (MDEA + [Bmim][Br]) aqueous solutions were measured by using the BZY-1 surface tension meter. The temperature ranged from (293.2 to 323.2) K. The mass fraction of MDEA ranged from 0.35 to 0.45. A thermodynamic equation was proposed to model the surface tension of (MDEA + ionic liquids) (ILS) aqueous solutions and the calculated results agreed well with the experiments. The effects of temperature, mass fractions of MDEA and ILS on the surface tension were demonstrated on the basis of experiments and calculations

  18. Thermal properties of [Cr(NH3)6](BF4)3 studied by adiabatic and relaxation calorimetry

    Highlights: • Four solid phase transitions are observed between T = (9 and 300) K for [Cr(NH3)6](BF4)3. • Low temperature properties were investigated with relaxation calorimetry below T = 20 K. • For nonzero values of applied magnetic field well-defined Schottky anomaly appears. • Isothermal magnetization curve recorded up to 5 T was measured at T = 1.8 K. - Abstract: Four (solid–solid) phase transitions were detected in the temperature range of (9 to 300) K in polycrystalline [Cr(NH3)6](BF4)3 at TC1 = 240.7 K, TC2 = 108.0 K, TC3 = 91.9 K, and TC4 = 61.3 K by adiabatic calorimetry. The measurements by relaxation calorimetry were followed on lowering temperature from 20 K down to 0.35 K under six different external magnetic field values (9, 7, 5, 3, 1 and 0) T. For non-zero values of applied magnetic field well-defined Schottky anomaly appears. Magnetic heat capacity was calculated assuming the zero-field splitting for the decoupled Cr(III) ions. There is no discrepancy between the observed and calculated values. Isothermal magnetization curve recorded up to 5 T was measured at temperature of 1.8 K

  19. The Chlamydomonas PF6 Locus Encodes a Large Alanine/Proline-Rich Polypeptide That Is Required for Assembly of a Central Pair Projection and Regulates Flagellar Motility

    Rupp, Gerald; O'Toole, Eileen; Porter, Mary E.


    Efficient motility of the eukaryotic flagellum requires precise temporal and spatial control of its constituent dynein motors. The central pair and its associated structures have been implicated as important members of a signal transduction cascade that ultimately regulates dynein arm activity. To identify central pair components involved in this process, we characterized a Chlamydomonas motility mutant (pf6-2) obtained by insertional mutagenesis. pf6-2 flagella ...

  20. First-principle investigation of the interactions between PtxRu55−x (x = 0, 13, 42, 55) nanoparticles and [BMIM][PF6] ionic liquid

    Highlights: • Interaction between PtRu nanoparticle and [BMIM][PF6] is performed by DFT calculations. • The structure of Pt13Ru42 nanoparticle is distorted induced by [BMIM][PF6]. • The d-band center show that catalytic activities of Pt13Ru42 and Ru55 are enhanced. • Two C atoms of [BMIM][PF6] form the bond with Pt13Ru42 nanoparticles. - Abstract: Density functional theory calculations have been performed to characterize the interactions between [BMIM][PF6] ionic liquid and icosahedral PtxRu55−x (x = 0, 13, 42, 55) nanoparticles. In Ru13Pt42–[BMIM][PF6], only one F atom of the anion form the bond with nanoparticle, resulting in the smallest interaction energy (−0.56 eV). While in Pt13Ru42–[BMIM][PF6], two F atoms of the anion together with two C atoms of cation form the bonds with nanoparticle, resulting in the biggest interaction energy (−10.65 eV). The interaction between [BMIM][PF6] and Pt13Ru42 is so strong that it induces a significant distortion in the original core–shell structure of Pt13Ru42. Moreover, after interacting with [BMIM][PF6], the Pt55, Pt13Ru42 and Ru55 nanoparticles become more stable based on the negative relaxation energy. The d-band centers of Pt13Ru42 and Ru55 shift from −1.90, −1.78 eV up to −1.78, −1.56 eV, suggesting that the catalytic activities of Pt13Ru42 and Ru55 are enhanced

  1. Preparation and Molten Salt as Performances of Room Electrolyte carbon Capacitor Based on Trifluoroacetamide n CarbonLiPF6 and


    A novel room moRen salt with an eutectic temperature of about -62℃ is prepared using LiPF6 and trifluoroacetamide as precursors. And then its performance is evaluated in carbon-carbon electrochemical double layerdifferent molar ratios are characterized and then the liquid-solid phase diagram is presented. The electrochemical performance tests show that the as-prepared LiPF6/trifluoroacetamide molten salt is a promising electrolyte candidate for carboncarbon EDLCs.

  2. Studies on structural, thermal and AC conductivity scaling of PEO-LiPF6 polymer electrolyte with added ionic liquid [BMIMPF6

    Chaurasia, S. K.; Saroj, A. L.; Shalu, Singh, V. K.; Tripathi, A. K.; Gupta, A. K.; Verma, Y. L.; Singh, R. K.


    Preparation and characterization of polymer electrolyte films of PEO+10wt.% LiPF6 + xwt.% BMIMPF6 (1-butyl-3-methylimidazolium hexafluorophosphate) containing dopant salt lithium hexafluorophosphate (LiPF6) and ionic liquid (BMIMPF6) having common anion PF6 - are reported. The ionic conductivity of the polymer electrolyte films has been found to increase with increasing concentration of BMIMPF6 in PEO+10 wt.% LiPF6 due to the plasticization effect of ionic liquid. DSC and XRD results show that the crystallinity of polymer electrolyte decreases with BMIMPF6 concentration which, in turn, is responsible for the increase in ionic conductivity. FTIR spectroscopic study shows the complexation of salt and/or ionic liquid cations with the polymer backbone. Ion dynamics behavior of PEO+LiPF6 as well as PEO+LiPF6 + BMIMPF6 polymer electrolytes was studied by frequency dependent conductivity, σ(f) measurements. The values σ(f) at various temperatures have been analyzed in terms of Jonscher power law (JPL) and scaled with respect to frequency which shows universal power law characteristics at all temperatures.

  3. Ab initio studies on [bmim][PF6]–CO2 mixture and CO2 clusters

    B L Bhargava; M Saharay; S Balasubramanian


    Ab initio molecular dynamics studies have been carried out on the room temperature ionic liquid, 1,n-butyl,3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and supercritical carbon dioxide mixture at room temperature and experimental density. Partial radial distribution functions (RDF) for different sites have been computed to see the organization of CO2 molecules around the ionic liquid. Several partial RDFs around the carbon atom of CO2 molecule are compared to find out that the CO2 has specific interaction with a carbon atom present in the imidazolium ring. The CO2 is also found to be very well organized around the terminal carbon atom of the butyl chain. The partial RDFs for the oxygen atoms around oxygen and carbon atoms of the CO2 suggests that there is very good organization of CO2 molecules around themselves even in the [bmim][PF6] – CO2 mixture. The instantaneous quadrupole moment tensor has been calculated for the anion and the cation. The ensemble average of diagonal components of quadrupole moment tensor of the cation have finite values, whereas the off-diagonal components of the cation and both the diagonal and off-diagonal components of the anion have the value of zero with a large standard deviation. The CPMD studies performed on CO2 clusters reveals the greater tendency of the clusters with more CO2 units, to deviate from the linear geometry.

  4. Ultra-fast and sensitive photo-induced phase switching in (EDO-TTF)2PF6

    Organic conductor (EDO-TTF)2PF6 crystal having 14 filled band shows a metal (M)-insulator (I) transition accompanied with Peierls transition, charge ordering, and anion ordering at transition temperature, TC=280K. This crystal is an important and fascinating candidate for photo-induced M-I transition because the multi-instability will afford sensitivity to the tiny stimulation. We make the report of the reflectivity change in (EDO-TTF)2PF6 crystal induced by the irradiation of femto-second (fs) pulsed laser (pulse width: 120fs, main wavelength: 800nm, repetition rate: 1kHz). The obtained results indicate that the highly efficient I-to-M transition occurs within 3ps in this material. Based on these results, the strong electron-lattice cooperative interaction is proved to play an essential role in the driving process of this M-I transition. Also, 14 filled materials, which show M-I transition, accompanied with the charge ordering, can be classified as fascinating candidates not only for superconductivity but also for photo-induced cooperative phenomena and application in phase switching devices

  5. Electrochemical fabrication of TiO2 nanoparticles/[BMIM]BF4 ionic liquid hybrid film electrode and its application in determination of p-acetaminophen

    A water soluble ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM]BF4), was incorporated into TiO2 nanoparticles to fabricate a hybrid film modified glassy carbon electrode (nano‐TiO2/[BMIM]BF4/GCE) through electrochemical deposition in a tetrabutyltitanate sol solution containing [BMIM]BF4. The obtained nano‐TiO2/[BMIM]BF4/GCEs were characterized scanning electronic microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). Electrochemical behaviors of p‐acetaminophen at the nano‐TiO2/[BMIM]BF4/GCEs were thoroughly investigated. Compared to the redox reaction of p‐acetaminophen using an unmodified electrode under the same conditions, a new reduction peak was observed clearly at 0.26 V with the modified electrode. In addition, the peak potential for the oxidation of p‐acetaminophen was found to shift negatively about 90 mV and the current response increased significantly. These changes indicate that the nano‐TiO2/[BMIM]BF4 hybrid film can improve the redox reactions of p‐acetaminophen in aqueous medium. Under optimum conditions, a linear relationship was obtained for the p‐acetaminophen solutions with concentration in the range from 5.0 × 10−8 to 5.0 × 10−5 M. The estimated detection limit was 1.0 × 10−8 M (S/N = 3). The newly developed method was applied for the determination of p-acetaminophen in urine samples. - Highlights: ► Nano-TiO2/[BMIM]BF4 hybrid film electrode was fabricated with electrodeposition. ► Voltammetric behavior of p-acetaminophen at the obtained electrode was investigated. ► The hybrid film electrode shows good electrocatalytic response to p-acetaminophen. ► p-acetaminophen in urine samples was successfully determined.

  6. Isothermal and non-isothermal crystallization kinetics of PVA + ionic liquid [BDMIM][BF4]-based polymeric films

    Saroj, A. L.; Chaurasia, S. K.; Kataria, Shalu; Singh, R. K.


    The effect of ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [BDMIM][BF4], on crystallization behavior of poly(vinyl alcohol) (PVA) has been studied by isothermal and non-isothermal differential scanning calorimetry techniques. The PVA + IL based polymer electrolyte films have been prepared using solution casting technique. To describe the isothermal and non-isothermal crystallization kinetics, several kinetic equations have been employed on PVA + IL based films. There is strong dependence of the peak crystallization temperature (Tc), relative degree of crystallity (Xt), half-time of crystallization (t1/2), crystallization rate constants (Avrami Kt and Tobin AT), and Avrami (n) and Tobin (nT) exponents on the cooling rate and IL loading.

  7. Synthesis, characterization and cytotoxic activities of the [RuCl2(NO)(dppp)(L)]PF6 complexes.

    Golfeto, Camilla C; Von Poelhsitz, Gustavo; Selistre-de-Araújo, Heloísa S; de Araujo, Márcio P; Ellena, Javier; Castellano, Eduardo E; Lopes, Luiz G L; Moreira, Icaro S; Batista, Alzir A


    The synthesis and characterization of ruthenium compounds of the type [RuCl(2)(NO)(dppp)(L)]PF(6) [dppp=1,3-bis(diphenylphosphino)propane; L=pyridine, 4-methylpyridine, 4-phenylpyridine and dimethyl sulfoxide] are described. The complexes were characterized by elemental analysis, UV/Vis and infrared spectroscopy, cyclic voltammetry, and X-ray crystallography for the complexes with the pyridine and 4-methylpyridine ligands. In vitro evaluation of these nitrosyl complexes revealed cytotoxic activity from 7.1 to 19.0 microM against the MDA-MB-231 breast tumor cells and showed that, in this case, they are more active than the reference metallodrug cisplatin. The 1,3-bis(diphenylphosphino)propane and the N-heterocyclic ligands alone failed to show cytotoxic activities at the concentrations tested (maximum concentration utilized=200 microM). PMID:20117840

  8. Electrochemical behavior of Ru(H2bpp)2(PF6)2 and its interaction with bovine serum albumin (BSA)

    Qiao Hua Wei; Li Jing Han; Jing Hua Chen; Fang Nan Xiao; Shen Liang Zeng; Guo Nan Chen


    In this paper, it was found that Ru(H2bpp)2(PF6)2 (H2bpp = 2,6-bis(pyrazol-3-yl)pyridine) complex had excellent electrochemical activity at the carbon paste electrode in the buffer solution of Tris-HCl (pH 7.0) with a couple reversible redox peaks at 0.296 V and 0.348 V, respectively. Voltammetry was used to investigate the electrochemical behavior of Ru(H2bpp)2(PF6)2 and the interaction between Ru(H2bpp)2(PF6)2 and bovine serum albumin (BSA). In the present of BSA, the oxidation peak current of Ru(H2bpp)2(PF6)2 complex was decreased linearly and the decrease of oxidation peak current of Ru(H2bpp)2(PF6)2 is proportional to BSA concentration from 0.1 to 2.5 mg/L with a detection limit 0.02 mg/L.

  9. [BMIM] [BF4] ionic liquid assistance effect on the crystallinity and morphology of Sb2S3 nanostructures synthesized by ultrasound

    Unidimensional crystalline Sb2S3 nanostructures were successfully synthesized by ultrasound irradiation assisted with the ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4]. The starting reagents were SbCl3, thioacetamide, absolute ethanol (AET), and the used ionic liquid was [BMIM][BF4]. The resultant materials were thermally annealed at 155 and 200 oC under controlled vacuum conditions. The experiments showed that IL assistance played a key role in the crystallinity and morphology of the obtained products. The resultant materials were characterized by powder X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray analysis (EDX). (author).

  10. NMR determination of the ordering of CH3NO2 co-intercalated with PF6-, AsF6-, or SbF6- in graphite

    Comparison of the intensities of the 19F and 1H NMR spectra of the graphite intercalation compound prepared by reaction of highly-oriented pyrolytic graphite with NO2PF6 dissolved in CH3NO2 showed that the number of CH3NO2 molecules present per PF6- ion varied from 1.64 to 1.14 depending upon sample preparation. The 1H NMR spectra of CH3NO2 in single pieces of HOPG intercalated with PF6-, AsF6-, or SbF6- show 1:2:1 triplets due to dipolar splittings resulting from partial ordering of the CH3NO2 molecules with the molecular symmetry axis parallel to the graphite planes. (Auth.)

  11. Synthesis and Structural Characterization of the Tetrakis(methimazolyl)borates Li[Bmt4] and [Ru(p-cymene)(Bmt4)][PF6

    Kunz, Kerstin; Bolte, Michael; Wagner, Matthias; Lerner, Hans-Wolfram


    Abstract The lithium tetrakis(methimazolyl)borate Li[Bmt4] is accessible from the reaction of Li[BH4] with four equivalents of methimazole. The crystal structure of Li[Bmt4] supported by four water molecules is described. Reaction of Li[Bmt4] with [Ru(p-cymene)Cl2]2 and subsequent treatment with NH4PF6 in CH3CN results in the formation of the complex [Ru(p-cymene)(Bmt4)][PF6]. In addition, we report the result of the X-ray structure analysis of the chiral Ru complex [Ru(p-cymene)(B...

  12. [PAMIM][PF6]离子液体作为气相色谱固定相的研究%Research of [PAMIM][PF6] ionic liquid as stationary phase for gas chromatography

    郑建华; 申书昌; 陈光


    以1-甲基咪唑、氯丙烯、六氟磷酸钾为原料合成了一种聚合离子液体聚-1-丙烯基-3-甲基咪唑六氟磷酸盐([PAMIM][PF6]).通过红外光谱法和核磁共振波谱法表征了产物的结构,通过热重分析,考察了其分解温度,并确定了此离子液体作为气相色谱固定液的最高使用温度.以离子液体作为气相色谱固定相,制备了色谱填充柱,通过对烃系物、醇系物的分离,考察了色谱柱的分离效果、极性.%A kind of polymer ionic liquid which is called poly (l-allyl-3- methylimidazolium hexafluo-rophosphate) was synthesized using 1-methylimidazole, allyl chloride and hexafluorophosphate as raw meterials. The structure of the ionic liquid was characterized by IR and NMR. The maximum.operating of this ionic liquid temperature as gas chromatography stationary phase was confirmed by TGA The chromatography column was made of the ionic liquids and supporter .The separating character and polarity of the chromatography column were studied by the hydrocarbons and alcohols mixtures respectively.

  13. First-Principles United Atom Force Field for the Ionic Liquid BMIM(+)BF4(-): An Alternative to Charge Scaling.

    Son, Chang Yun; McDaniel, Jesse G; Schmidt, J R; Cui, Qiang; Yethiraj, Arun


    Molecular dynamics study of ionic liquids (ILs) is a challenging task. While accurate fully polarizable atomistic models exist, they are computationally too demanding for routine use. Most nonpolarizable atomistic models predict diffusion constants that are much lower than experiment. Scaled charge atomistic models are cost-effective and give good results for single component ILs but are in qualitative error for the phase behavior of mixtures, due to inaccurate prediction of the IL cohesive energy. In this work, we present an alternative approach for developing computationally efficient models that importantly preserves both the correct dynamics and cohesive energy of the IL. Employing a "top-down" approach, a hierarchy of coarse-grained models for BMIM(+)BF4(-) are developed by systematically varying the polarization/atomic resolution of the distinct functional groups. Parametrization is based on symmetry-adapted perturbation theory (SAPT) calculations involving the homomolecular species; all cross interactions are obtained from mixing rules, and there are no adjustable parameters. We find that enhanced dynamics from a united-atom description counteracts the effect of reduced polarization, enabling computationally efficient models that exhibit quantitative agreement with experiment for both static and dynamic properties. We give explicit suggestions for reduced-description models that are computationally more efficient, more accurate, and more fundamentally sound than existing nonpolarizable atomistic models. PMID:26900644

  14. Initiation and growth of a single pit on 316L stainless steel: Influence of SO42- and ClO4- anions

    In this paper, an ion micro dispenser (IMD) was used to initiate a single pit by generating chloride anions above a 316L stainless steel electrode in either H2SO4 or HClO4 electrolyte. The current variations with respect to time provided an unambiguous characterization of the single pit evolution. Different pit shapes were observed depending on both the nature of the electrolyte and potential applied to the electrode. Substituting SO42- for ClO4- gave smaller (in diameter) but deeper pits at the early stage of pitting. However, when using a different setup that allows the sustaining of the pit propagation with a continuous supply of Cl-, the deeper pits were observed in HClO4 rather than H2SO4. The formation of an iron sulphate salt film at the bottom of the pit by precipitation of dissolution products in H2SO4 slowed down the corrosion rate. At high potentials, the repassivation mechanism outweighed the metal dissolution in the ClO4- containing solution. (authors)

  15. Crystal structure and characterization of the novel NH+⋯N hydrogen bonded polar crystal [NH2(CH2)4NH][BF4

    Wojtaś, M.; Gaģor, A.; Czupiński, O.; Medycki, W.; Jakubas, R.


    Dielectric properties and phase transitions of the piperazinium tetrafluoroborate ([NH2(CH2)4NH][BF4], abbreviated as PFB) crystal are related to the one-dimensional arrangement of the cations linked by the bistable NH+⋯N hydrogen bonds and molecular motions of the [BF4]- units. The crystal structure of [NH2(CH2)4NH][BF4] is monoclinic at room temperature with the polar space group Pn. The polar/acentric properties of the room temperature phase IV have been confirmed by the piezoelectric and pyroelectric measurements. DSC measurements show that the compound undergoes three first-order structural phase transitions: at 421/411 K (heating/cooling), at 386/372 K and at 364/349 K. 1H and 19F NMR measurements indicate the reorientational motions of [BF4]- anions and piperazinium(+) cations as well as the proton motion in the hydrogen-bonded chains of piperazine along the [001] direction. Over the phase I the isotropic reorientational motions or even self-diffusion of the cations and anions are expected. The conductivity measurements in the vicinity of the II-I PT indicate a superionic phase over the phase I.

  16. Mixing thermodynamic properties of 1-butyl-4-methylpyridinium tetrafluoroborate [b4mpy][BF4] with water and with an alkan-1ol (methanol to pentanol)

    This article presents a study of the behaviour in solution of 1-butyl-4-methylpyridinium tetrafluoroborate [b4mpy][BF4] in water and in the first five alkanols of the series methanol to pentan-1-ol. The excess enthalpies, HmE and volumes, VmE were determined at the temperatures (298.15 and 318.15) K. At these temperatures, the [b4mpy][BF4] was completely miscible in water, methanol, and ethanol, but only partially miscible in the other alkanols. A solubility study was carried out and the (liquid + liquid) equilibria of the ([b4mpy][BF4] + alkanol) systems were experimentally determined, evaluating zones of complete miscibility and determining the UCST in each case. The mixtures with water gave positive values of HmE and VmE, being also positive the changes of these quantities with temperature. The mixtures with alkanols gave values of HmE>0 and VmEmE/dT)p>0 and (dVmE/dT)p4]. Excess properties were correlated with a suitable equation and the area and volume parameters were calculated for [b4mpy][BF4

  17. Crystal structure and characterization of the novel NH+⋯N hydrogen bonded polar crystal [NH2(CH2)4NH][BF4

    Dielectric properties and phase transitions of the piperazinium tetrafluoroborate ([NH2(CH2)4NH][BF4], abbreviated as PFB) crystal are related to the one-dimensional arrangement of the cations linked by the bistable NH+⋯N hydrogen bonds and molecular motions of the [BF4]− units. The crystal structure of [NH2(CH2)4NH][BF4] is monoclinic at room temperature with the polar space group Pn. The polar/acentric properties of the room temperature phase IV have been confirmed by the piezoelectric and pyroelectric measurements. DSC measurements show that the compound undergoes three first-order structural phase transitions: at 421/411 K (heating/cooling), at 386/372 K and at 364/349 K. 1H and 19F NMR measurements indicate the reorientational motions of [BF4]− anions and piperazinium(+) cations as well as the proton motion in the hydrogen-bonded chains of piperazine along the [001] direction. Over the phase I the isotropic reorientational motions or even self-diffusion of the cations and anions are expected. The conductivity measurements in the vicinity of the II–I PT indicate a superionic phase over the phase I. - Graphical abstract: It must be emphasized that the titled compound represents the first organic–inorganic simple salt containing the single-protonated piperazinium cation which was studied by means of the wide variety of experimental techniques. A survey of Cambridge Structural Database (CSD version 5.32 (November 2010) and updates (May 2011)) for structure containing the piperazinium cations yields 248 compounds with the doubly protonated piperazinium(2+) cations and only eight compounds with the singly protonated piperazinium(+) cations. Among these structures only one is the hybrid organic–inorganic material. This is piperazinium nitrate characterized structurally. The crystal packing of [NH2(CH2)4NH][BF4], phase IV. The dashed lines stand for the hydrogen bonds. The hydrogen bonds to BF4 groups are not included for the picture quality Highlights:

  18. Activated carbon and single-walled carbon nanotube based electrochemical capacitor in 1 M LiPF6 electrolyte

    Highlights: • Activated carbon and single-walled CNT based electrochemical capacitor. • Electrochemical analysis by means of CV, charge/discharge and impedance. • 1 M LiPF6 non-aqueous solution as an electrolyte. • AC/SWCNT electrode exhibits a maximum capacitance of 60.97 F g−1. - Abstract: Carbon nanotubes have been extensively studied because of their wide range of potential application such as in nanoscale electric circuits, textiles, transportation, health, and the environment. Carbon nanotubes feature extraordinary properties, such as electrical conductivities higher than those of copper, hardness and thermal conductivity higher than those of diamond, and strength surpassing that of steel, among others. This research focuses on the fabrication of an energy storage device, namely, an electrochemical capacitor, by using carbon materials, i.e., activated carbon and single-walled carbon nanotubes, of a specific weight ratio as electrode materials. The electrolyte functioning as an ion carrier is 1 M lithium hexafluorophosphate. Variations in the electrochemical performance of the device, including its capacitance, charge/discharge characteristics, and impedance, are reported in this paper. The electrode proposed in this work exhibits a maximum capacitance of 60.97 F g−1 at a scan rate of 1 mV s−1

  19. Proton NMR study of spin density wave thermal fluctuations in (TMTSF)2PF6, where TMTSF is tetramethyltetraselenafulvalene

    Measurements of the proton spin-lattice relaxation rate (1/T1) at a pressure of 1 bar in a single crystal of (TMTSF)2PF6 (TMTSF is tetramethyltetraselenafulvalene) are reported for the magnetic field in the range 0.25-1.48 T aligned along the b'- and c*-axes over the temperature range 2-30 K. The methyl group rotation contribution to 1/T1 is subtracted to obtain the spin density wave (SDW) contribution. Through measurements of 1/T1 below and above the spin flop transition it is determined that phason fluctuations of the SDW are responsible for most of the relaxation. Depinning the SDW's by an electric field leaves 1/T1 nearly unchanged, which indicates that the SDW and its fluctuation rate near 108 rad/s persist when the SDW is sliding. Analysis of the peak in 1/T1 near 3 K on the applied magnetic field suggests that it represents a slowing of thermally activated fluctuations with an activation energy Δ/kB = 18.3 ± 4.0 K, which is close to the single particle gap for this material. The contribution of critical fluctuations to 1/T1 is consistent with the transition being weakly first order. Unlike the relaxation in the ordered phase, the contribution of the critical fluctuations is isotropic and has little, if any dependence on magnetic field. (orig.)

  20. Enzymatic synthesis of phytosterol esters catalyzed by Candida rugosa lipase in water-in-[Bmim]PF6 microemulsion.

    Zeng, Chaoxi; Qi, Suijian; Li, Zhigang; Luo, Riming; Yang, Bo; Wang, Yonghua


    A water-in-ionic liquid microemulsion ([Bmim]PF6/Tween20/H2O) was applied as reusable reaction medium to esterify phytosterols with fatty acid by Candida rugosa lipase (CRL) successfully. Two kinds of commercial CRLs, AY30 and AYS which cannot effectively catalyze esterification in conventional reaction system were found effective in the microemulsion system. Effects of reaction parameters on esterification were investigated; results showed that the conversion rate of 87.9 and 95.1 % was obtained in 24 and 48 h of reaction, respectively, under the optimized condition: the molar ratio of water to Tween 20 (w 0 value) at 5.4, Tween 20 at a concentration of 305 mM, 50 °C,pH 7.4, 10 % of enzyme loading (w/w, with respect to total reactants), and phytosterols/lauric acid molar ratio of 1:2. Moreover, by using n-hexane as the extraction agent, the lipase-encapsulated microemulsion could be reused at least seven times (>168 h) without significant changes in the conversion rate, while achieving a purpose of simple separation and purification. PMID:25575761

  1. Reaction of the Anticancer Organometallic Ruthenium Compound, [(η6-p-CymeneRu(ATSCCl]PF6 with Human Serum Albumin

    Floyd A. Beckford


    Full Text Available The reaction of [(η6-p-cymeneRu(ATSCCl]PF6 (ATSC =9-anthraldehyde thiosemicarbazone with human serum albumin was investigated at different temperatures using fluorescence and infrared spectrophotometry. The binding constant, K, for the reaction was determined using a number of different methods. Using a modified Stern-Volmer equation, K was determined to be 9.09×104,12.1×104, and 13.1×104 M−1 at 293 K, 298 K, and 308 K, respectively. A thermodynamic analysis showed that the reaction is spontaneous with ΔG being negative. The enthalpy of reaction ΔH=16.5 kJ mol−1 and the entropy of reaction ΔS=152 Jmol−1K−1. The values of ΔH and ΔS suggest that hydrophobic forces are dominant in the mode of interaction and that the process is mostly entropy driven.

  2. Novel electrolyte mixtures based on dimethyl sulfone, ethylene carbonate and LiPF6 for lithium-ion batteries

    Hofmann, Andreas; Hanemann, Thomas


    In this study, novel electrolyte mixtures for Li-ion cells are presented which are composed of ethylene carbonate/dimethyl sulfone (80:20 wt./wt.) as a solvent mixture and LiPF6, lithium bis(oxalato)borate and lithium difluoro(oxalato)borate as conducting salts. The main advantages of the solvent mixture are high flash points of >140 °C which enhance the intrinsic safety of Li-ion cells while maintaining good cell performance above 0-5 °C. The movability of the lithium ions in the electrolyte is investigated via programmed current derivative chronopotentiometry. It is found that pure electrolyte properties cannot necessarily predict the electrolyte behavior in real Li-ion cells but the complex interplay between electrolytes, electrode materials and separators has to be taken into account. Using the newly developed electrolytes, it is possible to achieve C-rates up to 1.5C with >80% of the initial specific discharge capacity (25 °C). Within 200 cycles during one month in cell tests (C||NMC) it is proven that the retention of the specific capacity is >98% of the third discharge cycle in dependence of the conducting salt.

  3. Hydrolysis mechanisms for the organopalladium complex [Pd(CNN)P(OMe)3]BF4 in sulfuric acid.

    García, Begoña; Hoyuelos, Francisco J; Ibeas, Saturnino; Muñoz, María S; Peñacoba, Indalecio; Leal, José M


    The acid-catalyzed hydrolysis of the organopalladium complex [Pd(CNN)P(OMe)3]BF4 species was monitored spectrophotometrically at different sulfuric acid concentrations (3.9 and 11.0 M) in 10% v:v ethanol-water over the 25-45 degrees C temperature range and in 30% and 50% (v/v) ethanol-water at 25 degrees C. Two acidity regions (I and II) could be differentiated. In each of the two regions the kinetic data pairs yielded two different rate constants, k(1obs) and k(2obs), the former being faster. These constants were fitted by an Excess Acidity analysis to different hydrolyses mechanisms: A-1, A-2, and A-SE2. In region I ([H2SO4] 7.0 M), a switchover was observed from an A-1 mechanism (k(0,A1) = 1.3 x 10(-4) s(-1)) to an A-2 mechanism (k(0,A2) = 3.6 x 10(-3) M(-1) s(-1)). The temperature effect on the rate constants in 10% (v/v) ethanol-water yielded positive DeltaH and negative DeltaS values, except for the A-1 mechanism, where DeltaS adopted positive values throughout. The solvent permittivity effect, epsilonr, revealed that k(1obs)(av) and k(0,A2) dropped with a fall in epsilonr, whereas the k(0,ASE2) value remained unaffected. The set of results deduced is in line with the schemes put forward. PMID:19621916

  4. Electrochemical characterisation and modelling of the mass transport phenomena in LiPF6-EC-EMC electrolyte

    The conductivity, the salt diffusion coefficient, the lithium-ion transport number and the thermodynamic factor of the salt and the solvent were reported for LiPF6 in EC:EMC (3:7) at 25 deg. C and for concentrations between 0.2 and 2.0 mol/dm3. The mass transport in the electrolyte was fully characterised by combining three types of electrochemical experiments; concentration cells, galvanostatic polarisation experiments and electrochemical impedance measurements with a mathematical description of the mass transport in the electrolyte. The apparent salt diffusion coefficient had a local maximum in the concentration range, while the viscosity-dependent salt diffusion coefficient decreased from 4.1 x 10-10 m2/s at 0.2 mol/dm3 to 4.4 x 10-11 m2/s at 2.0 mol/dm3. Both the thermodynamic factor and the conductivity varied strongly with the concentration. The conductivity had a maximum of 9.5 mS/cm at 1.0 mol/dm3. The lithium-ion transport number with respect to the room decreased with increasing salt concentration, with a maximum of 0.37 at 0.2 mol/dm3 in the concentration range. The Maxwell-Stefan diffusivities and the electrolyte potential drop in a lithium-ion battery at steady state were lastly calculated from the obtained transport properties. An analysis of the characterisation method was also done on the basis of the characterisation results

  5. Design and Fabrication of a 200N Thrust Rocket Motor Based on NH4ClO4+Al+HTPB as Solid Propellant

    Wahid, Mastura Ab; Ali, Wan Khairuddin Wan


    The development of rocket motor using potassium nitrate, carbon and sulphur mixture has successfully been developed by researchers and students from UTM and recently a new combination for solid propellant is being created. The new solid propellant will combine a composition of Ammonium perchlorate, NH4ClO4 with aluminium, Al and Hydroxyl Terminated Polybutadiene, HTPB as the binder. It is the aim of this research to design and fabricate a new rocket motor that will produce a thrust of 200N by using this new solid propellant. A static test is done to obtain the thrust produced by the rocket motor and analyses by observation and also calculation will be done. The experiment for the rocket motor is successful but the thrust did not achieve its required thrust.

  6. Spectroscopic and quantum-chemical investigation of association of ions in acetonitrile - LiX (X=I, ClO4, NCS) systems

    Data on association constants of ions in acetonitrile-salt binary systems, obtained from the data on intensity of IR absorption bands of acetonitrile (Acn) molecules contained in solvate shells of Li+ cations, have been analyzed. Using the CCP MO LCAO semiempirical method in the PPDP approximation, electronic structure of acetonitrile molecule and AcnkLi+ and AcnmLi+X- complexes has been studied. It is ascertained that relative stability of ionic pairs Acn3Li+X-, estimated by the squares of their dipole momenta (characterizing solvation energy) increases in the series X=I, ClO4, NCS in agreement with data of spectroscopic experiment, according to which the constant of ion association for LiNCS solution in acetonitrile is much higher than for the systems CH3CN-LiI and CH3CN-LiClO4. 13 refs.,2 figs., 2 tabs.64

  7. Extraction of penicillin G by aqueous two-phase system of [Bmim]BF4/NaH2PO4

    LIU Qingfen; HU Xuesheng; WANG Yuhong; YANG Ping; XIA Hansong; YU Jiang; LIU Huizhou


    A novel approach for the extraction of penicillin G by aqueous two-phase system comprised of hydrophilic ionic liquid [Bmim]BF4 (1-butyl-3- methylimidazolium tetrafluoroborate) and NaH2PO4 is reported. The effects of some important parameters involving the concentration of NaH2PO4, the concentration of penicillin G, the amount of [Bmim]BF4 on the formation of aqueous two-phase system and the extraction yield of penicillin were investigated. The primary result shows that the ATPS can take advantage of penicillin concentrated in upper phase at higher pH value for penicillin extraction from its aqueous solution without emulsification.

  8. Physicochemical properties and electrochemical performance of [ Pmim ] [ ClO4 ] ionic liquid electrolyte in supercapacitor%[ Pmim ][ ClO4]电解质的物化性质及其在超级电容器中的性能研究

    武宣宇; 李美超; 张鑫源; 张庆国


    A novel ionic liquid 1 -Pentyl -3 -methylimidazolium perchlorate salts ([ Pmim] ClO4 ) was synthesized by two -steps method .The density , surface tension , and electrical conductivity of the ionic liquid were investigated in different temperatures .A supercapacitor composed of the activated carbon electrode and the [ Pmim] ClO4 electrolyte was prepared .The electrochemical performance of the supercapacitor was studied by cy-clic voltammograms, alternating current resistance , and constant current charge -discharge tests, respectively. The results showed that the density and the surface tension of [ Pmim] ClO4 decreased with the increase of tem-perature.The working voltage window of the supercapacitor reached to 5.0 V.Moreover, the capacitor possessed typical capacitance characteristic , good reversibility , and better cycleability , which showed a great potential of this ionic liquid electrolyte in supercapacitor applications .%采用两步法设计合成了一种新型离子液体电解质(液)1-戊基-3-甲基咪唑高氯酸盐([ Pmim][ ClO4]),对这种电解质的密度、表面张力、电导率等物化性质进行了测定.并将其与活性炭电极组装成超级电容器,通过交流阻抗、循环伏安及恒流充放电等测试手段对其电化学性能进行了研究.测试结果表明,该离子液体的密度和表面张力都随温度升高而减小,超级电容器的电化学窗口可以达到5.0 V,并且具有良好的电容特性、可逆性及循环特性,是一种具有应用潜力的超级电容器电解液.

  9. Organic-inorganic compounds with strong nonlinear optical properties based on 2,4,6-trimethylpyridinium and tetrahedral BF4- networks

    Wojtaś, Maciej; Bil, Andrzej; Jakubas, Ryszard; Gągor, Anna; Pietraszko, Adam; Czupiński, Olaf; Tylczyński, Zbigniew; Isakov, Dmitry


    A different organic-inorganic crystal—[2,4,6-trimethylpyridinium][BF4]—of nonlinear optical properties at room temperature was synthesized and characterized. The compound is built up of the organic [2,4,6-trimethylpyridinium] cations incorporated into inorganic, tetrahedral BF4 anions. It crystallizes at room temperature in the polar space group Pmn21, and undergoes three first-order phase transitions at [cooling (heating)] 241 (245) K, 297 (328) K, and 389 (406) K. The lowest temperature ferroic phase transition (ferroelastic; mm2→m type) is related to the significant pyroelectric effect. The compound was studied by single-crystal x-ray diffraction at several temperatures, using thermal (differential scanning calorimetry and thermogravimetric analysis) methods and dielectric spectroscopy. The piezoelectric, pyroelectric, and second-harmonic generation (SHG) properties were determined. Density-functional theory calculations in two stable phases are given. The [2,4,6-trimethylpyridinium][BF4] crystal exhibits a SHG efficiency of 1.7 times that of KDP. The mechanism of structural phase transitions in the title compound is discussed.

  10. Studies on the micropolarities of bmimBF4/TX-100/toluene ionic liquid microemulsions and their behaviors characterized by UV-visible spectroscopy.

    Li, Na; Gao, Yan'an; Zheng, Liqiang; Zhang, Jin; Yu, Li; Li, Xinwei


    Ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4), were substituted for polar water and formed nonaqueous microemulsions with toluene by the aid of nonionic surfactant TX-100. The phase behavior of the ternary system was investigated, and microregions of bmimBF4-in-toluene (IL/O), bicontinuous, and toluene-in-bmimBF4 (O/IL) were identified by traditional electrical conductivity measurements. Dynamic light scattering (DLS) revealed the formation of the IL microemulsions. The micropolarities of the IL/O microemulsions were investigated by the UV-vis spectroscopy using the methyl orange (MO) and methylene blue (MB) as absorption probes. The results indicated that the polarity of the IL/O microemulsion increased only before the IL pools were formed, whereas a relatively fixed polar microenvironment was obtained in the IL pools of the microemulsions. Moreover, UV-vis spectroscopy has also shown that ionic salt compounds such as Ni(NO3)2, CoCl2, CuCl2, and biochemical reagent riboflavin could be solubilized into the IL/O microemulsion droplets, indicating that the IL/O microemulsions have potential application in the production of metallic or semiconductor nanomaterials, and in biological extractions or as solvents for enzymatic reactions. The IL/O microemulsions may have some expected effects due to the unique features of ILs and microemulsions. PMID:17241018

  11. Lithium difluoro(oxalate)borate and LiBF4 blend salts electrolyte for LiNi0.5Mn1.5O4 cathode material

    Zhou, Hongming; Xiao, Kaiwen; Li, Jian


    The electrochemical behaviors of lithium difluoro(oxalate)borate (LiODFB) and LiBF4 blend salts in ethylene carbonate + dimethyl carbonate + ethyl(methyl) carbonate (EC + DMC + EMC, 1:1:1, by wt.) have been investigated for LiNi0.5Mn1.5O4 cathode in lithium-ion batteries. The electric conductivity tests are utilized to examine the relationship among solution conductivity, the electrolyte composition and temperature. Through cyclic voltammetry, charge-discharge test and AC impedance measurements, we compare the capacity and cycling efficiency of LNMO cathode in different electrolyte systems at different temperatures and discharge current rates. Scanning electron microscopy (SEM) analysis and X-ray photoelectron spectroscopy (XPS) are served to analyze the surface nature of LNMO cathode after cycles at elevated temperature. These results demonstrate that LNMO cathode can exert excellent electrochemical performance with the increase of LiODFB concentration at room temperature and elevated temperature and it is found that just slight LiBF4, mixed with LiODFB as blend salts, can strikingly improve the cyclability at -20 °C, especially in high-rate cycling. Grouped together, the optimum LiODFB/LiBF4 molar ratio is around 4:1, which can present an excellent affinity to LNMO cathode in a wide electrochemical window.

  12. Densities and Viscosities of 1-butyl-3-methylimidazolium Hexafluorophosphate [bmim][PF6]+CO2 Binary System:Determination and Correlation

    乔燕; 闫方友; 夏淑倩; 马沛生


    A gas-dissolving device was designed and connected to the falling-body viscometer, which was used to determine the viscosities of liquids in our lab before. The equipment can be used to determine the gas composition, the densities and viscosities of the solution at the same time. The densities and viscosities of [bmim][PF6]+CO2 binary system were determined in the temperature range of 313.2 to 413.2 K and pressure range of 5.0 to 25.0 MPa by the equipment. Then the viscosities of [bmim][PF6]+CO2 binary system at constant temperature, constant pres-sure, and different temperature and pressure were correlated, respectively. For the correlation at different tempera-ture and different pressure for different concentration mixtures the average relative deviation ARD is 0.037.

  13. Pd nanoparticles immobilized in [bmim][PF6] supported on laponite clay as highly recyclable catalysts for the Mizoroki-Heck reaction

    Martínez, Alejandro V.; Mayoral, José A.; García, José I.


    Mizoroki-Heck cross-couplings of aryl halides catalyzed by highly active palladium nanoparticles, immobilized on [bmim][PF6] films supported on laponite clay, have been investigated. The reactions are performed at 100 °C in solventless conditions to afford the corresponding coupling products in good to excellent yields under non-anhydrous and non-degassed conditions. Highly recoverable catalytic systems have been prepared, allowing up to 17 catalytic cycles with good yields and excellent sele...

  14. Solvent extraction of Pu(IV) by CMPO in 1-octyl 3-methyl imidazolium hexa fluorophosphate (C8mim PF6)

    The solvent extraction of Pu(IV) from nitric acid by octyl phenyl diisobutyl carbamoyl methyl phosphine oxide (CMPO) dissolved in a room temperature ionic liquid (RTIL) viz. 1-octyl 3- methyl imidazolium hexa fluorophosphate (C8mimPF6) was carried out and the stoichiometry of extracted complex was determined. Slope analysis does not indicate the extraction of neutral Pu(NO3)4. CMPO complex in to the RTIL phase. (author)

  15. Low-temperature thermodynamic investigation of the sulphur organic salts (TMTTF)2PF6 and (TMTTF)2Br (TMTTF ≡ tetramethyltetrathiafulvalene): I. General aspects

    A detailed thermodynamical investigation of the quasi-one-dimensional sulphur-based organic salts (TMTTF)2PF6 and (TMTTF)2Br is presented in the temperature range from 30 mK to 7 K. In this part (part I), we consider the general aspects of the low-temperature specific heat of these materials in relationship with their ground states and we compare them with those previously measured for selenium members of the same family. All these compounds exhibit very similar thermodynamical behaviour, despite a variety of electronic ground states: spin-Peierls for (TMTTF)2PF6, commensurate antiferromagnetic spin modulation for (TMTTF)2Br, incommensurate spin-density wave for (TMTSF)2PF6 (TMTSF≡tetramethyltetraselenafulvalene). We show that the low-energy excitations which are predominant below 1 K have a similar character to that observed in glassy systems, at least on short timescales of measurements. The dynamical aspects of the non-equilibrium thermodynamics will be presented separately in the following part (part II). (author)

  16. Effects of irradiation disorder on the insulating phases of (TMTSF) (DMTCNQ) and (TMTSF)2PF6: the stabililization of the metallic state by a weak disorder

    The ordering of charge density waves (CDW) drives the organic conductor (TMTSF) (DMTCNQ) to an insulating state below 49 K while the magnetic ordering of spin density waves (SDW) produces the same effect around 20 K in (TMTSF)2PF6. X-ray irradiation has been used to introduce defects in low concentration of the order of 10-3 mole fraction. The mosaicity induced by these defects in the CDW or SDW phases has important consequences on the transport and magnetic properties of the two compounds. Measurements of conductivity, Hall effect, magnetoresistance, thermopower, electron spin resonance (EPR) linewidth, g-factor and susceptibility are presented and discussed. A X-ray diffuse scattering study of the disordered CDW in (TMTSF) (DMTCNQ) provides an accurate determination of the longitudinal and transverse coherence lengths of the CDW's. It shows that each defect fixes the phase rigidly in a volume containing 3 chain segments of 10 molecules. In (TMTSF)2PF6, the EPR linewidth is used to follow the magnetic ordering under irradiation. In both compounds, the coherence loss of the low temperature condensed phases produces a large increase of the number of free carriers in irradiated samples. Even at low doses, the mobility of these carriers decreases quickly under irradiation in (TMTSF)2PF6, while it changes much more slowly in (TMTSF) (DMTCNQ)

  17. Toward new organometallic architectures: synthesis of carbene-centered rhodium and palladium bisphosphine complexes. stability and reactivity of [PC(BIm)PRh(L)][PF6] pincers.

    Plikhta, Andriy; Pöthig, Alexander; Herdtweck, Eberhardt; Rieger, Bernhard


    In this article, we report the synthesis of a tridentate carbene-centered bisphosphine ligand precursor and its complexes. The developed four-step synthetic strategy of a new PC(BIm)P pincer ligand represents the derivatization of benzimidazole in the first and third positions by (diphenylphosphoryl)methylene synthone, followed by phosphine deprotection and subsequent insertion of a noncoordinating anion. The obtained ligand precursor undergoes complexation, with PdCl2 and [μ-OCH3Rh(COD)]2 smoothly forming the target organometallics [PC(BIm)PPdCl][PF6] and [PC(BIm)PRh(L)][PF6] under mild hydrogenation conditions. A more detailed study of the rhodium complexes [PC(BIm)PRh(L)][PF6] reveals significant thermal stability of the PC(BIm)PRh moiety in the solid state as well as in solution. The chemical behavior of 1,3-bis(diphenylphosphinomethylene)benzimidazol-2-ylrhodium acetonitrile hexafluorophosphate has been screened under decarbonylation, hydrogenation, and hydroboration reaction conditions. Thus, the PC(BIm)PRh(I) complex is a sufficiently stable compound, with the potential to be applied in catalysis. PMID:26390389

  18. Crystal structures and magnetic properties of the honeycomb-lattice antiferromagnet M2(pymca)3(ClO4), (M = Fe, Co, Ni)

    Honda, Zentaro; Kodama, Takafumi; Hagiwara, Masayuki; Kida, Takanori; Okutani, Akira; Sakai, Masamichi; Fukuda, Takeshi; Kamata, Norihiko


    We report on the syntheses, crystal structures, and magnetic properties of a series of transition metal coordination polymers M2(pymca)3(ClO4), (pymca = pyrimidine-2-carboxylic acid, M = Fe (1), Co (2), and Ni (3)). These compounds are found to crystallize in a trigonal crystal system, space group P31m, with the lattice constants a = 9.727 Å and c = 5.996 Å for 1, a = 9.608 Å and c = 5.996 Å for 2, and a = 9.477 Å and c = 5.958 Å for 3 at room temperature. In these compounds, each pymca ligand connects to two M2+ ions, forming a honeycomb network in the ab plane. The temperature dependences of magnetic susceptibilities in these compounds show broad maxima, indicating antiferromagnetic interactions within two-dimensional honeycomb layers. We also observed an antiferromagnetic phase transition at low temperatures by magnetic susceptibility and heat capacity measurements. From the crystal structures and magnetic properties, we conclude that the compounds 1, 2, and 3 are good realizations of honeycomb-lattice antiferromagnets.

  19. Investigation of Structure and Transport in Li-Doped Ionic Liquid Electrolytes: [pyr14][TFSI], [pyr13][FSI] and [EMIM][BF4

    Haskins, Justin B.; Bennett, William R.; Hernandez-Lugo, Dione M.; Wu, James; Borodin, Oleg; Monk, Joshua D.; Bauschlicher, Charles W.; Lawson, John W.


    Ionic liquid electrolytes have been proposed as a means of improving the safety and cycling behavior of advanced lithium batteries; however, the properties of these electrolytes under high lithium doping are poorly understood. Here, we employ both polarizable molecular dynamics simulation and experiment to investigate the structure, thermodynamics and transport of three potential electrolytes, N-methyl-Nbutylpyrrolidinium bis(trifluoromethylsufonyl)imide ([pyr14][TFSI]), N- methyl-Npropylpyrrolidinium bis(fluorosufonyl)imide ([pyr13][FSI]), and 1-ethyl-3-- methylimidazolium boron tetrafluoride ([EMIM][BF4]), as a function of Li-salt concentration and temperature. Structurally, Li(+) is shown to be solvated by three anion neighbors in [pyr14][TFSI] and four anion neighbors in both [pyr13][FSI] and [EMIM][BF4], and at all levels of x(sub Li) we find the presence of lithium aggregates. Furthermore, the computed density, diffusion, viscosity, and ionic conductivity show excellent agreement with experimental data. While the diffusion and viscosity exhibit a systematic decrease and increase, respectively, with increasing x(sub Li), the contribution of Li(+) to ionic conductivity increases until reaching a saturation doping level of x(sub Li) is approximately 0.10. Comparatively, the Li(+) conductivity of [pyr14][TFSI] is an order of magnitude lower than that of the other liquids, which range between 0.1 - 0.3 mS/cm. The differences in Li(+) transport are reflected in the residence times of Li(+) with the anions, which are revealed to be much larger for [pyr14][TFSI] (up to 100 ns at the highest doping levels) than in either [EMIM][BF4] or [pyr13][FSI]. Finally, we comment on the relative kinetics of Li(+) transport in each liquid and we present strong evidence for transport through anion exchange (hopping) as opposed to the net motion of Li(+) with its solvation shell (vehicular).

  20. Investigation of Structure and Transport in Li-Doped Ionic Liquid Electrolytes: [pyr14][TFSI], [pyr13][FSI], [EMIM][BF4

    Haskins, Justin B.; Bennett, William R.; Wu, James J.; Hernandez, Dionne M.; Borodin, Oleg; Monk, Joshua D.; Bauschlicher, Charles W., Jr.; Lawson, John W.


    Ionic liquid electrolytes have been proposed as a means of improving the safety and cycling behavior of advanced lithium batteries; however, the properties of these electrolytes under high lithium doping are poorly understood. Here, we employ both polarizable molecular dynamics simulation and experiment to investigate the structure, thermodynamics and transport of three potential electrolytes, N-methyl-N-butylpyrrolidinium bis(trifluoromethylsufonyl)imide ([pyr14][TFSI]), N- methyl-N-propylpyrrolidinium bis(fluorosufonyl)imide ([pyr13][FSI]), and 1-ethyl-3-- methylimidazolium boron tetrafluoride ([EMIM][BF4]), as a function of Li (-) salt concentration and temperature. Structurally, Li(+) is shown to be solvated by three anion neighbors in [pyr14][TFSI] and four anion neighbors in both [pyr13][FSI] and [EMIM][BF4], and at all levels of xLi we find the presence of lithium aggregates. Furthermore, the computed density, diffusion, viscosity, and ionic conductivity show excellent agreement with experimental data. While the diffusion and viscosity exhibit a systematic decrease and increase, respectively, with increasing xLi, the contribution of Li(+) to ionic conductivity increases until reaching a saturation doping level of xLi 0.10. Comparatively, the Li(+) conductivity of [pyr14][TFSI] is an order of magnitude lower than that of the other liquids, which range between 0.1-0.3 mScm. The differences in Li(+) transport are reflected in the residence times of Li(+) with the anions, which are revealed to be much larger for [pyr14][TFSI] (up to 100 ns at the highest doping levels) than in either [EMIM][BF4] or [pyr13][FSI]. Finally, we comment on the relative kinetics of Li(+) transport in each liquid and we present strong evidence for transport through anion exchange (hopping) as opposed to the net motion of Li(+) with its solvation shell (vehicular).

  1. On structural phase transitions in 4-aminopyridinium fluoroborate, [4-NH 2C 5H 5N][BF 4]: differential scanning calorimetry, dielectric and infrared studies

    Czupiński, O.; Jakubas, R.; Pietraszko, A.


    Crystal structure of the 4-aminopyridinium tetrafluoroborate, [4-NH 2C 5H 5N][BF 4], has been determined at 293 K by means of X-ray diffraction as monoclinic space group, C2. The crystal shows a reach sequence of phase transition, four solid-solid transitions: at 250, 281, 388 and 485 K on heating. Most of the phase transitions, except that at 388 K, are clearly of first order and classified as an 'order-disorder' type. The rotational disorder both of cations and anions was studied by differential scanning calorimetry, dielectric and infrared spectroscopy. The low temperature phase transitions are associated with plastic crystal behavior.

  2. LiPF6/LiBOB混合锂盐改善LiFePO4/石墨动力电池高温循环性能研究%Use of LiPF6/LiBOB blend salt for improving cycling performances of LiFePO4/graphite battery at elevated temperature

    宋海申; 赖延清; 李劼; 刘业翔; 张治安


    分别以 LiPF6、LiBOB 和 LiPF6/LiBOB 混合盐为电解质,研究了不同电解液对 LiFePO4/石墨动力电池高温循环性能的影响。结果表明,LiBOB 盐抑制了正极溶铁行为,并提高了正极高温循环充放电效率;由于 LiBOB基电解液对正极的保护及在负极表面良好的成膜作用,使得LiFePO4/石墨电池高温循环性能得到明显改善,但是增大了电池阻抗。LiPF6/Li-BOB混合盐可以发挥 LiBOB盐的优点增加正极稳定性,在石墨表面形成致密的 SEI 膜并能够有效改善电池高温循环性能,同时避免了单纯使用 LiBOB盐时阻抗较高的缺点。使用 LiPF6/LiBOB 混合盐,利用LiPF6盐低阻抗特性及 LiBOB盐对正、负电极的保护作用,可以有效提高电池电化学性能。%LiPF6 ,LiBOB and LiPF6/LiBOB blend salt-based electrolytes were investigated for improving cycling performances of LiFePO4/graphite lithium-ion batteries at elevated temperature.It was demonstrated that dis-solution of Fe from LiFePO4 was depressed in LiBOB based electrolyte,and columbic efficiency of LiFePO4/Li cell at elevated temperature was increased;LiBOB was reduced earlier on anode surface,forming compact SEI layer;and the capacity retention of LiFePO4/graphite cells at 55℃ increases with LiBOB concentration due to protective depositions of LiBOB on cathode surface and the SEI layer on anode surface,while the impedance of the cell is increased.LiPF6/LiBOB blend salt-based electrolyte combines the advantages of the different salts and maximizes the performance of cells.When electrolytes with LiPF6/LiBOB blend salt was used,the LiFe-PO4/graphite cells have excellent capacity retention at 55℃,while the impedance was dramatically decreased.

  3. Visible Light Driven Photocascade Catalysis: Ru(bpy)3(PF6)2/TBHP-Mediated Synthesis of Fused β-Carbolines in Batch and Flow Microreactors.

    Chandrasekhar, D; Borra, Satheesh; Nanubolu, Jagadeesh Babu; Maurya, Ram Awatar


    1,2,3,4-Tetrahydro-β-carbolines were coupled with α-keto vinyl azides through an unprecedented visible light-Ru(bpy)3(PF6)2/TBHP mediated photocascade strategy that involves photosensitization, photoredox catalysis and [3 + 2] cycloaddition reaction. The scope and scale-up feasibility of the photocascade strategy was demonstrated by synthesizing 18 different fused β-carbolines in moderate to good yields using batch and continuous flow microreactor. This operationally simple synthetic protocol allows the formation of one C-C and two C-N new bonds in the overall transformation. PMID:27226119

  4. Solvent extraction studies of Pu(IV) with CMPO in 1-octyl 3-methyl imidazolium hexa fluorophosphate (C8mimPF6) room temperature ionic liquid (RTIL)

    Solvent extraction studies of Pu(IV) from aqueous nitric acid by carbamoyl methyl phosphine oxide (CMPO) in 1-octyl 3-methyl imidazolium hexa fluorophosphate (C8mimPF6) room temperature ionic liquid (RTIL) were carried out. It was inferred that the stoichiometry of the Pu(IV) species extracted into RTIL phase, through cation exchange mechanism, is [Pu(NO3)(CMPO)x]-3 where x varies from 1 to 2 under the experimental conditions used. Thermodynamic parameters showed the extraction to be favoured by negative enthalpy change, but counteracted by negative entropy change. (orig.)

  5. Interaction of ionic liquid with water with variation of water content in 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6])/TX-100/water ternary microemulsions monitored by solvent and rotational relaxation of coumarin 153 and coumarin 490

    Seth, Debabrata; Chakraborty, Anjan; Setua, Palash; Sarkar, Nilmoni


    The interaction of water with room temperature ionic liquid (RTIL) [bmim][PF6] has been studied in [bmim][PF6]/TX-100/water ternary microemulsions by solvent and rotational relaxation of coumarin 153 (C-153) and coumarin 490 (C-490). The rotational relaxation and average solvation time of C-153 and C-490 gradually decrease with increase in water content of the microemulsions. The gradual increase in the size of the microemulsion with increase in w0 (w0=[water]/[surfactant]) is evident from dynamic light scattering measurements. Consequently the mobility of the water molecules also increases. In comparison to pure water the retardation of solvation time in the RTIL containing ternary microemulsions is very less. The authors have also reported the solvation time of C-490 in neat [bmim][PF6]. The solvation time of C-490 in neat [bmim][PF6] is bimodal with time constants of 400ps and 1.10ns.

  6. Unique role of ionic liquid [bmin][BF 4] during curcumin-surfactant association and micellization of cationic, anionic and non-ionic surfactant solutions

    Patra, Digambara; Barakat, Christelle


    Hydrophilic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroburate, modified the properties of aqueous surfactant solutions associated with curcumin. Because of potential pharmaceutical applications as an antioxidant, anti-inflammatory and anti-carcinogenic agent, curcumin has received ample attention as potential drug. The interaction of curcumin with various charged aqueous surfactant solutions showed it exists in deprotonated enol form in surfactant solutions. The nitro and hydroxyl groups of o-nitrophenol interact with the carbonyl and hydroxyl groups of the enol form of curcumin by forming ground state complex through hydrogen bonds and offered interesting information about the nature of the interactions between the aqueous surfactant solutions and curcumin depending on charge of head group of the surfactant. IL[bmin][BF 4] encouraged early formation of micelle in case of cationic and anionic aqueous surfactant solutions, but slightly prolonged micelle formation in the case of neutral aqueous surfactant solution. However, for curcumin IL [bmin][BF 4] favored strong association (7-fold increase) with neutral surfactant solution, marginally supported association with anionic surfactant solution and discouraged (˜2-fold decrease) association with cationic surfactant solution.

  7. High-pressure densities and derived volumetric properties (excess, apparent, and partial molar volumes) of binary mixtures of {methanol (1) + [BMIM][BF4] (2)}

    The density of seven {(0.0087, 0.0433, 0.1302, 0.2626, 0.4988, 0.7501, and 0.9102) mole fraction of [BMIM][BF4]} binary {methanol (1) + [BMIM][BF4] (2)} (1-butyl-3-methylimidazolium tetrafluoroborate) mixtures has been measured with a vibrating-tube densimeter. Measurements were performed at temperatures from (298 to 398) K and at pressures up to 40 MPa. The total uncertainties of density, temperature, pressure, and concentration measurements was estimated to be less than 0.15 kg . m-3, 15 mK, 5 kPa, and 10-4, respectively. The uncertainties reported in this paper are expanded uncertainties at the 95% confidence level with a coverage factor of k = 2. The effect of temperature, pressure, and concentration on the density and derived volumetric properties such as excess, apparent, and partial molar volumes was studied. The measured densities were used to develop a Tait-type equation of state for the mixture. The structural properties such as direct and total correlation function integrals and cluster size were calculated using the Krichevskii function concept and the equation of state for the mixture at infinite dilution

  8. Self-aggregation of ionic liquid 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [C4mmim][BF4] in aqueous media: A conductometric, volumetric and spectroscopic study

    Highlights: • Self-aggregation behaviour of [C4mmim][BF4] has been studied using various techniques. • Thermodynamic parameters showing aggregation is an entropy-driven process. • Volumetric analysis indicates aggregation is influenced by solute–solvent interactions. • 1H NMR revealed formation of loosely bound aggregates in the system. - Abstract: Aggregation behaviour of ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, [C4mmim][BF4] in aqueous media has been studied by electrical conductivity, density and speed of sound measurements across temperature range (288.15–308.15) K. The critical aggregation concentration (cac), the standard Gibb’s free energy of aggregation, ΔG°agg, adiabatic compressibility, βS and changes in the adiabatic compressibility upon aggregation, ΔβS,agg for the IL in aqueous solution have been derived from the experimental data. Further to get the deeper insights into the aggregation process spectroscopic study using 1H NMR measurements have been carried out. The aggregation behaviour observed from conductance and volumetric approaches has been found to be in good agreement with each other. NMR study revealed the formation of loosely bound ion associates as aggregates in the system upon aggregation

  9. Effects of Propylene Carbonate Content in CsPF6-Containing Electrolytes on the Enhanced Performances of Graphite Electrode for Lithium-Ion Batteries.

    Zheng, Jianming; Yan, Pengfei; Cao, Ruiguo; Xiang, Hongfa; Engelhard, Mark H; Polzin, Bryant J; Wang, Chongmin; Zhang, Ji-Guang; Xu, Wu


    The effects of propylene carbonate (PC) content in CsPF6-containing electrolytes on the performances of graphite electrode in lithium half cells and in graphite∥LiNi0.80Co0.15Al0.05O2 (NCA) full cells are investigated. It is found that the performance of graphite electrode is significantly affected by PC content in the CsPF6-containing electrolytes. An optimal PC content of 20% by weight in the solvent mixtures is identified. The enhanced electrochemical performance of graphite electrode can be attributed to the synergistic effects of the PC solvent and the Cs(+) additive. The synergistic effects of Cs(+) additive and appropriate amount of PC enable the formation of a robust, ultrathin, and compact solid electrolyte interphase (SEI) layer on the surface of graphite electrode, which is only permeable for desolvated Li(+) ions and allows fast Li(+) ion transport through it. Therefore, this SEI layer effectively suppresses the PC cointercalation and largely alleviates the Li dendrite formation on graphite electrode during lithiation even at relatively high current densities. The presence of low-melting-point PC solvent improves the sustainable operation of graphite∥NCA full cells under a wide temperature range. The fundamental findings also shed light on the importance of manipulating/maintaining the electrode/electrolyte interphasial stability in various energy-storage devices. PMID:26862677

  10. Simultaneous determination of α-, β- and γ-asarone in Acorus tatarinowii by microemulsion electrokinetic chromatography with [BMIM]PF6 as oil phase.

    Wang, Ying; Li, Feng; Yang, Feng-Qing; Zuo, Hua-Li; Xia, Zhi-Ning


    In the present study, a rapid and repeatable microemulsion electrokinetic chromatography (MEEKC) method was developed for the simultaneous determination of three isomers (α-, β- and γ-asarone) in Acorus tatarinowii by using ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF(6)) as oil phase. Experimental parameters including the microemulsion compositions (concentrations of surfactant, co-surfactant and oil phase), pH, concentration of borate buffer, capillary temperature and voltage were intensively investigated. Finally, the main compounds in the methanol extract of A. tatarinowii were well separated within 11 min using a running buffer composed of 40 mmol/L sodium dodecyl sulfonate (SDS), 2.0 mol/L n-propanol, 8 mmol/L [BMIM]PF(6) in 10 mmol/L borate buffer of pH 9.5. The developed method was applied to determine the contents of α-, β- and γ-asarone in A. tatarinowii from five different producing areas in China (Anhui, Hebei, Sichuan, Zhejiang and Chongqing). The results indicated that the contents of three asarones are quite different in the investigated A. tatarinowii samples. On the other hand, the MEEKC with ionic liquid as oil phase should be a promising method for the analysis of volatile components especially isomers in medicinal herbs. PMID:23158356

  11. Low-temperature thermodynamic investigation of the sulphur organic salts (TMTTF)2PF6 and (TMTTF)2Br (TMTTF = tetramethyltetrathiafulvalene): II. Dynamical aspects

    Lasjaunias, J. C.; Monceau, P.; Staresinic, D.; Biljakovic, K.; Carcel, C.; Fabre, J. M.


    This contribution is in continuation of our preceding publication (Lasjaunias J C, Brison J P, Monceau P, Staresinic D, Biljakovic K, Carcel C and Fabre J M 2002 J. Phys.: Condens. Matter 14 837) in which we have considered general aspects of the low-temperature thermodynamical properties of the quasi-one-dimensional organic salts based on sulphur donors with different ground states: (TMTTF)2PF6 in the spin-Peierls state and (TMTTF)2Br (TMTTF = tetramethyltetrathiafulvalene) with commensurate spin modulation. In this part, part II, we present our results on the dynamical aspects related to the non-equilibrium phenomena measured below 1 K. The metastable states excited to slightly higher temperature (by only a few per cent of the starting T0) relax very slowly to the heat bath environment, depending on the duration of the heat pumping. We compare the features observed in the relaxation rates in these two sulphur compounds with those measured for the incommensurate spin-density-wave compound (TMTSF)2PF6. We discuss the possible nature of the long-living low-energy excitations lying at the origin of this complex dynamical behaviour, in relation to their ground states.

  12. Dinuclear Cu(II) complexes of compartmental Schiff base ligands formed from unsymmetrical tripodal amines of varying arm lengths: Crystal structure of [Cu2L1](ClO4)2 and theoretical studies

    Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Sayin, Koray


    Three new dinuclear copper complexes were synthesized via condensation reaction of three new unsymmetrical N-capped tripodal amines and 2,6-diformyl-4-methylphenol, in the presence of copper(II) perchlorate. The solid-state structure of the dinuclear complex, [Cu2L1](ClO4)2, has been determined by X-ray crystallography, showing that the CuII centers have distorted square-pyramidal geometry with N3O2 coordination. The copper (II) ions are bridged by phenolic and hydroxyalkyl groups when in both cases, deprotonation of the hydrogen atoms of the OH groups occurs. The distance between the copper atoms is 3.062 Å. This compound consists of the dication [Cu2L1]2+ and two ClO4- anions in which one of ClO4- groups has a week interaction with one of the Cu atoms. All complexes were characterized by a variety of physico-chemical techniques such as elemental analyses, IR, mass spectra, conductivity measurements and electronic spectral studies. Computational investigation of mentioned binuclear Cu(II) complexes was done by using M062X method with LANL2DZ basis set in vacuo.

  13. Synthesis, crystal structure and spectral properties of Np5+ complex with triphenylphosphine oxide, [NpO2(PO(C6H5)3)4]ClO4

    Monocrystals [NpO2(TPO)4]ClO4 (1) were prepared by interaction of NpO2ClO4 with triphenylphosphine oxide (TPO). The crystals of (1) are triclinic, unit cell parameters at 20 deg C are as follows: a 9.140 (2), b 13.528 (3), c = 13.918 (3) A, α = 97.14 (3), β 108.17 (3), γ = 91.75 (3), sp. gr. P1-bar, Z = 1, dcalcld. = 1.521 g/cm3. Compound (1) consists of complex cations [NpO2(TPO)4]+ and disordered anions ClO4-. Neptunium atom has tetragonal-bipyramid oxygen surrounding (coordination number 6). The length of Np-O axial bond is 1.797 (2) A, average value of Np-O equatorial bonds equals 2.438 A. Data of IR and absorption spectroscopy suggest the absence of cation-cation interaction of NpO2+ dioxocations centrally symmetric in the equatorial plane

  14. A facile route for the preparation of nanoparticles of the spin-crossover complex [Fe(Htrz)2(trz)](BF4) in xerogel transparent composite films.

    Faulmann, Christophe; Chahine, Joe; Malfant, Isabelle; de Caro, Dominique; Cormary, Benoît; Valade, Lydie


    Films and monoliths containing the spin crossover complex [Fe(Htrz)(2)(trz)](BF(4)) (trz = 1,2,4-triazole) as nanoparticles have been obtained. The dispersion and consecutive inclusion of the Fe complex in a silica matrix prepared from tetramethoxysilane or tetraethoxysilane afford monoliths or films with a violet colour at room temperature, which turns white above 380 K. This change of colour is reversible. This thermochromic behaviour has been characterized by measuring the magnetic properties together with thermogravimetric studies and Raman spectroscopy, the result of which all demonstrate that both films and monoliths undergo a spin crossover. Microscopy studies confirm the occurrence of the Fe complex as nanoparticles, in both the monoliths and the films. The facile synthesis of these materials as nanoparticles in transparent films should open the possibility of the synthesis of high quality films. PMID:21290082

  15. Preparation and characterization of electropolymerized poly(3,4-ethylenedioxythiophene) thin films with different dopant anions

    Deguchi, Toshiaki; Tomeoku, Hiroya; Takashiri, Masayuki


    We investigated the structural and thermoelectric properties poly(3,4-ethylenedioxythiophene) (PEDOT) films with several dopants (counter ions, ClO4, PF6, and BF4), synthesised by electropolymerization. We first performed cyclic voltammetry analysis to determine the optimum synthesis conditions of the PEDOT thin films. We found that the surface morphology of the PEDOT thin films was dependent on the type of the dopant. The PF6-doped PEDOT (PEDOT:PF6) thin films showed a dense structure, and the PEDOT:ClO4 thin films showed a highly porous microstructure. Fourier transform infrared (FT-IR) spectroscopy showed that all the PEDOT thin films showed similar chemical structures and the p-type state. Regarding their thermoelectric properties, the electrical conductivity of the all the doped PEDOT thin films increased as the dopant concentration increased, with the PEDOT:PF6 thin films showing the highest value. On the other hand, the Seebeck coefficient of the PEDOT thin films with all the dopants decreased as the dopant concentration increased, with the PEDOT:BF4 thin films achieving the highest value. As a result, the PEDOT:BF4 thin films exhibited the highest power factor of 0.75 µW/(m·K2) at a dopant concentration of 1.0 M. We think that the PEDOT microstructure produced using the different types of dopant may affect the thermoelectric properties.

  16. Study on thermo physical and excess molar properties of binary systems of ionic liquids. I: [Cnmim][PF6] (n = 6, 8) and alkyl acetates

    Highlights: • Densities, speeds of sound and refractive indices were reported for [Cnmim][PF6] (n = 6, 8) + alkyl acetates. • The measurements were performed at T = 5 K interval between (293.15 and 323) K over full range of concentrations. • Excess molar properties were derived from measured values of density, speed of sound and refractive index. • The effects of temperature and chain length of IL and acetate on excess molar properties were discussed. • Excess molar volumes VmE were predicted by PFP theory. - Abstract: The measurements of densities, ρ, speeds of sound, u and refractive indices, nD for binary mixtures containing 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6mim][PF6]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]) + ethyl acetate (EA) and butyl acetate (BA) were reported over full range of concentrations. The measurements were performed at atmospheric pressure and seven different temperatures of five degree intervals between (293.15 and 323.15) K. The excess properties on mixing were derived from measured values of these properties. The values of density were utilized to obtain excess molar volumes, VmE, speeds of sound to obtain excess molar isentropic compressibilities, κS,mE and refractive index to get refractive index deviations, ΔφnD. The binary co-efficients of excess properties were obtained by Redlich–Kister polynomial equation. The influences of temperature and addition of –CH2 group in imidazolium cation of ionic liquids as well as acetate on excess properties have been discussed. The VmE and κS,mE are negative and decease with increase in temperature while ΔφnD are positive and increase with increase in temperature. For common acetate, The VmE increases with each increment of –CH2 group in imidazolium cation of IL and similar is true when –CH2 group increases in alkyl acetate for common IL. The deviation in VmEwas investigated by employing Prigogine–Flory–Patterson theory

  17. Combination of acid-resistor and -scavenger improves the SEI stability and cycling ability of tin–nickel battery anodes in LiPF6-containing electrolyte

    Control of electrode–electrolyte interfacial reactivity and the formation of the solid electrolyte interphase (SEI) layer is a key technology for high performance rechargeable lithium batteries. Here we present the first report on a promising interfacial approach for Sn–Ni electrode that the use of acid-resisting and -scavenging fluorine-dopant on Sn combined with acid-scavenging trimethyl phosphite electrolyte additive to LiPF6-contiaing carbonate-based organic electrolyte improves the interfacial stability of Sn to acidic electrolyte species. As a result, a stable SEI layer consisting of a plenty of carbonate decomposition products forms and cycling ability significantly improves, in contrast to less efficient SEI formation and rapid performance fade for the electrodes without fluorine-dopant or trimethyl phosphite additive

  18. Cycling profile of MgAl2O4-incorporated composite electrolytes composed of PEO and LiPF6 for lithium polymer batteries

    Magnesium aluminate (MgAl2O4)-incorporated poly(ethylene oxide) (PEO)–lithium hexafluorophosphate (LiPF6) based composite polymer electrolyte (CPE) membranes were prepared by a hot press for the first time. The membranes were subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric (TG), differential scanning calorimetry (DSC), tensile, impedance spectroscopy, compatibility and transport number studies. The incorporation of MgAl2O4 greatly enhanced the ionic conductivity, compatibility and mechanical integrity of the polymeric membrane. Finally, an all solid state lithium cell composed of Li/CPE/LiFePO4 was assembled and its cycling profile was analyzed at 70 °C. The cells delivered a discharge capacity of 127 mAh g−1 at 1 C-rate with very good capacity retention up to 100 cycles which is found to be better than those reported earlier

  19. Solvation of uranyl-CMPO complexes in dry vs. humid forms of the [BMI][PF6] ionic liquid. A molecular dynamics study.

    Chaumont, Alain; Wipff, Georges


    The solvation of the [UO(2)(NO(3))(CMPO)](+) and [UO(2)(NO(3))(2)(CMPO)(2)] complexes (CMPO = octyl(phenyl)-N,N-diisobutylmethylcarbamoyl phosphine oxide) is investigated by molecular dynamics in the "dry" and "humid" forms of a room temperature ionic liquid (IL) based on the 1-butyl-3-methylimidazolium (BMI(+)) cation and the hexafluorophosphate (PF(6)(-)) anion. The simulations reveal the importance of the solvent anions in "dry" conditions and of water molecules in the "humid" solvent. For the [UO(2)(NO(3))(CMPO)](+) complex, the monodentate vs. bidentate coordination modes of CMPO are compared, and the first solvation shell of uranyl is completed by 1-3 PF(6)(-) anions in the dry IL and by 2-3 water molecules in the humid IL, leading to a total coordination number close to 5. The energy analysis shows that interactions with the IL stabilize the [UO(2)(NO(3))(bi)(CMPO)(mono)](+) form (with bidentate nitrate and monodentate CMPO) in the dry IL and the [UO(2)(NO(3))(mono)(CMPO)(mono)](+) form (with monodentate nitrate and CMPO) in the humid IL. The extracted compound characterized by EXAFS is thus proposed to be the [UO(2)(NO(3))(mono)(CMPO)(mono)(H(2)O)(3)](+) species. Furthermore we compare the [UO(2)(NO(3))(2)(CMPO)(2)] complex in its associated and dissociated forms ([UO(2)(NO(3))(mono)(CMPO)(mono)](+) + CMPO + NO(3)(-)) and discuss the results in the context of uranyl extraction by CMPO to ionic liquids. PMID:16482292

  20. Effects of ionic liquid [bmim][PF6] on absorption spectra and reaction kinetics of the duroquinone triplet state in acetonitrile.

    Zhu, Guanglai; Wu, Guozhong; Sha, Maolin; Long, Dewu; Yao, Side


    The transient absorption spectra and photoinduced electron-transfer process of duroquinone (DQ) in mixed binary solutions of ionic liquid (IL) [bmim][PF6] and acetonitrile (MeCN) have been investigated by laser photolysis at an excitation wavelength of 355 nm. A spectral blue shift of 3DQ* was observed in the IL/MeCN mixtures compared to MeCN. At lower VIL(volume fraction of IL), the interaction between DQ and the solvent is dominant, and the decay rate constant (kobs) of 3DQ* increases steadily with the increasing of VIL; to the contrary, at higher VIL, the network structures due to the hydrogen bond and viscosity are dominant, and the decay rate constant decreases obviously with increasing VIL. A critical point (turnover) was observed at VIL = approximately 0.30. The dependence of the observed growth rate (kgr) of the photoinduced electron-transfer (PET) products on VIL is complex and shows a special change; kgr first decreases with increasing VIL, then increases, and finally decreases slowly with further increasing of VIL. It is speculated that the PET process in the mixture can be affected by factors including the local structure and the reorganization energy of the solvent and salt and cage effects. The change of local structure of [bmim][PF6]/MeCN is supported by following the steady-state fluorescence behavior of the mixture, in combination with the molecular dynamics simulation of the thermodynamic property. The results revealed that the degree of self-aggregation of monomeric cations (bmim+) to associated forms increases with increasing VIL. This is in good agreement with the laser photolysis results for the same solutions. PMID:18331005

  1. Effects of Propylene Carbonate Content in CsPF6-Containing Electrolytes on the Enhanced Performances of Graphite Electrode for Lithium-Ion Batteries

    Zheng, Jianming; Yan, Pengfei; Cao, Ruiguo; Xiang, Hongfa; Engelhard, Mark H.; Polzin, Bryant; Wang, Chong M.; Zhang, Jiguang; Xu, Wu


    Cesium salt has been demonstrated as an efficient electrolyte additive in suppressing the lithium (Li) dendrite formation and directing the formation of an ultrathin and stable solid electrolyte interphase (SEI) even in propylene carbonate (PC)-ethylene carbonate (EC)-based electrolytes. Here, we further investigate the effect of PC content in the presence of CsPF6 additive (0.05 M) on the performances of graphite electrode in Li||graphite half cells and in graphite||LiNi0.80Co0.15Al0.05O2 (NCA) full cells. It is found that the performance of graphite electrode is also affected by PC content even though CsPF6 additive is present in the electrolytes. An optimal PC content of 20% by weight in the solvent mixtures is identified. The enhanced electrochemical performance of graphite electrode is attributed to the synergistic effects of the Cs+ additive and the PC solvent. The formation of a robust, ultrathin and compact SEI layer containing lithium-enriched species on the graphite electrode, directed by Cs+, effectively suppresses the PC co-intercalation and thus prevents the graphite exfoliation. This SEI layer is only permeable for de-solvated Li+ ions and allows fast Li+ ion transport through it, which therefore largely alleviates the Li dendrite formation on graphite electrode during lithiation even at high current densities. The presence of low-melting-point PC solvent also enables the sustainable operation of the graphite||NCA full cells under a wide spectrum of temperatures. The fundamental findings of this work shed light on the importance of manipulating/maintaining the electrode/electrolyte interphasial stability in a variety of energy storage devices.

  2. The EPR zero-field splitting D and its pressure and temperature dependence for trigonal Mn2+ centers in [Zn(H2O)6](BF4)2:Mn2+ crystal

    The EPR zero-field splitting D (= b20) and its pressure and temperature dependence for trigonal Mn2+ centers in low and room temperature phases in [Zn(H2O)6](BF4)2:Mn2+ crystal are studied by a high-order perturbation formula based on the dominant spin-orbit coupling mechanism. From the studies, the local trigonal distortion angles, the local angular compressibilities and the local angular thermal expansion coefficients for Mn2+ centers in both phases of the [Zn(H2O)6](BF4)2 crystal are estimated. The results are discussed. (orig.)

  3. Azide Binding Controlled by Steric Interactions in Second Sphere. Synthesis, Crystal Structure, and Magnetic Properties of [Ni(II)2(L)(μ1,1-N3)][ClO4] (L = Macrocyclic N6S2 Ligand).

    Jeremies, Alexander; Gruschinski, Sina; Meyer, Michel; Matulis, Vitaly; Ivashkevich, Oleg A; Kobalz, Karolin; Kersting, Berthold


    The dinuclear Ni(II) complex [Ni2(L(2))][ClO4]2 (3) supported by the 28-membered hexaaza-dithiophenolate macrocycle (L(2))(2-) binds the N3(-) ion specifically end-on yielding [Ni2(L(2))(μ1,1-N3)][ClO4] (7) or [Ni2(L(2))(μ1,1-N3)][BPh4] (8), while the previously reported complex [Ni2L(1)(μ1,3-N3)][ClO4] (2) of the 24-membered macrocycle (L(1))(2-) coordinates it in the end-to-end fashion. A comparison of the X-ray structures of 2, 3, and 7 reveals the form-selective binding of complex 3 to be a consequence of its preorganized, channel-like binding pocket, which accommodates the azide anion via repulsive CH···π interactions in the end-on mode. In contrast to [Ni2L(1)(μ1,3-N3)][ClO4] (2), which features a S = 0 ground state, [Ni2(L(2))(μ1,1-N3)][BPh4] (8) has a S = 2 ground state that is attained by competing antiferromagnetic and ferromagnetic exchange interactions via the thiolato and azido bridges with a value for the magnetic exchange coupling constant J of 13 cm(-1) (H = -2JS1S2). These results are further substantiated by density functional theory calculations. The stability of the azido-bridged complex determined by isothermal titration calorimetry in MeCN/MeOH 1/1 v/v (log K11 = 4.88(4) at I = 0.1 M) lies in between those of the fluorido- (log K11 = 6.84(7)) and chlorido-bridged complexes (log K11 = 3.52(5)). These values were found to compare favorably well with the equilibrium constants derived at lower ionic strength (I = 0.01 M) by absorption spectrophotometry (log K11 = 5.20(1), 7.77(9), and 4.13(3) for N3(-), F(-), and Cl(-) respectively). PMID:26836637

  4. Low-temperature heat capacity and thermal decomposition of crystalline [Er2(His·H+)(H2O)8](ClO4)6·4H2O

    The heat capacities of rare earth complex with amino acid histidine, [Er2(His·H+)(H2O)8](ClO4)6·4H2O, were measured with an automatic adiabatic calorimeter from 79 to 320 K. It was found that there was a sudden increment in heat capacity within the temperature range 182-190 K. Thermal decomposition behavior of the complex in nitrogen atmosphere was studied by thermogravimetric (TG) analysis, and a possible decomposition mechanism was suggested according to TG-DTG results

  5. Development of the PF-6 Device ffor the Goal Of the Mainstream Fusion Research and Spin-Off Applications; Medocine, Biology, Material Sciences etc

    In the framework of the Project we have elaborated a new design of the electrical circuit (in co-operation with ICTP) to increase the repetition rate f of the operational regime of PF-6 device till the level: U = 23 kV, E = 7.4 kJ, f = 5 Hz. With this power supply we have elaborated and tested our new DPF chambers able to work with the deuterium-tritium mixture as a working gas. We have developed, implemented and tested new diagnostics of X ray and neutron pulses with temporal resolution 0.3 ns and 16-frame 1-ns laser interferometry. In cooperation with our partners on this IAEA CRP we provided radiation tests of materials candidate for the main-stream fusion reactors (tungsten, CFC, ceramics Al2O3 and NB, low- activation steels, etc.) using besides the PF-6 facility the Dense Plasma Focus devices PF-5M, ING-103 and PF-1000. In addition with the same partners we undertake initial experiments with an aim to improve characteristics of the surface layer of materials (mechanical and tribological behavior, radiation resistance, etc.) using the above devices. The idea is to use hot plasma streams and beams of fast ions generated in DPF in treatment of internal hard-to-reach compartments of the machine components. In cooperation with Pirelli we have provided first experiments in the field of X ray dynamic quality control with DPF aimed to disclosure imperfections in car tyres. Also we spread our previous X ray based experiments on pulsed radio- enzymology to the pulsed neutron irradiation of enzymes and other bio-test objects. We have provided experiments intended to detect large-volume objects containing illegal substances (explosives, drugs, etc.) and first experiments on irradiation by neutron pulses a fuel element containing fissile materials by means of time-of flight neutron technique. These experiments give an opportunity to use DPF in a single-shot technique of unveiling illegal materials hidden in a luggage or in containers. (author)

  6. Synthesis, structural characterization, and gas-phase unimolecular reactivity of the silver hydride nanocluster [Ag3((PPh2)2CH2)3(μ3-H)](BF4)2.

    Zavras, Athanasios; Khairallah, George N; Connell, Timothy U; White, Jonathan M; Edwards, Alison J; Mulder, Roger J; Donnelly, Paul S; O'Hair, Richard A J


    A bis(diphenylphosphino)methane-ligated trinuclear silver hydride nanocluster, [Ag3((Ph2P)2CH2)3(μ3-H)](BF4)2, featuring three silver(I) ions coordinated to a μ3-hydride, and its deuteride analogue, [Ag3((Ph2P)2CH2)3(μ3-D)](BF4)2, have been isolated and structurally characterized using electrospray ionization mass spectrometry (ESI-MS), X-ray crystallography, NMR and IR spectroscopy. The position of the deuteride in [Ag3((Ph2P)2CH2)3(μ3-D)](BF4)2 was determined by neutron diffraction. ESI-MS of [Ag3L3(μ3-H/D)](BF4)2 [L = ((Ph2P)2CH2)2] produces [Ag3L3(μ3-H/D)](2+) and [Ag3L3(μ3-H/D)(BF4)](+). A rich gas-phase ion chemistry of [Ag3L3(μ3-H/D)](2+) is observed under conditions of collision-induced dissociation (CID) and electron-capture dissociation (ECD). CID gives rise to the following complementary ion pairs: [Ag3L2](+) and [L+(H/D)](+); [Ag2(H/D)L2](+) and [AgL](+); [Ag2(H/D)L](+) and [AgL2](+). ECD gives rise to a number of dissociation channels including loss of the bis(phosphine) ligand, fragmentation of a coordinated bis(phosphine) ligand via C-P bond activation, and loss of a hydrogen (deuterium) atom with concomitant formation of [Ag3L3](+). Under CID conditions, [Ag3L3(μ3-H/D)(BF4)](+) fragments via ligand loss, the combined loss of a ligand and [H,B,F4], and cluster fragmentation to give [Ag2(BF4)L2](+) and [Ag2(L-H)L](+) [where (L-H) = (Ph2P)2CH(-)]. PMID:24991699

  7. Inelastic and elastic neutron scattering studies of the vibrational and reorientational dynamics, crystal structure and solid-solid phase transition in [Mn(OS(CH3)2)6](ClO4)2 supported by theoretical (DFT) calculations

    Szostak, Elżbieta; Hetmańczyk, Joanna; Migdał-Mikuli, Anna


    The vibrational and reorientational dynamics of CH3 groups from (CH3)2SO ligands in the high- and low-temperature phases of [Mn(OS(CH3)2)6](ClO4)2 were investigated by quasielastic and inelastic incoherent neutron scattering (QENS and IINS) methods. The results show that above the phase transition temperature (detected earlier by differential scanning calorimetry (DSC) at TC5c = 222.9 K on cooling and at TC5h = 225.4 K on heating) the CH3 groups perform fast (τR ≈ 10-12-10-13 s) reorientational motions. These motions start to slow down below TC5c Neutron powder diffraction (NPD) measurements, performed simultaneously with QENS and IINS, indicated that this phase transition is associated with a change of the crystal structure, too. Theoretical infrared absorption, Raman and inelastic incoherent neutron scattering spectra were calculated using DFT method (B3LYP functional, LANL2DZ ECP basis set (on Mn atom) and 6-311+G(d,p) basis set (on C, H, S, O atoms) for the isolated equilibrium model (isolated [Mn(DMSO)6]2+ cation and ClO4- anion). Calculated spectra show a good agreement with the experimental spectra (FT-IR, RS and IINS). The comparison of the results obtained by these complementary methods was made.

  8. Synthesis, characterization of a new photosensitive compound [Ru(bpy)2 (TPAD)](PF6)2 and its application for photocatalytic hydrogen production

    Zheng, Hui-Qin; Guo, Yi-Ping; Yin, Ming-Cai; Fan, Yao-Ting


    A new photosensitive compound based on triphenylamine donor and ruthenium(II), namely [Ru(bpy)2(TPAD)](PF6)2 (PS1, bpy = 2,2‧-bipyridine, TPAD = N-(4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-yl)phenyl)-N-phenylbenzenamine), had been synthesized and characterized by elemental analysis, 1H NMR, MS spectra, UV, PL and CV measurements. The target photocatalyst, PS1/0.5 wt% Pt/TiO2, was prepared by sensitizing PS1 to 0.5 wt% Pt/TiO2 and characterized by SEM and XRD. The highest hydrogen evolution reached to 9500 μmol·(g·catalyst)-1 (475 μmol, 31.7 TON and TOF 5.8 vs. PS1) under the optimal conditions with 0.05 g·L-1 of PS1, and 5% of TEOA at pH 11 with the irradiation of 5.5 h. The mechanism of hydrogen evolution was also briefly discussed in the present work.

  9. Synthesis and Crystal Structure of{[Mn(H2O)4(3, 3′-azpy)](3, 3′-azpy)3(PF6)2}n

    李宝龙; 曹正白; 王寿武; 徐正; 郁开北


    The complex {[Mn(H2O)4(3, 3?-azpy)](3, 3?-azpy)3(PF6)2}n (3, 3?-azpy = 3, 3?- azobispyridine) has been synthesized and characterized. The crystal (C40H40F12MnN16O4P2, Mr = 1153.76) belongs to the triclinic system, space group P ī with the following crystallographic parameters: a = 10.761(2), b = 11.040(2), c = 23.365(4) ?, ( = 85.52(1), ( = 82.69(1), ( = 70.44(1)°, V = 2592.5(8) ?3, Dc = 1.478 g/cm3, ((MoK() = 4.16 cm-1, F(000) = 1174, Z = 2, final R = 0.0493 and wR = 0.1158 for the observed reflections (I > 2.00((I)). The X-ray analysis revealed that manganese(Ⅱ) cation coordination environment is a distorted octahedral geometry, and the Mn2+ cation is coordinated by four oxygen atoms of water in the equatorial plane, while the two nitrogen atoms of 3, 3?-azpy occupy the axial positions. The complex forms a one-dimensional chain structure via 3, 3?-azpy bridging ligand.

  10. Effect of water on structure and dynamics of [BMIM][PF6] ionic liquid: An all-atom molecular dynamics simulation investigation

    Sharma, Anirban; Ghorai, Pradip Kr.


    Composition dependent structural and dynamical properties of aqueous hydrophobic 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid (IL) have been investigated by using all-atom molecular dynamics simulation. We observe that addition of water does not increase significant number of dissociated ions in the solution over the pure state. As a consequence, self-diffusion coefficient of the cation and anion is comparable to each other at all water concentration similar to that is observed for the pure state. Voronoi polyhedra analysis exhibits strong dependence on the local environment of IL concentration. Void and neck distributions in Voronoi tessellation are approximately Gaussian for pure IL but upon subsequent addition of water, we observe deviation from the Gaussian behaviour with an asymmetric broadening with long tail of exponential decay at large void radius, particularly at higher water concentrations. The increase in void space and neck size at higher water concentration facilitates ionic motion, thus, decreasing dynamical heterogeneity and IL reorientation time and increases self-diffusion coefficient significantly.

  11. Reactions of [Cu(X)(BPEP-Ph)] (X = PF6, SbF6) with silyl compounds. Cooperative bond activation involving non-coordinating anions.

    Nakajima, Yumiko; Tsuchimoto, Takahiro; Chang, Yung-Hung; Takeuchi, Katsuhiko; Ozawa, Fumiyuki


    Bond activation of silyl compounds, assisted by the cooperative action of non-coordinating anions, is achieved using Cu(I) complexes coordinated with a PNP-pincer type phosphaalkene ligand, [Cu(X)(BPEP-Ph)] (X = PF6 (1a), SbF6 (1b); BPEP-Ph = 2,6-bis[1-phenyl-2-(2,4,6-tri-tert-butylphenyl)-2-phosphaethenyl]pyridine). Complexes 1a and 1b react with Me3SiCN to form Me3SiF and Cu(i) cyanide complexes of the formula [Cu(CN-EF5)(BPEP-Ph)] (E = P (2a), Sb (2b)), in which the CN ligand is associated with the EF5 group arising from EF6(-). Formation of the intermediary isonitrile complex [Cu(CNSiMe3)(BPEP-Ph)](+)SbF6(-) (3b) is confirmed by its isolation. Thus, a two-step reaction process involving coordination of Me3SiCN, followed by nucleophilic attack of SbF6(-) on the silicon atom of 3b is established for the conversion of 1b to 2b. Complex 1b cleaves the H-Si bond of PhMe2SiH as well. The isolation and structural identification of [Cu(BPEP-Ph)](+)BAr(F)4(-) (1c) (BAr(F)4 = B{3,5-(CF3)2C6H3}4) as a rare example of a T-shaped, three-coordinated Cu(i) complex is reported. PMID:26455594

  12. Deposition, accumulation, and alteration of Cl-, NO3-, ClO4- and ClO3- salts in a hyper-arid polar environment: Mass balance and isotopic constraints

    Jackson, Andrew; Davila, Alfonso F.; Böhlke, John Karl; Sturchio, Neil C.; Sevanthi, Ritesh; Estrada, Nubia; Brundrett, Maeghan; Lacelle, Denis; McKay, Christopher P.; Poghosyan, Armen; Pollard, Wayne; Zacny, Kris


    The salt fraction in permafrost soils/sediments of the McMurdo Dry Valleys (MDV) of Antarctica can be used as a proxy for cold desert geochemical processes and paleoclimate reconstruction. Previous analyses of the salt fraction in MDV permafrost soils have largely been conducted in coastal regions where permafrost soils are variably affected by aqueous processes and mixed inputs from marine and stratospheric sources. We expand upon this work by evaluating permafrost soil/sediments in University Valley, located in the ultraxerous zone where both liquid water transport and marine influences are minimal. We determined the abundances of Cl-, NO3-, ClO4- and ClO3- in dry and ice-cemented soil/sediments, snow and glacier ice, and also characterized Cl- and NO3- isotopically. The data are not consistent with salt deposition in a sublimation till, nor with nuclear weapon testing fall-out, and instead point to a dominantly stratospheric source and to varying degrees of post depositional transformation depending on the substrate, from minimal alteration in bare soils to significant alteration (photodegradation and/or volatilization) in snow and glacier ice. Ionic abundances in the dry permafrost layer indicate limited vertical transport under the current climate conditions, likely due to percolation of snowmelt. Subtle changes in ClO4-/NO3- ratios and NO3- isotopic composition with depth and location may reflect both transport related fractionation and depositional history. Low molar ratios of ClO3-/ClO4- in surface soils compared to deposition and other arid systems suggest significant post depositional loss of ClO3-, possibly due to reduction by iron minerals, which may have important implications for oxy-chlorine species on Mars. Salt accumulation varies with distance along the valley and apparent accumulation times based on multiple methods range from ∼10 to 30 kyr near the glacier to 70-200 kyr near the valley mouth. The relatively young age of the salts and relatively low and homogeneous anion concentrations in the ice-cemented sediments point to either a mechanism of recent salt removal, or to relatively modern permafrost soils (end-member of stratospheric sources not subject to biological processes or extensive remobilization.

  13. Deposition, Accumulation, and Alteration of Cl(-), NO3(-), ClO4(-) and ClO3(-) Salts in a Hyper-Arid Polar Environment: Mass Balance and Isotopic Constraints

    Jackson, Andrew; Davila, Alfonso F.; Boehlke, J. K.; Sturchio, Neil C.; Sevanthi, Ritesh; Estrada, Nubia; Brundrette, Megan; Lacell, Denis; McKay, Christopher P.; Poghosyan, Armen; Pollard, Wayne; Zacny, Kris


    The salt fraction in permafrost soils/sediments of the McMurdo Dry Valleys (MDV) of Antarctica can be used as a proxy for cold desert geochemical processes and paleoclimate reconstruction. Previous analyses of the salt fraction in MDV permafrost soils have largely been conducted in coastal regions where permafrost soils are variably affected by aqueous processes and mixed inputs from marine and stratospheric sources. We expand upon this work by evaluating permafrost soil/sediments in University Valley, located in the ultraxerous zone where both liquid water transport and marine influences are minimal. We determined the abundances of Cl(-), NO3(-, ClO4(-)and ClO3(-)in dry and ice-cemented soil/sediments, snow and glacier ice, and also characterized Cl(-) and NO3(-) isotopically. The data are not consistent with salt deposition in a sublimation till, nor with nuclear weapon testing fall-out, and instead point to a dominantly stratospheric source and to varying degrees of post depositional transformation depending on the substrate, from minimal alteration in bare soils to significant alteration (photodegradation and/or volatilization) in snow and glacier ice. Ionic abundances in the dry permafrost layer indicate limited vertical transport under the current climate conditions, likely due to percolation of snowmelt. Subtle changes in ClO4(-)/NO3(-) ratios and NO3(-) isotopic composition with depth and location may reflect both transport related fractionation and depositional history. Low molar ratios of ClO3(-)/ClO4(-) in surface soils compared to deposition and other arid systems suggest significant post depositional loss of ClO3(-), possibly due to reduction by iron minerals, which may have important implications for oxy-chlorine species on Mars. Salt accumulation varies with distance along the valley and apparent accumulation times based on multiple methods range from approximately 10 to 30 kyr near the glacier to 70-200 kyr near the valley mouth. The relatively young age of the salts and relatively low and homogeneous anion concentrations in the ice-cemented sediments point to either a mechanism of recent salt removal, or to relatively modern permafrost soils (less than 1 million years). Together, our results show that near surface salts in University Valley serve as an end-member of stratospheric sources not subject to biological processes or extensive remobilization.

  14. Multiple light-induced NO linkage isomers in the dinitrosyl complex [RuCl(NO)2(PPh3)2]BF4 unravelled by photocrystallographic and IR analysis.

    Casaretto, Nicolas; Pillet, Sebastien; Bendeif, El Eulmi; Schaniel, Dominik; Gallien, Anna K E; Klüfers, Peter; Woike, Theo


    Multiple light-induced reversible metastable NO linkage isomers (PLIs) have been detected in the dinitrosyl compound [RuCl(NO)2(PPh3)2]BF4 by a combination of photocrystallographic and IR analysis. The IR signature of three PLI states has been clearly identified, with estimated populations of 59% (PLI-1), 8% (PLI-2) and 5% (PLI-3) for a total population of the metastable state of 72%. The structural configuration of the major component (PLI-1) has been derived by X-ray photocrystallography. In the ground state, the structure is characterized by a bent and a linear nitrosyl, the bent one being oriented towards the linear equatorial nitrosyl with an Ru-N-O angle of 133.88 (9)°. X-ray Fourier difference maps indicate a selectivity of the photo-isomerization process in PLI-1: only the bent NO ligand changes its position, while the linear NO is unaffected. After irradiation at 405 nm, the orientation is changed by rotation towards the Cl ligand opposite the linear NO, with an Ru-N-O angle in this new position of 109 (1)°. The photocrystallographic analysis provides evidence that, in the photo-induced metastable state, the bent NO group is attached to the Ru atom through the N atom (Ru-N-O), rather than in an isonitrosyl Ru-O-N binding mode. In the IR spectra, the asymmetric NO vibrational band shifts by -33 cm(-1) to a lower value, whereas the symmetric band splits and shifts by 5 cm(-1) to a higher value and by -8 cm(-1) to a lower value. The down shift is a clear indication of the structural change, and the small upward shift in response to the new electronic configuration of the metastable structure. Variable-temperature IR kinetic measurements in the range 80-114 K show that the decay of the PLI-1 state follows an Arrhenius behaviour with an activation energy of 0.22 eV. PMID:25610626

  15. Multiple light-induced NO linkage isomers in the dinitrosyl complex [RuCl(NO2(PPh32]BF4 unravelled by photocrystallographic and IR analysis

    Nicolas Casaretto


    Full Text Available Multiple light-induced reversible metastable NO linkage isomers (PLIs have been detected in the dinitrosyl compound [RuCl(NO2(PPh32]BF4 by a combination of photocrystallographic and IR analysis. The IR signature of three PLI states has been clearly identified, with estimated populations of 59% (PLI-1, 8% (PLI-2 and 5% (PLI-3 for a total population of the metastable state of 72%. The structural configuration of the major component (PLI-1 has been derived by X-ray photocrystallography. In the ground state, the structure is characterized by a bent and a linear nitrosyl, the bent one being oriented towards the linear equatorial nitrosyl with an Ru—N—O angle of 133.88 (9°. X-ray Fourier difference maps indicate a selectivity of the photo-isomerization process in PLI-1: only the bent NO ligand changes its position, while the linear NO is unaffected. After irradiation at 405 nm, the orientation is changed by rotation towards the Cl ligand opposite the linear NO, with an Ru—N—O angle in this new position of 109 (1°. The photocrystallographic analysis provides evidence that, in the photo-induced metastable state, the bent NO group is attached to the Ru atom through the N atom (Ru—N—O, rather than in an isonitrosyl Ru—O—N binding mode. In the IR spectra, the asymmetric NO vibrational band shifts by −33 cm−1 to a lower value, whereas the symmetric band splits and shifts by 5 cm−1 to a higher value and by −8 cm−1 to a lower value. The down shift is a clear indication of the structural change, and the small upward shift in response to the new electronic configuration of the metastable structure. Variable-temperature IR kinetic measurements in the range 80–114 K show that the decay of the PLI-1 state follows an Arrhenius behaviour with an activation energy of 0.22 eV.

  16. Perchlorate cerium(3) complexes with 1,10-phenanthroline. Crystal structure of [Ce(C12H8N2)4(CH3CN)2](ClO4)3 · 3CH3CN

    The Ce(ClO4)3 · 2Phen · 2H2O (1) and Ce(ClO4)3 · 3Phen (2) complexes are obtained through interaction of anhydrous Ce(ClO4)3 · H2O with 1,10-phenanthroline. The Ce(ClO4)3 · 4Phen · 5CH3CN (3) complex is separated from the solution 2. The IR-spectra of compounds 1-3, their thermal behavior are studied, X-ray diffraction data on compounds 1 and 2 are presented. The RSA is carried out for compound 3: rhombic crystals, a = 12.059(3), b 20.657(5), c = 24.170(6) A, sp. gr. Pccn, Z = 4. The structure 3 consists of complex cations [Ce(Phen)4 · (CH3CN)2]3+, outerspheric anions ClO4- and solvate molecules of acetonitrile

  17. Does [TcF(CO)5] exist? The crystal and molecular structure of [Tc(CO)3(OH)0.49F0.51]4·[Tc(CO)5(BF4)].

    Stepanova, E S; Gurzhiy, V V; Tyupina, M Yu; Miroslavov, A E; Sidorenko, G V; Lumpov, A A


    Technetium pentacarbonyl fluoride [TcF(CO)5] was prepared for the first time by reaction of [TcI(CO)5] with solid AgF in a dichloromethane solution at -23 °C. Low temperature crystallization of the resulting compound in a glass vial yielded an unusual complex [Tc(CO)3(OH)0.49F0.51]4·[Tc(CO)5(BF4)] characterized by single crystal XRD. PMID:27108652

  18. Synthesis of the compound tetrakis (2- methoxy isobutyl isonitrile) copper (I) tetrafluoroborate -(Cu[MIBI]4BF4): substance used in the production of the radiopharmaceutical sestamibi 99m Tc

    The radiopharmaceutical SESTAMIBI-99mTc presents interest and application in the clinical routine in Nuclear Medicine, especially for evaluation of the myocardium function and in the diagnosis of some tumors types, and the Center of Radiopharmacy of the IPEN has interest in the development of this radiopharmaceutical for attendance of the nuclear medicine class necessities. In this work it was demonstrated the synthesis and characterization of the active compound tetrakis (2- methoxy isobutyl isonitrile) copper (I) tetrafluoroborate - Cu[MIBI]4BF4- to be used in the preparation of lyophilized reagents for labeling with technetium-99m as well as labeling studies and biological distribution. The synthesis of the reagent Cu[MIBI]4BF4 was carried out in accordance with previously described procedures, in 5 steps and the compounds were characterized for infra-red, magnetic nuclear resonance, melting point and thin layer chromatography. The characterization of the chelate of MIBI -Cu[MIBI]4BF4 - was carried out using high performance liquid chromatography, compared with a standard sample of the product and presented similar results, as described in literature. The lyophilized reagent was prepared and labeled with technetium-99m, showing high radiochemical purity, higher than 97%, with high stability. Biological distribution in different animals showed good uptake in the heart, in time compatible with the acquisition of scintigraphy images, demonstrating the applicability of the reagent synthesized in the attainment of cardiac scintigraphy images. (author)

  19. Effect of LiPF6 concentration in Li[Ni0.4Mn0.4Co0.2]O2/graphite pouch cells operated at 4.5 V

    Petibon, R.; Madec, L.; Abarbanel, D. W.; Dahn, J. R.


    The effect of LiPF6 concentration in the 1 M-2.5 M range was studied in Li[Ni0.4Mn0.4Co0.2O]2 (NMC(442))/graphite and LaPO4 coated-NMC(442)/graphite pouch cells cycled to high voltage. Electrochemical impedance spectroscopy on symmetric cells revealed that the dramatic impedance growth observed in NMC(442)/graphite cells cycled to high voltage comes from the interface impedance of the positive electrode. The use of high LiPF6 concentrations in the 2-2.5 M range dramatically slowed down the impedance growth of both coated and uncoated NMC(442)/graphite cells containing certain electrolyte additive blends and cycled to high voltage. However no beneficial effect was observed in control cells containing no electrolyte additive. X-ray photoelectron spectra of cycled electrodes of coated-NMC(442)/graphite cells showed that LiPF6 concentration greatly affected the composition of the solid electrolyte interphase of both the positive and negative electrodes of cells containing additives.

  20. 离子液体[C4mim ][PF6]萃取-石墨炉原子吸收法检测食品中的痕量铅%The Determination of Lead by Graphit Furnace Atomic Absorption Spectrometry Couple with Ionic Liquid [C4 min][PF6 ] Extraction in Food

    王乃丽; 王金梅


    离子液体因其具有不挥发,粘度大等特性,已被广泛代替有机溶剂用于液液萃取。建立了以二乙基二硫代氨基甲酸钠(DDTC)为螯合剂、离子液体1-丁基-3-甲基咪唑六氟磷酸盐([C4 mim][PF6])为萃取剂、稀硝酸为反萃取溶剂的萃取体系,并对所建立的萃取体系的相关影响因素进行了优化,包括:体系pH、螯合剂DDTC的用量、反萃取溶剂的选择等。同时对该离子液体是否可循环利用以及该体系的抗干扰能力进行了评价。此外,将所建立的离子液体萃取-稀硝酸反萃取体系结合石墨炉原子吸收分光光度法应用于大米,茶,鱼,小麦,蛤以及油菜中的痕量铅的检测。%The ionic liquid has replaced the organic solvent as the extraction solvent for it's including non-volatile and high viscosity .DDTC was selected as chelating agent ,[C4 mim][PF6 ] as the extraction agent and HNO3 as back-extraction agent .The optimized experimental condition was :pH of the extraction , the concentration of DDTC ,the back-extraction solvent .Meanwhile ,recyclable of the ionic liquid and an-ti-interference were also discussed .Finally ,this method was successfully applied in the determination of the trace Pb existed in the rice ,tea ,fish ,wheat ,clam and rape .

  1. Microcalorimetric study about biological effect of a synthetic complex: La(Glu)(Im)6(ClO4)3.4HClO4.4H2O

    A complex of lanthanum perchloric acid coordinated with glutamic acid, La(Glu)(Im)6(ClO4)3.4HClO4.4H2O was synthesized and characterized. The biological effect of the complex was evaluated by microcalorimetry on the growth of E. coli DH5α. Power-time curves of the growth metabolism of E. coli DH5α were studied using a TAM Air Isothermal Microcalorimeter at 37 oC. From the power-time curves, the parameters such as growth rate constants (k), inhibitory ratio (I), the maximum heat power (Pm) and the time of the maximum heat power (tm) were obtained. The results show that the concentrations of the complex affect obviously the growth metabolism of E. coli DH5α. The stimulatory effect on growth of E. coli DH5α was observed when the concentration of the complex was kept in the range of (0-0.5 μg mL-1). In contrast to the lower concentration, in the case of higher concentration of the complex (0.5-5.0 μg mL-1), an inhibitory effect occurred.

  2. Low-temperature heat capacity and thermodynamic properties of [Re2(Ile)4(H2O)8](ClO4)6 (Re=Nd, Er, Ile=isoleucine)

    The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re2(Ile)4(H2O)8](ClO4)6 (where Re=Nd, Er, and Ile=isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature range from 80 to 370 K. Two solid-solid phase transitions were found from the Cp curve of Nd formed complex in the range of 165-175 K with a peak temperature of 167.88 K and in the range of 195-210 K with a peak temperature of 202.13 K. The corresponding molar enthalpies of these phase transitions were determined to be 404.61 J mol-1 and 2.955 kJ mol-1, respectively. One solid-solid phase transition was found for the Er formed complex in the range of 190-205 K with a peak temperature of 193.42 K. The corresponding molar enthalpy of this transition was 14.11 kJ mol-1. Smooth heat capacities and thermodynamic functions relative to the standard state (298.15 K), HT-H298.15, ST-S298.15 and -[GT-G298.15], of the two compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositions for the pair of compounds were suggested according to the thermogravimetric (TG) analysis

  3. Heat capacity and thermodynamical properties of the crystal of [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE=Nd,Eu,Dy)

    WU XinMin; LI Wei; TAN ZhiCheng; QU SongSheng


    Thermodynamical data of rare earth complexes with amino acid are important for engineering chemistry and fundamental chemistry.However,they have rarely been reported.In this work,a series of crystalline complexes of rare earth perchlorate coordinated with glutamic acid have been synthesized in water medium,and their thermodynamical data,including the heat capacity in low temperature range and the standard enthalpy of formation,were determined.These complexes were identified to be [RE2(Glu)2(H2O)8](ClO4)4.H2O (RE=Nd,Eu,Dy) by using thermogravimetric analysis (TG),differential thermal analysis (DTA),and chemical and elementary analyses.Their purity has been determined.No melting points were observed for all the three complexes.The heat capacity of the complexes was measured by an adiabatic calorimeter from 79 to 370 K.Abnormal heat capacity values were detected for two of the complexes and the decomposition range of one complex was found.The temperature,enthalpy change and entropy change of the decomposition processes of the three complexes were calculated.The polynomial equations of heat capacity in the experimental temperature range have been obtained by least squares fitting.The standard enthalpy of formation was determined by an isoperibol reaction calorimeter at 298.15 K.

  4. Influence of the intermolecular interaction on photo-induced spin-transition of [Fe(R-pap)2]X

    Iron(III) spin-crossover complexes [Fe(pap)2]ClO4 x H2O, [Fe(pap)2]BF4 x H2O, [Fe(pap)2]PF6 x CH3OH), [Fe(CH3-pap)2]ClO4 x H2O, [Fe0.5Al0.5(pap)2]ClO4 x CH3OH and [Fe0.25Al0.75(pap)2] ClO4 x CH3OH were prepared and the spin transition behaviors of the complexes have been studied from magnetic susceptibility and Moessbauer spectroscopy measurements. The magnetic properties of light-induced metastable state are measured using Hg-Xe light source. T1/2 is temperature at which the populations of the high-spin and low-spin species are fifty-fifty. Metastable HS is produced by light irradiation at 5 K. T(LIESST) is the temperature at which the populations of the metastable high-spin species decrease to one half and cooperativity factor Cis defined as the parameter which presents the strength of cooperativity. The value of T(LIESST) decreases as T1/2 increases and the plots of T(LIESST) vs. C show linear correlation. The effect of cooperativity of the complexes on the relaxations in solid was confirmed for the iron(III) complexes. (author)

  5. Magnetism and Pressure-Induced Superconductivity of Checkerboard-Type Charge-Ordered Molecular Conductor β-(meso-DMBEDT-TTF2X (X = PF6 and AsF6

    Yutaka Nishio


    Full Text Available The metallic state of the molecular conductor β-(meso-DMBEDT-TTF2X (DMBEDT-TTF = 2-(5,6-dihydro-1,3-dithiolo[4,5-b][1,4]dithiin-2-ylidene-5,6-dihydro-5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin, X = PF6, AsF6 is transformed into the checkerboard-type charge-ordered state at around 75–80 K with accompanying metal-insulator (MI transition on the anisotropic triangular lattice. With lowering temperatures, the magnetic susceptibility decreases gradually and reveals a sudden drop at the MI transition. By applying pressure, the charge-ordered state is suppressed and superconductivity appears in β-(meso-DMBEDT-TTF2AsF6 as well as in the reported β-(meso-DMBEDT-TTF2PF6. The charge-ordered spin-gapped state and the pressure-induced superconducting state are discussed through the paired-electron crystal (PEC model, where the spin-bonded electron pairs stay and become mobile in the crystal, namely the valence-bond solid (VBS and the resonant valence bonded (RVB state in the quarter-filled band structure.

  6. Study on Stability and Electrochemical Properties of Nano-LiMn1.9Ni0.1O3.99S0.01-Based Li-Ion Batteries with Liquid Electrolyte Containing LiPF6

    Monika Bakierska


    Full Text Available Herein, we report on the stability and electrochemical properties of nanosized Ni and S doped lithium manganese oxide spinel (LiMn1.9Ni0.1O3.99S0.01, LMN1OS in relation to the most commonly used electrolyte solution containing LiPF6 salt. The influence of electrochemical reaction in the presence of selected electrolyte on the LMN1OS electrode chemistry was examined. The changes in the structure, surface morphology, and composition of the LMN1OS cathode after 30 cycles of galvanostatic charging/discharging were determined. In addition, thermal stability and reactivity of the LMN1OS material towards the electrolyte system were verified. Performed studies revealed that no degradative effects, resulting from the interaction between the spinel electrode and liquid electrolyte, occur during electrochemical cycling. The LMN1OS electrode versus LiPF6-based electrolyte has been indicated as an efficient and electrochemically stable system, exhibiting high capacity, good rate capability, and excellent coulombic efficiency. The improved stability and electrochemical performance of the LMN1OS cathode material originate from the synergetic substitution of LiMn2O4 spinel with Ni and S.

  7. Effective asymmetric bioreduction of ethyl 4-chloro-3-oxobutanoate to ethyl (R)-4-chloro-3-hydroxybutanoate by recombinant E. coli CCZU-A13 in [Bmim]PF6-hydrolyzate media.

    He, Yu-Cai; Tao, Zhi-Cheng; Di, Jun-Hua; Chen, Liang; Zhang, Lin-Bing; Zhang, Dan-Ping; Chong, Gang-Gang; Liu, Feng; Ding, Yun; Jiang, Chun-Xia; Ma, Cui-Luan


    It was the first report that the concentrated hydrolyzates from the enzymatic hydrolysis of dilute NaOH (3wt%)-soaking rice straw at 30°C was used to form [Bmim]PF6-hydrolyzate (50:50, v/v) media for bioconverting ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl (R)-4-chloro-3-hydroxybutanoate [(R)-CHBE] (>99% e.e.) with recombinant E. coli CCZU-A13. Compared with pure glucose, the hydrolyzates could promote both initial reaction rate and the intracellular NADH content. Furthermore, emulsifier OP-10 (20mM) was employed to improve the reductase activity. Moreover, Hp-β-cyclodextrin (0.01mol Hp-β-cyclodextrin/mol COBE) was also added into this bioreaction system for enhancing the biosynthesis of (R)-CHBE from COBE by E. coli CCZU-A13 whole-cells. The yield of (R)-CHBE (>99% e.e.) from 800mM COBE was obtained at 100% in the [Bmim]PF6-hydrolyzate (50:50, v/v) media by supplementation of OP-10 (20mM) and Hp-β-CD (8mM). In conclusion, an effective strategy for the biosynthesis of (R)-CHBE was successfully demonstrated. PMID:27155796

  8. Influence of gamma irradiation on the physical properties of hydrophobic room temperature ionic liquids [BuMeIm]PF6 and [BuMeIm][(CF3SO2)2N

    It was shown that density, surface tension, and refraction index of room temperature ionic liquids (RTIL) [BuMeIm]X, where BuMeIm+ is 1-butyl-3-methyl-imidazolium and X- is PF6-, and (CF3SO2)2N-, are not changed being subjected to approximately 600 kGy of absorbed dose of gamma irradiation (137Cs). At the same time gamma radiolysis causes significant increase in viscosities of RTILs. Studied RTILs exhibit darkening under the gamma irradiation. The light absorbance of ionic liquids increases linearly with irradiation dose. Water has no influence on the radiolytic darkening. Formation of colored products is related to radiolysis of BuMeIm+ cation. The kinetics of radiolytic darkening of RTILs is influenced by the anions as follows: Cl-3SO2)2N-6-. The revealed effect is attributed to the interaction of the primary products of anion radiolysis with BuMeIm+ cation. (authors)

  9. trans-[Ru(NO)Cl(cyclam)](PF6)2 and [Ru(NO)(Hedta)] incorporated in PLGA nanoparticles for the delivery of nitric oxide to B16-F10 cells: cytotoxicity and phototoxicity.

    Gomes, Anderson J; Espreafico, Enilza M; Tfouni, Elia


    The immobilization and characterization of trans-[Ru(NO)Cl(cyclam)](PF6)2 (cyclam=1,4,8,11-tetraazacyclotetradecane), and [Ru(NO)(Hedta)] (Hedta=ethylenediaminetetraacetic acid) entrapped in poly(d,l-lactic-co-glycolic) acid (PLGA) nanoparticles (NP) using the double emulsification process is described. Scanning electron microscopy and dynamic light scattering revealed that the particles are spherical in shape, have a size distribution between 220 and 840 nm of diameter, and have a tendency to aggregate confirmed by a zeta potential between -3.2 and +3.5 mV. Using this method the loading efficiency was 26% for trans-[Ru(NO)Cl(cyclam)](PF6)2 and 32% for [Ru(NO)(Hedta)]. The release of the complexes from the NPs shows that cyclam-NP and Hedta-NP exhibited a two-phase exponential association release pattern, which was characterized by an initial complex burst during the first 24 h, followed by a slower release phase complex profile, due to a few pores observed in surface of nanoparticles using atomic force microscopy. The in vitro cytotoxic activity of the nitrosyl complexes in solution and incorporated in PLGA nanoparticles on melanoma cancer cells (cell line B16-F10) was investigated. The lower cytotoxicity of trans-[RuCl(cyclam)(NO)]2+ (12.4±2.6%) and [Ru(NO)(Hedta)] (4.0±2.7%) in solution compared to that of trans-[Ru(NO)(NH3)4py]3+ (46.1±6.4%) is consistent with the rate constant release of NO of these complexes (k-NO=6.2×10(-4) s(-1), 2.0×10(-3) s(-1), and 6.0×10(-2) s(-1), respectively); the cytotoxicities are also inhibited in the presence of the NO scavenger carboxy-PTIO. The phototoxicity of these complexes is due to NO release, which lead to 53.8±6.2% of cell death in the presence of trans-[Ru(NO)Cl(cyclam)](PF6)2 and 22.3±5.1% in the presence of [Ru(NO)(Hedta)]. The PLGA nanoparticles loaded with trans-[Ru(NO)Cl(cyclam)](PF6)2 and [Ru(NO)(Hedta)] exerted in vitro a reduced activity against melanoma cells when compared to the activity of complex in

  10. Epoxidação do óleo de soja com o sistema catalítico [MoO2(acac2]/TBHP EM [bmim][PF6

    Maritana Farias


    Full Text Available Epoxidation of soybean oil was investigated using 1-n-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] ionic liquid as biphasic medium with molybdenum(VI acetylacetonate complex and tert-butyl hydroperoxide TBHP as oxidizing agent. Reaction conditions were molar ratio TBHP:number of double bonds of oil:catalyst of 100:100:1, reaction temperature of 60 ºC and reaction time between 2 and 24 h. The proposed system showed catalytic activity for epoxidation reactions under tested conditions. Reuse of ionic liquid/catalyst system for epoxidation reactions was also investigated. Evaluation of epoxidation observed in this catalytic system was done by quantitative ¹H NMR data.

  11. Exceptionally long-lived light-emitting electrochemical cells: multiple intra-cation π-stacking interactions in [Ir(C^N)2(N^N)][PF6] emitters

    Buenzli, Andreas M.; Constable, Edwin C.; Housecroft, Catherine E.; Prescimone, Alessandro; Zampese, Jennifer A.; Longo, Giulia; Gil-Escrig, Lidon; Pertegas, Antonio; Orti, Enrique; Bolink, Henk J.


    A series of cyclometalated iridium(III) complexes [Ir(C^N)2(N^N)][PF6] (N^N = 2,2′-bipyridine (1), 6-phenyl-2,2′-bipyridine (2), 4,4′-di-tert-butyl-2,2′-bipyridine (3), 4,4′-di-tert-butyl-6-phenyl-2,2′-bipyridine (4); HC^N = 2-(3-phenyl)phenylpyridine (HPhppy) or 2-(3,5-diphenyl)phenylpyridine (HPh2ppy)) are reported. They have been synthesized using solvento precursors so as to avoid the use of chlorido-dimer intermediates, chloride ion contaminant being detrimental to the performance of [Ir...

  12. On the changes of the structure of perchlorate (ClO4-)-degrading bacterial communities under heterotrophic conditions%异养条件下高氯酸盐降解细菌群落变化研究

    谢宇轩; 关翔宇; 王阳; 王鹤立


    了解特定环境中高氯酸盐(ClO4-)降解菌的群落组成,对ClO4-的降解具有重要的指导意义.通过添加醋酸盐作为电子供体降解ClO4-,利用高通量测序(HiSeq 2000)的方法获得了复杂环境中生物群落的组成,对比了降解前后菌种结构的变化.结果表明,补充醋酸盐的降解体系(Acetate Degradation,AD)将10 mg/L ClO4-降至检出限以下需100 h.降解完毕后代表性的ClO4-降解菌Dechloromonas的相对丰度为0.2%,与原始活性污泥相比无明显差别;另一典型ClO2降解菌脱氯菌属Azospira相对丰度为3.2%;一些同时参与ClO4-降解和脱氮作用的细菌如假单胞菌属Pseudomonas也有检出,相对丰度为8%.异养条件下ClO4-降解是假单胞菌属Pseudomonas和脱氨菌属Azospira起主导作用.AD体系内菌种多样性小于原始活性污泥.电子供体的加入使活性污泥类的混合体系内生物群落结构单一化,使降解基质具备了在特定环境下针对某种污染物降解的能力.

  13. Synthesis, crystal structure and magnetic properties of a thiocyanate bridged dinuclear copper(Ⅱ) complex:[μ-SCN Cu dien]2 (ClO4)2%硫氰酸根桥连双核铜配合物[μ-(SCN)Cu(dien)]2(ClO4)2的合成、晶体结构和磁性研究

    米春喜; 胡怀明


    合成了硫氰酸根桥连双核铜配合物[μ-(SCN)Cu(dien)]2(ClO4)2,测定了它的晶体结构.晶体为三斜晶系,P-1空间群,a=0.746 5(2),b=0.748 4(2),c=1.182 2(2)nm,α=90.51(3),β=105.39(3),γ=109.06(3)°,V=0.598 5(2)nm3,Dc=1.799 Mg/m3,μ=2.227 mm-1,F(000)=330,Z=1.最小二乘修正得R1=0.0325,wR2=0.0906.结构由高氯酸根离子和双核铜配正离子组成,两个铜离子由两个硫氰酸根离子桥连,两个铜离子之间的距离为0.5512(2)nm.每个铜离子与二乙烯三胺的三个氮原子和硫氰酸根的一个氮原子在赤道平面上配位,另一个硫氰酸根的一个硫原子和高氯酸根的一个氧原子在轴向配位,形成了畸变的八面体配位几何构型.Cu-N键长在0.195 0(1)~0.20l 8(1)nm范围内,Cu-S键长0.276 6(1),Cu-O键长0.288 4(2)nm.研究了75~300K温度范围内固体样品的磁性,表明在铜离子间存在着反铁磁相互作用.

  14. Two-Step Photon Absorption Driving the Chemical Reaction in the Model Ruthenium Nitrosyl System [Ru(py)4Cl(NO)](PF6)2·(1)/2H2O.

    Khadeeva, Liya; Kaszub, Wawrzyniec; Lorenc, Maciej; Malfant, Isabelle; Buron-Le Cointe, Marylise


    Various systems containing the [ML5NO] molecule, where M = Fe, Ru, ... and L = F, Cl, ..., exhibit switching under continuous light (CW) irradiation between the ground-state nitrosyl (GS), isonitrosyl (MSI), and side-on (MSII) configurations. The metastable populations, however, are often limited to a few percent. The [Ru(py)4Cl(NO)](PF6)2·(1)/2H2O system is thus a remarkable model compound as the GS to MSI transformation is nearly complete in a single crystal. A predominant two-step photon absorption process during GS to MSI switching under blue light is revealed by visible absorption spectroscopy, although a low concentration of the transient species hinders the determination of this process by the structural signature. During the depopulation of MSI, both two-step and direct processes are evidenced under red CW irradiation. Different intermediate visible spectra revealing transient species during GS to MSI and the reverse photochemical processes are discussed in relation to MSII properties. PMID:27054377

  15. Fire behavior of carbonates-based electrolytes used in Li-ion rechargeable batteries with a focus on the role of the LiPF6 and LiFSI salts

    Eshetu, Gebrekidan Gebresilassie; Bertrand, Jean-Pierre; Lecocq, Amandine; Grugeon, Sylvie; Laruelle, Stephane; Armand, Michel; Marlair, Guy


    A detailed investigation of the combustion behavior of LiPF6 or LiFSI-based carbonate electrolytes was conducted with the objective of getting better knowledge of lithium-ion battery system fire induced thermal and chemical threats. The well-controlled experimental conditions provided by the Tewarson calorimeter have enabled the accurate evaluation of fire hazard rating parameters such as heat release rate and effective heat of combustion and the quantification of toxic effluents (HF, SO2, NOx…). Results have shown that all the electrolytes tested burn in phases depending on the flammability nature of their mixture constituents. The first stage of combustion is solely governed by the more volatile solvent (linear carbonate) and the influence of adding salt comes into effect predominantly in the second stage. It has been also shown that combustion enthalpy of electrolytes lies in the solvent mixture, irrespective of the salt added. The fire induced toxicity in well-ventilated conditions is found to be mainly dictated by the salt and its chemical structure, showing very limited concerns that emanate from the organic solvents.

  16. A perspective on coatings to stabilize high-voltage cathodes: LiMn1.5Ni0.5O4 with subnanometer Lipon cycled with LiPF6 electrolyte

    Kim, Yoongu [ORNL; Dudney, Nancy J [ORNL; Chi, Miaofang [ORNL; Martha, Surendra K [ORNL; Nanda, Jagjit [ORNL; Veith, Gabriel M [ORNL; Liang, Chengdu [ORNL


    High voltage Li-ion cathodes push the limits of stability for both cathode and electrolyte. Here subnanometer coatings of an amorphous thin film electrolyte (Lipon) improved the room temperature and 60 C cycling stability of a LiMn1.5Ni0.5O4 spinel cathode when charged to 4.9V with a standard LiPF6 carbonate electrolyte. The cathodes delivered superior C-rate performances up to a 5C discharge, when compared to the uncoated cathodes. Enhanced performance extended for at least 100 cycles. Electrochemical impedance spectroscopy indicates that Lipon slows the increase of interface resistance. Thicker 1-3nm Lipon coatings are sufficiently insulating as to block electronic transport to the cathode particles. Thick coatings also slow Mn dissolution. Results suggest that Lipon may act to scavenge impurities or block active sites that promote electrolyte decomposition. While greatly improved by the Lipon coating, this cathode is not sufficiently stable for long cycle life applications. Further work is needed to assess if and what surface coatings will ultimately stabilize the high voltage cathodes. Comments include insight from other studies of Lipon coated cathodes and directions for future research.

  17. 离子液体[C4mim][PF6]与N,N-二甲基甲酰胺二元混合物在298.15 K~318.15 K的密度和粘度%Densities and Viscosities of the Ionic Liquid [C4mim][PF6]+N,N-dimethylformamide Binary Mixtures at 293.15 K to 318.15 K

    耿彦芳; 王腾芳; 虞大红; 彭昌军; 刘洪来; 胡英


    Viscosities and densities for 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and N,N-dimethylformamide (DMF) binary mixtures have been measured at the temperature range from 293.15 K to 318.15 K. It is shown that the viscosities and densities decrease monotonously with temperature and the content of DME Various correlation methods including Arrhenius-like equation, Seddon et al.'s equation, Redlich-Kister equation with four parameters, and other empirical equations were applied to evaluate these experimental data. A model based on an equation of state for estimating the viscosity of mixtures containing ionic liquids were proposed by coupling with the excess Gibbs free energy model of viscosity, which can synchronously calculate the viscosity and the molar volume. The results show that the model gives a deviation of 8.29% for the viscosity, and a deviation of 1.05% for the molar volume when only one temperature-independent adjustable parameter is adopted. The cor-relation accuracy is further improved when two parameters or one temperature-dependent parameter is used.

  18. Host-guest supramolecular interactions in the coordination compounds of 4,4'-azobis(pyridine) with MnX2 (X = NCS–, NCNCN–, and PF6(–)): structural analyses and theoretical study.

    Kar, Paramita; Biswas, Rituparna; Drew, Michael G B; Frontera, Antonio; Ghosh, Ashutosh


    Three new Mn(II) coordination compounds {[Mn(NCNCN)(2)(azpy)]·0.5azpy}(n) (1), {[Mn(NCS)(2)(azpy)(CH(3)OH)(2)]·azpy}(n) (2), and [Mn(azpy)(2)(H(2)O)(4)][Mn(azpy)(H(2)O)(5)]·4PF(6)·H(2)O·5.5azpy (3) (where azpy = 4,4'-azobis(pyridine)) have been synthesized by self-assembly of the primary ligands, dicyanamide, thiocyanate, and hexafluorophosphate, respectively, together with azpy as the secondary spacer. All three complexes were characterized by elemental analyses, IR spectroscopy, thermal analyses, and single crystal X-ray crystallography. The structural analyses reveal that complex 1 forms a two-dimensional (2D) grid sheet motif. These sheets assemble to form a microporous framework that incorporates coordination-free azpy by host-guest π···π and C-H···N hydrogen bonding interactions. Complex 2 features azpy bridged one-dimensional (1D) chains of centrosymmetric [Mn(NCS)(2)(CH (3)OH)(2)] units which form a 2D porous sheet via a CH(3)···π supramolecular interaction. A guest azpy molecule is incorporated within the pores by strong H-bonding interactions. Complex 3 affords a 0-D motif with two monomeric Mn(II) units in the asymmetric unit. There exist π···π, anion···π, and strong hydrogen bonding interactions between the azpy, water, and the anions. Density functional theory (DFT) calculations, at the M06/6-31+G* level of theory, are used to characterize a great variety of interactions that explicitly show the importance of host-guest supramolecular interactions for the stabilization of coordination compounds and creation of the fascinating three-dimensional (3D) architecture of the title compounds. PMID:22272694

  19. Effects of Rut-bpy (Cis-[Ru(bpy2(SO3(NO]PF 6, a novel nitric oxide donor, in L-NAME-induced hypertension in rats Efeitos do Rut-bpy (Cis-[Ru(bpy2(SO3(NO]PF 6, um novo doador de óxido nítrico, na hipertensão induzida com L-NAME em ratos

    Marcio Wilker Soares Campelo


    Full Text Available PURPOSE: To evaluate the effect of Rut-bpy (Cis-[Ru(bpy2(SO3(NO]PF 6, a novel nitric oxide donor in Nω-nitro-L-arginine methyl ester (L-NAME-induced hypertensive rats. METHODS: Twenty-four male Wistar rats were randomly assigned to four groups (n=6, named according to the treatment applied (G1-Saline, G2-Rut-bpy, G3-L-NAME and G4-L-NAME+Rut-bpy. L-NAME (30 mg/Kg was injected intraperitoneally 30 minutes before the administration of Rut-bpy (100 mg/Kg. Mean abdominal aorta arterial blood pressure (MAP was continuously monitored. RESULTS: Mean arterial blood pressure (MAP in G3 rats rose progressively, reaching 147±16 mmHg compared with 100±19 mm Hg in G1 rats (pOBJETIVO: Avaliar o efeitos do Rut-bpy (Cis-[Ru (bpy2(SO3(NO] PF6, um novo doador de óxido nítrico, em ratos hipertensos induzidos pelo éster metílico de N-nitro-L-arginina (L-NAME. MÉTODOS: Vinte e quatro ratos Wistar machos foram distribuídos aleatoriamente em quatro grupos (n = 6, nomeados de acordo com o tratamento aplicado (G1-Salina, G2-Rut-bpy, G3-L-NAME e G4-L-NAME+Rut -bpy. L-NAME (30 mg / Kg foi injetado por via intraperitoneal 30 minutos antes da administração de Rut-bpy (100 mg / kg. A pressão arterial média (PAM da aorta abdominal foi monitorada continuamente. RESULTADOS: A pressão arterial média (PAM em ratos do grupo G3 subiu progressivamente, chegando a 147 ±16 mm Hg, em comparação com 100 ±19 mm Hg em ratos do G1 (p <0,05. Em ratos G4, tratados com L-NAME + Rut-bpy, a PAM atingiu 149±11 milímetros de Hg, enquanto no G2 (ratos tratados com Rut bpy os valores da PAM foram 106 ±11 mm Hg. No G1 esses valores decresceram progressivamente, atingindo 87±14 mm Hg após 30 minutos. Um achado importante foi a manutenção da PAM durante todo o experimento em ratos do grupo G2. CONCLUSÃO: O uso de Rut bpy não diminui a PAM em ratos hipertensos por L-NAME. No entanto, quando ele é usado em ratos anestesiados, hipotensos, uma pressão arterial estável

  20. Anodic behavior of stainless-steel substrate in organic electrolyte solutions containing different lithium salts

    Highlights: • We investigated anodic behavior of stainless-steel in organic electrolytes for advanced capacitor. • Anion of the electrolyte affected the anodic stability of the alloy. • Anodic passivation occurs in LiPF6 solution but pitting or active dissolution proceeds in other electrolyte solutions. • Fluoride source in the solution contributes to forming a stable surface layer on the stainless steel. - Abstract: The anodic behavior of austenitic stainless-steel, SUS304, as a current collector of positive electrode in lithium-ion battery/capacitor has been investigated in organic electrolyte solutions based on a mixed alkyl carbonate solvent with different lithium salts. Stable passivation characteristics were observed for the stainless-steel in the LiPF6 solution, but pitting corrosion or active dissolution proceeded in the solutions containing other anions, BF4-, (CF3SO2)2N- (TFSA-) and ClO4-. The mass ratios of the dissolved metal species in the solutions of LiTFSA and LiClO4 were equivalent to that of the alloy composition, which suggests that no preferential dissolution occurs during the anodic polarization in these electrolyte solutions. An HF component formed by decomposition of PF6- with the contaminate water will act as an F- source for the formation of a surface fluoride layer, that will contribute to the anodic stability of SUS304 in the LiPF6 solution. The anodic corrosion in the LiTFSA solution was suppressed in part by mixing the PF6 salt or adding HF in the electrolyte


    Carolina Manzur


    Full Text Available The dinuclear organometallic hydrazone [(h 5-CpFe(h 6-p-MeO-C6H4-NHN=CH-(h 5-C5H4Fe(h 5-Cp]+PF6- (Cp=C5H5 is stereoselectively prepared as its trans isomer by reacting the organometallic hydrazine precursor [(h 5-CpFe(h 6-p-MeO-C6H4-NHNH2]+PF6- with the ferrocenecarboxaldehyde. Its crystalline and molecular structure has been determined and consists of two iron(II sandwiches of the type [(h 5-CpFe(h 6-arene]+ and [(h 5-C5H4Fe(h 5-Cp], in anti position one with respect to the other, and linked by a zigzag hydrazonic spacerLa hidrazona organometálica dinuclear [(h 5-CpFe(h 6-p-MeO-C6H4-NHN=CH-(h 5-C5H4Fe(h 5-Cp]+PF6- es preparada estereoquímicamente como su isómero trans por reacción de la hidracina organometálica precursora [(h 5-CpFe(h 6-p-MeO-C6H4-NHNH2]+PF6- con ferrocencarboxaldehido. Se ha determinado su estructura cristalina y molecular que consiste en dos sanwiches de hierro(II del tipo [(h 5-CpFe(h 6-areno]+ y [(h 5-C5H4Fe(h 5-Cp] en posición anti uno respecto del otro, los que se encuentran enlazados por un espaciador hidrazónico en forma de zig-zag

  2. Excess Molar Volume, Refractive Index and Viscosity of N-Butylpyridinium Tetrafluoroborate Ionic Liquid + Methanol Binary System%离子液体[BPy]BF4和甲醇二元混合体系的超额摩尔体积、折射率和黏度

    许映杰; 黄钗英; 李浩然


    合成了室温离子液体N-丁基吡啶四氟硼酸盐([BPy]BF4),通过核磁共振1H-NMR和红外光谱IR对其结构进行了表征.在298.15 K和常压下,采用U形振荡管密度计测定[BPy]BF4-甲醇体系的密度;用阿贝尔折射仪测定了该二元混合体系在相同温度和压力下的折射率;用乌氏黏度计测定了该二元混合体系在相同温度和压力下的黏度,并由密度数据计算出超额摩尔体积(VE)、由折射率数据计算出了折射率改变值(△nD)、由黏度数据计算出了体系的黏度B系数.结果表明:[BPy]BF4-甲醇体系的VE在全浓度范围内为负值,而△nD在全浓度范围内为正值,两者均在摩尔分数x1≈0.4处出现极值;采用Redlich-Kister方程对VE、△nD与组成的关系进行了关联,最大标准偏差小于3%,说明此方程可适用于回归该二元体系上述的物性数据.由Jones-Dole方程计算出体系的黏度B系数为0.35608,这表明甲醇有效地降低了离子液体的黏度.%Room temperature ionic liquid N-butylpyridinium tetrafluoroborate ([BPy]BF4) was synthesized, and its structure was characterized and confirmed by 1H-NMR and IR. The densities and refractive indices of binary mixtures ([BPy]BF4+methanol) with different compositions were determined at T= 298.15 K and under atmospheric pressure by using a vibrating U-shaped sample tube densimeter and semi-automatic refractometer,respectively. The viscosities of the mixtures were also determined at T= 298.15 K and under atmospheric pressure by using Ubbelohde Suspended-level viscometer. Density values were used in the calculation of the excess molar volumes (V E), and the refractive indices were used to calculate the changes of refractive index (△nD). The achieved viscosities were used to calculate the viscosity B coefficient of the mixtures. The results show that the values of VE are negative over the entire composition range, while the △nD are positive. When the mole fraction of [BPy]BF4

  3. Primary retention following nuclear recoil in β-decay: Proposed synthesis of a metastable rare gas oxide (38ArO4) from (38ClO4−) and the evolution of chemical bonding over the nuclear transmutation reaction path

    Argon tetroxide (ArO4) is the last member of the N=50 e– isoelectronic and isosteric series of ions: SiO44−, PO43−, SO42−, and ClO4−. A high level computational study demonstrated that while ArO4 is kinetically stable it has a considerable positive enthalpy of formation (of ∼298 kcal/mol) (Lindh et al., 1999. J. Phys. Chem. A 103, pp. 8295–8302) confirming earlier predictions by Pyykkö (1990. Phys. Scr. 33, pp. 52–53). ArO4 can be expected to be difficult to synthesize by traditional chemistry due to its metastability and has not yet been synthesized at the time of writing. A computational investigation of the changes in the chemical bonding of chlorate (ClO4−) when the central chlorine atom undergoes a nuclear transmutation from the unstable artificial chlorine isotope 38Cl to the stable rare argon isotope 38Ar through β-decay, hence potentially leading to the formation of ArO4, is reported. A mathematical model is presented that allows for the prediction of yields following the recoil of a nucleus upon ejecting a β-electron. It is demonstrated that below a critical angle between the ejected β-electron and that of the accompanying antineutrino their respective linear momentums can cancel to such an extent as imparting a recoil to the daughter atom insufficient for breaking the Ar–O bond. As a result, a primary retention yield of ∼1% of ArO4 is predicted following the nuclear disintegration. The study is conducted at the quadratic configuration interaction with single and double excitations [QCISD/6−311+G(3df)] level of theory followed by an analysis of the electron density by the quantum theory of atoms in molecules (QTAIM). Crossed potential energy surfaces (PES) were used to construct a PES from the metastable ArO4 ground singlet state to the Ar–O bond dissociation product ArO3+O(3P) from which the predicted barrier to dissociation is ca. 22 kcal/mol and the exothermic reaction energy is ca. 28 kcal/mol [(U)MP2/6–311+G(d)]. - Highlights: • Mathematical model for the yield of primary retention after β-decay. • The nature of metastable chemical bonding in thermodynamically unstable compounds. • The changes in the nature of chemical bond upon nuclear transmutation. • Synthetic protocol of metastable rare gas oxides (ArO4) from a hot chemistry route

  4. Crystal and molecular structure of four copper(II) ethylenediaminedisuccinates, [Cu2(RR,SS-Edds)] . 6H2O, Ba2[Cu(RR,SS-Edds)](ClO4)2 . 8H2O, Ba[Cu(SS-HEdds)]ClO4 . 2H2O, and Ba3[Cu2(RR,SS-Edds)2](ClO4)2 . 6H2O

    Four Cu(II) complexes with the RR,SS-Edds4- and SS-HEdds3- anions are synthesized, and their crystal structures are studied. In the compounds [Cu2(RR,SS-Edds)] . 6H2O (I) and Ba2[Cu(RR,SS-Edds)](ClO4)2 . 8H2O (II), the ligand forms hexacoordinate chelate [Cu(Edds)]2- complexes with the N atoms and O atoms of the propionate groups in the equatorial positions and the O atoms of the acetate groups in the axial vertices. In the compounds Ba[Cu(SS-HEdds)]ClO4 . 2H2O (III) and Ba3[Cu2(RR,SS-Edds)2](ClO4)2 . 6H2O (IV), one of the propionate arms, the protonated arm in III and the deprotonated arm in IV, does not enter into the coordination sphere of the Cu atom. An acetate arm moves to its position in the equatorial plane, and the free axial vertex is occupied by an O atom of the perchlorate ion. In I-IV, the lengths of the equatorial Cu-N and Cu-O bonds fall in the ranges 1.970-2.014 and 1.921-1.970 A, respectively. The axial Cu-O bonds with the acetate groups and ClO4- anions are elongated to 2.293-2.500 and 2.727-2.992 A, respectively. In structure I, the second Cu atom acts as a counterion forming bonds with the O atoms of two water molecules and three O atoms of the Edds ligands. In II-IV, the Ba2+ cations are hydrated and bound to the O atoms of the anionic complexes and (except for one of the cations in IV) ClO4- anions. The coordination number of the Ba cations is nine. The structural units in I-IV are connected into layers. In I, an extended system of hydrogen bonds links the layers into a framework. In II and III, the layers are linked only by weak hydrogen bonds, one bond per structural unit. In IV, ClO4- anions are bound to the Ba and Cu atoms of neighboring layers, thus serving as bridges between the layers.

  5. Synthesis, crystal structure and thermochemical behaviour of complex of host-guest type [(LH2)(BF4)2·H2O] (L=racemate-5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)

    Interaction of BF3·(C2H5)2O with racemate 5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane in the presence of moisture of air results in [(LH2)(BF4)2·H2O] complex formation structure of which is determined by the method of x-ray diffraction analysis and is confirmed by thermogravimetry data. Crystal of the complex are monoclinic, space group - P21/n, a=25.570(7), b=11.231(5), c=8,715(4) A. Structure is built from two-charged organic cations of tetraazamacrocycle, tetrafluoroborate anions and water molecules in correlation 1:2:1 combined by hydrogen bond system in which all four nitrogen atoms of macrocycle performs the function of proton donors. Macrocycle in the complex takes a symmetry close by C2

  6. Spectral reflectance of the one-dimensional organic metals (perylene)2(PF6)1.1 × 0.8CH2Cl2 and (perylene)2(AsF6)1.1 × 0.7CH2Cl2

    Wilckens, Rudolf; Geserich, Hans Peter; Ruppel, Wolfgang; Koch, P.; Schweitzer, Dieter; Keller, Heimo J.


    We report on the optical reflectance of (perylene)2(PF6)1.1 × 0.8CH2Cl2 and (perylene)2(AsF6)1.1 × 0.7CH2Cl2 single crystals in the energy range from 0.25 to 4 eV. For light polarized perpendicular to the molecular stacks the crystals exhibit the optical behaviour of an insulating molecular crystals, whereas for light polarized parallel to the stacks a pronounced plasma edge at hω=0,9eV image is observed. The experimental data were analyzed by a Lorentz-Drude model in order to determine ...

  7. Sulfur-containing trinuclear arene ruthenium clusters

    Tschan, Mathieu; Therrien, Bruno; Chérioux, Frédéric; Süss-Fink, Georg


    The single-crystal X-ray structure analyses of [HRu3(C6H6)(C6Me6)2(μ3-SC6H4Me)(μ2-O)][BF4]2 ([1][BF4]2), [HRu3(C6H6)(C6Me6)2(μ3-SC6H4Me)(μ2-S)][PF6]2 ([2][PF6]2) and [H2Ru3(1,2,4,5-Me4C6H2)3(μ2-S)(Cl)]PF6([3][PF6]) are presented. The structures show the sulfur ligands to act as bridges between ruthenium atoms. In [1][BF4]2 and [2][PF6]2 the metallic core adopts a nido framework. However, in [3][PF6] the absence of a μ3-SR ligand combined with the presence of one terminal chloro unit gives ris...

  8. Synthesis, Crystal Structure and Polyphenol Oxidase Activities Study of [Cu(NTB)Cl] ClO4·2.5CH3 OH%[Cu(NTB)Cl]ClO4·2.5CH3OH的合成、晶体结构和多酚氧化酶活性研究

    邱江华; 王光辉; 廖展如; 孟祥高


    合成了配合物[Cu(NTB)Cl]ClO4·2.5CH3OH(NTB为N,N,N-三(2(-苯并咪唑甲基)胺),并进行了紫外可见光谱、元素分析、循环伏安和单晶X射线衍射分析等表征.用UV-Vis.研究了以邻苯二酚、邻苯三酚为底物时配合物的多酚氧化酶活性,结果表明:配合物的多酚氧化酶活性符合米氏方程曲线;在pH为8.0和30℃的条件下,配合物催化邻苯三酚和邻苯二酚反应的转化数分别为88.2 h-1和0.54 h-1.通过动力学数据比较发现,邻苯三酚比邻苯二酚更容易氧化,而且它们的催化氧化速率都随着pH的升高而增大.%The title complex [ Cu (NTB) Cl ] ClO4 2.5 CH3 OH (NTB=Tris (benzimidazolyl-2-methyl) amine) has been synthesized and characterized by UV-Vis.,elemental analysis,cyclic voltammetry and single crystal X-ray diffraction anal-ysis.Polyphenol oxidase activities toward pyrogallol and catechol have been studied spectroscopically. Their kinetics obey the Michaelis-Menten equation. The turnover numbers of the complex toward pyrogallol are 88.2 h-1 and 0.54 h-1 for cate-chol at pH 8.0 and 30 ℃. Compared with the kinetic data,it is apparent that pyrogallol oxidation is easier than catechol,and catalytic activities increase with increasing of pH values.

  9. 水/离子液体[BMIM]PF6两相体系中全细胞催化生成单葡萄糖醛酸基甘草次酸%Biosynthesis of glycyrrhetic acid 3-O-mono-β-D-glucuronide by whole cell in ionic liquid/water biphasic system

    陈金燕; 邹树平; 何冬梅; 杨晓刚; 李春


    研究了水/离子液体两相体系中重组毕赤酵母Pichia pastoris GS115(r-PGUS-P)全细胞转化甘草酸(GL)生成单葡萄糖醛酸基甘草次酸(GAMG)的反应.确定最适反应体系为离子液体[BMIM] PF6/水(2∶8,体积比),最适缓冲液pH、反应温度、底物浓度和细胞加入量分别为5.4、45℃、6.O mmol·L-1和8.0g·L-1.在此条件下反应58 h,产物GAMG得率和化学键选择性分别为69.6%和67.2%,与纯水相反应体系相比,分别提高了12.4%和12.61%.离子液体循环使用7次后,回收利用率为93.47%.产物GAMG和副产物甘草次酸(GA)在此两相体系中得到有效分离,为后续产物分离带来便利.%Glycyrrhizin (GL), the biologically active compounds of liquorice, can be hydrolysed to glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG) by whole cells containing β-D-glucuronidase. GAMG is widely used in the pharmaceutical and food industries due to its stronger physiological functions, higher biological activity, more favorable sweetness, and lower caloric value as compared with GL. The recombinant Pichia pastoris (r-PGUS-P) designated in this work expressing β-D-glucuronidase, was used as a whole-cell biocatalyst catalyzing GL to GAMG in non-aqueous solvents systems. The results showed that r-PGUS-P gave the highest yield of GAMG in l-butyl-3-methylimidazolium hexafluorophosphate ( [BMIM] PF6 )/water (2 ∶ 8, vol) biphasic system. The optimal conditions of this reaction were determined as follows; optimum pH, substrate concentration, temperature and cell content were 5. 4, 6. 0 mmol · L-1, 45°C, and 8. 0 g · L-1, respectively. Under these optimized conditions, 69.6% yield of GAMG and 67. 2% of the chemical bond selectivity was achieved after 58 h reaction time, increase by 12. 4% and 12. 61%, respectively against aqueous phase. Simultaneously, the ionic liquid [BMIM]PF6 also remained at higher recovery percentage of about 93.47% during repeated use for 7 reaction cycles. Especially

  10. 离子液体[Bmim]PF6萃取-火焰原子吸收法测定水中痕量镉%Determination of Trace Cadmium in Water by Flame Atomic Absorption Spectrometry/with Ionic Liquid Extraction

    王良; 李清; 闫永胜; 崔运成


    A novel method for the separation and determination of trace cadmium in environmental water sample by flame atomic absorption spectrometry (FAAS) with ionic liquid extraction was proposed. When the acidity of the solvent was pH 8, ionic liquid 1-butyl-3-methylimi dazolium hexafluorophosphate ([Bmim]PF6) was used as extractant, dithizone as the chelant, the sample was extracted for 3 min and determined by FAAS. The research result indicated that under optimum conditions, there was favorable linearity relation between 0. 15 and 58. 2 μg/L, detection limit (3δ) was 0. 095 ng/L (n=11). The recovery of this method was in the range of 90. 0% -108. 0% . The relative standard deviation is less than 5. 8% for the analysis of practical sample.%1 引言化学工业排放的废水含有大量金属镉,对环境产生严重危害,因而环境水样中痕量镉的准确测定具有重要意义.目前,常用原子吸收光谱法[1]测定痕量的镉,但由于环境水样中镉的含量低且样品复杂,为了提高分析方法的灵敏度和选择性,样品的预分离与富集至关重要.液-液萃取是一种常用的预分离与富集方法,但常用有机溶剂作萃取剂,易带来二次污染.离子液体是一种无毒、无污染、不挥发的"绿色溶剂"[2],具有安全、高效、环保等优点[3],已萃取分离了多种金属离子[4-5].本实验以双硫腙(H2Dz)为螯合剂,以离子液体1-丁基-3-甲基咪唑六氟磷酸盐( [Bmim]PF6)为萃取剂.用火焰原子吸收光谱法(FAAS)测定了离子液体相中的Cd,建立了痕量Cd的分离与分析方法,并应用于环境水样的分析.

  11. 水/[ NH2 ebim][ PF6]/Triton X-100/正丁醇/环己烷微乳液体系的制备%Preparation of microemulsion system based on[ NH2 ebim] [ BF6 ]/H2 O/TritonX-100/n-butonal/cyclohexane

    刘红晶; 焦阳; 潘阳; 李冬


    Microemulsion with self-made task-specific ionic liquid[ NH2 ebim] [ BF6 ] ,[ NH2 ebim] [ BF6 ]/H2 O/TritonX-100/n-bu-tonal/cyclohexane microemulsion has been prepared. Microemulsion types have been determined by the analysis of electrical con-ductivity and the dynamic light scattering technique,and microemulsion region is divided into O/( S+W) and O/W microemulsion. The ternary phase diagrams has been drawn according to the experimental results. The aggregation behavior of water in the microe-mulsion system was studied by dissipative particle dynamics(DPD). The results of simulation are agree with those of experiment. The effects of the microemulsion region on the proportion of Triton X-100 and n-butonal were investigated. Experimental results show that the region of microemulsion increases with the increase of the proportion of Triton X-100 and n-butonal.%采用自制的功能离子液体1-(胺乙基)-3-丁基咪唑六氟磷酸盐([NH2ebim][PF6]),制备了水/[ NH2 ebim][ PF6]/Triton X-100/正丁醇/环己烷微乳液体系,通过动态光散射技术测定微乳液的粒径分布和分散相浓度,通过电导率仪测定体系电导率的变化,由这两种分析方法确定微乳液类型,微乳液类型被分为表面活性剂与水的互溶相包油型(O/S+W)和水包油型(O/W),并绘制出拟三元相图;通过耗散动力学(DPD)模拟不同水含量时微乳液体系中的聚集行为,模拟结果呈现出的微乳液类型与实验测定分析结果一致,证明了相图绘制的正确性;文中还考察了Triton X-100与正丁醇的比例对微乳液区域的影响,实验结果表明,随着Triton X-100与正丁醇的比例增加微乳液区域增大。

  12. Two Related Copper(I) π-Complexes Based on 2-Allyl-5-(2-pyridyl)-2H-tetrazole Ligand: Synthesis and Structure of [Cu(2-apyt)NO3] and [Cu(2-apyt)(H2O)](BF4) Compounds.

    Slyvka, Yurii; Goreshnik, Evgeny; Pokhodylo, Nazariy; Pavlyuk, Oleksiy; Mys'kiv, Marian


    By means of the alternating current electrochemical technique two new π-compounds [Cu(2-apyt)NO3] (1) and [Cu (2-apyt)(H2O)](BF4) (2) have been obtained starting from the mixture of 1-allyl-5-(2-pyridyl)-2H-tetrazole (1-apyt), 2-allyl-5-(2-pyridyl)-2H-tetrazole (2-apyt) and corresponding copper(II) salts, and have been structurally studied. Selective complexation towards 2-allyl- isomer results in a formation of 2-apyt complexes. Copper(I) ion in both 1 and 2 complexes coordinates the allylic C=C bond, one pyridyl and one tetrazole N atoms. In both structures Cu+ center adopts distorted tetrahedral surrounding which additionally includes oxygen of NO3 - in 1 and H2O moiety in 2. Structure 1 is built from [Cu(2-apyt)NO3]2 dimeric fragments. Contrary, participation of H2O in the metal coordination in 2 leads to the infinite [Cu(2-apyt)(H2O)]+n chain construction. To analyze interactions between the particles in 1 and 2 Hirshfeld surface analysis was performed. PMID:27333565

  13. Study of reactivity of p-cymene ruthenium(II) dimer towards diphenyl-2-pyridylphosphine: Synthesis, characterization and molecular structures of [(6--cymene)RuCl2(PPh2Py)] and [(6--cymene)RuCl(PPh2Py)]BF4

    R Lalrempuia; Patrick J Carroll; Mohan Rao Kollipara


    The reaction of [{(6--cymene)Ru(-Cl)}2Cl2] with functionalized phosphine viz, diphenyl-2-pyridylphosphine yielded complexes of the type: (a) P-bonded complex [(6--cymene)RuCl2(PPh2Py)] (1), (b) P-, N-chelated complex [(6--cymene)RuCl-(PPh2Py)]BF4 (2) and [RuCl2(PPh2Py)2] (3) resulting from the displacement of the -cymene ligand. These complexes were characterized by 1H NMR, 31P NMR and analytical data. The structures of complexes 1 and 2 have been confirmed by single crystal X-ray diffraction study. Complex 1 crystallised in triclinic space group $\\bar{1}$ with = 10.9403 (3) Å, = 13.3108 (3) Å, = 10.5394 (10) Å, = 88.943 (2)°, = 117.193 (2)°, = 113.1680 (10)°, = 2 and = 1230.39 (5) Å3. The complex 2 crystallises in monoclinic space group 21 with = 9.1738 (4) Å, =14.0650 (6) s, = 10.7453 (5) Å, = 106.809 (1)°, = 2 and = 1327.22 (10) Å3.

  14. Theoretical Study on Ionic Liquid Based on 1-Ethyl-3-Methyl- Imidazolium Cation and Hexafluorophosphate or Tetrafluoroborate

    Renqing Lü; Zuogang Cao; Guoping Shen


    The Hartree-Fock and DFT/B3LYP methods have been employed to investigate the electronic structures of l-ethyl-3-methyl-imidazolium cation (EMIM+), BF-4 , PF-6, EMIM+-BF-4, and EMIM+-PF6-using the Gaussian-94 soft-package at 6-31+G(d,p) basis set level for hydrogen, carbon, nitrogen, boron, phosphorus, and fluorine atoms. Comparison of the electronic structures of the lowest energy of EMIM+-BF4- and EMIM+-PF6- pairs, and single EMIM+, BF-4 and PF-6 showed that the optimized EMIM+-BF-4 and EMIM+-PF-6 pair conformers were BF-4 and PF-6 outside the 5-ring plane between the ethyl group and the methyl group. The cohesion of C-H…F hydrogen bond between cation and anion is reinforced by charge assistance. The interaction energy between EMIM+ and PF-6 is 328.8 kJ/mol at the B3LYP level and 326.6 kj/mol at the Hartree-Fock level, whereas that between EMIM+ and BFJ is 353.5 kj/mol at the B3LYP level and 350.5 kj/mol at the Hartree-Fock level. The low energy interactions caused by bulky asymmetric EMIM+, and charge dispersion of cation and anion give rise to the low melting point of ionic liquid EMIM+-BF-4 and EMIM+-PF-6. The two hydrogen bonding models of single hydrogen bond formation, and the hydrogen transfer between C2 in EMIM+ and F in BF-4 or PF-6 were principally depicted.


    In the last years there has been much interest in applying ink-jet printing (IJP) technology to the deposition of several materials for organic electronics applications, including metals, polymers and nanoparticles dispersions on flexible substrates. The aim of this work is to study the effect of ink-jet deposition of polymer films in the manufacturing of OLED devices comparing their performances to standard technologies. The ink-jet printed polymer is introduced in an hybrid structure in which other layers are deposited by vacuum thermal evaporation. The electrical and optical properties of the obtained devices are investigated.OLEDs with the same structure were fabricated by spin-coating a polymer film by the same solution used as ink. Results have been compared to the above ones to determine how the deposition method affects the device optoelectronic properties

  16. Oxidative degradation of the organometallic iron(II) complex [Fe{bis[3-(pyridin-2-yl)-1H-imidazol-1-yl]methane}(MeCN)(PMe3)](PF6)2: structure of the ligand decomposition product trapped via coordination to iron(II).

    Haslinger, Stefan; Pöthig, Alexander; Cokoja, Mirza; Kühn, Fritz E


    Iron is of interest as a catalyst because of its established use in the Haber-Bosch process and because of its high abundance and low toxicity. Nitrogen-heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron-NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1'-bis(pyridin-2-yl)-2,2-bi(1H-imidazole)-κN(3)][3,3'-bis(pyridin-2-yl-κN)-1,1'-methanediylbi(1H-imidazol-2-yl-κC(2))](trimethylphosphane-κP)iron(II) bis(hexafluoridophosphate), [Fe(C17H14N6)(C16H12N6)(C3H9P)](PF6)2, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C-C-coupled biimidazole, is trapped by coordination to still-intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions. PMID:26632838

  17. 二苯并噻吩及其氧化物与离子液体相互作用的理论研究%Theoretical study on the interactions between dibenzothiophene/dibenzothiophene sulfone and ionic liquids

    吕仁庆; 林进; 曲占庆


    采用密度泛函理论方法比较了DBT/DBTO2和[BMIM]+[PF6]-/[BMIM]+[BF4]-的相互作用.对最稳定的[BMIM]+[PF6]-、[BMIM]+[PF6--DBT、[BMIM]+[PF6]-DBTO2、[BMIM]+[BF4]-、[BMIM]+ [BF4]--DBT、[BMIM]+[BF4]--DBTO2进行了NBO和AIM分析.结果表明,DBT和[BMIM]+[PF6]/[BMIM]+[BF4]-中的咪唑环彼此相互平行,NBO和AIM分析表明它们之间发生了π-π相互作用.H1’和H9’形成的F…H氢键有利于π-π堆积作用的形成.DBTO2倾向于趋近C2-H2和甲基基团形成O…H相互作用;DBTO2优先吸附在[BMIM]+[PF6]-/[BMIM]+[BF4]-.在模拟油中,[BMIM]+[PF6]-和[BMIM]+[BF4]-离子液体对DBTO2的萃取能力大于DBT,其原因是可能是DBTO2具有较大的极性和O…H与F…H的氢键作用.%The interactions between sulfur-containing compounds of dibenzothiophene (DBT) and dibenzothiophene sulfone (DBTO2) and ionic liquids of 1-butyl-3-methylimidazolium hexafiuoropnospnate ([BMIM] + [PF6]-) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] + [BF4]-) were comparatively studied by using density functional theory.The most stable structures of [BMIM]+ [PF6]-,[BMIM]+ [PF6]--DBT,[BMIM]+ [PF6]--DBTO2,[BMIM]+ [BF4]-,[BMIM] + [BF4]--DBT,and [BMIM] + [BF4]--DBTO2 systems were obtained by natural bond orbitals (NBO) and atoms in molecules (AIM) anaiyses.The results indicated that DBT and [BMIM] rings of [BMIM] + [PF6]-/[BMIM] + [BF4]-are parallel to each other.There is a strong π-π interaction between them in terms of NBO and AIM analyses.The H1' and H9' involved F…H hydrogen bonding interactions may favor the formation of π-π stacking interactions.The DBTO2 preferentially locates near the C2-H2 and methyl group of [BMIM] + to form O…H interactions.The predicted geometries and interaction energies imply the preferential adsorption of DBTO2 on [BMIM] + [PF6]-/[BMIM] + [BF4]-.The [BMIM] + [PF6] /[BF4]-have better extracting ability to remove DBTO2 than DBT,possibly due to the larger polarity of DBTO2 and stronger interactions

  18. Direct Electrochemistry of a GCE Modified with HRP/Gel-MWCNTs in Ionic Liquid [BMIM] BF4%基于明胶-碳纳米管的辣根过氧化物酶修饰电极在离子液体中的直接电化学

    姚慧; 王燕; 董元; 孙迪; 张严化


    制备了明胶(Gel)-多壁碳纳米管(MWCNTs)纳米复合物,将其修饰在玻碳电极表面,再吸附辣根过氧化物酶(HRP),制得明胶-多壁碳纳米管-辣根过氧化物酶修饰电极(Gel-MWCNTs-HRP/GCE).该修饰电极在PBS中的循环伏安图上出现了一对峰形良好、几乎对称的氧化还原峰,式量电位为-0.356 V(vs.SCE),表明包埋在Gel-MWCNTs中的HRP与电极之间发生了直接电子传递.当扫速在20 ~ 180 mV/s时,氧化峰电流(Ipa)与还原峰电流(Ipc)均与扫速成正比,表明电极过程是受电子传递速率控制的表面传质过程.运用循环伏安法研究了修饰电极的电化学特性,探讨了工作电位、pH值、干扰物质等对修饰电极的影响.实验结果表明,HRP在修饰电极表面能有效和稳定地进行直接电子转移,并保持了其对过氧化氢(H2O2)的生物催化活性.进一步研究发现,在含有亲水性离子液体1-丁基-3-甲基咪唑四氟硼酸([BMIM]BF4)的溶液中,修饰电极对H2O2显示出更灵敏的催化活性,其线性范围为2.0×10-7~0.13 mol/L,检出限(S/N =3)为2.3×10-8 mol/L.该电极具有灵敏度高、重现性及稳定性好、使用寿命较长等优点,同时还显示了较好的抗干扰能力.%A novel hydrogen peroxide biosensor was constructed based on horseradish peroxidase (HRP) immobilized onto glass carbon electrode (GCE) , which was modified with the nanocomposite of gelatin and multi-walled carbon nanotubes ( MWCNTs ). The electrochemistry and electrocatalysis of the modified biosensor were investigated. A pair of well-defined and nearly symmetrical redox peaks with a formal potential of -0.356 Y(vs. SCE) in PBS were observed, which attribute to the direct electron transfer between the entrapped HRP and the electrode. The redox peak current was proportional to scan rate in the range of 20 -180 mV/s, indicating that the process was affected by e-lectronic transfer electrode rate control surface of mass transfer process

  19. Experimentally determining the exchange parameters of quasi-two-dimensional Heisenberg magnets

    Though long-range magnetic order cannot occur at temperatures T>0 in a perfect two-dimensional (2D) Heisenberg magnet, real quasi-2D materials will invariably possess nonzero inter-plane coupling Jperpendicular driving the system to order at elevated temperatures. This process can be studied using quantum Monte Carlo calculations. However, it is difficult to test the results of these calculations experimentally since for highly anisotropic materials in which the in-plane coupling is comparable with attainable magnetic fields Jperpendicular is necessarily very small and inaccessible directly. In addition, because of the large anisotropy, the Neel temperatures are low and difficult to determine from thermodynamic measurements. Here, we present an elegant method of assessing the calculations via two independent experimental probes: pulsed-field magnetization in fields of up to 85 T, and muon-spin rotation. We successfully demonstrate the application of this method for nine metal-organic Cu-based quasi-2D magnets with pyrazine (pyz) bridges. Our results suggest the superexchange efficiency of the [Cu(HF2)(pyz)2]X family of compounds (where X can be ClO4, BF4, PF6, SbF6 and AsF6) might be controlled by the tilting of the pyz molecule with respect to the 2D planes

  20. Pulse radiolysis study of salt effects on reactions of aromatic radical cations with Cl-

    The effect of quaternary ammonium salts on the decays of the radical cations of biphenyl, trans-stilbene, anthracene and pyrene generated by pulse radiolysis in chlorohydrocarbons has been investigated. The decays, which are due to neutralization reactions with Cl-, are retarded by the addition of salts having non-nucleophilic PF6-, BF4- and ClO4-, whereas the radical cations are rapidly quenched by salts having I- and BPh4-. The retarding effect of the salts is attributed to the formation of ion pairs between the reacting ions and the counter-ions from the salts. The rate constants for the neutralization reactions in 1,2-dichloroethane have been determined for the free-ion and ion-paired states; the latter state is attained by the addition of Bu4NPF6. The rate constant determined in the absence of the salt for Pysup(radical)+ is one order of magnitude smaller than those for the others. The salt effect is also smallest on the reaction of Pysup(radical)+. The charge delocalisation of the large aromatic radical cation may be responsible for the exceptional results for Pysup(radical)+. The largest salt effect was observed on the reaction of Ph2CH+, a charge-localized carbenium ion investigated for comparison. The solvent effect on the neutralization reactions is also discussed. (author)

  1. Synthesis and properties of trimethyl-TSF containing alloys of the TMTSF2 family

    Johannsen, Ib; Bechgaard, Klaus; Jacobsen, C. S.;


    Cation-radical salts of the general formula (TriMTSFzTMTSF1-z)2 (X=PF6, ClO4, z ranging from 0 to 0.3) were isostructural. The incorporation of TriMTSF resulted only in minor changes in the transport properties, but the superconducting ground state was completely suppressed...


    ZHANG Chi; LU Fengcai


    The preparation of conducting PPQ film was first reported in the previous paper[1]. It is very interesting that this film is highly sensitive to moisture in air. The hydration and dehydration of the film are accompanied by change not only in color but also in conductivity and UV-visible spectrum. The conducting PPQ is reduced to PPQ and loses its conductivity after being soaked in water.

  3. Experimental and Theoretical Investigation of a Series of Novel Dimanganese(III) μ-Hydroxo Bisporphyrins: Magneto-Structural Correlation and Effect of Metal Spin on Porphyrin Core Deformation.

    Sil, Debangsu; Bhowmik, Susovan; Khan, Firoz Shah Tuglak; Rath, Sankar Prasad


    The synthesis, structure, and properties of a new family of five ethane-bridged dimanganese(III) μ-hydroxo bisporphyrins with the same core structure but different counteranions are reported here. Additions of 10% Brønsted acids such as HI, HBF4, HSbF6, HPF6, and HClO4 to a dichloromethane solution of the dichloro dimanganese(III) bisporphyrin produces complexes having a remarkably bent μ-hydroxo group with I3(-), BF4(-), SbF6(-), PF6(-), and ClO4(-) as counteranions, respectively. The X-ray structures of all complexes have been determined, which have revealed the presence of two equivalent high-spin manganese(III) centers with equally distorted porphyrin rings in the complexes, in sharp contrast with the case for the diiron(III) μ-hydroxo bisporphyrin analogues. (1)H NMR spectra have shown highly deshielded meso resonances, unlike the case for the diiron(III) analogues, where the meso resonances are highly shielded. The variable-temperature magnetic data have been subjected to a least-squares fit which provides a moderate antiferromagnetic coupling through the hydroxo bridge between two zero-field split Mn(III) centers with coupling constant (J) values ranging from -29.5 to -38.6 cm(-1). Fairly good correlations are observed for J with Mn-O(H) distances and Mn-O(H)-Mn angles for all the complexes except for that having an I3(-) counteranion. DFT calculations support the stabilization of two equivalent high-spin Mn(III) porphyrin cores in the complexes and have also explored the role of metal spin in controlling porphyrin ring deformation. Unlike diiron(III) μ-hydroxo bisporphyrin complexes, the dimanganese(III) analogues do not have easily accessible spin states of the metal attainable by subtle environmental perturbations and, therefore, can only stabilize the high-spin state with a variety of counteranions. PMID:27002790

  4. Syntheses, structures and properties of silver(I) complexes with flexible 1,3,5-tris(pyridylmethoxyl)benzene ligands

    Five new silver(I) complexes [Ag2(L2)2](BF4)2.CH3CN.CH3OH (1), [Ag(L2)(CF3SO3)] (2), [Ag(L3)]ClO4.CH3OH (3), [Ag2(L3)2](CF3SO3)2.CH3CN.CH3OH.H2O (4) and [Ag(L3)]PF6.2CH3CN (5) [L2=1,3,5-tris(2-pyridylmethoxyl)benzene, L3=1,3,5-tris(3-pyridylmethoxyl)benzene] were synthesized and characterized by single crystal X-ray diffraction analyses. In complexes 1-5, ligands L2 and L3 show different conformations and act as three-connectors, while the Ag(I) atom serves as three-connecting node to result in the formation of 2D and 3D frameworks. Complexes 1 and 2 with different counteranions have similar 2D network structure with the same (4,82) topology. Complex 3 has a 3D structure with (10,3)-a topology while complexes 4 and 5 have the same 2D (6,3) topological structure. The results showed that the structure of organic ligands and counteranions play subtle but important role in determining the structure of the complexes. In addition, the photoluminescence and anion-exchange properties of the complexes were investigated in the solid state at room temperature. - Graphical abstract: Five new silver(I) coordination frameworks with different topology were obtained and their structures were determined by single crystal X-ray diffraction studies. The influence of counteranion and ligand on the structure of complexes was discussed, the photoluminescence and anion-exchange properties were reported.

  5. Excess heat capacities of (binary + ternary) mixtures containing [emim][BF4] and organic liquids

    Highlights: • The CPE and (CPE)ijk data have been measured over entire composition range at four temperatures. • The observed data have been fitted to Redlich–Kister equation. • The observed data have been analyzed in terms of Graph theory. • The values determined by Graph theory compare well with experimental values. - Abstract: The excess heat capacities, CPE and (CPE)ijk (calculated from the measured molar heat capacities, Cp data) of binary 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + pyrrolidin-2-one or 1-methylpyrrolidin-2-one or pyridine (j); pyrrolidin-2-one (i) + pyridine (j) and ternary 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + pyrrolidin-2-one or 1-methylpyrrolidin-2-one (j) + pyridine (k) mixtures have been measured as a function of composition at T = (293.15, 298.15, 303.15 and 308.15) K and 0.1 MPa using micro differential scanning calorimeter. The (CPE)ijk values for the present ternary mixtures are positive over entire range of composition. The CPE and (CPE)ijk data have been fitted to Redlich–Kister equation to compute binary and ternary adjustable parameters along with their standard deviations. The topology of the constituent molecules (Graph theory) has been utilized to obtain the expressions that describe well the CPE and (CPE)ijk data of the present mixtures. It has been observed that Graph theory describes well the CPE and (CPE)ijk data of the binary as well as ternary mixtures

  6. Electrochemical Reduction of 2-Nitroanisole in Ionic Liquid BMIm-BF4: Synthesis of 2-Anisidine


    A new electrochemical synthesis of 2-anisidine from 2-nitroanisole has been developed in room-temperature ionic liquid (RTIL), which was carded out under mild and safe conditions, where the volatile, toxic solvents, catalysts, as well as any additional supporting electrolyte were avoided. The maximal yield of 2-anisidine reached 51.3% on Cu-graphite couple electrodes under potentiostatic electrolysis at -1.0 V (vs. SCE) until 6 F·mol-1 of charge was passed at 50℃, which offers a new and clean route to synthesis of 2-anisidine. The reduction behavior of 2-nitroanisole was studied in RTIL by cycle voltammertry. The RT1L could be recycled.

  7. Liquid-Liquid Equilibrium in Quaternary System [bmim][PF6] + Water + 1-Methylimidazole + 1-Chlorobutane

    Bendová, Magdalena; Klusoň, P.; Sedláková, Zuzana; Wagner, Zdeněk; Černá, I.; Vašinová, J.

    Wageningen : De Vlinderstichting, 2008, s. 1. ISBN N. [13th International Symposium on Solubility Phenomena and Related Equilibrium Processes. Trinity College Dublin (IE), 28.07.2008-31.07.2008] R&D Projects: GA ČR GA104/07/0444; GA ČR GP104/06/P066; GA AV ČR IAA400720710 Institutional research plan: CEZ:AV0Z40720504 Keywords : liquid-liquid equilibrium * ionic liquids * thermodynamics Subject RIV: CF - Physical ; Theoretical Chemistry

  8. Liquid-Liquid Equilibrium in Ternary Systems 1-Chlorobutane + 1-Methylimidazole + Water / [bmim][PF6

    Bendová, Magdalena; Klusoň, Petr; Sedláková, Zuzana; Černá, I.; Vašinová, J.

    - : -, 2009, s. 61. ISBN N. [Encontro Nacional de Química Física / 1st Iberian Meeting on Ionic Liquids /9./. Aveiro (PT), 15.06.2009-16.06.2009] R&D Projects: GA ČR GA104/07/0444; GA ČR GP104/06/P066; GA AV ČR IAA400720710 Institutional research plan: CEZ:AV0Z40720504 Keywords : liquid-liquid equilibrium * ionic liquids * extraction Subject RIV: CF - Physical ; Theoretical Chemistry

  9. Rapid and simultaneous determination of tetrafluoroborate, thiocyanate and hexafluorophosphate by high-performance liquid chromatography using a monolithic column and direct conductivity detection.

    Yang, Ling; Yu, Hong; Wang, Yaqin


    A method was developed for fast and simultaneous determination of tetrafluoroborate (BF(4)(-)), thiocyanate (SCN(-)) and hexafluorophosphate (PF(6)(-)) by high-performance liquid chromatography using a silica-based monolithic column and direct (non-suppressed) conductivity detection. Chromatographic separation was performed on a Chromolith Speed ROD RP-18e column with tetrabutylammonium hydroxide (TBA) + citric acid + acetonitrile as eluent. The effects of the types of eluent, TBA concentration, acetonitrile volume fraction, eluent pH, column temperature and flow rate on the retention of anions were investigated. The optimized chromatographic conditions were selected. Under the optimal conditions, the baseline separation of BF(4)(-), SCN(-) and PF(6)(-) was achieved without any interference by other anions (F(-), Cl(-), Br(-), I(-), NO(3)(-), ClO(3)(-) and SO(4)(2-)). The detection limit (S/N = 3) was 0.42, 0.46 and 1.42 mg L(-1) for BF(4)(-), SCN(-) and PF(6)(-), respectively. The present method was successfully applied to the determination of BF(4)(-), SCN(-) and PF(6)(-) in ionic liquids. PMID:20702939

  10. Designing New Electrolytes for Lithium Ion Batteries Using Superhalogen Anions

    Srivastava, Ambrish Kumar


    The electrolytes used in Lithium Ion Batteries (LIBs) such as LiBF4, LiPF6 etc. are Li-salts of some complex anions, BF4-, PF6- etc. The investigation shows that the vertical detachment energy (VDE) of these anions exceeds to that of halogen, and therefore they behave as superhalogen anions. Consequently, it might be possible to design new electrolytic salts using other superhalogen anions. We have explored this possibility using Li-salts of various superhalogen anions such as BO2-, AlH4-, TiH5- and VH6- as well as hyperhalogen anions, BH4-y(BH4)y-(y = 1 to 4). Our density functional calculations show that Li-salts of these complex anions possess similar characteristics as those of electrolytic salts in LIBs. Note that they all are halogen free and hence, non-toxic and safer than LiBF4, LiPF6 etc. In particular, LiB4H13 and LiB5H16 are two potential candidates for electrolytic salt due to their smaller Li-dissociation energy ({\\Delta}E) than those of LiBF4, LiPF6 etc. We have also noticed that {\\Delta}E of Li...

  11. Insights into the strong in-vitro anticancer effects for bis(triphenylphosphane)iminium compounds having perchlorate, tetrafluoridoborate and bis(chlorido)argentate anions.

    Folda, Alessandra; Scalcon, Valeria; Ghazzali, Mohamed; Jaafar, Mohammed H; Khan, Rais Ahmad; Casini, Angela; Citta, Anna; Bindoli, Alberto; Rigobello, Maria Pia; Al-Farhan, Khalid; Alsalme, Ali; Reedijk, Jan


    Three new compounds containing the bis(triphenylphosphane)iminium cation (PPN(+)) with ClO4(-), BF4(-) and [AgCl2](-) as counter anions have been synthesized and structurally characterized. The two derivatives with ClO4(-) and BF4(-) were found to be isostructural by single crystal X-ray diffraction. Interestingly, the three compounds show extremely potent antiproliferative effects against the human cancer cell line SKOV3. To gain insights into the possible mechanisms of biological action, several intracellular targets have been considered. Thus, DNA binding has been evaluated, as well as the effects of the compounds on the mitochondrial function. Furthermore, the compounds have been tested as possible inhibitors of the seleno-enzyme thioredoxin reductase. PMID:26384162

  12. Tuning the optical properties of 2-thienylpyridyl iridium complexes through carboranes and anions.

    Zhu, Lin; Tang, Xiao; Yu, Qi; Lv, Wen; Yan, Hong; Zhao, Qiang; Huang, Wei


    2-Thienylpyridyl iridium(III) complexes containing an o-, m-, or p-carboranylvinyl-2,2'-bipyridine ligand and various counteranions (denoted o-PF6, m-BF4, m-PF6, m-SbF6, m-ClO4, m-OTf, m-NO3, m-BPh4, m-F, m-Cl, and p-PF6) were synthesized by using C-formyl carboranes as starting materials. The solid-state structures of o-PF6, m-PF6, m-ClO4, and m-BF4 showed that the cations form twisted cavities in which the anions are fixed by multiple hydrogen bonds. Anion-hydrogen interactions were investigated for nine m-carborane-based complexes with different counteranions. All carborane-based iridium(III) complexes show similar phosphorescence yields in solution but significantly different emission in the solid state. Anion-exchange titration and theoretical calculations revealed the relationships between structures and optical properties. The size of the anion and C-H⋅⋅⋅X anion-hydrogen bonds strongly influence the phosphorescence quantum yield in the solid state. In particular, the Ccar-H⋅⋅⋅X hydrogen bonds between the carboranyl unit and the anion play an important role in solid-state phosphorescence. Complex p-PF6 was successfully applied in phosphorescence-lifetime bioimaging owing to its low toxicity and near-infrared emission. PMID:25663604

  13. Overlayer-mediated superconductivity of Bechgaard-salt single crystals

    Thin films of superconducting (TMTSF)2ClO4 (where TMTSF = tetramethyltetraselenafulvalene) have been prepared by simply immersing crystals of (TMTSF)2PF6 in dichloromethane solutions of nBu4N+-ClO4-. The mechanism of this unprecedented, highly efficient, ion-exchange process is examined in this communication, while the resistance and magnetoresistance of these layers are studied as a function of temperature. The morphologies of the films are studied by energy dispersive spectrometry. (orig.)

  14. Zinc(II) and Cadmium(II) complexes with N4-coordinate pyrazole based ligand: Syntheses, characterization and structure

    Solanki, Ankita; Sadhu, Mehul H.; Kumar, Sujit Baran; Mitra, Partho


    A series of six new mononuclear zinc(II) complexes of the type [Zn(X)(dbdmp)]Y (1-6) (X = N3-/NCO-/NCS-, Y = ClO4-/PF6-, and dbdmp = N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine), two binuclear cadmium(II) complexes [{Cd(dbdmp)}2(μ-N3)2](Y)2 (7-8) and three mononuclear cadmium(II) complexes [Cd(NCO)(dbdmp)]Y (Y = ClO4-/PF6-) (9-10) and [Cd(NCS)2(dbdmp)] (11) have been synthesized and characterized by physico-chemical methods. Crystal structures of the complexes [Zn(N3)(dbdmp)]ClO4 (1), [{Cd(dbdmp)}2(μ-N3)2](ClO4)2 (7), [Cd(NCO)(dbdmp)]ClO4 (9) and [Cd(NCS)2(dbdmp)] (11) have been solved by single crystal X-ray diffraction studies and showed that [Zn(N3)(dbdmp)]ClO4 (1) and [Cd(NCO)(dbdmp)]ClO4 (9) have distorted trigonal bipyramidal geometry, [Cd(NCS)2(dbdmp)] (11) and [(dbdmp)Cd(μ-N3)]2(ClO4)2 (7) have distorted octahedral geometry.

  15. Syntheses, characterization and electrochemical and spectroscopic properties of ruthenium-iron complexes of 2,3,5,6-tetrakis(2-pyridyl)pyrazine and ferrocene-acetylide ligands.

    Wen, Hui-Min; Wang, Jin-Yun; Zhang, Li-Yi; Shi, Lin-Xi; Chen, Zhong-Ning


    Heterodimetallic Ru-Fe complexes [(tppz)(PPh3)2RuL](ClO4) (L = C[triple bond, length as m-dash]CFc, [](ClO4); C[triple bond, length as m-dash]C-C6H4-C[triple bond, length as m-dash]CFc), [](ClO4); C[triple bond, length as m-dash]C-C6H4-C6H4-C[triple bond, length as m-dash]CFc, [](ClO4)) were synthesized by the reactions of [(tppz)(PPh3)2RuCl](ClO4) (tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) with ferrocence-acetylide ligands and characterized by ESI-MS, and (1)H and (31)P NMR spectroscopies. The structure of [](PF6) was determined by X-ray crystallography. The electrochemical studies show that compounds [](ClO4)-[](ClO4) possess two widely separated anodic peaks, ascribable to one-electron oxidation of Fc and Ru(II), respectively. This assignment is further corroborated by the results of UV-vis-NIR, XPS, and theoretical calculation studies. Compound [](ClO4) exhibits significant RuFe metal-metal interactions across the Ru-C[triple bond, length as m-dash]C-Fc backbone. As revealed by electrochemical, spectroscopic and theoretical computational studies, one-electron oxidized species [](ClO4)2 is between the electronically delocalized and valence-trapped state and shows a typical Robin-Day class II mixed-valence behavior. PMID:27273611

  16. Assembly of Heterometallic Rigid-Rod Complexes and Coordination Oligomers from Gold(I) Metalloligands.

    Cámara, Verónica; Barquero, Natalia; Bautista, Delia; Gil-Rubio, Juan; Vicente, José


    The reactions of TpylC6H4C≡CAuL (Tpyl = 2,2':6',2″-terpyridin-4'-yl; L = PPh3, CNXy; Xy = 2,6-dimethylphenyl) with MX2·nH2O (M = Fe, X = ClO4; M = Co, X = BF4; M = Zn, X = TfO, ClO4) in a 2:1 molar ratio give complexes [M(TpylC6H4C≡CAuL)2]X2. Similarly, the reactions of PPN[(TpylC6H4C≡C)2Au] (PPN = (Ph3P)2N) with an equimolar amount of MX2·nH2O give coordination oligomers [M{(TpylC6H4C≡C)2Au}]nXn (M = Fe, Zn, X = ClO4; M = Co, X = BF4). The complexes and oligomers have been isolated and characterized. The crystal structures of [Fe(TpylC6H4C≡CAuCNXy)2](ClO4)2 and [Co(TpylC6H4C≡CAuPPh3)2](BF4)2 have been determined by X-ray diffraction. The hydrodynamic sizes of complexes [M(TpylC6H4C≡CAuPPh3)2]X2 and coordination oligomers [M{(TpylC6H4C≡C)2Au}]nXn have been studied by NMR diffusion spectroscopy and dynamic light scattering measurements. PMID:26087239

  17. Second virial coefficient of bmimBF4/triton X-100/ cyclohexane ionic liquid microemulsion as investigated by microcalorimetry.

    Li, Na; Zhang, Shaohua; Zheng, Liqiang; Gao, Yan'an; Yu, Li


    The second virial coefficient of the ionic liquid (IL) microemulsion was obtained for the first time using microcalorimetry. The heat of dilution of the microemulsion solutions was measured by isothermal titration microcalorimetry (ITC), and the second virial coefficient was derived from the heat of dilution and the number density of the IL microemulsion solutions on the basis of a hard-sphere interaction potential assumption and as a function of the second-order polynomial. The validity of the second virial coefficient was confirmed by the percolation behavior of different ionic liquid microemulsion solutions of Triton X-100 in cyclohexane with or without added salts. The information obtained from the second virial coefficient shows that the interactions between ionic liquid microemulsion droplets are much stronger than those for traditional microemulsions, which may be attributed to the relatively larger size of the microemulsion droplets. PMID:18312017

  18. Charge-Transfer Excitations in the Model Superconductor HgBa$_2$CuO$_{\\bf 4+\\delta}$

    L. Lu; Zhao, X.; Chabot-Couture, G.; Hancock, J. N.; Kaneko, N; Vajk, O. P.; Yu, G.; Grenier, S.; Kim, Y. J.; Casa, D.; Gog, T.; Greven, M.


    We report a Cu $K$-edge resonant inelastic x-ray scattering (RIXS) study of charge-transfer excitations in the 2-8 eV range in the structurally simple compound HgBa$_2$CuO$_{4+\\delta}$ at optimal doping ($T_{\\rm c} = 96.5 $ K). The spectra exhibit a significant dependence on the incident photon energy which we carefully utilize to resolve a multiplet of weakly-dispersive ($ < 0.5$ eV) electron-hole excitations, including a mode at 2 eV. The observation of this 2 eV excitation suggests the exi...

  19. Differential Pathogenicity of Two Feline Leukemia Virus Subgroup A Molecular Clones, pFRA and pF6A

    Phipps, Andrew J.; Chen, Hang; Hayes, Kathleen A.; Roy-Burman, Pradip; Mathes, Lawrence E.


    F6A, a molecular clone of subgroup A feline leukemia virus (FeLV) is considered to be highly infectious but weakly pathogenic. In recent studies with a closely related subgroup A molecular clone, FRA, we demonstrated high pathogenicity and a strong propensity to undergo recombination with endogenous FeLV (enFeLV), leading to a high frequency of transition from subgroup A to A/B. The present study was undertaken to identify mechanisms of FeLV pathogenesis that might become evident by comparing...

  20. Electrochemical Investigation of Li-Al Anodes in Oligo (ethylene glycol) Dimethyl ether/LiPF6

    Y Zhou; X Wang; H Lee; K Nam; X Yang; O Haas


    LiPF{sub 6} dissolved in oligo(ethylene glycol) dimethyl ether with a molecular weight 5 g mol{sup -1} was investigated as a new electrolyte (OEGDME5, 1 M LiPF{sub 6}) for metal deposition and battery applications. At 25 C a conductivity of .48 x 1{sup -3} S cm{sup -1} was obtained and at 85 C, 3.78 x 1{sup -3} S cm{sup -1}. The apparent activation barrier for ionic transport was evaluated to be 3.7 kJ mol{sup -1}. OEGDME5, 1 M LiPF{sub 6} allows operating temperature above 1 C with very attractive conductivity. The electrolyte shows excellent performance at negative and positive potentials. With this investigation, we report experimental results obtained with aluminum electrodes using this electrolyte. At low current densities lithium ion reduction and re-oxidation can be achieved on aluminum electrodes at potentials about 28 mV more positive than on lithium electrodes. In situ X-ray diffraction measurements collected during electrochemical lithium deposition on aluminum electrodes show that the shift to positive potentials is due to the negative Gibbs free energy change of the Li-Al alloy formation reaction.

  1. Study on the competition between density waves, singlet, and triplet pairing superconductivity in an organic conductor (TMTSF)2PF6

    We study the effect of the dimerization of molecules and the effect of magnetic field on the phase competition in quasi-one-dimensional organic superconductors (TMTSF)2X by applying the random phase approximation method. We conclude the following: (i) Due to the decrease of the dimerization, which corresponds to applying the pressure and cooling, spin and charge density wave states are suppressed and give way to a superconducting state. (ii) Applying the magnetic field favors the spin triplet f-wave pairing with spins parallel to the magnetic field due to the cooperation between the magnetic field and the long range off-site interactions

  2. A Facile Approach of Diels-Alder Reaction in Imidazolium-based Ionic Liquids at Room Temperature

    Nur Liyana Sakinah Johari


    Full Text Available A Diels-Alder reaction between anthracene and 1-p-tolyl-2,5-dione was conducted in imidazolium-based ionic liquids. Imidazolium cation was utilised with counter anions, [BF4] and [PF6], as the solvents to carry out the desired Diels-Alder reaction. In this work, the diene and dienophile were introduced into the ionic liquids for 72 hours at room temperature. The desired cycloadduct was prepared by a green chemistry procedure in high yield. The expected cycloadduct was characterized on the MS as well as FTIR and NMR spectroscopy. Herein we report, only the [Bmim][BF4] ionic liquid gave the desired cycloadduct in 86 % yield compared to [Bmim][PF6].

  3. Adsorption, Thermodynamic and Quantum Chemical Studies of 1-hexyl-3-methylimidazolium Based Ionic Liquids as Corrosion Inhibitors for Mild Steel in HCl

    Motsie E. Mashuga


    Full Text Available The inhibition of mild steel corrosion in 1 M HCl solution by some ionic liquids (ILs namely, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate [HMIM][TfO], 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM][BF4], 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF6], and 1-hexyl-3-methylimidazolium iodide [HMIM][I] was investigated using electrochemical measurements, spectroscopic analyses and quantum chemical calculations. All the ILs showed appreciably high inhibition efficiency. At 303 K, the results of electrochemical measurements indicated that the studied ILs are mixed-type inhibitors. The adsorption studies showed that all the four ILs adsorb spontaneously on steel surface with [HMIM][TfO], [HMIM][BF4] and [HMIM][I] obeying Langmuir adsorption isotherm, while [HMIM][PF6] conformed better with Temkin adsorption isotherm. Spectroscopic analyses suggested the formation of Fe/ILs complexes. Some quantum chemical parameters were calculated to corroborate experimental results.

  4. Use of Ionic Liquids in Recycle of Palladium Catalysts for Synthesis of Polyketone

    TIAN Jing; GUO Jintang; ZHANG Xuemei; ZHANG Xin; XU Yongshen


    Room temperature ionic liquids as solvents for palladium-catalyzed copolymerization of carbon monoxide and styrene were prepared by reaction of aqueous lead tetrafluoroborate with correspond-ing chloride or bromide salts. The recyclability of palladium composite catalyst in various ionic liquids was investigated.[Pd(bipy)2][BF4]2 showed a lower catalytic activity than [Pd(bipy)2][PF6]2 in similar conditions, although the catalytic activity of each composite catalyst in ionic liquids still existed after 4 successive recycles. It was shown the catalytic activity of palladium composite catalyst was higher than that of the catalyst formed in situ from palladium acetate, 2,2'-bipyridyl, and HA (A=PF6-, BF4-) in ionic liquids. The effects of volume of ionic liquids, reaction time, and the dosage of benzoquinone on the copolymerization were also studied.

  5. Solvation of the fluorine containing anions and their lithium salts in propylene carbonate and dimethoxyethane.

    Chaban, Vitaly


    Electrolyte solutions based on the propylene carbonate (PC)-dimethoxyethane (DME) mixtures are of significant importance and urgency due to emergence of lithium-ion batteries. Solvation and coordination of the lithium cation in these systems have been recently attended in detail. However, analogous information concerning anions (tetrafluoroborate, hexafluorophosphate) is still missed. This work reports PM7-MD simulations (electronic-structure level of description) to include finite-temperature effects on the anion solvation regularities in the PC-DME mixture. The reported result evidences that the anions appear weakly solvated. This observation is linked to the absence of suitable coordination sites in the solvent molecules. In the concentrated electrolyte solutions, both BF4(-) and PF6(-) prefer to exist as neutral ion pairs (LiBF4, LiPF6). PMID:26067106

  6. First Claisen Rearrangement Reaction in Ionic Liquids with Microwave Heating

    XU Li-Wen; LI Fu-Wei; XIA Chun-Gu


    @@ We have demonstrated the first use of the common ionic liquids, [1] bmimBr, bmimBF4 and bmimPF6 as an environmentally benign solvent for the simple Claisen rearrangement under microwave irradiation. In many cases, the re action was carried out in toxic solvents of high boiling point. [2] Here we reported the first example of Claisen rear rangement reaction in green solvents, ionic liquids, under microwave irradiation.

  7. Electroreduction of Copper Dichloride Powder to Copper Nanoparticles in an Ionic Liquid


    There were a large number of ionic liquids electrodeposition reported in the literature; but were still in the laboratory stage some problems in the practical application of electrodeposition remain such as easily reacted with moisture in the air (AlCl3 ionic liquid), high cost, and corrosive (dialkylimidazolium cation and BF4−, PF6− ionic liquid). In addition to the above shortcomings, low solubility of many metal salts in ionic liquids limits the practical application. In order to solve the...

  8. Extraction of arsenic from a soil in the blackfoot disease endemic area with ionic liquids

    Liao, Chang-Yu; Peng, Ching-Yu; Wang, Hong-Chung; Kang, Hsu-Ya; Paul Wang, H.


    Speciation of arsenic extracted with room temperature ionic liquids (RTILs) ([bmim][BF 4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [bmim][PF 6] (1-butyl-3-methylimidazolium hexafluorophosphate)) from an As-humic acid (As-HA) complex contaminated soil (As-HA/soil) in a blackfoot disease endemic area has been studied by X-ray absorption (near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS)) spectroscopy. About 45% of arsenic in the As-HA/soil can be extracted with [bmim][BF 4] while the relatively less hydrophilic [bmim][PF 6] extracts 25% of arsenic. The extracted arsenic in the [bmim][BF 4] and [bmim][PF 6] from the As-HA/soil possesses mainly As(III) species, suggesting that at least two reaction paths may be involved in the extraction process: (1) splitting of As-HA and (2) reduction of As(V) to As(III). The refined EXAFS spectra also indicate that the As(III) extracted in the RTILs possesses the AsO 2- structure, which has the As-O bond distances of 1.77-1.79 Å and coordination numbers of 4.0-4.2.

  9. Extraction of arsenic from a soil in the blackfoot disease endemic area with ionic liquids

    Speciation of arsenic extracted with room temperature ionic liquids (RTILs) ([bmim][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [bmim][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate)) from an As-humic acid (As-HA) complex contaminated soil (As-HA/soil) in a blackfoot disease endemic area has been studied by X-ray absorption (near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS)) spectroscopy. About 45% of arsenic in the As-HA/soil can be extracted with [bmim][BF4] while the relatively less hydrophilic [bmim][PF6] extracts 25% of arsenic. The extracted arsenic in the [bmim][BF4] and [bmim][PF6] from the As-HA/soil possesses mainly As(III) species, suggesting that at least two reaction paths may be involved in the extraction process: (1) splitting of As-HA and (2) reduction of As(V) to As(III). The refined EXAFS spectra also indicate that the As(III) extracted in the RTILs possesses the AsO2- structure, which has the As-O bond distances of 1.77-1.79 A and coordination numbers of 4.0-4.2.

  10. Heterometallic modular metal-organic 3D frameworks assembled via new tris-β-diketonate metalloligands: nanoporous materials for anion exchange and scaffolding of selected anionic guests.

    Carlucci, Lucia; Ciani, Gianfranco; Maggini, Simona; Proserpio, Davide M; Visconti, Marco


    The modular engineering of heterometallic nanoporous metal-organic frameworks (MOFs) based on novel tris-chelate metalloligands, prepared using the functionalised β-diketone 1,3-bis(4'-cyanophenyl)-1,3-propanedione (HL), is described. The complexes [M(III)L(3)] (M=Fe(3+), Co(3+)) and [M(II)L(3)](NEt(4)) (M=Mn(2+), Co(2+), Zn(2+), Cd(2+)) have been synthesised and characterised, all of which exhibit a distorted octahedral chiral structure. The presence of six exo-oriented cyano donor groups on each complex makes it a suitable building block for networking through interactions with external metal ions. We have prepared two families of MOFs by reacting the metalloligands [M(III)L(3)] and [M(II)L(3)](-) with many silver salts AgX (X=NO(3)(-), BF(4)(-), PF(6)(-), AsF(6)(-), SbF(6)(-), CF(3)SO(3)(-), tosylate), specifically the [M(III)L(3)Ag(3)]X(3)·Solv and [M(II)L(3)Ag(3)]X(2)·Solv network species. Very interestingly, all of these network species exhibit the same type of 3D structure and crystallise in the same trigonal space group with similar cell parameters, in spite of the different metal ions, ionic charges and X(-) counteranions of the silver salts. We have also succeeded in synthesising trimetallic species such as [Zn(x)Fe(y)L(3)Ag(3)](ClO(4))((2x+3y))·Solv and [Zn(x)Cd(y)L(3)Ag(3)](ClO(4))(2)·Solv (with x+y=1). All of the frameworks can be described as sixfold interpenetrated pcu nets, considering the Ag(+) ions as simple digonal spacers. Each individual net is homochiral, containing only Δ or Λ nodes; the whole array contains three nets of type Δ and three nets of type Λ. Otherwise, taking into account the presence of weak Ag-C σ bonds involving the central carbon atoms of the β-diketonate ligands of adjacent nets, the six interpenetrating pcu networks are joined into a unique non-interpenetrated six-connected frame with the rare acs topology. The networks contain large parallel channels of approximate hexagonal-shaped sections that represent 37

  11. Determining diffusion coefficients of ionic liquids by means of field cycling nuclear magnetic resonance relaxometry

    Field Cycling Nuclear Magnetic Resonance (FC NMR) relaxation studies are reported for three ionic liquids: 1-ethyl-3- methylimidazolium thiocyanate (EMIM-SCN, 220–258 K), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4, 243–318 K), and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6, 258–323 K). The dispersion of 1H spin-lattice relaxation rate R1(ω) is measured in the frequency range of 10 kHz–20 MHz, and the studies are complemented by 19F spin-lattice relaxation measurements on BMIM-PF6 in the corresponding frequency range. From the 1H relaxation results self-diffusion coefficients for the cation in EMIM-SCN, BMIM-BF4, and BMIM-PF6 are determined. This is done by performing an analysis considering all relevant intra- and intermolecular relaxation contributions to the 1H spin-lattice relaxation as well as by benefiting from the universal low-frequency dispersion law characteristic of Fickian diffusion which yields, at low frequencies, a linear dependence of R1 on square root of frequency. From the 19F relaxation both anion and cation diffusion coefficients are determined for BMIM-PF6. The diffusion coefficients obtained from FC NMR relaxometry are in good agreement with results reported from pulsed- field-gradient NMR. This shows that NMR relaxometry can be considered as an alternative route of determining diffusion coefficients of both cations and anions in ionic liquids

  12. Structural influence on the photochromic response of a series of ruthenium mononitrosyl complexes.

    Cormary, Benoit; Ladeira, Sonia; Jacob, Kane; Lacroix, Pascal G; Woike, Theo; Schaniel, Dominik; Malfant, Isabelle


    In mononitrosyl complexes of transition metals two long-lived metastable states corresponding to linkage isomers of the nitrosyl ligand can be induced by irradiation with appropriate wavelengths. Upon irradiation, the N-bound nitrosyl ligand (ground state, GS) turns into two different conformations: isonitrosyl O bound for the metastable state 1 (MS1) and a side-on nitrosyl conformation for the metastable state 2 (MS2). Structural and spectroscopic investigations on [RuCl(NO)py(4)](PF(6))(2)·1/2H(2)O (py = pyridine) reveal a nearly 100% conversion from GS to MS1. In order to identify the factors which lead to this outstanding photochromic response we study in this work the influence of counteranions, trans ligands to the NO and equatorial ligands on the conversion efficiency: [RuX(NO)py(4)]Y(2)·nH(2)O (X = Cl and Y = PF(6)(-) (1), BF(4)(-) (2), Br(-)(3), Cl(-) (4); X = Br and Y = PF(6)(-) (5), BF(4)(-) (6), Br(-)(7)) and [RuCl(NO)bpy(2)](PF(6))(2) (8), [RuCl(2)(NO)tpy](PF(6)) (9), and [Ru(H(2)O)(NO)bpy(2)](PF(6))(3) (10) (bpy = 2,2'-bipyridine; tpy = 2,2':6',2"-terpyridine). Structural and infrared spectroscopic investigations show that the shorter the distance between the counterion and the NO ligand the higher the population of the photoinduced metastable linkage isomers. DFT calculations have been performed to confirm the influence of the counterions. Additionally, we found that the lower the donating character of the ligand trans to NO the higher the photoconversion yield. PMID:22757756

  13. Conductivities of AlCl3/Ionic Liquid Systems and Their Application in Electrodeposition of Aluminium

    岳贵宽; 吕兴梅; 朱艳丽; 王慧; 张香平; 张锁江


    Solubilities and conduetivities of anliydrons AlCl3 in six kinds of ionic liquids (ILs) were measured. Among the sixkinds of ILs [bmim]Cl, [bmim]Br, [bmim]BF4, [bmim]PF6, [emim][EtSO4] and [bmim][HSO4], anhydrous AlCl3 could bedissolved in the first five kinds but was hardly dissolved in [bmim][HSO4]. The results showed that the nominal solubilities ofAlCl3 in ILs increased in the order of [bmim][HSO4] < [bmim]PF6 < [emim][EtSO4] <[bmim]BF4<[bmim]Cl<[bmim]Br.Conduetivities of the AlCl3/ILs systems depended apparently on the nominal molar ratio of AlCl3 to ILs. The conduetivities ofAlCl3/[bmim]Cl, AlCl3/[bmim]Br and AlCl3/[bmim]PF6 systems had a similar tendency as a fimetion of the nominal molarratio, that is, as the molar ratio was increased, conductivities increased first and then decreased, with the maximumconductivity obtained at approximately 0.9:1, 1.0:1 and 0.5:1, respectively. Conduetivities of the AlCl3/[bmim]BF4 exhibited adentate change and decreased with the molar ratio of AlCl3 to [bmim]BF4 increasing in general. With the increasing of theanhydrous AlCl3 amount in [emim][EtSO4], conductivity of AlCl3/[emim][EtSO4] monotonically decreased. AlCl3/[bmim]Clsystem was chosen as the electrolyte for the electrodeposition of Al. Preliminary experimental results showed that dense,adherent and homogeneous Al coatings could be electrodeposited on stainless steel by means of constant potential techniqueand the surface coverage was quite satisfactory.

  14. Ionic liquids increase the catalytic efficiency of a lipase (Lip1) from an antarctic thermophilic bacterium.

    Muñoz, Patricio A; Correa-Llantén, Daniela N; Blamey, Jenny M


    Lipases catalyze the hydrolysis and synthesis of triglycerides and their reactions are widely used in industry. The use of ionic liquids has been explored in order to improve their catalytic properties. However, the effect of these compounds on kinetic parameters of lipases has been poorly understood. A study of the kinetic parameters of Lip1, the most thermostable lipase from the supernatant of the strain ID17, a thermophilic bacterium isolated from Deception Island, Antarctica, and a member of the genus Geobacillus is presented. Kinetic parameters of Lip1 were modulated by the use of ionic liquids BmimPF6 and BmimBF4. The maximum reaction rate of Lip1 was improved in the presence of both salts. The highest effect was observed when BmimPF6 was added in the reaction mix, resulting in a higher hydrolytic activity and in a modulation of the catalytic efficiency of the enzyme. However, the catalytic efficiency did not change in the presence of BmimBF4. The increase of the reaction rates of Lip1 promoted by these ionic liquids could be related to possible changes in the Lip1 structure. This effect was measured by quenching of tryptophan fluorescence of the enzyme, when it was incubated with each liquid salt. In conclusion, the hydrolytic activity of Lip1 is modulated by the ionic liquids BmimBF4 and BmimPF6, improving the reaction rate and the catalytic efficiency of this enzyme when BmimPF6 was used. This effect is probably due to changes in the structure of Lip1 induced by the presence of these ionic liquids, stimulating its catalytic activity. PMID:25425150

  15. One-dimensional Chain Topology in [Ag(C6H6NCl)2](ClO4),Generated through Weak Interaction between Molecules

    孙道峰; 曹荣; 梁玉仓; 洪茂椿; 苏伟平


    The mononuclear complex [Ag(C6H6NC1)2](C1O4) has been prepared and structurally analyzed by single-crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group C2/c with unit cell parameters: a=15.5314(2), b=8.0247(8),c=15.3701 (2)A. β =118.832(2)°, V=1678.2(3)A3, Z=4, Mr=462.46, Dc=1.830Mg/m3, F(000)=912,μt (MoKa) = 1.694cm-1. The final R and wR are 0.0472 and 0.1272 for 1484 observed reflections with I≥3σ (Ⅰ). The Ag atom is coordinated by two nitrogen atoms of 4-chloromethyl-pyridine in a linear coordination geometry. Each molecule is further linked by the weak interaction between the C1 and Ag atoms to form a one-dimensional chain structure with Ag-C1 distance of 3.240(A).

  16. Thermochemical Properties of RE(Gly) 4Im( ClO4) 3· 2H2O(RE = La, Pr, Nd, Sm, Eu)

    何水样; 刘向荣; 宋迪生; 胡荣祖


    The enthalpies of solution in water for five new light rare earth ternary complexes RE(Gly)4Im(ClO4)3@ 2H2O (gE =La, Pr, Nd, Sm, Eu; Gly-glycine; Im-imidazole) were measured by means of a Calvet microcalorimeter. The empirical formula of enthalpy of solution (Asol H), relative apparent molar enthalpy ( φLi ), relative partial molar enthalpy ( Li )and enthalpy of dilution (AdilH1,2) were drawn up by the data of entalpies of solution of these complexes. From three plots of the values of standard enthalpy of solution AsolHΘm, φLi,Li) versus the values of ionic radius (r) of the light rare earth elements, the grouping effect of lanthanide was observed, showing that the coordination bond between rare earth ion and ligand possesses a certain extent of the property of a covalent bond. The standard enthalpies of solution in water of similar complexes, Ce(Gly)4Im(ClO4)3@2H2O were estimated according to the plot of AsolHΘm, versus r.

  17. On anodic stability and decomposition mechanism of sulfolane in high-voltage lithium ion battery

    Graphical abstract: - Highlights: • Influence of lithium salts on the anodic stability of sulfolane has been investigated. • Oxidation decomposition mechanisms of LiPF6/Sulfolane electrolyte have been well understood by theoretical and experimental methods. • Decomposition products of the electrolyte can be found on the electrode surface and in the interfacial electrolyte. - Abstract: In this work, we investigated the anodic stability and decomposition mechanism of sulfolane (SL). The anodic stability of SL-based electrolyte with different lithium salts on Pt and LiNi0.5Mn1.5O4 electrodes was found to decrease as follows: LiPF6/SL > LiBF4/SL > LiClO4/SL. The oxidation potential of 1M LiPF6/SL electrolyte on both Pt and electrodes is about 5.0V vs Li/Li+. The presence of PF6- and another SL solvent dramatically alters the decomposition mechanism of SL. Oxidation decomposition of SL-SL cluster is the most favorable reaction in LiPF6/SL electrolyte. The dimer products with S-O-R group were detected by IR spectra on the charged LiNi0.5Mn1.5O4 electrode surface and in the electrolyte near the electrode surface, and were found to increase the interfacial reaction resistance of the LiNi0.5Mn1.5O4 electrode

  18. Comparative study on lithium borates as corrosion inhibitors of aluminum current collector in lithium bis(fluorosulfonyl)imide electrolytes

    Park, Kisung; Yu, Sunghun; Lee, Chulhaeng; Lee, Hochun


    Lithium bis(fluorosulfonyl)imide (LiFSI) is a promising salt that can possibly overcome the limitations of lithium hexafluorophosphate (LiPF6) in current Li-ion batteries (LIBs). Aluminum (Al) corrosion issue, however, is a major bottleneck for the wide use of LiFSI. This study investigates lithium borate salts as Al corrosion inhibitors in LiFSI electrolytes. Through a systematic comparison among lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium difluoro(oxalato)borate (LiDFOB), and LiPF6, the inhibition ability of the additives is revealed to be in the following order: LiDFOB > LiBF4 ≈ LiPF6 > LiBOB. In particular, the inhibition effect of LiDFOB is outstanding; the anodic behavior of Al in 0.8 M LiFSI + 0.2 M LiDFOB ethylene carbonate (EC)-based electrolyte is comparable to that of corrosion-free 1 M LiPF6 solution. The superior inhibition ability of LiDFOB is attributed to the formation of a passive layer composed of Al-F, Al2O3, and B-O species, as evidenced by X-ray photoelectron spectroscopy (XPS) measurements. A LiCoO2/graphite cell with 0.8 M LiFSI + 0.2 M LiDFOB electrolyte exhibits a rate capability comparable to a cell with 1 M LiPF6 solution, whereas a cell with 0.8 M LiFSI solution without LiDFOB suffers from poor power performance resulting from severe Al corrosion.

  19. Synthesis, structures and reactivity of ruthenium nitrosyl complexes containing Kläui's oxygen tripodal ligand.

    Ip, Ho-Fai; Yi, Xiao-Yi; Wong, Wai-Yeung; Williams, Ian D; Leung, Wa-Hung


    Ruthenium nitrosyl complexes containing the Kläui's oxgyen tripodal ligand L(OEt)(-) ([CpCo{P(O)(OEt)(2)}(3)](-) where Cp = η(5)-C(5)H(5)) were synthesized and their photolysis studied. The treatment of [Ru(N^N)(NO)Cl(3)] with [AgL(OEt)] and Ag(OTf) afforded [L(OEt)Ru(N^N)(NO)][OTf](2) where N^N = 4,4'-di-tert-butyl-2,2'-bipyridyl (dtbpy) (2·[OTf](2)), 2,2'-bipyridyl (bpy) (3·[OTf](2)), N,N,N'N'-tetramethylethylenediamine (4·[OTf](2)). Anion metathesis of 3·[OTf](2) with HPF(6) and HBF(4) gave 3·[PF(6)](2) and 3·[BF(4)](2), respectively. Similarly, the PF(6)(-) salt 4·[PF(6)](2) was prepared by the reaction of 4·[OTf](2) with HPF(6). The irradiation of [L(OEt)Ru(NO)Cl(2)] (1) with UV light in CH(2)Cl(2)-MeCN and tetrahydrofuran (thf)-H(2)O afforded [L(OEt)RuCl(2)(MeCN)] (5) and the chloro-bridged dimer [L(OEt)RuCl](2)(μ-Cl)(2) (6), respectively. The photolysis of complex [2][OTf](2) in MeCN gave [L(OEt)Ru(dtbpy)(MeCN)][OTf](2) (7). Refluxing complex 5 with RNH(2) in thf gave [L(OEt)RuCl(2)(NH(2)R)] (R = tBu (8), p-tol (9), Ph (10)). The oxidation of complex 6 with PhICl(2) gave [L(OEt)RuCl(3)] (11), whereas the reduction of complex 6 with Zn and NH(4)PF(6) in MeCN yielded [L(OEt)Ru(MeCN)(3)][PF(6)] (12). The reaction of 3·[BF(4)](2) with benzylamine afforded the μ-dinitrogen complex [{L(OEt)Ru(bpy)}(2)(μ-N(2))][BF(4)](2) (13) that was oxidized by [Cp(2)Fe]PF(6) to a mixed valence Ru(II,III) species. The formal potentials of the RuL(OEt) complexes have been determined by cyclic voltammetry. The structures of complexes 5,6,10,11 and 13 have been established by X-ray crystallography. PMID:21927766

  20. Coordination of 3,3'- bipyridazine with bivalent copper, palladium and platinum

    Bis(ligand) complexes of the diimine 3,3'-bipyridazine (L) with bivalent copper, palladium and platinum are described. Green and violet forms of [CuL-2] [BF-4]2 were obtained, and the electronic and vibrational spectra suggest coordinated fluoroborate groups in the violet species. In the green complex a tetragonal structure is indicated. Coordination of perchlorate in [PdL2] [ClO4]2 is also indicated but not in [PtL2] [ClO4]2. Structure determination of the latter complex reveals a strictly planar PtN4 moiety, and in fact the whole complex cation is approximately planar. Reduced interligand repulsions, compared to those operative in bis(ligand) complexes of 2,2'-bipyridine, are believed to allow the essentially planar conformation. The structure of [PtL2] [ClO4]2 was determined at 295 K by single-crystal X-ray diffraction methods, and was refined to a residual of 0.033 for 1942 'observed' independent reflections. Crystalographic data are also provided. 18 refs., 3 tab., 4 figs

  1. Transition metal complexes with thiosemicarbazide-based ligands. Part46. Synthesis and physico-chemical characterization of mixed ligand cobalt(III-complexes with salicylaldehyde semi-, thiosemi- and isothiosemicarbazone and pyridine



    Full Text Available Mixed ligand octahedral cobalt(III complexes with the tridentate salicylaldehyde semi-, thiosemi- and isothiosemicarbazone and pyridine of general formula [CoIII(L11-3(py3]X (H2L1 = salicylaldehyde semicarbazone, X = [CoIICl3(py]-, ClO4- . H2O, I- . 0.5 I2; H2L2 = salicylaldehyde thiosemicarbazone, X = [CoIICl3(py]-, [CoIIBr3(py]-, ClO4- . H2O, I3-; H2L3 = salicylaldehyde S-methylisothiosemicarbazone, X = [ CoIIBr3(py ]-, ClO4- . H2O, BF4- were synthesized. The tridentate coordination of all the three dianionic forms of the ligands involves the phenol oxygen, hydrazine nitrogen and the chalcogen (O or S in case of salicylaldehyde semi-, thiosemicarbazone and the terminal nitrogen atom in the case of isothiosemicarbazone. For all the complexes, a meridial octahedral arrangement is proposed, which is a consequence of the planarity of the chelate ligand. The compounds were characterized by elemental analysis, molar conductivity, magnetic susceptibility, IR and electronic absorption spectra. The thermal decomposition of the complexes was investigated by thermogravimetry, coupled TG-MS measurements and DSC.

  2. Excess molar enthalpies for [emim][BF4] + pyrrolidin-2-one or 1-methyl pyrrolidin-2-one + pyridine or water mixtures

    Highlights: • The HE and HijkE data have been measured over entire composition range at 298.15 K. • The observed data have been fitted to Redlich–Kister equation. • The observed data have been analyzed in terms of Graph and PFP theories. • The values calculated by Graph theory compare well with experimental values. -- Abstract: Excess molar enthalpies, HijkE of ternary 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + Pyrrolidin-2-one (j) + Pyridine or Water (k); 1-ethyl-3-methylimidazolium tetrafluoroborate (i) 1-methyl pyrrolidin-2-one (j) + Pyridine or Water (k) and HE of Pyrrolidin-2-one (i) + Pyridine or Water (j); 1-methyl pyrrolidin-2-one (i) + Pyridine (j); 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + Water (j) mixtures have been measured over entire mole fraction range at 298.15 K. The HijkE value for 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + Pyrrolidin-2-one (j) + Water (k); 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + 1-methyl pyrrolidin-2-one (j) + Pyridine or Water (k) are positive over whole range of composition and for 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + Pyrrolidin-2-one (j) + Pyridine (k) mixture, the sign of HijkE values varies with change in composition of the components. The observed data have been analyzed in terms of (i) Graph; and (ii) Prigogine–Flory–Patterson (PFP) theories. Results indicate that HE and HijkE values obtained by Graph theory are in good agreement with experimental data. The PFP theory correctly predict sign as well as magnitude of HE values for the binary mixtures. However, theory fails to predict the sign of HijkE values for the ternary mixtures

  3. Negative quantum Hall effect in field-induced spin-density-wave states: Dependence on shape of the quasi-one-dimensional Fermi surface

    Kishigi, Keita; Hasegawa, Yasumasa


    The successive transitions of the field-induced spin-density wave, which is labeled by the quantum number N of the Hall conductivity and the nesting vector, are known to depend on the shape of the quasi-one-dimensional Fermi surface. We study the condition for the appearance of the negative N states, where the quantized Hall conductivity changes the sign. We obtain the phase diagram for the negative N states in the parameter space of the higher harmonics in the Fermi surface ( tb' , t3 , and t4 ) to be stabilized with and without the periodic anion potential V in the perpendicular direction to the conducting axis, which are the cases in (TMTSF)2ClO4 and (TMTSF)2PF6 , respectively. The negative N phase is shown to be stabilized for the smaller values of t3 and t4 in the case of the finite V . Comparing with the experiment by Matsunaga [J. Phys. IV 131, 269 (2005)], where the quantum Hall effect is observed in (TMTSF)2ClO4 with various cooling rates, we obtain the parameter regions of t3 and t4 for (TMTSF)2ClO4 ( 0.06≲t3/tb'≲0.23 , 0≲t4/tb'≲0.08 , and V/tb'≲2.0 ).

  4. Group contribution and parachor analysis of experimental data on densities and surface tension for six ionic liquids with the [PF6] anion

    Klomfar, Jaroslav; Součková, Monika; Pátek, Jaroslav


    Roč. 385, January (2015), s. 62-71. ISSN 0378-3812 R&D Projects: GA ČR GA13-00145S Institutional support: RVO:61388998 Keywords : ionic liquid * density * surface tension * odd-even effect Subject RIV: BJ - Thermodynamics Impact factor: 2.200, year: 2014

  5. Measurements and group contribution analysis of 0.1 MPa densities for still poorly studied ionic liquids with the [PF6] and [NTf2] anions

    Součková, Monika; Klomfar, Jaroslav; Pátek, Jaroslav


    Roč. 77, October (2014), s. 31-39. ISSN 0021-9614 R&D Projects: GA ČR GA13-00145S; GA ČR GA101/09/0010 Institutional support: RVO:61388998 Keywords : ionic liquid * density * group contribution method * bis(trifluoromethylsulfonyl)imide anion * hexafluorophosphate anion Subject RIV: BJ - Thermodynamics Impact factor: 2.679, year: 2014

  6. Conductivity and thermopower studies of bis-tetramethyltetraselenafulvalenium hexafluorophosphide, bis-tetramethyltetrathiafulvalenium hexafluorophosphide, and their solid solutions, (TMTSF1-xTMTTFx)2PF6

    Mortensen, Kell; Engler, E. M.


    attributed to the small transverse transfer integral tb associated with the TMTTF molecule, which leads to large on-site Coulomb repulsion. The parallel transfer integrals ta appear to be very similar for the two constituent molecules. A slight x dependence of S, appearing below approximately 100 K, is...... attributed to enhanced one-dimensionality when the amount of TMTTF is increased. Close to and below the spin-density-wave ordering temperature, more marked x dependences appear, indicative of impurities. The x=0.85 salt behaves generally similar to the pristine TMTTF material, though dominated by additional...

  7. Preparation of Ionic Liquids and Their Application in Hydrogenation of Aromatic Nitriles

    LIN,Qi; CHEN,Li; XIE,Yi-Peng; ZHENG,Hong-Jie; LI,Xian-Jun; CHEN,Hua


    @@ On the basis of their characteristic polar nature, phase behavior and lack of vapour pressure, ionic liquids are considered as green solvents and have attracted significant attention as an alternative reaction medium for homogeneous catalysis.[1] However, the "greenness" of typical ionic liquids used in the literature consisted of halogen-containing anions (such as [AlCl4]-, [BF4]- and [PF6]-) was limited in some sense, due to the serious environment concerns if the hydrolysis stability of the anion is poor (e.g. for [AlCl4]-and [PF6]-) or thermal stability of used ionic liquid is undesired. In both cases, the additional effort is needed to avoid the liberation of toxic and corrosive HF or HCl into the environment.

  8. Measurement of activity coefficients at infinite dilution for hydrocarbons in imidazolium-based ionic liquids and QSPR model

    ZHU Jiqin; YU Yanmei; CHEN Jian; FEI Weiyang


    The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficients γ∞ at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement of γ∞ by gas-liquid chromatography is a speedy and costsaving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylbenzenes,styrene,in 1-allyl-3-methylimidazolium tetrafluoroborate ([AMIM][BF4]) and 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF6]), 1-isobutenyl-3-methylimidazolium tetrafluoroborate ([MPMIM][BF4]) and [MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure parameters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.

  9. Recoiled ions from polyatomic cluster impacts on organic and inorganic targets

    Diehnelt, C. W.; Van Stipdonk, M. J.; Schweikert, E. A.


    We report the observation of a polyatomic cluster constituent, fluorine in this case, recoiling from the projectile upon impact with a surface. The clusters (NaF) nNa + ( n=1, 2, and 4), PF 6-, BF 4-, and SiF 5-, with incident kinetic energies of 12-28 keV, were impacted on Au, SiO 2, and α-cyano-4-hydroxycinnamic acid targets. The Au surface gave the highest F - yield when compared to the "light" SiO 2 surface, for the same incident cluster. This supports previous MD predications of polyatomic cluster constituents "splashing" upon impact with a surface.

  10. Solvation free energies in [bmim]-based ionic liquids: Anion effect toward solvation of amino acid side chain analogues

    Latif, Muhammad Alif Mohammad; Micaêlo, Nuno; Abdul Rahman, Mohd Basyaruddin


    Stochastic molecular dynamics simulations were performed to investigate the solvation free energy of 15 neutral amino acid side chain analogues in aqueous and five, 1-butyl-3-methylimidazolium ([BMIM])-based ionic liquids. The results in aqueous were found highly correlated with previous experimental and simulation data. Meanwhile, [BMIM]-based RTILs showed better solvation thermodynamics than water to an extent that they were capable of solvating molecules immiscible in water. Non-polar analogues showed stronger solvation in hydrophobic RTIL anions such as [PF6]- and [Tf2N]- while polar analogues showed stronger solvation in the more hydrophilic RTIL anions such as [Cl]-, [TfO]- and [BF4]-.

  11. Electrochemical characterization of electrolytes and electrodes for lithium-ion batteries. Development of a new measuring method for electrochemical investigations on electrodes with the electrochemical quartz crystal microbalance (EQCM); Elektrochemische Charakterisierung von Elektrolyten und Elektroden fuer Lithium-Ionen-Batterien. Entwicklung einer neuen Messmethode fuer elektrochemische Untersuchungen an Elektroden mit der EQCM

    Moosbauer, Dominik Johann


    In this work the conductivities of four different lithium salts, LiPF6, LiBF4, LiDFOB, and LiBOB in the solvent mixture EC/DEC (3/7) were investigated. Furthermore, the influence of eight ionic liquids (ILs) as additives on the conductivity and electrochemical stability of lithium salt-based electrolytes was studied. The investigated salts were the well-known lithium LiPF6 and LiDFOB. Conductivity studies were performed over the temperature range (238.15 to 333.15) K. The electrochemical stabilities of the solutions were determined at aluminum electrodes. The salt solubility of LiBF4 and LiDFOB in EC/DEC (3/7) was measured with the quartz crystal microbalance (QCM), a method developed in our group. Moreover, a method to investigate interactions between the electrolyte and electrode components with the electrochemical quartz crystal microbalance (EQCM) was developed. First, investigations of corrosion and passivation effects on aluminum with different lithium salts were performed and masses of deposited products estimated. Therefore, the quartzes were specially prepared with foils. Active materials of cathodes, in this work lithium iron phosphate (LiFePO4), were also investigated with the EQCM by a new method. [German] In dieser Arbeit wurden die Leitfaehigkeiten von vier unterschiedlichen Salzen, LiPF6, LiBF4, LiDFOB und LiBOB in dem Loesemittelgemisch EC/DEC (3/7) untersucht. Des Weiteren wurde der Einfluss von acht Ionischen Fluessigkeiten (ILs) als Additive fuer Lithium-Elektrolyte auf die elektrochemische Stabilitaet und die Leitfaehigkeit studiert. Die untersuchten Salze waren LiPF6 und LiDFOB. Die Leitfaehigkeitsmessungen wurden in einem Temperaturbereich von (238,15 bis 333,15) K durchgefuehrt. Die elektrochemischen Stabilitaeten der Elektrolyte fanden an Aluminium statt. Mit einer an der Arbeitsgruppe entwickelten neuen Methode wurden zudem die Salzloeslichkeiten von LiBF4 und LiDFOB in EC/DEC (3/7) mit der Quarzmikrowaage (QCM) bestimmt. Weiterhin wurden

  12. The preparation of carbon dots/ionic liquids-based electrolytes and their applications in quasi-solid-state dye-sensitized solar cells

    Highlights: ► A facile means to generate carbon dots/ionic liquids (ILs) – were demonstrated. ► The carbon dots/ILs blend were used for fabricating quasi-solid-state DSSCs. ► Cells exhibited good stability in room temperature without any further sealing. -- Abstract: A facile means to generate carbon dots/ionic liquids (ILs) blend using ionic liquid-assisted electrochemical exfoliation was demonstrated. Two kinds of ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), were used in this work. Transmission electron microscopy and UV–vis spectrum were employed to characterize the formed carbon dots/ILs. The carbon dots/ILs were used for fabricating quasi-solid-state dye-sensitized solar cells (DSSCs), where 1-butyl-3-methylimidazolium iodide and LiI/I2 were added to enhance the performance of DSSCs. Effects of the varied contents of components in the complex on the performance of DCCSs have been studied in detail at ambient temperature. The electrochemical impedance spectroscopy showed that the introduction of carbon dots into ionic liquids can enhance the electrical properties by facilitating charge transfer processes of the electrolytes. The overall energy-conversion efficiency (η) was 2.71% and 2.41% for carbon dots/[bmim][PF6] and carbon dots/[bmim][BF4] based blend electrolytes, respectively. A 82% enhancement in η was obtained by introduction of carbon dots into [bmim][PF6] comparing with pure [bmim][PF6] (η = 1.49%). In addition, the cells exhibited good stability under continuous illumination in room temperature without any further sealing

  13. Effect of Lithium Bis(trifluoromethylsulfonyl)imide on the High-temperature Behavior of LiFePO4 Positive Electrode%二(三氟甲基磺酰)亚胺锂对磷酸铁锂正极高温行为的影响

    车海英; 杨军; 吴凯; 王久林; 努丽燕娜


    The effect of lithium salts in electrolytes on the high-temperature performance of LiFePO4 electrode is investigated systematically and the related mechanism is revealed. Differential scanning calorimetry measurements show that lithium bis(trifluorornethylsulfonyl)imide (LiTFSI) and LiBF4 are more favorable for the use at high temperature than LiPF6 because of their water insensitivities and excellent thermal stabilities. Inductively coupled plasma is used to examine the dissolving degree of ferrous ions from LiFePO4 in the different electrolytes at 55℃. It is found that little ferrous ions can be dissolved from LiFePO4 in LiTFSI and fluorine-free lithium salt electrolytes. On the contrary, it is quite serious in LiPF6 electrolyte. In addition, FePO4 is easier to release iron ions than LiFePO4 in the LiPF6 electrolyte. The experimental results of cyclic voltammetry and light microscope indicate that a small amount of LiBF4 can inhibit the corrosion of aluminum foil current collector from LiTFSI. The electrolyte containing mixed salts of LiTFSI and LiBF4 significantly improves the high-temperature performance of LiFePCVLi cell. The discharge capacity is still 147.7 mAh/g after 40 cycles at 55℃ and 1 C rate.%系统研究了电解质锂盐对磷酸铁锂电极高温性能的影响,并探讨了相关的作用机理.差示扫描量热仪测试显示,与LiPF6相比,二(三氟甲基磺酰)亚胺锂(LiTFSI)和LiBF4具有对水份稳定且热稳定性好的优点,更适合高温条件下使用.应用等离子体发射光谱考察LiFePO4在55℃和不同电解液体系中铁离子溶出程度,结果表明,在LiTFSI和无氟锂盐电解液中LiFePO4的铁很少溶出,而在LiPF6电解液中却溶出严重,且FePO4的铁溶出量高于LiFePO4.循环伏安和光学显微镜测试结果显示少量LiBF4的加入能有效抑制LiTFSI对集流体铝箔的腐蚀.以LiTFSI和LiBF4作为混合锂盐配成的电解液能显著改善LiFePO4/Li电池的高温电化学性能,在55

  14. Comprehensive Insights into the Reactivity of Electrolytes Based on Sodium Ions.

    Eshetu, Gebrekidan Gebresilassie; Grugeon, Sylvie; Kim, Huikyong; Jeong, Sangsik; Wu, Liming; Gachot, Gregory; Laruelle, Stephane; Armand, Michel; Passerini, Stefano


    We report a systematic investigation of Na-based electrolytes that comprise various NaX [X=hexafluorophosphate (PF6 ), perchlorate (ClO4 ), bis(trifluoromethanesulfonyl)imide (TFSI), fluorosulfonyl-(trifluoromethanesulfonyl)imide (FTFSI), and bis(fluorosulfonyl)imide (FSI)] salts and solvent mixtures [ethylene carbonate (EC)/dimethyl carbonate (DMC), EC/diethyl carbonate (DEC), and EC/propylene carbonate (PC)] with respect to the Al current collector stability, formation of soluble degradation compounds, reactivity towards sodiated hard carbon (Nax -HC), and solid-electrolyte interphase (SEI) layer formation. Cyclic voltammetry demonstrates that the stability of Al is highly influenced by the nature of the anions, solvents, and additives. GC-MS analysis reveals that the formation of SEI telltales depends on the nature of the linear alkyl carbonates and the battery chemistry (Li(+) vs. Na(+) ). FTIR spectroscopy shows that double alkyl carbonates are the main components of the SEI layer on Nax -HC. In the presence of Na salts, EC/DMC and EC/DEC presented a higher reactivity towards Nax -HC than EC/PC. For a fixed solvent mixture, the onset temperature follows the sequence NaClO4 PF6 PF6

  15. Synthesis of fluorene-based polyelectrolytes tethering different counterions for single-component white light-emitting electrochemical cells

    Yang, Sheng-Hsiung; Tsai, Chia-Sheng; Liu, Bo-Cun; Su, Hai-Ching


    A series of polyfluorene (PF) electrolytes bearing Br-, BF4 -, or PF6 - counterions were synthesized and characterized. 2,1,3-benzoselenadiazole moieties were incorporated into polymer main chains to produce single-component white lightemitting polymers. The thermal stability of Br-containing ionic PF was decreased because of the Hofmann elimination occurred at higher temperature. By replacing Br- with BF4 - or PF6 - counterions, the thermal stability of polymers was significantly improved. The emission intensity around 550 nm was decreased for ionic polyelectrolytes. The optimized spin-coated light-emitting electrochemical cell (LEC) with the configuration of ITO/PEDOT/polymer/Ag showed a maximum luminescence efficiency of 1.56 lm/W at a low operation bias of 3 V. The single-component LEC device exhibited pure white light emission with CIE'1931 coordinates approaching (0.33, 0.33) and high color rendering index (CRI < 85), referring to its potential use in solid-state-lighting application.

  16. Density and viscosity of three (2,2,2-trifluoroethanol + 1-butyl-3-methylimidazolium) ionic liquid binary systems

    Highlights: • Densities and viscosities from 278.15 to 333.15 K are reported for three binary (2,2,2-trifluoroethanol + an IL) systems. • TFE + [bmim][BF4] system presents positive VE values except for the highest mole fractions of TFE, at the highest temperatures. • TFE + [bmim][PF6] presents negative VE values except at the low TFE mole fractions for the lowest temperatures. • TFE + [bmim][NTf2] presents negative VE values for all the mole fractions and temperatures studied. • The three systems present negative viscosity deviations becoming less negative with increasing temperature. -- Abstract: Densities and viscosities were determined for binary mixtures of 2,2,2-trifluoroethanol (TFE) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([bmim][NTf2]) over the entire range of composition. The experimental measurements were carried out at temperatures ranging from 278.15 K to 333.15 K, at atmospheric pressure. The densities and viscosities of the pure ionic liquids and their mixtures with TFE were described successfully by an empirical third-order polynomial and by the Vogel–Fulcher–Tammann equation, respectively. In addition, excess molar volumes and viscosity deviations were determined from densities and viscosities of mixtures, respectively, and fitted by using the Redlich–Kister equation

  17. Strongly luminous tetranuclear gold(I) complexes supported by tetraphosphine ligands, meso- or rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane.

    Tanase, Tomoaki; Otaki, Risa; Nishida, Tomoko; Takenaka, Hiroe; Takemura, Yukie; Kure, Bunsho; Nakajima, Takayuki; Kitagawa, Yasutaka; Tsubomura, Taro


    A series of tetragold(I) complexes supported by tetraphosphine ligands, meso- and rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane (meso- and rac-dpmppm) were synthesized and characterized to show that the tetranuclear Au(I) alignment varies depending on syn- and anti-arrangements of the two dpmppm ligands with respect to the metal chain. The structures of syn-[Au4 (meso-dpmppm)2X]X'3 (X = Cl; X' = Cl (4 a), PF6 (4 b), BF4 (4 c)) and syn-[Au4 (meso-dpmppm)2]X4 (X = PF6 (4 d), BF4 (4 e), TfO (4 f); TfO = triflate) involved a bent tetragold(I) core with a counter anion X incorporated into the bent pocket. Complexes anti-[Au4 (meso-dpmppm)2]X4 (X = PF6 (5 d), BF4 (5 e), TfO (5 f)) contain a linearly ordered Au4 string and complexes syn-[Au4 (rac-dpmppm)2X2]X'2 (X = Cl, X' = Cl (6 a), PF6 (6 b), BF4 (6 c)) and syn-[Au4 (rac-dpmppm)2]X4 (X = PF6 (6 d), BF4 (6 e), TfO (6 f)) consist of a zigzag tetragold(I) chain supported by the two syn-arranged rac-dpmppm ligands. Complexes 4 d-f, 5 d-f, and 6 d-f with non-coordinative large anions are strongly luminescent in the solid state (λmax = 475-515 nm, Φ = 0.67-0.85) and in acetonitrile (λmax = 491-520 nm, Φ = 0.33-0.97); the emission was assigned to phosphorescence from (3) [dσ*σ*σ* pσσσ] excited state of the Au4 centers on the basis of DFT calculations as well as the long lifetime (a few μs). The emission energy is predominantly determined by the HOMO and LUMO characters of the Au4 centers, which depend on the bent (4), linear (5), and zigzag (6) alignments. The strong emissions in acetonitrile were quenched by chloride anions through simultaneous dynamic and static quenching processes, in which static binding of chloride ions to the Au4 excited species should be the most effective. The present study demonstrates that the structures of linear tetranuclear gold(I) chains can be modified by utilizing the stereoisomeric tetraphosphines, meso- and rac-dpmppm, which may

  18. Solubilities of p-coumaric and caffeic acid in ionic liquids and organic solvents

    Highlights: ► New solubility data of p-coumaric and caffeic acid in ionic liquids and organic solvents. ► Normal melting point temperature and enthalpy of fusion of p-coumaric and caffeic acid. ► Thermogravimetric analysis for p-coumaric and caffeic acid. ► Correlation with UNIQUAC and NRTL. -- Abstract: The solubilities of two cinnamic acid derivatives, namely p-coumaric acid and caffeic acid, in six 1-alkyl-3-methyl imidazolium based ionic liquids composed of the PF6−, BF4−, TFO− and TF2N− anions, and in two organic solvents, t-pentanol and ethyl acetate, have been measured at the temperature range of about (303 to 317) K. The p-coumaric acid was found to be more soluble than caffeic acid in all studied solvents. Higher solubilities of both acids were observed in the ionic liquids composed of the BF4− and TFO− anions. The increase of the alkyl chain length on the cation invokes a decrease in solubility in the case of hydrophilic ionic liquids composed of BF4− anion, while in the case of hydrophobic ones composed of PF6− anion an increase in the solubility is observed. Between the two organic solvents t-pentanol is better solvent than ethyl acetate for both acids. Moreover, using the van’t Hoff equations the apparent Gibbs energy, enthalpy, and entropy of solution were calculated. Finally, successful correlation of the experimental data was achieved with the UNIQUAC and the NRTL activity coefficient models, while poor predictions of the solubility of the two acids in the organic solvents were obtained with two UNIFAC models

  19. Antileishmanial activity of ruthenium(II)tetraammine nitrosyl complexes.

    Pereira, José Clayston Melo; Carregaro, Vanessa; Costa, Diego Luís; da Silva, João Santana; Cunha, Fernando Q; Franco, Douglas Wagner


    The complexes trans-[Ru(NO)(NH(3))(4)L](X)(3) (X = BF(4)(-), PF(6)(-) or Cl(-) and L = N-heterocyclic ligands, P(OEt)(3), SO(3)(-2)), and [Ru(NO)Hedta)] were shown to exhibit IC(50pro) in the range of 36 (L = imN) to 5000 microM (L = imC). The inhibitory effects of trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) and of the Angeli's salt on the growth of the intramacrophage amastigote form studied were found to be similar while the trans-[Ru(NH(3))(4)imN(H(2)O)](2+) complex was found not to exhibit any substantial antiamastigote effect. The trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) compound, administered (500 nmol kg(-1) day(-1)) in BALB/c mice infected with Leishmania major, was found to exhibit a 98% inhibition on the parasite growth. Furthermore, this complex proved to be at least 66 times more efficient than glucantime in in vivo experiments. PMID:20598778

  20. Structural insights into the counterion effects on the manganese(iii) spin crossover system with hexadentate Schiff-base ligands.

    Wang, Shi; Xu, Wu-Tan; He, Wen-Rui; Takaishi, Shinya; Li, Yong-Hua; Yamashita, Masahiro; Huang, Wei


    A series of new salts [Mn(5-MeO-sal-N-1,5,8,12)]Y (Y = ClO4 for 1, Y = BF4 for 2, Y = NO3 for 3 and Y = CF3SO3 for 4) based on the six-coordinated mononuclear manganese(iii) Schiff-base complex cation [Mn(5-MeO-sal-N-1,5,8,12)](+), has been investigated to determine the impact of counter anion effects, intramolecular ligand distortion and intermolecular supramolecular structures on the spin crossover (SCO) behavior. The SCO in salt 1 has resulted in a crystallographic observation of the coexistence of high-spin (HS, S = 2) and low-spin (LS, S = 1) manganese(iii) complex cations in equal proportions around 100 K. At room temperature, the two crystallographically distinct manganese centers are both close to the complete HS state. Only one of the two slightly different units undergoes SCO in the temperature range 300-180 K, whereas the other remains in the HS state down to 20 K. For salts 2 and 3, crystal structural analysis indicates change in the anion from ClO4(-) to BF4(-) and NO3(-) was led to the close arrangement of the cations and the stacking between phenyl groups from the ligands. With CF3SO3(-) as the counterion, although the cations and the anions separate clearly in one direction, the close arrangement of cations in other directions precludes the spin transformation of the Mn(iii) cations. Magnetic measurements on 2-4 indicate that the manganese(iii) complex cations remain in the HS state in the temperature range 2-300 K. PMID:26927027

  1. Heterohexanuclear (Cu3Fe3) Complexes of Substituted Hexaazatrinaphthylene (HATN) Ligands: Twofold BF4- Association in the Solid and Stepwise Oxidation (3 e) or Reduction (2 e) to Spectroelectrochemically Characterized Species

    Roy, S.; Sarkar, B.; Duboc, C.; Fiedler, Jan; Sarper, O.; Lissner, F.; Mobin, S. M.; Lahiri, G. K.; Kaim, W.


    Roč. 15, č. 28 (2009), s. 6932-6939. ISSN 0947-6539 R&D Projects: GA MŠk OC 139; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40400503 Keywords : copper * EPR spectroscopy * ferrocene compounds * heterocycles * spectroelectrochemistry Subject RIV: CG - Electrochemistry Impact factor: 5.382, year: 2009

  2. After-effects of electron capture of 57Co in Fe(ClO4)2x6H2O and Fe(BF4)2x6H2O

    Moesbauer emission and absorption spectra of ferrous hexahydrates show no difference in the phase transformation temperature but the quadrupole splitting of ferrous ions is by 13% less in the emission case. Probably, this can be attributed to the autoradiolysis of water ligands resulting in the formation of a metastable state of the molecule. Time delayed coincidence Moessbauer measurements show the lifetime of this state to be in the order of 10-8-10-7s. (author)

  3. A New Series of Complexes Possessing Rare “Tertiary” Sulfonamide Nitrogen-to-Metal Bonds of Normal Length: fac-[Re(CO)3(N(SO2R)dien)]PF6 Complexes with Hydrophilic Sulfonamide Ligands

    Abhayawardhana, Pramuditha L.; Marzilli, Patricia A.; Fronczek, Frank R.; Marzilli, Luigi G.


    Tertiary sulfonamide nitrogen-to-metal bonds of normal length are very rare. We recently discovered such a bond in one class of fac-[Re(CO)3(N(SO2R)(CH2Z)2)]n complexes (Z = 2-pyridyl) with N(SO2R)dpa ligands derived from di-(2-picolyl)amine (N(H)dpa). fac-[M(CO)3(N(SO2R)(CH2Z)2)]n agents (M = 186/188Re, 99mTc) could find use as radiopharmaceutical bioconjugates when R is a targeting moiety. However, the planar, electron-withdrawing 2-pyridyl groups of N(SO2R)dpa destabilize the ligand to bas...

  4. NMR study of the quasi one dimensional organic metal (perylene)2(AsF6)0,75(PF6)0,35x0,85CH2Cl2

    Wieland, Jürgen; Haeberlen, Ulrich; Schweitzer, Dieter; Keller, Heimo J.


    Measurements of the temperature and frequency dependences of the proton spin lattice relaxation rate and of the proton and carbon Knight shifts in the title compound are presented. The results are interpreted in terms of a quasi-one dimensional microscopic conduction electron mobility and of the local unpaired spin densities at the carbon sites of the perylene donor molecules.

  5. Cu(II complexes of an ionic liquid-based Schiff base [1-{2-(2-hydroxy benzylidene amino ethyl}-3-methyl­imidazolium]Pf6: Synthesis, characterization and biological activities

    Saha Sanjoy


    Full Text Available Two Cu(II complexes of an ionic liquid based Schiff base 1-{2-(2-hydroxybenzylideneamino ethyl}-3-methylimidazolium hexaflurophosphate, were prepared and characterized by different analytical and spectroscopic methods such as elemental analysis, magnetic susceptibility, UV-Vis, IR, NMR and mass spectroscopy. The Schiff base ligand was found to act as a potential bidentate chelating ligand with N, O donor sites and formed 1:2 metal chelates with Cu(II salts. The synthesized Cu(II complexes were tested for biological activity.

  6. Superconductivity in the family of organic salts based on the tetramethyltetraselenafulvalene (TMTSF) molecule: (TMTSF)2X (X = Cl04, PF6, AsF6, SbF6, TaF6)

    Resistivity measurements along the high-conductivity axis of (TMTSF)2Cl04, (TMTSF)2TaF6 and (TMTSF)2SbF6 are reported for various hydrostatic pressures up to 12.5 kbar, and for transverse magnetic fields of up to 50 kG, in the temperature range 100 mK-4 K. These measurements show that all three compounds have a superconducting phase transition near 1 K when sufficient pressure is applied. (TMTSF)2SbF6 and (TMTSF)2TaF6 become superconducting for pressures above 10 kbar and 11 kbar respectively. At lower pressures a metal-insulator phase transition is observed which is probably associated with a spin density wave (SDW) instability. A superconducting phase transition is observed in (TMTSF)2Cl04 at much lower pressures (2X salts. (author)

  7. Ion exchange synthesis and thermal characteristics of some $[\\text{N}^{+}_{2222}]$ based ionic liquids

    Vasishta D Bhatt; Kuldip Gohil


    Eight salts were obtained by reacting tetraethylammonium cation $[\\text{N}^{+}_{2222}]$ with inorganic anions like BF$^{-}_{4}$, NO$^{-}_{3}$, NO$^{-}_{2}$, SCN-, BrO$^{-}_{3}$, IO$^{-}_{3}$, PF$^{-}_{6}$ and HCO$^{-}_{3}$ using ion exchange method. These ionic liquids (ILs) were characterized using thermal methods, infrared spectroscopy and densitometry. Thermophysical properties such as density, coefficient of volume expansion, heat of fusion, heat capacity and thermal energy storage capacity were determined. Thermal conductivity of the samples was determined both in solid and liquid phases. Owing to high values of thermal energy storage capacity coupled with handsome liquid phase thermal conductivity, ILs under investigation were recommended as materials for thermal energy storage (TES) as well as heat transfer applications.

  8. Anion Solvation in Carbonate Electrolytes

    Zhang, Zhengcheng


    With the correlation between Li+ solvation and interphasial chemistry on anodes firmly established in Li-ion batteries, the effect of cation–solvent interaction has gone beyond bulk thermodynamic and transport properties and become an essential element that determines the reversibility of electrochemistry and kinetics of Li-ion intercalation chemistries. As of now, most studies are dedicated to the solvation of Li+, and the solvation of anions in carbonate-based electrolytes and its possible effect on the electrochemical stability of such electrolytes remains little understood. As a mirror effort to prior Li+ solvation studies, this work focuses on the interactions between carbonate-based solvents and two anions (hexafluorophosphate, PF6–, and tetrafluoroborate, BF4–) that are most frequently used in Li-ion batteries. The possible correlation between such interaction and the interphasial chemistry on cathode surface is also explored.

  9. The Anion Effect on Li+ Ion Coordination Structure in Ethylene Carbonate Solutions

    Jiang, Bo; Shen, Yuneng; Yang, Xueming; Yuan, Kaijun; Vetere, Valentina; Mossa, Stefano; Skarmoutsos, Ioannis; Zhang, Yufan; Zheng, Junrong


    Rechargeable lithium ion batteries are an attractive alternative power source for a wide variety of applications. To optimize their performances, a complete description of the solvation properties of the ion in the electrolyte is crucial. A comprehensive understanding at the nanoscale of the solvation structure of lithium ions in nonaqueous carbonate electrolytes is, however, still unclear. We have measured by femtosecond vibrational spectroscopy the orientational correlation time of the CO stretching mode of Li+-bound and Li+-unbound ethylene carbonate molecules, in LiBF4, LiPF6, and LiClO4 ethylene carbonate solutions with different concentrations. Surprisingly, we have found that the coordination number of ethylene carbonate in the first solvation shell of Li+ is only two, in all solutions with concentrations higher than 0.5 M. Density functional theory calculations indicate that the presence of anions in the first coordination shell modifies the generally accepted tetrahedral structure of the complex, all...

  10. Magnetically rotational reactor for absorbing benzene emissions by ionic liquids

    Yangyang; Jiang; Chen; Guo; Huizhou; Liu


    A magnetically rotational reactor (MRR) has been developed and used in absorbing benzene emissions. The MRR has a permanent magnet core and uses magnetic ionic liquid [bmim]FeCl4 as absorbent. Benzene emissions were carried by N2 into the MRR and were absorbed by the magnetic ionic liquid. The rotation of the permanent magnet core provided impetus for the agitation of the magnetic ionic liquid, enhancing mass transfer and making benzene better dispersed in the absorbent. 0.68 g benzene emissions could be absorbed by a gram of [bmim]FeCl4, 0.27 and 0.40 g/ghigher than that by [bmim]PF6 and [bmim]BF4, respectively. The absorption rate increased with increasing rotation rate of the permanent magnet.