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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

    DEFF Research Database (Denmark)

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

    1983-01-01

    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...... vs T. We give arguments that the gap at the Fermi energy exists at temperatures above the maximum as well. The existence of a gap is good evidence that the material is characterized by Coulomb repulsion U for a second electron on a site larger than the bandwidth 4t. However, the constant finite S...

  2. One-dimensional spin-crossover Iron(II) complexes bridged by intermolecular imidazole-pyridine NH...N hydrogen bonds, [Fe(HL(Me))(3)]X(2) (HL(Me) = (2-methylimidazol-4-yl-methylideneamino-2-ethylpyridine; X = PF(6), ClO(4), BF(4)).

    Science.gov (United States)

    Nishi, Koshiro; Arata, Shinobu; Matsumoto, Naohide; Iijima, Seiichiro; Sunatsuki, Yukinari; Ishida, Hiroyuki; Kojima, Masaaki

    2010-02-15

    2-Methylimidazol-4-yl-methylideneamino-2-ethylpyridine (abbreviated as HL(Me)) is the 1:1 condensation product of 2-methyl-4-formylimidazole and 2-aminoethylpyridine and functions as a bidentate ligand to the iron(II) ion to produce the 3:1 complexes together with anions, [Fe(HL(Me))(3)]X(2) (X = PF(6) (1), ClO(4) (2), BF(4) (3)). The magnetic susceptibilities, differential scanning calorimetric measurements, and Mossbauer spectral measurements demonstrated that complexes 1, 2, and 3 showed a steep one-step spin crossover (SCO) between the high-spin (HS, S = 2) and low-spin (LS, S = 0) states with small thermal hysteresis. Three complexes have an isomorphous structure and are crystallized in the same monoclinic space group, C2/c, both in the HS and LS states. The iron(II) ion has the octahedral coordination geometry of a facial isomer with N(6) donor atoms of three bidentate ligands, in which an imidazole and an imine nitrogen atom per ligand participate in the formation of the coordination bond, but the pyridine nitrogen is free from coordination. The complex cation fac-[Fe(HL(Me))(3)](2+) is a chiral species with a Delta or Lambda isomer, and the adjacent Delta and Lambda isomers are linked alternately by an intermolecular imidazole-pyridine NH...N hydrogen bond to produce an achiral 1D chain. The two remaining imidazole moieties per complex are hydrogen-bonded to the anions that occupy the space among the chains. The SCO profile becomes steeper with the decrease of the anion size (73.0 A(3) for PF(6)(-), 54.4 A(3) for ClO(4)(-), and 53.4 A(3) for BF(4)(-)). The SCO transition temperature T(1/2) of the PF(6) (1), ClO(4) (2), and BF(4) (3) salts estimated from the magnetic susceptibility measurements are (T( downward arrow) = 151.8 K, T( upward arrow) = 155.3 K), (T( downward arrow) = 184.5 K, T( upward arrow) = 186.0 K), and (T( downward arrow) = 146.4 K, T( upward arrow) = 148.2 K), respectively, indicating that the T(1/2) value is not in accord with the anion

  3. Effect of the counter-anion on the spin-transition properties of a family of Fe(II) tetrazole complexes, [Fe(i4tz)6]X2 (X = ClO4-, PF6-, SbF6-, BF4-).

    Science.gov (United States)

    Tafili-Kryeziu, Myrvete; Weil, Matthias; Muranaka, Takahiro; Bousseksou, Azzedine; Hasegawa, Miki; Jun, Akimitsu; Linert, Wolfgang

    2013-11-28

    The monodentate ligand 1-isobutyl-1H-tetrazole (i4tz) was used to synthesize a series of iron(II) spin-crossover (SCO) complexes with the general formula [Fe(i4tz)6]X2, where X = ClO4(-) (1), PF6(-) (2), SbF6(-) (3), or BF4(-) (4). Upon cooling, magnetic susceptibility measurements of compounds 1, 2 and 3 show a reversible one-step spin crossover (SCO) behaviour between HS (S = 2) and LS (S = 0) states without hysteresis. The ClO4(-) compound shows a gradual spin transition at T(1/2) = 208 K at a considerably higher temperature than the other compounds. The larger anions PF6(-) (T(1/2) = 114 K) and SbF6(-) (T(1/2) = 116 K) show more gradual transitions, and a "frozen-in effect" was observed after fast cooling. The crystal structure of [Fe(i4tz)6](SbF6)2 (3) was determined at 296, 200 and 100 K, revealing a reversible first-order phase transition between 200 and 100 K, accompanied by a triplication of the unit cell volume at 100 K. Temperature-dependent vibration and electronic spectroscopic measurements of compound 1 were compared with the magnetic susceptibility measurements.

  4. Systematic study of spin crossover and structure in [Co(terpyRX)2](Y)2 systems (terpyRX = 4'-alkoxy-2,2':6',2''-terpyridine, X = 4, 8, 12, Y = BF4(-), ClO4(-), PF6(-), BPh4(-)).

    Science.gov (United States)

    Nielsen, Pia; Toftlund, Hans; Bond, Andrew D; Boas, John F; Pilbrow, John R; Hanson, Graeme R; Noble, Christopher; Riley, Mark J; Neville, Suzanne M; Moubaraki, Boujemaa; Murray, Keith S

    2009-08-03

    A family of spin crossover cobalt(II) complexes of the type [Co(terpyRX)(2)](Y)(2) x nH(2)O (X = 4, 8, 12 and Y = BF(4)(-), ClO(4)(-), PF(6)(-), BPh(4)(-)) has been synthesized, whereby the alkyl chain length, RX, and counteranion, Y, have been systematically varied. The structural (single crystal X-ray diffraction) and electronic (magnetic susceptibility, electron paramagnetic resonance (EPR)) properties have been investigated within this family of compounds. Single crystal X-ray diffraction analysis of [Co(terpyR8)(2)](ClO(4))(2), [Co(terpyR8)(2)](BF(4))(2) x H(2)O, and [Co(terpyR4)(2)](PF(6))(2) x 3 H(2)O, at 123 K, revealed compressed octahedral low spin Co(II) environments and showed varying extents of disorder in the alkyl tail portions of the terpyRX ligands. The magnetic and EPR studies were focused on the BF(4)(-) family and, for polycrystalline solid samples, revealed that the spin transition onset temperature (from low to high spin) decreased as the alkyl chain lengthened. EPR studies of polycrystalline powder samples confirmed these results, showing signals only due to the low spin state at the temperatures seen in magnetic measurements. Further to this, simultaneous simulation of the EPR spectra of frozen solutions of [Co(terpyR8)(2)](BF(4))(2) x H(2)O, recorded at S-, X-, and Q-band frequencies, allowed accurate determination of the g and A values of the low spin ground state. The temperature dependence of the polycrystalline powder EPR spectra of this and the R4 and R12 complexes is explained in terms of Jahn-Teller effects using the warped Mexican hat potential energy surface model perturbed by the low symmetry of the ligands. While well recognized in Cu(II) systems, this is one of the few times this approach has been used for Co(II).

  5. Systematic study of spin crossover and structure in [Co(terpyRX)2](Y)2 systems (terpyRX = 4'-alkoxy-2,2':6',2''-terpyridine, X = 4, 8, 12, Y = BF4(-), ClO4(-), PF6(-), BPh4(-))

    DEFF Research Database (Denmark)

    Nielsen, Pia; Nielsen, Hans Toftlund; Bond, Andrew;

    2009-01-01

    simulation of the EPR spectra of frozen solutions of [Co(terpyR8)(2)](BF(4))(2) x H(2)O, recorded at S-, X-, and Q-band frequencies, allowed accurate determination of the g and A values of the low spin ground state. The temperature dependence of the polycrystalline powder EPR spectra of this and the R4 and R......A family of spin crossover cobalt(II) complexes of the type [Co(terpyRX)(2)](Y)(2) x nH(2)O (X = 4, 8, 12 and Y = BF(4)(-), ClO(4)(-), PF(6)(-), BPh(4)(-)) has been synthesized, whereby the alkyl chain length, RX, and counteranion, Y, have been systematically varied. The structural (single crystal......12 complexes is explained in terms of Jahn-Teller effects using the warped Mexican hat potential energy surface model perturbed by the low symmetry of the ligands. While well recognized in Cu(II) systems, this is one of the few times this approach has been used for Co(II)....

  6. Electrochemical fabrication of (TMTSF)2X (X = PF6, BF4, CIO4) nanowires.

    Science.gov (United States)

    Jung, Youn Jung; Kim, Yonha; Kim, Gyu Tae; Kang, Woun; Noh, Dong-Youn

    2012-07-01

    TMTSF-based (TMTSF = tetramethyltetraselenafulvalene = C10H12Se4) charge-transfer salt nanowires were fabricated using the galvanostatic deposition technique that was assisted by an anodic aluminum oxide (AAO) template. By applying a low current density of 1-2 microA/cm2 for more than one month, nanowire arrays with diameters of approximately 150 nm and lengths of approximately 6 microm were obtained. The length of nanowires can be controlled by the duration of the constant current application. Energy-dispersive X-ray spectroscopic (EDX) analysis confirmed that selenium is one of the main components of the nanowires. The micro-Raman (v3C == C) and FT-IR spectra (v3PF6-, v3BF4-, v3CIO4-) indicated that the nanowire arrays had the (TMTSF)2X (X = PF6, BF4, CIO4) phase. The TEM images and the selected area electron diffraction (SAED) patterns indicate that the nanowires were not single crystals, but the current-voltage characteristic that was measured with the four-terminal method showed the conductivity of the (TMTSF)2PF6 single crystals (sigmaRT = 1.6 S/cm) at room temperature.

  7. CO2在[bmim]BF4/[bmim]PF6中的电化学还原研究%Electrochemical reduction of CO2 in binary ionic liquid bmim BF4/ bmim PF6

    Institute of Scientific and Technical Information of China (English)

    毛信表; 任淑鹰; 张寅旭; 马淳安

    2014-01-01

    对离子液体[bmim]BF4和[bmim]PF6进行了二元复配,测定了不同复配比例离子液体的电导率及红外光谱图,研究了CO2在单一离子液体和二元离子液体[bmim] BF4/[bmim] PF6中的电化学还原行为.结果表明,铜电极上,CO2在单一离子液体和二元离子液体中发生不可逆的电化学还原反应,生成物为CO1-,通过调节[bmim]BF4/[bmim]PF6的体积比,得到了性能较好的二元离子液体,对CO2的电化学还原有显著促进作用.

  8. The structural classification of the highly disordered crystal phases of [Nn][BF4], [Nn][PF6], [Pn][BF4], and [Pn][PF6] salts (Nn(+) = tetraalkylammonium and Pn(+) = tetraalkylphosphonium).

    Science.gov (United States)

    Matsumoto, Kazuhiko; Harinaga, Ukyo; Tanaka, Ryo; Koyama, Akira; Hagiwara, Rika; Tsunashima, Katsuhiko

    2014-11-21

    The structures of 16 symmetric tetraalkylammonium (Nn(+)) and tetraalkylphosphonium (Pn(+)) salts ([Nn][BF4], [Nn][PF6], [Pn][BF4], and [Pn][PF6], where n = 1 to 4, and denotes the number of carbon atoms in each alkyl chain) have been investigated by X-ray diffraction in order to elucidate the effect of ion size on the disordered structure of organic salts. All the salts exhibit one or more solid-solid phase transitions in differential scanning calorimetric curves. Powder X-ray diffraction revealed that the highest temperature solid phase of these salts belongs to a crystal system with a high cubic or hexagonal symmetry. The structures are classified into 5 different types: CsCl', NaCl, NaCl', inverse NiAs, and TBPPF6. The CsCl'-type whose octant corresponds to the original CsCl unit cell is observed for [N1][PF6] owing to the orientational difference for the cation or the anion. The NaCl-type structure is observed for the N2(+) and P2(+) salts while the NaCl'-type structure is observed for [N3][PF6], where the configuration of ions is based on the NaCl-type but the four equivalent positions in the original NaCl lattice split into two sets of equivalent positions (three and one). The inverse NiAs structure is observed for [P3][PF6]. Single-crystal X-ray diffraction reveals that the disordering of ions in [P4][PF6] becomes more significant with increasing temperature. The new structure of a cubic phase, the TBPPF6-type structure, is found for the salts with long alkyl chains. The structure is roughly determined at 333 K and the ions therein are highly disordered but not rotating. The validity of the radius ratio rule is confirmed through appropriate assessment of the ion size.

  9. Rate theory of solvent exchange and kinetics of Li(+) - BF4 (-)/PF6 (-) ion pairs in acetonitrile.

    Science.gov (United States)

    Dang, Liem X; Chang, Tsun-Mei

    2016-09-07

    In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li(+) and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li(+) in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li(+)-[BF4] and Li(+)-[PF6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li(+). We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li(+)-[BF4] and Li(+)-[PF6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

  10. Growth of Escherichia coli, Pichia pastoris and Bacillus cereus in the presence of the ionic liquids [BMIM][BF4] and [BMIM][PF6] and Organic Solvents.

    Science.gov (United States)

    Ganske, Franka; Bornscheuer, Uwe T

    2006-04-01

    The influence of the two most commonly used ionic liquids (1-butyl-3-methyl imidazolium tetrafluoroborate, [BMIM][BF(4)], 1-butyl-3-methyl imidazolium hexafluorophosphate, [BMIM][PF(6)]) and three selected organic solvents (dimethylsulfoxide, ethanol, methanol) on the growth of Escherichia coli, Pichia pastoris and Bacillus cereus was investigated. [BMIM][BF(4)] was toxic at 1% (v/v) on all three microorganisms. The minimal inhibitory concentration (MIC) of [BMIM][BF(4)] on E. coli growth was between 0.7 and 1% (v/v). In contrast, [BMIM][PF(6)] was less toxic for P. pastoris and B. cereus, whereas E. coli was not able to tolerate [BMIM][PF(6)] (MIC value: 0.3-0.7% v/v). Growth of P. pastoris was unaffected by [BMIM][PF(6)] at 10% (v/v). Similar results were found for dimethylsulfoxide. Thus, ionic liquids (ILs) can have substantial inhibitory effects on the growth of microorganisms, which should be taken into account for environmental reasons as well as for the use of ILs as co-solvents in biotransformations.

  11. Empirical parameters for solvent acidity, basicity, dipolarity, and polarizability of the ionic liquids [BMIM][BF4] and [BMIM][PF6].

    Science.gov (United States)

    del Valle, J C; García Blanco, F; Catalán, J

    2015-04-02

    The empirical solvent scales for polarizability (SP), dipolarity (SdP), acidity (SA), and basicity (SB) have been successfully used to interpret the solvatochromism of compounds dissolved in organic solvents and their solvent mixtures. Providing that the published solvatochromic parameters for the ionic liquids 1-(1-butyl)-3-methylimidazolium tetrafluoroborate, [BMIM][BF4] and 1-(1-butyl)-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], are excessively widespread, their SP, SdP, SA, and SB values are measured herein at temperatures from 293 to 353 K. Four key points are emphasized herein: (i) the origin of the solvatochromic solvent scales--the gas phase, that is the absence of any medium perturbation--; (ii) the separation of the polarizability and dipolarity effects; (iii) the simplification of the probing process in order to obtain the solvatochromic parameters; and (iv) the SP, SdP, SA, and SB solvent scales can probe the polarizability, dipolarity, acidity, and basicity of ionic liquids as well as of organic solvents and water-organic solvent mixtures. From the multiparameter approach using the four pure solvent scales one can draw the conclusion that (a) the solvent influence of [BMIM][BF4] parallels that of formamide at 293 K, both of them miscible with water; (b) [BMIM][PF6] shows a set of solvatochromic parameters similar to that of chloroacetonitrile, both of them water insoluble; and (c) that the corresponding solvent acidity and basicity of the ionic liquids can be explained to a great extent from the cation species by comparing the empirical parameters of [BMIM](+) with those of the solvent 1-methylimidazole. The insolubility of [BMIM][PF6] in water as compared to [BMIM][BF4] is tentatively connected to some extent to the larger molar volume of the anion [PF6](-), and to the difference in basicity of [PF6](-) and [BF4](-).

  12. 离子液体[bmim]PF_6[bmim]BF_4的合成、性质及应用

    Institute of Scientific and Technical Information of China (English)

    闫转萍

    2011-01-01

    离子液体[bmim]PF6和[bmim]BF4可以广泛用于有机反应和催化反应中,并因其对环境友好被称为"绿色溶剂"。本文综述近年来离子液体在化学反应中应用的前景。

  13. Magnetic field induced absorption of zero-phonon lines in (Ru(bpy)3)(PF6)2 and (Ru(bpy)3)(ClO4)2 single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Hensler, G.; Gallhuber, E.; Yersin, H.

    1987-06-03

    In recent studies they have investigated the spectroscopic properties of (Ru(bpy)3)X2 single crystals (with X = PF6 and ClO4 and bpy = 2,2'-bipyridine). In particular, it was possible to discover sharp, purely electronic (zero-phonon) transitions corresponding to the two lowest excited states in the emission spectra of (Ru(bpy)3)(ClO4)2 and (Ru(bpy)3)(PF6)2. They communicate here the observation of the corresponding zero-phonon lines also in the absorption spectra and report on changes of the absorption under application of high magnetic fields.

  14. The Viscosities of [bmim][BF_4] and [bmim][PF_6] Ionic Liquids and Their Binary Systems with N,N-Dimethylformamide%[bmim][BF_4]、[bmim][PF_6]离子液体及其与DMF二元体系在293.15~338.15K下的粘度

    Institute of Scientific and Technical Information of China (English)

    高亮; 郭斌; 段二红; 任爱玲

    2011-01-01

    In order to obtain the data of the physical properties for ionic liquids and organic,the viscosities of two imidazolium-based ionic liquids,1-butyl-3-methylimidazole tetrafluoroborate() and 1-butyl-3-methylimidazolium hexafluorophosphate(),and their binaries with N,N-dimethylformamide(DMF) at the temperature range from 293.15 K to 343.15 K in atmospheric pressure were determined,respectively,and the viscosity datas were correlated by the Vogel-Tamman-Fulcher(VFT) and Arrhenius-like equation.The results showed that the viscosities of the three pure solutions were in sequence: DMF ,and the viscosities for and ionic liquids and their binary systems with DMF all decreased with the increase of temperature and the mole fraction of DMF.The range of the viscosities of binary systems of DMF- and DMF- were from(1.26 to 125.5) and(1.11 to 165.7) MPa·s,respectively,in the experimental conditions.The correlation results based on the VFT equation for binary systems of DMF- and DMF- were found to be more satisfactory than the Arrhenius-like equation.The total mean absolute deviations,total mean relative deviations,and total mean standard deviations were estimated to be 0.561 9 MPa·s and 0.918 6 MPa·s,0.026 8 MPa·s and 0.020 9 MPa·s,0.725 5 MPa·s and 1.125 1 MPa·s,respectively.%为获得离子液体与有机物物理性质的数据,常压下,293.15~338.15 K温度范围内,分别测定了1-丁基-3-甲基咪唑四氟硼酸盐([bmim][BF4])、1-丁基-3-甲基咪唑六氟磷酸盐([bmim][PF6])2种咪唑类离子液体以及它们和N,N-二甲基甲酰胺(DMF)构成的2个二元体系的粘度,采用Vogel-Tamman-Fulcher(VFT)方程和Arrhenius-like方程对所测粘度数据进行关联。结果表明,同一温度下,3种纯溶液粘度大小顺序依次为:DMF〈[bmim][BF4]〈[bmim][PF6]。[bmim][BF4]、[bmim][PF6]离子液体及其与DMF构成的二元体系的粘度均随着温度的升高和DMF摩尔分率的增加而降低。实验条件下,DMF+[bmim][BF

  15. Formation of a solid solution between [N(C2H5)4][BF4] and [N(C2H5)4][PF6] in crystal and plastic crystal phases.

    Science.gov (United States)

    Matsumoto, Kazuhiko; Nonaka, Ryojun; Wang, Yushen; Veryasov, Gleb; Hagiwara, Rika

    2017-01-18

    The phase behavior of [N2222][BF4] and [N2222][PF6] (N2222(+) = tetraethylammonium cation) binary systems has been investigated in the present study. Differential scanning calorimetry revealed that the crystal-to-plastic-crystal transition temperature decreases upon mixing the two salts, with a minimum at x([N2222][PF6]) = 0.4, where x([N2222][PF6]) denotes the molar fraction of [N2222][PF6]. Powder X-ray diffraction analysis indicated the formation of a solid solution with a rock-salt type structure in the plastic crystal phase at all ratios and the lattice parameter a changes according to Vegard's law. In the crystal phase, two solid solution phases based on the structures of the single salts are observed. Raman spectroscopy confirmed the changes in the solid-solid transition temperature as observed by differential scanning calorimetry. Consequently, in the resulting phase diagram, the solid solution is formed in a wide x([N2222][PF6]) range for both the crystal and plastic crystal phases.

  16. A molecular dynamics simulation study of the electric double layer and capacitance of [BMIM][PF6] and [BMIM][BF4] room temperature ionic liquids near charged surfaces.

    Science.gov (United States)

    Hu, Zongzhi; Vatamanu, Jenel; Borodin, Oleg; Bedrov, Dmitry

    2013-09-14

    A molecular dynamics simulation study of electric double layer (EDL) structure and differential capacitance (DC) of two 1-butyl-3-methylimidazolium (BMIM)-based room temperature ionic liquids, i.e. [BMIM][BF4] and [BMIM][PF6], has been conducted on basal and prismatic graphite as well as (001) and (011) gold electrode surfaces. The influence of the electrode surface and electrolyte structure on electrode capacitance and EDL structure are discussed. For a given electrode surface both the [BMIM][BF4] and [BMIM][PF6] electrolytes generate very similar DC and EDL structures. The DC for these ionic liquids in contact with atomically flat surfaces (i.e. basal graphite and (001)Au) shows very small variations within the electrolyte chemical stability potential window and fluctuates around an average value of ∼5 μF cm(-2). On atomically more corrugated surfaces (i.e., Au(011) and prismatic graphite) the DC shows more variation with electrode potential and depends on the correspondence between dimensions of the surface roughness and electrolyte ion sizes. The trends and dependencies obtained for DC are used to discriminate between mutually contradictory experimental data reported in the literature for related systems.

  17. Interlayer interaction of two-dimensional layered spin crossover complexes [FeIIH3L(Me)][FeIIL(Me)]X (X-=ClO4-, BF4-, PF6-, AsF6-, and SbF6-; H3L(Me)=tris[2-(((2-methylimidazol-4-yl)methylidene)amino)ethyl]amine).

    Science.gov (United States)

    Yamada, Masahiro; Ooidemizu, Makoto; Ikuta, Yuichi; Osa, Shutaro; Matsumoto, Naohide; Iijima, Seiichiro; Kojima, Masaaki; Dahan, Françoise; Tuchagues, Jean-Pierre

    2003-12-15

    A series of two-dimensional (2D) spin crossover complexes, [FeIIH3L(Me)][FeIIL(Me)]X (X-=ClO4-, BF4-, PF6-, AsF6-, SbF6-) 1-5, have been synthesized, where H3L(Me) denotes an hexadentate N6 tripodlike ligand containing three imidazole groups, tris[2-(((2-methylimidazol-4-yl)methylidene)amino)ethyl]amine. Compounds 1-5 exhibit a two-step (HS-[FeIIH3L(Me)](2+) + HS-[FeIIL(Me)]-) (HS-[FeIIH3L(Me)](2+) + LS-[FeIIL(Me)]-) (LS-[FeIIH3L(Me)](2+) + LS-[FeIIL(Me)]-) spin-transition. The crystal structure of [FeIIH3L(Me)][FeIIL(Me)]PF6 (3) was determined at 295, 200, and 100 K. The structure consists of homochiral extended 2D puckered sheets, in which the complementary [FeIIH3L(Me)](2+) and [FeIIL(Me)]- capped tripodlike components, linked together by imidazole-imidazolate hydrogen bonds, are alternately arrayed in an up-and-down mode. The Fe-N bond distances and angles revealed that the FeII sites of both constituting units are in the high-spin (HS) state at 295 K; at 200 K, the FeII sites of [FeIIH3L(Me)](2+) and [FeIIL(Me)]- are in the HS and low-spin (LS) states, respectively. The FeII sites of both constituting units are in the LS state at 100 K. The size of the counteranion affects significantly the intra- and interlayer interactions leading to modifications of the spin crossover behavior. The onset of the second spin-transition of the ClO4- (1) and BF4- (2) salts adjoins the first spin-transition, while a mixed (HS-[FeIIH3L(Me)](2+) + LS-[FeIIL(Me)]-) spin-state spans a temperature range as wide as 70 K for salts 3-5 with larger counteranions, PF6-, AsF6-, and SbF6-, respectively. Compounds 1 and 2 showed remarkable LIESST (light induced excited spin state trapping) and reverse-LIESST effects, whereas 3-5 showed no remarkable LIESST effect. The interlayer interaction due to the size of the counteranion is an important factor governing the spin crossover behavior and LIESST effect.

  18. New iron(II) spin crossover coordination polymers [Fe(μ-atrz)3]X2·2H2O (X = ClO4¯, BF4¯) and [Fe(μ-atrz)(μ-pyz)(NCS)2]·4H2O with an interesting solvent effect.

    Science.gov (United States)

    Chuang, Yu-Chun; Liu, Chi-Tsun; Sheu, Chou-Fu; Ho, Wei-Lun; Lee, Gene-Hsiang; Wang, Chih-Chieh; Wang, Chih-Cheh; Wang, Yu

    2012-04-16

    A potential bridging triazole-based ligand, atrz (trans-4,4'-azo-1,2,4-triazole), is chosen to serve as building sticks and incorporated with a spin crossover metal center to form a metal organic framework. Coordination polymers of iron(II) with the formula [Fe(μ-atrz)(3)]X(2)·2H(2)O (where X = ClO(4)(-) (1·2H(2)O) and BF(4)(-) (2·2H(2)O)) in a 3D framework and [Fe(μ-atrz)(μ-pyz)(NCS)(2)]·4H(2)O (3·4H(2)O) in a 2D layer structure were synthesized and structurally characterized. The magnetic measurements of 1·2H(2)O and 2·2H(2)O reveal spin transitions near room temperature; that of 3 exhibits an abrupt spin transition at ~200 K with a wide thermal hysteresis, and the spin transition behavior of these polymers are apparently correlated with the water content of the sample. Crystal structures have been determined both at high spin and at low spin states for 1·2H(2)O, 2·2H(2)O, and 3·4H(2)O. Each iron(II) center in 1·2H(2)O and 2·2H(2)O is octahedrally coordinated with six μ-atrz ligands, which in turn links the other Fe center forming a strong three-dimensional (3D) network; counteranion and water molecules are located in the voids of the lattice. The FeN(6) octahedron of 3·4H(2)O is formed with two atrz, two pyrazine (pyz) ligands, and two NCS(-) ligands, where the ligands atrz and pyz are bridged between iron centers forming a 2D layer polymer. A zigzag chain of water molecules is found between the layers, and there is a distinct correlation between the thermal hysteresis with the amount of water molecules the exist in the crystal.

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

    Directory of Open Access Journals (Sweden)

    Hideki Yamochi and Shin-ya Koshihara

    2009-01-01

    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.

  20. TOPICAL REVIEW: Organic metal (EDO-TTF)2PF6 with multi-instability

    Science.gov (United States)

    Yamochi, Hideki; Koshihara, Shin-ya

    2009-04-01

    The multi-instability of the electronic structure of (EDO-TTF)2PF6, 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-TTF)2X (X=BF4, ClO4) shows a two-dimensional electronic structure. The working hypotheses for developing the systems with multi-instability are described.

  1. Organic metal (EDO-TTF)2PF6 with multi-instability.

    Science.gov (United States)

    Yamochi, Hideki; Koshihara, Shin-Ya

    2009-04-01

    The multi-instability of the electronic structure of (EDO-TTF)2PF6, 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-TTF)2X (X=BF4, ClO4) shows a two-dimensional electronic structure. The working hypotheses for developing the systems with multi-instability are described.

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

    Directory of Open Access Journals (Sweden)

    Stojan Stavber

    2009-07-01

    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.

  3. Halo- and azidodediazoniation of arenediazonium tetrafluoroborates with trimethylsilyl halides and trimethylsilyl azide and sandmeyer-type bromodediazoniation with Cu(I)Br in [BMIM][PF6] ionic liquid.

    Science.gov (United States)

    Hubbard, Abigail; Okazaki, Takao; Laali, Kenneth K

    2008-01-04

    Reaction of [ArN(2)][BF(4)] salts immobilized in [BMIM][PF(6)] ionic liquid (IL) with TMSX (X = I, Br) and TMSN(3) represents an efficient method for the preparation of iodo-, bromo-, and azido-derivatives via dediazoniation. The reactions can also be effected starting with ArNH(2) by in situ diazotization with [NO][BF(4)] followed by reaction with TMSX or TMSN(3). Depending on the substituents on the benzenediazonium cation, competing fluorodediazoniation (ArF formation) and hydrodediazoniation (ArH formation) were observed. Dediazoniation with TMSN(3) and with TMSI generally gave the highest chemoselectivity toward ArN(3) and ArI formation. The IL was recycled and reused up to 5 times with no appreciable decrease in the conversions. Multinuclear NMR monitoring of the interaction of [ArN(2)][BF(4)]/TMSX, [BMIM][PF6]/TMSX, and [BMIM][PF(6)]/TMSX/[ArN(2)][BF(4)] indicated that TMSF is formed primarily via [ArN(2)][BF(4)]/TMSX, generating [ArN(2)][X] in situ, which gives ArX on dediazoniation. Competing formation of ArF in Sandmeyer-type bromodediazoniation of [ArN(2)][BF(4)] with Cu(I)Br immobilized in the IL points to significant involvement of heterolytic dediazoniation.

  4. 锂离子电池LiBF4基液体电解质研究进展%Progresses in LiBF4-based Liquid Electrolytes for Li-ion Batteries

    Institute of Scientific and Technical Information of China (English)

    张昕岳; 周园; 邓小宇; 杜秀月

    2007-01-01

      To avoid the drawbacks of LiPF6-based electrolytes such as its moisture sensitivity, thermal instability, narrow operating temperature range and easiness to release PF5, much attention has been paid to developing new type electrolytes. Attempts to develop LiBF4-based electrolytes are among one of them. Electrolytes based on LiBF4 are thermally more stable and insensitive to moisture, which would probably make it a promising electrolyte system for civilian, military, navigation, aviation and aeronautic use in miniature, energy storage and vehicle Li-ion batteries. Progresses in studies of LiBF4-based electrolytes recently such as attempts to improve its conductivity, to extend its temperature operation, to help form stable SEI film and its compatibility with electrodes are reviewed. Future prospect of LiBF4-based electrolytes is also discussed.%  LiBF4基电解质的热稳定性较好,对环境水分不太敏感,有希望发展成为被民用、军事、三航领域微型、储能及动力锂离子电池广泛采用的优秀电解质体系。本文综述了近期在改善LiBF4的电导率,拓宽应用温度范围,促进SEI膜的形成,提高其电解液电导率及与电极材料的相容性等方面所取得的成果,并对其未来发展方向作了展望。

  5. Role of PF6- in the radiolytical and electrochemical degradation of propylene carbonate solutions

    Science.gov (United States)

    Ortiz, Daniel; Jimenez Gordon, Isabel; Legand, Solène; Dauvois, Vincent; Baltaze, Jean-Pierre; Marignier, Jean-Louis; Martin, Jean-Frédéric; Belloni, Jacqueline; Mostafavi, Mehran; Le Caër, Sophie

    2016-09-01

    The behavior under irradiation of neat propylene carbonate (PC), a co-solvent usually used in Li-ion batteries (LIB), and also of Li salt solutions is investigated. The decomposition of neat PC is studied using radiolysis in the pulse and steady state regime and is assigned to the ultrafast formation, in the reducing channel, of the radical anion PCrad - by electron attachment, followed by the ring cleavage, leading to CO. In the oxidative channel, the PC(sbnd H)rad radical is formed, generating CO2. The CO2 and CO yields are both close to the ionization yield of PC. The CO2 and CO productions in LiClO4, LiBF4 and LiN(CF3)2(SO2)2 solutions are similar as in neat PC. In contrast, in LiPF6/PC a strong impact on PC degradation is measured with a doubling of the CO2 yield due to the high reactivity of the electron towards PF6- observed in the picosecond range. A small number of oxide phosphine molecules are detected among the various products of the irradiated solutions, suggesting that most of them, observed in carbonate mixtures used in LIBs, arise from linear rather than from cyclical molecules. The similarity between the degradation by radiolysis or electrolysis highlights the interest of radiolysis as an accelerated aging method.

  6. Doebner condensation in ionic liquids [Bmim]BF4 and [Bpy]BF4 to synthesize α, β-unsaturated carboxylic acid

    Institute of Scientific and Technical Information of China (English)

    Dong Jiang; Yuan Yuan Wang; Yan Nan Xu; Li Yi Dai

    2009-01-01

    Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α,β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were efficient media for Doebner condensation, which could be recycled easily. The highest yields could reach 93% and 90% in [Bmim]BF4 and [Bpy]BF4, respectively.

  7. BIODEGRADATION OF [bmim][PF6] USING Fusarium sp

    OpenAIRE

    A. Esquivel-Viveros; F. Ponce-Vargas; P. Esponda-Aguilar; L.A. Prado-Barragán; M. Gutiérrez-Rojas; Lye, G.J.; S. Huerta-Ochoa

    2009-01-01

    The increased use of ionic liquids in industry has led to the study of their biodegradability and toxicity to preventcontamination of the environment by these synthetic compounds. A Fusarium strain was isolated and tested for its ability to tolerate and grow in the presence of [bmim] [PF6], a potential contaminant of wastewaters. The Fusarium strain was able to grow in both surface and submerged liquid media using [bmim] [PF6] as the sole carbon source up to 19 and 21 g [bmim] [PF6] L-1, resp...

  8. Laser photolysis of ionic liquid [bmim][PF6

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Photoinduced chemical reactions of 1-butyl-3-methylimidazolium hexafiuorophosphate ([bmim][PF6])were studied by laser photolysis at a wavelength of 266 nm. Excited triplet state 3[bmim]+* was observed, radical cation [bmim] 2+* and neutral [bmim]* radical via photoionization were also formed. Energy transfer from 3[bmim]+* to β-carotene was confirmed. Oxidation via one electron transfer from TMPD to 3[bmim]+* was also observed and the rate constant was determined to be 1.2 × 105 L. mol-1-s-1. The reaction of [bmim][PF6] with hydrated electron (eaq)was confirmed by laser photolysis in aqueous solution.

  9. Ultrafast photo-response in (EDO){2}PF{6}

    Science.gov (United States)

    Uchida, Naoki; Koshihara, Shin-Ya; Ishikawa, Tadahiko; Ota, Akira; Fukaya, Souichi; Chollet, M.; Yamochi, Hideki; Saito, Gunzi

    2004-04-01

    Organic conductor (EDO){ 2}PF{6} crystal shows a noble metal (M) insulator (I) transition accompanied with charge ordering, anion ordering and changes in the magnetic character and molecular conformation at Tc= 280 K. This M-I transition can be also sensitively probed by spectroscopic method. Here, we report the reflectivity change in (EDO){ 2}PF{6} crystal induced by the irradiation of weak femto-second (fs) pulsed laser (pulse width: 120 fs) which has been observed utilizing the pump-probe technique. The photo-induced spectral changes strongly suggest the occurrence of the very fast and highly efficient photo-conversion from insulator to metal in the temperature region between 180 K and 270 K. Under certain condition, a half (50%) of the crystal surface was converted into another phase by one excitation photon for every 1000 EDO molecules. Key words. Photo-induced phase transition, insulator to metal, femto-second pulse laser.

  10. Role of LiBF4 in Ionic Liquid Membranes for Facilitated CO2 Transport.

    Science.gov (United States)

    Choi, Yeji; Hong, Gil Hwan; Kang, Sang Wook

    2016-03-01

    The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4)/LiBF4 electrolyte was prepared for highly selective facilitated CO2 transport membranes. When LiBF4 was incorporated into BMIM BF4, synergy effects by free Li+ ion and imidazolium cations is expected to enhance the separation performance for CO2/N2 and CO2/CH4. The free state of BF4- ions in BMIM BF4/LiBF4 solutions was investigated by FT-Raman spectroscopy. For the coordination of LiBF4 with BMIMBF4, thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) was utilized. Electrolyte membranes consisting of BMIM BF4 and LiBF4 showed selectivities of 8.40 and 8.25 for CO2/N2 and CO2/CH4, respectively. Neat BMIM BF4 membrane showed selectivities of 5.0 and 4.8, respectively. Enhanced separation performance was attributed to increased free Li+ and abundant free imidazolium cations.

  11. A Simple Synthetic Methodology for NH4PF6%制备 NH4PF6简易方法研究

    Institute of Scientific and Technical Information of China (English)

    李洪亮; 郭国霖

    1999-01-01

      In this paper, a new simple methodology for preparing NH4PF6 was studied. It has been found that a trace of water can catalyze the reaction between NH4F and PCl5, and the reaction can react without extra heater. The products were separated applying the different solubility of NH4Cl and NH4PF6 in acetone and water. The X-ray diffraction spectra and the FT-IR spectra demonstrated that the NH4PF6 was prepared in this condition, and the separation method is effective. Two mechanism of the water-catalyzed reaction were proposed and explained in detail.

  12. Toxicity of two imidazolium ionic liquids, [bmim][BF4] and [omim][BF4], to standard aquatic test organisms: Role of acetone in the induced toxicity.

    Science.gov (United States)

    Tsarpali, Vasiliki; Dailianis, Stefanos

    2015-07-01

    The main goal of this study was to investigate the toxicity of the imidazolium-based ionic liquids (ILs), [bmim][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [omim][BF4] (1-octyl-3-methylimidazolium tetrafluoroborate), in battery of standard aquatic toxicity test organisms. Specifically, exposure of the algae Scenedesmus rubescens, crustaceans Thamnocephalus platyurus and Artemia franciscana, rotifers Brachionus calyciflorus and Brachionus plicatilis and bivalve Mytilus galloprovincialis to different concentrations of [bmim][BF4], [omim][BF4] and/or a binary mixture of [bmim][BF4]-[omim][BF4] (1:1) with or without acetone (carrier solvent), revealed that solvent can differentially mediate ILs' toxic profile. Acetone's ability to differentially affect ILs' cation's alkyl chain length, as well as the hydrolysis of [BF4(-)] anions was evident. Given that the toxic potency of the tested ILs seemed to be equal or even higher (in some cases) than those of conventional organic solvents, the present study revealed that the characterization of imidazolium-based ILs as "green solvents" should not be generalized, at least in case of their natural occurrence in mixtures with organic solvents, such as acetone.

  13. Zero-Pressure Organic Superconductor: Di-(Tetramethyltetraselenafulvalenium)-Perchlorate [(TMTSF)2ClO4

    DEFF Research Database (Denmark)

    Bechgaard, Klaus; da Costa Carneiro, Kim; Olsen, Malte;

    1981-01-01

    Evidence for superconductivity in the organic conductor di-(tetramethyltetraselenafulvalenium)-perchlorate [(TMTSF)2ClO4] has been found by resistance measurements in the absence of applied pressure. For different crystals the transitions are approximately 0.3 K wide and are centered around...

  14. Pebax/[Bmim][PF6]共混膜的制备及性能研究%Gas permeation properties of Pebax/[Bmim][PF6] blend membranes

    Institute of Scientific and Technical Information of China (English)

    邱永涛; 任吉中; 赵丹; 李晖; 花开胜; 王颖; 黄雪飞; 邓麦村

    2016-01-01

    选用聚醚共聚酰胺(Pebax1657)和1-丁基-3-甲基咪唑六氟磷酸盐([Bmim][PF6])为膜材料,以1-丁醇为溶剂,通过流延成膜法制备Pebax1657/[Bmim][PF6]共混膜.FTIR和XRD分析结果表明,[Bmim][PF6]的引入,破坏了Pebax1657链段间原有的氢键,造成共混膜结晶度降低;而随着[Bmim][PF6]质量分数的增加,N2、CH4、H2和CO2渗透系数逐渐降低.温度、压力和[Bmim] [PF6]的含量对Pebax1657/[Bmim][PF6]共混膜的N2、CH4、H2和CO2渗透性能的影响表明,随着操作压差变化,CO2和非极性气体的渗透系数呈现不同的变化趋势;N2、CH4、H2和CO2的渗透系数都随着温度的升高而增大,且它们的渗透活化能随着[Bmim] [PF6]含量的增加呈增加趋势.

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

    Science.gov (United States)

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

    2016-03-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

    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.

  17. Identification of radiolytic products of [C4mim][PF6] underγ-irradiation

    Institute of Scientific and Technical Information of China (English)

    敖银勇; 徐敏; 彭静; 李久强; 翟茂林; 吴国忠

    2015-01-01

    The trace water-soluble radiolytic products of neat 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) were identified by analysing water-washed samples of γ-irradiated ionic liquids. HF and difluorophosphinic acid were confirmed as the main radiolytic products of [C4mim][PF6], and their radiation chemical yields were quantified by 19F NMR (G(F−)=0.14 µmol/J, G(HOP(O)F2)=0.053 µmol/J). Com-pared to [C4mim][NTf2], [C4mim][PF6] shows better radiation stability.

  18. Structure and properties of Li@C60-PF6 endofullerene complex

    Science.gov (United States)

    Srivastava, Ambrish Kumar; Kumar, Abhishek; Misra, Neeraj

    2016-10-01

    Li@C60 is a prototype endofullerene, which has been widely studied. Employing density functional theory we study the interaction of Li@C60 with PF6 superhalogen, which leads to the formation of Li@C60-PF6 endofullerene complex. The spectral properties such as infrared and UV-visible spectra have been calculated, which agree well with corresponding experimental data. The vibrational assignments and electronic transitions in the complex have been explored. We have noticed that this complex is stabilized by charge transfer from Li@C60 to PF6, which results in its large dipole moment (20 Debye), high mean polarizability (494 a.u.) and significant mean hyperpolarizability (1500 a.u.). We, therefore, believe that Li@C60-PF6 endofullerene complex might attract further attention for their possible electrooptical applications due to its enhanced nonlinear optical properties.

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

    Institute of Scientific and Technical Information of China (English)

    WANG Qingsong; SUN Jinhua; CHEN Chunhua

    2006-01-01

    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 .

  20. [Bmim]PF6-promoted ligandless Suzuki-Miyaura coupling reaction of potassium aryltrifluoroborates in water.

    Science.gov (United States)

    Liu, Leifang; Dong, Yan; Pang, Bo; Ma, Jiahai

    2014-08-01

    The Suzuki-Miyaura coupling reactions of potassium aryltrifluoroborates with aryl bromides in water are promoted by the addition of [bmim]PF6 using Pd(OAc)2 as a catalyst and Na2CO3 as a base under air. The quantity of [bmim]PF6 used is crucial to the efficiency of the catalytic system. A wide range of biaryls and polyaryls can be easily prepared in good to excellent yields.

  1. Study on Transferring for PF_6 Plasticized PVC Paste Resin Film%[bmim]PF_6增塑PVC糊树脂膜迁移规律研究

    Institute of Scientific and Technical Information of China (English)

    江炜; 刘江涛

    2012-01-01

    文章应用固相萃取、液相色谱联用技术,研究了[bmim]PF6增塑PVC糊树脂膜中的[bmim]PF6在水环境及低酒精含量模拟溶剂(15%乙醇-水溶液)中的迁移规律,同时研究了[bmim]PF6迁移对薄膜力学性能的影响。结果表明:时间和温度对[bmim]PF6向水环境中迁移均有加速效应,在中性条件下迁移量较小,在酸性和碱性条件下迁移量较大。[bmim]PF6在低酒精含量模拟溶剂中与浸泡在去离子水中的薄膜迁移量相比,迁移量明显降低。增塑剂迁出后PVC糊树脂膜的断裂伸长率降低,弹性模量、拉伸强度均升高,可望用于医疗制品的开。%Transfer of plasticizers in water and simulated solvent of low-alcohol were studied by using solid-phase-extraction and high-performance-liquid-chromatography.Effect of plasticizer transfer on mechanical properties of the film was studied.The result showed that the operating conditions such as temperature and macerating time had a great accelerated effect on it.There was smaller migration in the neutral conditions,however,the migrations were volume in acidic and alkaline conditions.Compared with in the water environment,the migration was reduced evidenced in the simulated solvent of low-alcohol.The tensile strength and elastic moduli hoisted;and their elongation at break were dropped obviously.After transferring,the tensile strength and elastic moduli of PVC paste resin films' were hoisted,and their elongation at break dropped obviously.

  2. Study on the conductivity and viscosity of [Bmim]PF6 in methanol or acetonitrile%[Bmim] PF6在甲醇和乙腈中的电导率和黏度研究

    Institute of Scientific and Technical Information of China (English)

    章国栋; 沈尧; 许映杰

    2011-01-01

    测定了298.15K条件下1-丁基-3-甲基眯唑六氟磷酸盐离子液体([Bmim]PF6)在甲醇和乙腈中的电导率和黏度,讨论了[Bmim]PF6/甲醇和[Bmim]PF6/乙腈体系的溶液性质.结果表明,在0~0.3mol/L的浓度范围内,[Bmim]PF6/甲醇和[Bmim]PF6/乙腈体系的电导率随[Bmim]PF6浓度的增加而增加,并且[Bmim]PF6在甲醇中的电导率高于在乙腈中的电导率,说明[Bmim]PF6在甲醇中更容易电离;[Bmim]PF6/甲醇和[Bmim]PF6/乙腈体系的摩尔电导率随浓度的增加而降低,采用Kohlrausch公式计算回归了[Bmim]PF6在甲醇以及乙腈中的无限稀释摩尔电导率(∧wm),其值分别为156.96和153.83 s·cm2·mol-1.由Jones-Dole方程计算回归了[Bmim]PF6在甲醇和乙腈中黏度B系数,其值分别为0.36813和0.63248,表明[Bmim]PF6在甲醇中的黏度小于在乙腈中的黏度,这与电导率实验的结果是一致的.

  3. Pressure-induced phase transition of 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6

    Science.gov (United States)

    Takekiyo, Takahiro; Hatano, Naohiro; Imai, Yusuke; Abe, Hiroshi; Yoshimura, Yukihiro

    2011-03-01

    We have investigated the pressure-induced Raman spectral change of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) using Raman spectroscopy. The relative Raman intensity at 590 cm-1 of the CH2 rocking band assigned to the gauche conformer of the NCCC dihedral angle of the butyl group in the [bmim]+ cation increases when the pressure-induced liquid-crystalline phase transition occurs, while that at 610 cm-1 assigned to the trans conformer decreases. Our results show that the high-pressure phase transition of [bmim][PF6] causes the increase of the gauche conformer of the [bmim]+ cation.

  4. [Effect of ionic liquid [bmim][PF6] on the transient photolysis behavior of xanthone].

    Science.gov (United States)

    Fu, Hai-Ying; Cao, Xi-Yan; Xing, Zhao-Guo; Wu, Guo-Zhong

    2013-07-01

    The transient photochemical behavior of xanthone (XAN) in 1-butyl-3-methyl imidazolium hexafluoride phosphate ionic liquid ([bmim][PF6]) or binary mixed solution with acetonitrile (MeCN) was investigated by nano-second laser photolysis techniques. The spectral blue shift of 3XAN* was observed in the neat [bmim][PF6] or IL/MeCN mixture solution compared to MeCN solution. And the yield was also increased. Moreover, the energy transfer rate constant of XAN and naphthalene (NAP) was affected by the concentrations of ionic liquid. The values decreased rapidly with increasing VIL. For example, the values were 1.2 x 10(10) mol x L(-1) x s(-1) in MeCN, and 1.1 x 10(8) mol x L(-1) x s(-1) in [bmim][PF6], respectively. The photo-induced electron transfer between XAN and N,N-dimethylaniline was also investigated by changing the concentrations of [bmim][PF6] in binary solution.

  5. Antiferromagnetic interactions in the quarter-filled organic conductor (EDO-TTF)(2)PF6

    NARCIS (Netherlands)

    Filatov, Michael

    2011-01-01

    The ground state electronic structure of the high-temperature (HT) and the low-temperature (LT) phases of (EDO-TTF)(2)PF6 is investigated using the embedded cluster approach in combination with the density functional method designed to describe the strong non-dynamic electron correlation. It is foun

  6. Fast photo-induced phase switching in organic conductor crystal; (EDO-TTF)2PF6

    Science.gov (United States)

    Chollet, Matthieu; Guerin, Laurent; Uchida, Naoki; Fukaya, Souichi; Ishikawa, Tadahiko; Koshihara, Shin-ya; Matsuda, Kazunari; Ota, Akira; Yamochi, Hideki; Saito, Gunzi

    Organic conductor (EDO-TTF) 2PF6 crystal shows metal (M)-insulator (I) transition at 280 K. Here, we report the occurrence of highly efficient photo-conversion from insulator to metal phase within a few pico-seconds.

  7. Theoretical study of the ground state of (EDO-TTF)(2)PF6

    NARCIS (Netherlands)

    Linker, Gerrit-Jan; van Duijnen, Piet Th.; van Loosdrecht, Paul H.M.; Broer, Ria

    2015-01-01

    In this paper we present a theoretical study of the nature of the ground state of the (EDO-TTF)(2)PF6 charge transfer salt by using ab initio quantum chemical theory for clusters in vacuum, for embedded clusters and for the periodic system. Exemplary for other organic charge transfer systems, we sho

  8. Low temperature specific heat of the spin-density-wave compound (TMTSF)2PF6

    DEFF Research Database (Denmark)

    Odin, J.; Lasjaunias, J.C.; Biljakovic, K.;

    1994-01-01

    We report on specific heat measurements of the SDW compound (TMTSF)2PF6 between 2 and 25 K, performed by two different techniques. We discuss the two successive transitions which occur in this T-range : the SDW ordering transition at T = 12.1 K, and a glass transition around-3-3.5 K. The latter...

  9. Dimensionality Crossover in the Organic Superconductor Tetramethyltetraselenafulvalene Hexafluorophosphate [(TMTSF)2PF6

    DEFF Research Database (Denmark)

    Jacobsen, Claus Schelde; Tanner, D. B.; Bechgaard, K.

    1981-01-01

    Polarized reflectance measurements from the far infrared to the visible are reported for (TMTSF)2PF6. At low temperatures, both parallel and perpendicular polarizations show plasma edges in the infrared with metallic reflection below these edges, indicating two- or three-dimensional behavior. The...

  10. Hall effect in the normal phase of the organic superconductor (TMTSF)2PF6

    DEFF Research Database (Denmark)

    Moser, J.; Cooper, J.R.; Jerome, D.

    2000-01-01

    We report accurate Hall effect measurements performed in the normal phase of the quasi-one-dimensional organic conductor (TMTSF)(2)PF(6) at ambient pressure. The Hall coefficient is found to be strongly temperature dependent all the way from 300 K down to the spin density wave onset arising aroun...

  11. Spectrophotometric Study of Adduct Formation Between [Co(Salen)PPh3]ClO4.H2O and [Co(7,7'-Dimethylsalen)PPh3]ClO4.H2O with Amines Donors in Acetonitrile

    OpenAIRE

    2010-01-01

    The equilibrium quotient of the adduct formation of [Co(Salen)PPh3]ClO4.H2O and [Co(7,7'-dimethylSalen)PPh3]ClO4.H2O, as acceptor with amines donors are studied by spectrophotometer. Thermodynamics of these pentacoordinate cobalt(III) Schiff-base complexes have been examined with n-butylamine, sec-butylamine, tert-butylamine, benzylamine and diethylamine in constant ionic strength of 0.1 M sodium perchlorate and acetonitrile solvent at room temperature. We aimed to investigate the effects of ...

  12. Observation of orbital resonance Hall effect in (TMTSF)2ClO4.

    Science.gov (United States)

    Kobayashi, Kaya; Satsukawa, H; Yamada, J; Terashima, T; Uji, S

    2014-03-21

    We report the observation of a Hall effect driven by orbital resonance in the quasi-1-dimensional (q1D) organic conductor (TMTSF)2ClO4. Although a conventional Hall effect is not expected in this class of materials due to their reduced dimensionality, we observed a prominent Hall response at certain orientations of the magnetic field B corresponding to lattice vectors of the constituent molecular chains, known as the magic angles (MAs). We show that this Hall effect can be understood as the response of conducting planes generated by an effective locking of the orbital motion of the charge carriers to the MA driven by an electron-trajectory resonance. This phenomenon supports a class of theories describing the rich behavior of MA phenomena in q1D materials based on altered dimensionality. Furthermore, we observed that the effective carrier density of the conducting planes is exponentially suppressed in large B, which indicates possible density wave formation.

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

    Indian Academy of Sciences (India)

    S Rajendran; T Uma

    2000-02-01

    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.

  14. One- and two-step spin-crossover behavior of [Fe(II)(isoxazole)(6)](2+) and the structure and magnetic properties of triangular [Fe(III)(3)O(OAc)(6)(isoxazole)(3)][ClO(4)].

    Science.gov (United States)

    Hibbs, Wendy; van Koningsbruggen, Petra J; Arif, Atta M; Shum, William W; Miller, Joel S

    2003-09-08

    The structure and spin-crossover magnetic behavior of [Fe(II)1(6)][BF(4)](2) (1 = isoxazole) and [Fe(II)1(6)][ClO(4)](2) have been studied. [Fe(II)1(6)][BF(4)](2) undergoes two reversible spin-crossover transitions at 91 and 192 K, and is the first two-step spin transition to undergo a simultaneous crystallographic phase transition, but does not exhibit thermal hysteresis. The single-crystal structure determinations at 260 [space group P3, a = 17.4387(4) A, c = 7.6847(2) A] and at 130 K [space group P1, a = 17.0901(2) A, b = 16.7481(2) A, c = 7.5413(1) A, alpha = 90.5309(6) degrees, beta = 91.5231(6) degrees, gamma = 117.8195(8) degrees ] reveal two different iron sites, Fe1 and Fe2, in a 1:2 ratio. The room-temperature magnetic moment of 5.0 mu(B) is consistent with high-spin Fe(II). A plateau in mu(T) having a moment of 3.3 mu(B) centered at 130 K suggests a mixed spin system of some high-spin and some low-spin Fe(II) molecules. On the basis of the Fe-N bond distances at the two temperatures, and the molar fraction of high-spin molecules at the transition plateau, Fe1 and Fe2 can be assigned to the 91 and 192 K transitions, respectively. [Fe(II)1(6)][ClO(4)](2) [space group P3, a = 17.5829(3) A, c = 7.8043(2) A, beta = 109.820 (3) degrees, T = 295 K] also possesses Fe1:Fe2 in a 1:2 ratio, and magnetic measurements show a single spin transition at 213 K, indicating that both Fe1 and Fe2 undergo a simultaneous spin transition. [Fe(II)1(6)][ClO(4)](2) slowly decomposes in solutions containing acetic anhydride to form [Fe(III)(3)O(OAc)(6)1(3)][ClO(4)] [space group I2, a = 10.1547(7) A, b = 16.5497(11) A, c = 10.3205(9) A, beta = 109.820 (3) degrees, T = 200 K]. The isosceles Fe(3) unit contains two Fe.Fe distances of 3.2844(1) A and a third Fe.Fe distance of 3.2857(1) A. The magnetic data can be fit to a trinuclear model with H = -2J(S(1)xS(2) + S(2)xS(3)) - 2J(13)(S(1)xS(3)), where J = -27.1 and J(13) = -32.5 cm(-1).

  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.

    Science.gov (United States)

    Tsarpali, Vasiliki; Belavgeni, Alexia; Dailianis, Stefanos

    2015-07-01

    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 96h, 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 (10mgL(-1)), while [omim][BF4]-mediated effects were enhanced at lower concentrations (0.01-0.05mgL(-1)). Overall, the present study showed that [bmim][BF4] and [omim][BF4] could induce not only lethal but also nonlethal effects on mussel M. galloprovincialis. The extent of [bmim][BF4] and/or [omim][BF4]-mediated effects could be ascribed to the length of each IL alkyl chain, as well as to their lipophilicity. Moreover, the role of acetone on the obtained toxic effects of the specific ILs was

  16. [BMIM][PF(6)] promotes the synthesis of halohydrin esters from diols using potassium halides.

    Science.gov (United States)

    Oromí-Farrús, Mireia; Eras, Jordi; Villorbina, Gemma; Torres, Mercè; Llopis-Mestre, Veronica; Welton, Tom; Canela, Ramon

    2008-10-01

    Haloesterification of diverse diols with various carboxylic acids was achieved using potassium halides (KX) as the only halide source in ionic liquids. The best yield was obtained in [BMIM][PF(6)] when 1,2-octanediol, palmitic acid and KBr were used. This yield was 85% and the regioisomer with the bromine in primary position was present in a 75:25 ratio. The regioisomeric ratio could be improved using either KCl or some phenylcarboxylic acids. [BMIM][PF(6)] acts as both reaction media and catalyst of the reaction. To the best of our knowledge, this type of combined reaction using an ionic liquid is unprecedented. The other solvents tested did not lead either to the same yield or to the same regioisomeric ratio.

  17. Polymorphism in the spin-crossover ferric complexes [(TPA)Fe(III)(TCC)]PF6.

    Science.gov (United States)

    Collet, Eric; Boillot, Marie Laure; Hebert, Johan; Moisan, Nicolas; Servol, Marina; Lorenc, Maciej; Toupet, Loïc; Buron-Le Cointe, Marylise; Tissot, Antoine; Sainton, Joelle

    2009-08-01

    We have identified two polymorphs of the molecular complex [(TPA)Fe((III))(TCC)]PF(6) [TPA = tris(2-pyridylmethyl)amine and TCC = 3,4,5,6-tetrachlorocatecholate dianion]: one is monoclinic and the other is orthorhombic. By lowering the temperature both undergo a thermal spin-crossover between a high-spin (S = 5/2) and a low-spin (S = 1/2) state, which we detected by magnetic, optical and X-ray diffraction measurements. The thermal crossover is only slightly shifted between the polymorphs. Their crystalline structures consist of similar cation layers alternating with PF(6) anion layers, packed differently in the two polymorphs. The magnetic and optical properties of the polymorphs are presented.

  18. In situ crystallization of ionic liquid [Emim][PF6] from methanol solution under high pressure.

    Science.gov (United States)

    Li, Haining; Su, Lei; Zhu, Xiang; Cheng, Xuerui; Yang, Kun; Yang, Guoqiang

    2014-07-24

    The solubility of 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6]) in methanol under high pressure is newly measured quantitatively according to the correlation between the ratios of Raman intensity and the concentrations. In situ crystallization and cation conformation of [Emim][PF6] from methanol solution under high pressure have been investigated by using Raman spectroscopy in detail. Remarkably, crystal polymorphism was observed and two crystalline phases (phases I and II) coexisted under high pressure up to ∼ 1.4 GPa. However, only phase II was obtained by recrystallization at ∼ 2 GPa. Our findings may facilitate the development of an effective way for crystallization and purification of ionic liquids under high pressure.

  19. Modeling Lipase-Catalyzed Biodiesel Production in [BMIM][PF6

    OpenAIRE

    JianJun Yang; MingYan Yang

    2016-01-01

    Lipase-catalyzed biodiesel production models in room temperature ionic liquids (RTILs) reaction medium available in the literature are valid especially for mixing intensity. In this paper, a preliminary model is established in order to try to describe the lipase-catalyzed biodiesel production process in RTILs in a stirring type bioreactor. Mixing intensity and time delay were inspected for the reaction model in [BMIM][PF6] medium. As a result, this model is a good explanation for these actual...

  20. Extraction of Yttrium (Ⅲ) into [C8mim][PF6] Containing Cyanex 923

    Institute of Scientific and Technical Information of China (English)

    Peng Bo; Sun Xiaoqi; Chen Ji; Ma Jiutong

    2007-01-01

    The extraction of Yttrium (Ⅲ) into [Cnmim] [PF6] (n=4,6,8) containing Cyanex 923 was studied in this paper. The mechanism of this extraction was indicated to be cation exchange. In addition, the extraction process is an endothermic reaction. The RTILs with shorter alkyl chain behave higher extraction efficiency during the extraction, however, which has also more loss to aqueous phase since the cation exchange mechanism.

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

    Indian Academy of Sciences (India)

    Debabrata Seth; Palash Setua; Anjan Chakraborty; Nilmoni Sarkar

    2007-03-01

    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 .

  2. Ion association in [bmim][PF6]/naphthalene mixtures: an experimental and computational study.

    Science.gov (United States)

    Del Pópolo, M G; Mullan, C L; Holbrey, J D; Hardacre, C; Ballone, P

    2008-06-04

    Mixtures of room temperature ionic liquids (IL) with neutral organic molecules provide a valuable testing ground to investigate the interplay of the ionic and molecular-dipolar state in dense Coulomb systems at near ambient conditions. In the present study, the viscosity eta and the ionic conductivity sigma of 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6])/naphthalene mixtures at T = 80 degrees C have been measured at 10 stoichiometries spanning the composition range from pure naphthalene to pure [bmim][PF6]. The viscosity grows nearly monotonically with increasing IL mole fraction ( x), whereas the conductivity per ion displays a clear peak at x approximately 15%. The origin of this maximum has been investigated using molecular dynamics simulations based on a classical force field. Snapshots of the simulated samples show that the conductivity maximum is due to the gradual transition in the IL component from an ionic state at high x to a dipolar fluid made of neutral ion pairs at low x. At concentrations x bmim][PF6]/naphthalene mixtures at low IL concentration.

  3. Ionic liquid [bmim][BF4] acts as solvent and promoter for synthesis of halo-containing N-arylphthalimides

    Institute of Scientific and Technical Information of China (English)

    Dong Chu Chen; Hong Qi Ye; Hao Wu

    2007-01-01

    A new synthetic process of N-arylphthalimide and halo-containing N-arylphthalimides through the reaction between phthalic anhydride and aromatic amines bearing halo groups in [bmim][BF4] was described, ionic liquid [bmim][BF4] acted as the dual role of solvent and promoter.

  4. The photochemistry of [Fe(III)N3(cyclam-ac)]PF6 at 266 nm.

    Science.gov (United States)

    Torres-Alacan, Joel; Krahe, Oliver; Filippou, Alexander C; Neese, Frank; Schwarzer, Dirk; Vöhringer, Peter

    2012-03-01

    The photochemistry of iron azido complexes is quite challenging and poorly understood. For example, the photochemical decomposition of [Fe(III)N(3)(cyclam-ac)]PF(6) ([1]PF(6)), where cyclam-ac represents the 1,4,8,11-tetraazacyclotetradecane-1-acetate ligand, has been shown to be wavelength-dependent, leading either to the rare high-valent iron(V) nitrido complex [Fe(V)N(cyclam-ac)]PF(6) ([3]PF(6)) after cleavage of the azide N(α)-N(β) bond, or to a photoreduced Fe(II) species after Fe-N(azide) bond homolysis. The mechanistic details of this intriguing reactivity have never been studied in detail. Here, the photochemistry of 1 in acetonitrile solution at room temperature has been investigated using step-scan and rapid-scan time-resolved Fourier transform infrared (FTIR) spectroscopy following a 266 nm, 10 ns pulsed laser excitation. Using carbon monoxide as a quencher for the primary iron-containing photochemical product, it is shown that 266 nm excitation of 1 results exclusively in the cleavage of the Fe-N(azide) bond, as was suspected from earlier steady-state irradiation studies. In argon-purged solutions of [1]PF(6), the solvent-stabilized complex cation [Fe(II)(CH(3)CN)(cyclam-ac)](+) (2red) together with the azide radical (N(3)(.)) is formed with a relative yield of 80%, as evidenced by the appearance of their characteristic vibrational resonances. Strikingly, step-scan experiments with a higher time resolution reveal the formation of azide anions (N(3)(-)) during the first 500 ns after photolysis, with a yield of 20%. These azide ions can subsequently react thermally with 2red to form [Fe(II)N(3)(cyclam-ac)] (1red) as a secondary product of the photochemical decomposition of 1. Molecular oxygen was further used to quench 1red and 2red to form what seems to be the elusive complex [Fe(O(2))(cyclam-ac)](+) (6).

  5. Hydrogen-bonding interactions between [BMIM][BF4] and acetonitrile.

    Science.gov (United States)

    Zheng, Yan-Zhen; Wang, Nan-Nan; Luo, Jun-Jie; Zhou, Yu; Yu, Zhi-Wu

    2013-11-07

    In this work, the interactions between a representative imidazolium-based ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and acetonitrile (CH3CN) were investigated in detail using attenuated total reflection infrared spectroscopy (ATR-IR), hydrogen nuclear magnetic resonance ((1)H NMR), and density functional theory calculations. The main conclusions are: (1) a number of species in the [BMIM][BF4]-CH3CN mixtures were identified with the help of excess infrared spectroscopy and quantum chemical calculations. The dilution process of the ionic liquid by acetonitrile was found to be the transformation from ion clusters to ion pairs. (2) The solvent molecules cannot break apart the strong Coulombic interaction between [BMIM](+) and [BF4](-) but can break apart the ion cluster into an ion pair within the concentration range investigated. The strength of hydrogen bonds between the C-Hs of [BMIM](+) and the N of acetonitrile is enhanced during the dilution process. (3) The methyl group of CH3CN locates above/below the imidazolium ring in the solution. These in-depth studies on the properties of the ionic liquid-acetonitrile mixed solvents may shed light on exploring their applications as reaction media in electrochemistry and chemical synthesis.

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

    Indian Academy of Sciences (India)

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

    2008-03-01

    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. In situ crystallization of low-melting ionic liquid [BMIM][PF6] under high pressure up to 2 GPa.

    Science.gov (United States)

    Su, Lei; Li, Min; Zhu, Xiang; Wang, Zheng; Chen, Zhenping; Li, Fangfei; Zhou, Qiang; Hong, Shiming

    2010-04-22

    To develop a new practical method of purifying and recycling ionic liquids, we performed direct microscopic observations and in situ crystallization of low-melting ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF(6)]), in detail by high pressure Raman spectroscopy. Compression of [BMIM][PF(6)] was measured under pressures up to about 2.0 GPa at temperatures 293-353 K by using a high pressure diamond anvil cell (DAC). At room temperature, with pressure increasing, the characteristic bands of [BMIM][PF(6)] displayed nonmonotonic pressure-induced frequency shifts, and [BMIM][PF(6)] experienced the liquid-solid phase transition at about 0.50 GPa. In separate experiments, in situ crystallization of low-melting ionic liquid [BMIM][PF(6)] were also measured at various P-T regions, in order to improve the understanding of its stability limits. Finally, the T versus P phase diagram of [BMIM][PF(6)] was constructed, and it showed that the melting point was an increase function of pressure. It was also indicated that the structure changes in the crystalline and liquid states under high pressure might also be associated with conformational changes in the butyl chain. Pressure-released Raman spectra also showed that the phase transition of [BMIM][PF(6)] was reversible.

  8. Effect of C8mimPF6 on miniemulsion polymerization for application in new latex coating products.

    Science.gov (United States)

    Hu, Binjie; Kong, Yiyang; Zheng, Rongmeihui; Dong, Jie; Choy, Kwang-Leong; Zhao, Huanhuan

    2016-08-15

    C8mimPF6, as a type of room temperature ionic liquid (RTIL) with non-volatility and a low melting point, may replace conventional coalescing agents in latex coatings, thus preventing volatile organic compound (VOC) emissions caused by coalescing agents. In this study, systematic investigations on the effect of various factors including initiator type, initiator concentration, temperature and C8mimPF6 concentration on the conversion of latex and droplet/particle size of a miniemulsion during polymerization have been conducted. The presence of C8mimPF6 has shown to have a marked effect on the reaction rate. Such an effect strongly depends on the type of initiator being used. For polymerization initiated by 2,2-azobis (isobutyronitrile) (AIBN), C8mimPF6 had a promoting effect on the reaction rate at low concentrations, but this effect might be reversed upon certain C8mimPF6 concentrations, e.g. 10 wt%. While initiated by H2O2/Vc, this promoting effect faded even at low C8mimPF6 concentrations. The different limiting factors, which determine the reaction rate with different types of initiator, may contribute to the results. For reactions initiated by hydrophobic AIBN, the reaction was dominated by kinetics. The presence of C8mimPF6 may cause an enhanced chain propagation rate and reduced chain termination rate, which may further contribute to the increase in reaction rate at lower concentrations of C8mimPF6. With hydrophilic H2O2/Vc, the resistance for the transfer of radicals into a droplet/particle might be increased significantly with increasing C8mimPF6 concentration due to a tighter interfacial structure at lower concentrations of C8mimPF6. Thus, such transfer of radicals may become a limiting step whilst the presence of C8mimPF6 increases the transfer resistance on radicals resulting in a decrease in reaction rate. The reaction temperature, which is related to the decomposition temperature of the initiator being used, was another factor affecting the conversion

  9. 应用离子液体[bmim]PF6萃取印染中含酚废水%Extraction of phenols from wastewater in textile industry with ionic liquids[bmim]PF6

    Institute of Scientific and Technical Information of China (English)

    于长顺; 黄英蕾; 王少君; 尉志萍

    2009-01-01

    采用两步法合成了[bmim]PF6离子液体,并用[bmim]PF6对纺织印染过程中含酚废水的环保处理进行研究,探讨了物料的相比、温度对萃取过程的影响.结果表明,[bmim]PF6离子液体与反应物含酚废水的相比为1:2时,萃取效果最好;随着萃取次数的增加,萃取效率降低;萃取的最佳温度是25℃,反萃取的最佳温度是30℃;[bmim]PF6离子液体作为萃取剂可循环使用.

  10. Modeling Lipase-Catalyzed Biodiesel Production in [BMIM][PF6

    Directory of Open Access Journals (Sweden)

    JianJun Yang

    2016-01-01

    Full Text Available Lipase-catalyzed biodiesel production models in room temperature ionic liquids (RTILs reaction medium available in the literature are valid especially for mixing intensity. In this paper, a preliminary model is established in order to try to describe the lipase-catalyzed biodiesel production process in RTILs in a stirring type bioreactor. Mixing intensity and time delay were inspected for the reaction model in [BMIM][PF6] medium. As a result, this model is a good explanation for these actual reaction conditions in RTILs. The model prediction curves well describe the experimental data indicating this bioenzymatic reaction model is effective and reliable in certain conditions.

  11. Gigantic Photoresponse in 14-Filled-Band Organic Salt (EDO-TTF)2PF6

    Science.gov (United States)

    Chollet, Matthieu; Guerin, Laurent; Uchida, Naoki; Fukaya, Souichi; Shimoda, Hiroaki; Ishikawa, Tadahiko; Matsuda, Kazunari; Hasegawa, Takumi; Ota, Akira; Yamochi, Hideki; Saito, Gunzi; Tazaki, Ryoko; Adachi, Shin-ichi; Koshihara, Shin-ya

    2005-01-01

    We report that the organic salt (EDO-TTF)2PF6 with 34-filled-band (14-filled in terms of holes), which forms an organic metal with strong electron and lattice correlation, shows a highly sensitive response to photoexcitation. An ultrafast, photoinduced phase transition from the insulator phase to the metal phase can be induced with very weak excitation intensity at near room temperature. This response makes the material attractive for applications in switching devices with room-temperature operation. The observed photoinduced spectroscopic change shows that this photoinduced phase transition process is caused by the cooperative melting of charge ordering assisted by coherent phonon generation.

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

    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

  13. Hydrogen-bonding interactions between [BMIM][BF4] and dimethyl sulfoxide

    Science.gov (United States)

    Zheng, Yan-Zhen; He, Hong-Yan; Zhou, Yu; Yu, Zhi-Wu

    2014-07-01

    Mixtures of Ionic liquids and small polar organic solvent are potential green solvents for cellulose dissolution under mild conditions. In this work, the interactions between a representative imidazolium-based ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and dimethyl sulfoxide (DMSO) were investigated in detail by attenuated total reflection infrared spectroscopy (ATR-IR) and density functional theory calculations (DFT). The main conclusions are: (1) C2-H is the main interaction site in forming cation-anion, cation-DMSO, and [BMIM][BF4]-DMSO complexes. (2) The two turning points of the wavenumber shift changes of C2-H may indicate that the dilution process can be divided into several stages: from larger ion clusters to smaller ion clusters, then to ion pairs, and finally to individual ions. The solvent molecules cannot break apart the strong Coulombic interaction between [BMIM]+ and [BF4]- but can break apart the ion clusters into ion pairs when the mole fraction of DMSO is less than 0.9. When the mole fraction of DMSO is greater than 0.9, ion pairs can be broke into ions. (3) The hydrogen-bonds of the aromatic C-Hs in [BMIM]+ are strengthened in the dilution process while those of the alkyl C-Hs of [BMIM]+ are weakened. (4) The aromatic C-Hs of the [BMIM]+ cation strength before the weakening of the alkyl C-Hs. These in-depth studies on the properties of the ionic liquid-DMSO mixed solvents may shed light on exploring their applications as mixed solvents in cellulose dissolution and other practices.

  14. Hydrogen-fluorine exchange in NaBH4-NaBF4.

    Science.gov (United States)

    Rude, L H; Filsø, U; D'Anna, V; Spyratou, A; Richter, B; Hino, S; Zavorotynska, O; Baricco, M; Sørby, M H; Hauback, B C; Hagemann, H; Besenbacher, F; Skibsted, J; Jensen, T R

    2013-11-07

    Hydrogen-fluorine exchange in the NaBH4-NaBF4 system is investigated using a range of experimental methods combined with DFT calculations and a possible mechanism for the reactions is proposed. Fluorine substitution is observed using in situ synchrotron radiation powder X-ray diffraction (SR-PXD) as a new Rock salt type compound with idealized composition NaBF2H2 in the temperature range T = 200 to 215 °C. Combined use of solid-state (19)F MAS NMR, FT-IR and DFT calculations supports the formation of a BF2H2(-) complex ion, reproducing the observation of a (19)F chemical shift at -144.2 ppm, which is different from that of NaBF4 at -159.2 ppm, along with the new absorption bands observed in the IR spectra. After further heating, the fluorine substituted compound becomes X-ray amorphous and decomposes to NaF at ~310 °C. This work shows that fluorine-substituted borohydrides tend to decompose to more stable compounds, e.g. NaF and BF3 or amorphous products such as closo-boranes, e.g. Na2B12H12. The NaBH4-NaBF4 composite decomposes at lower temperatures (300 °C) compared to NaBH4 (476 °C), as observed by thermogravimetric analysis. NaBH4-NaBF4 (1:0.5) preserves 30% of the hydrogen storage capacity after three hydrogen release and uptake cycles compared to 8% for NaBH4 as measured using Sievert's method under identical conditions, but more than 50% using prolonged hydrogen absorption time. The reversible hydrogen storage capacity tends to decrease possibly due to the formation of NaF and Na2B12H12. On the other hand, the additive sodium fluoride appears to facilitate hydrogen uptake, prevent foaming, phase segregation and loss of material from the sample container for samples of NaBH4-NaF.

  15. 室温离子液体[Bmim]PF6的合成及其与乙腈体系的过量摩尔体积的研究%Synthesis of room-temperature ionic liquid [Bmim]PF6 and study on excess molar volumes of [Bmim]PF6 with acetonitrile

    Institute of Scientific and Technical Information of China (English)

    许映杰; 沈剑锋; 王奇伟; 林会

    2009-01-01

    合成了1-丁基-3-甲基六氟磷酸盐离子液体([Bmim]PF6),并用傅里叶红外光谱仪表征其结构.在25 ℃下,测定[Bmim]PF6-乙腈体系在全浓度范围内的过量摩尔体积(VE).二元混合体系的VE实验测定值为负值,表明[Bmim]PF6与乙腈之间以弱化学作用占主导;并且当[Bmim]PF6的摩尔分数x1=0.25时,VE出现极值,表明此时两者相互作用最大.

  16. First-Principles, Physically Motivated Force Field for the Ionic Liquid [BMIM][BF4].

    Science.gov (United States)

    Choi, Eunsong; McDaniel, Jesse G; Schmidt, J R; Yethiraj, Arun

    2014-08-07

    Molecular simulations play an important role in establishing structure-property relations in complex fluids such as room-temperature ionic liquids. Classical force fields are the starting point when large systems or long times are of interest. These force fields must be not only accurate but also transferable. In this work, we report a physically motivated force field for the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) based on symmetry-adapted perturbation theory. The predictions (from molecular dynamics simulations) of the liquid density, enthalpy of vaporization, diffusion coefficients, viscosity, and conductivity are in excellent agreement with experiment, with no adjustable parameters. The explicit energy decomposition inherent in the force field enables a quantitative analysis of the important physical interactions in these systems. We find that polarization is crucial and there is little evidence of charge transfer. We also argue that the often used procedure of scaling down charges in molecular simulations of ionic liquids is unphysical for [BMIM][BF4]. Because all intermolecular interactions in the force field are parametrized from first-principles, we anticipate good transferability to other ionic liquid systems and physical conditions.

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

    CERN Document Server

    Carignano, Marcelo A

    2013-01-01

    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.

  18. Physical nature of intermolecular interactions in [BMIM][PF6] ionic liquid.

    Science.gov (United States)

    Szefczyk, Borys; Sokalski, W Andrzej

    2014-02-27

    The intermolecular interaction energy in a popular ionic liquid, [BMIM][PF6] is analyzed using the Hybrid Variation-Perturbation Theory approach. The analysis is performed on a sample of configurations from molecular dynamics simulation, instead of minimized structures. The interaction energy components are quantified, showing that the electrostatics is the dominating but not the only important term. It is found that two- and three-body electron delocalization components also contribute to the stabilization of the complexes; however, these interactions vanish beyond the first coordination sphere. The presented study shows a systematic way to obtain the amount of physically meaningful components of the interaction energy, which possibly could be related to macroscopic properties of ionic liquids (e.g., viscosity, melting point) or electron transfer in ionic liquids.

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

    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.

  20. Ordering layers of [bmim][PF6] ionic liquid on graphite surfaces: molecular dynamics simulation.

    Science.gov (United States)

    Maolin, Sha; Fuchun, Zhang; Guozhong, Wu; Haiping, Fang; Chunlei, Wang; Shimou, Chen; Yi, Zhang; Jun, Hu

    2008-04-01

    Microscopic structures of room temperature ionic liquid (IL) [bmim][PF6] on hydrophobic graphite surfaces have been studied in detail by molecular dynamics simulation. It is clearly shown that both the mass and electron densities of the surface adsorbed ionic liquid are oscillatory, and the first peak adjacent to the graphite surface is considerably higher than others, corresponding to a solidlike IL bottom layer of 6 angstroms thick. Three IL layers are indicated between the graphite surface and the inner bulk IL liquid. The individually simulated properties of single-, double-, and triple-IL layers on the graphite surface are very similar to those of the layers between the graphite surface and the bulk liquid, indicating an insignificant effect of vapor-IL interface on the ordered IL layers. The simulation also indicates that the imidazolium ring and butyl tail of the cation (bmim+) of the IL bottom layer lie flat on the graphite surface.

  1. [Bmim]BF4/salt aqueous two-phase extraction and separation of ampicillin sodium%[Bmim]BF4/盐双水相萃取分离氨苄西林钠

    Institute of Scientific and Technical Information of China (English)

    王磊; 邵晨

    2012-01-01

    采用离子液体/盐双水相萃取的方法,研究了亲水性离子液体[Bmim]BF4/盐双水相对氨苄西林钠萃取性能,分别讨论(NH4)2S04加入量、离子液体[Bmim]BF4体积及氨苄西林钠溶液浓度对萃取率的影响,并通过紫外分光光度计进一步验证了氨苄西林钠与离子液体的相互作用.结果表明,[BTnim]BF4/盐双水相萃取分离氨苄西林钠的最佳参数为:(NH4)2SO4质量0.55g,氨苄西林钠溶液浓度0.013mol·L-1,离子液体[Bmim]BF4体积2.5mL,氨苄西林钠溶液和离子液体[Bmim]BF4的体积比为1∶1.

  2. [bmim][PF6]-DMF-水三元体系的液液相平衡测定%Determination of Liquid-Liquid Phase Equilibrium for the Ternary System of [bmim] [PF6]-DMF-Water

    Institute of Scientific and Technical Information of China (English)

    郭斌; 高亮; 段二红; 任爱玲; 刘振伟

    2012-01-01

    为得到含N,N-二甲基甲酰胺(DMF)废水中萃取回收DMF工艺所需的基础数据,用液液平衡釜常压下测定了1-丁基-3-甲基咪唑六氟磷酸盐([bmim][PF6)离子液体-DMF-H2O三元体系在283.15~323.15 K下的液液分层曲线和液液相平衡数据.在此基础上,考察了三元体系中DMF和[bmim][PF6]离子液体的含量以及温度对[bmim][PF6]的选择性系数的影响.实验结果表明,液液平衡相图中两相区面积随温度升高而减小;相同温度下,[bmim][PF6]的选择性系数随着三元体系中DMF的含量增加而减小,随着离子液体用量增加而增大;溶液组成一定时,[bmim][PF6]的选择性系数随着温度升高而减小;当DMF的含量大于10%时,温度对选择性系数影响不大;283.15 K,三元体系中DMF的质量分数为2.04%时,选择性系数可达33.62,[bmim][PF6]用于萃取分离水中的DMF可行.%In order to obtain the basic data for the recovery of N,N-dimethylformamide (DMF) from wastewater by extraction, the liquid-liquid delamination curves and liquid-liquid phase equilibrium data of the 1 -butyl-3-methylimidazoHum hexafluorophosphate ([bmimJfPFg]) ionic liquid-DMF-H2O ternary system were determined by using an equilibrium autoclave at 283.15 to 323.15 K and atmospheric pressure. The effects of the contents of DMF and [bmim][PF6] in the ternary system and the temperature on the selectivity coefficient of [bmim][PF6] were investigated. The results show that the area of two-phase in the liquid-liquid equilibrium phase diagram decreases with the increase of the temperature. The selectivity coefficient of [bmim] [PF6] decreases with the increase of the content of DMF in the ternary system and increases with the increase of the amount of ionic liquid at the same temperature. And when the composition of the solution keeps unchanged, the selectivity coefficient of [bmim] [PF6] decreases with the increase of temperature. However, the temperature has little effect on

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-20

    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.

  4. Toxicity of [C_8mim]PF_6 to aquatic organisms%离子液体[C_8mim]PF_6对水生生物的毒性作用

    Institute of Scientific and Technical Information of China (English)

    牧辉; 彭新晶; 戴宁; 陈继; 张凤君

    2009-01-01

    Three standard test methods for evaluating the toxicity of chemicals to aquatic organisms were applied to assess the toxic effects of l-octyl-3-methylimidazolium PF_6([C_8mim]PF_6)on the three aquatic organisms: Chlorella vulgaris, Daphnia magna and zebra fish. Growth and chlorophyll a content of C. vulgaris were inhibited in the experimental content of [C_8mim]PF_6, the inhibiting effect increased significantly with increasing concentrations, and the toxic effects on chlorophyll a content were stronger than that of growth. The C. vulgaris cell even would be lethal in the higher concentration group (200mg/L). The toxic effects of [C_8mim] PF_6 was high-toxic to Daphnia magna, while was low-toxic to zebra fish, and the 48h LC_(50) and 96h LC_(50) was 4.47mg/L and 126.08mg/L, respectively. EC50/LC50 changed regularly with the test time. Maybe the two main reasons leading to the potential threat to the aquatic organisms were the affinity of [C_8mim]PF_6 with algae and lipophilic property itself.%运用评价化学品对水生生物毒性的标准试验方法,探讨离子液体1-辛基-3-甲基-咪唑六氟磷酸盐([C_8mim]PF_6)对普通小球藻、大型蚤和斑马鱼的毒性影响.结果表明,[C_8mim]PF_6在实验浓度下,对普通小球藻的生长和叶绿素a的产生均有抑制作用,浓度越高抑制作用越明显,且对叶绿素a含量的影响更为显著.高浓度组(200mg/L)可致死部分小球藻细胞;[C_8mim]PF_6对大型蚤的48h LC50为4.47mg/L,属于高毒性;[C_8mim]PF_6对斑马鱼的96h LC50为126.08mg/L,属于低毒性.[C_8mim]PF_6对这3种水生生物的抑制率/致死率(EC50/LC50)随时间呈规律性变化.[C_8mim]PF_6与藻类的亲和性及其亲脂特性可能是其对水生生物存在潜在毒性的2个主要原因.

  5. Characterization of BF4− in terms of its effect on water by the 1-propanol probing methodology

    DEFF Research Database (Denmark)

    Morita, Takeshi; Ayako, Nitta; Nishikawa, Keilo;

    2014-01-01

    One of the most common constituent anions for room temperature ionic liquids (RTILs), BF4−, was characterized in terms of its effect on H2O using the so-called 1-propanol (1P) probing methodology developed by us earlier [PCCP, 15(2013) 14548-14565]. The results indicated that BF4− is quantitatively...... characterized as an amphiphile with weak hydrophobic and moderate hydrophilic contributions. These results were plotted on a two-dimensional map with hydrophobicity and hydrophilicity axes, H2O defining the origin. The melting point of 1-ethyl-3-methylimidazoliumtetrafluoroborate ([C2mim]BF4) was found within...... the trend that the larger the hydrophobicity and the hydrophilicity of the chosen counter anion, the lower the melting point of the resulting RTIL made of [C2mim]+ cation and the chosen anion. For the 1-butyl-3-methylimidazolium ([C4mim]+) based RTILs, however, redetermination of the melting point...

  6. A comparative study on the ionic liquid [bmim][BF4] and its solution with transient absorption spectroscopy.

    Science.gov (United States)

    Zhu, Guanglai; Wu, Guozhong; Xu, Xinsheng; Ji, Xuehan

    2011-11-01

    A detailed study was explored to compare the transient absorption spectra of the neat 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) with its solution in water or acetonitrile. It was concluded that the excited triplet state (3)[bmim](+*) was produced after 266 nm laser irradiation, and then the neutral radical [bmim] and the cation radical [bmim] (2+) were formed through two possible paths. The transient absorption spectra of the neat [bmim][BF(4)] and its solution were similar but the reaction kinetics were different due to their different local structures such as dimeric or cluster. The energy transfer between excited [bmim][BF(4)] and β-carotene further affirmed the existence of (3)[bmim](+*). And the reaction that the hydrated electron captured by [bmim](+) to produce [bmim] in solution was observed.

  7. Separation of N2O and CO2 using room-temperature ionic liquid [bmim][BF4].

    Science.gov (United States)

    Shiflett, Mark B; Niehaus, Anne Marie S; Yokozeki, A

    2011-04-07

    We have developed a ternary equation of state (EOS) model for the N(2)O/CO(2)/1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) system in order to understand separation of these gases using room-temperature ionic liquids (RTILs). The present model is based on a generic RK (Redlich-Kwong) EOS, with empirical interaction parameters for each binary system. The interaction parameters have been determined using our measured VLE (vapor-liquid equilibrium) data for N(2)O/[bmim][BF(4)] and CO(2)/[bmim][BF(4)] and literature data for N(2)O/CO(2). The binary EOS models for the N(2)O/[bmim][BF(4)] and CO(2)/[bmim][BF(4)] systems correctly predicted the liquid-liquid phase separation found in VLLE experiments. The validity of the ternary EOS model has been checked by conducting VLE experiments for the N(2)O/CO(2)/[bmim][BF(4)] system over a range in temperature from 296 to 315 K. With this EOS model, solubility (VLE) behavior has been calculated for various (T, P, and feed compositions) conditions. For both large and small N(2)O/CO(2) feed ratios, the N(2)O/CO(2) gas selectivity [α(N(2)O/CO(2)) = (y(N(2)O)/x(N(2)O))/(y(CO(2))/x(CO(2)))] is α = 1.4-1.5, compared with (α = 0.96-0.98) in the absence of ionic liquid. While the concentration of the ionic liquid does not affect the selectivity, the addition of an ionic liquid provides the only practical means of separating CO(2) and N(2)O.

  8. The effect of water on the microstructure and properties of benzene/[bmim][AOT]/[bmim][BF4] microemulsions.

    Science.gov (United States)

    Bai, Tingting; Ge, Rile; Gao, Yanan; Chai, Jinling; Slattery, John M

    2013-11-28

    In the present contribution, results concerning the role of small amounts of water in the 1-butyl-3-methylimidazolium bis 2-ethylhexyl sulfosuccinate ([bmim][AOT]) based 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4])-in-benzene reverse microemulsions are emphasized. The microemulsion aggregates have demonstrated features in common with traditional aqueous systems, such as a normal microemulsion droplet size and decreased stability due to the addition of a polar component. Dynamic light scattering (DLS) showed that the size change of microemulsion with added water depends on the loaded [bmim][BF4] content in the microemulsion: when the [bmim][BF4] content is low, the microemulsion diameter first decreases and then increases, while the size remains about the same for microemulsions with a moderate [bmim][BF4] loading and a successive increase in size was found for high-loaded [bmim][BF4] microemulsions. (1)H NMR along with two-dimensional rotating frame nuclear Overhauser effect (NOE) experiments (ROESY) revealed that water molecules formed wide interactions with both 1-butyl-3-methylimidazolium ([bmim]) and bis 2-ethylhexyl sulfosuccinate ([AOT]), leading to a decrease in the headgroup area of [bmim][AOT], i.e. α value, which will decrease the microemulsion size. On the other hand, addition of water can simultaneously swell the microemulsions, causing an increase in the diameter. It is also deduced that the Coulomb forces between the [AOT] and [bmim] should be one of the main driving forces for the formation of [bmim][BF4]-in-benzene microemulsions.

  9. Insights into the structure and dynamics of a room-temperature ionic liquid: ab initio molecular dynamics simulation studies of 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and the [bmim][PF6]-CO2 mixture.

    Science.gov (United States)

    Bhargava, B L; Balasubramanian, S

    2007-05-03

    Ab initio molecular dynamics (AIMD) studies have been carried out on liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and its mixture with CO2 using the Car-Parrinello molecular dynamics (CPMD) method. Results from AIMD and empirical potential molecular dynamics (MD) have been compared and were found to differ in some respects. With a strong resemblance to the crystal, the AIMD simulated neat liquid exhibits many cation-anion hydrogen bonds, a feature that is almost absent in the MD results. The anions were observed to be strongly polarized in the condensed phase. The addition of CO2 increased the probability of this hydrogen bond formation. CO2 molecules in the vicinity of the ions of [bmim][PF6] exhibit larger deviations from linearity in their instantaneous configurations. The polar environment of the liquid induces a dipole moment in CO2, lifting the degeneracy of its bending mode. The calculated splitting in the vibrational mode compares well with infrared spectroscopic data. The solvation of CO2 in [bmim][PF6] is primarily facilitated by the anion, as seen from the radial and spatial distribution functions. CO2 molecules were found to be aligned tangential to the PF6 spheres with their most probable location being the octahedral voids of the anion. The structural data obtained from AIMD simulations can serve as a benchmark to refine interaction potentials for this important room-temperature ionic liquid.

  10. Asymmetric Bilayer Muscles: Cooperative Actuation, Dynamic Hysteresis, and Creeping in NaPF6 Aqueous Solutions.

    Science.gov (United States)

    Fuchiwaki, Masaki; Martinez, Jose G; Fernandez Otero, Toribio

    2016-08-01

    Three bilayer muscles [polypyrrole-paraphenolsulfonic acid/polypyrrole-dodecylbenzensulfonic acid (PPy-HpPS/PPy-DBS) asymmetric bilayer, PPy-HpPS/tape, and PPy-DBS/tape] were characterized during potential cycling in NaPF6 aqueous solutions. In parallel, the angular displacement of the muscle was video-recorded. The dynamo-voltammetric (angle-potential) and coulo-dynamic (charge-potential) results give the reaction-driven ionic exchanges in each PPy film. Electrochemical reactions drive the exchange of anions from the PPy-HpPS layer and cations from the PPy-DBS layer. This means that both layers from the asymmetric bilayer follow complementary volume changes (swelling/shrinking or shrinking/swelling), owing to complementary ionic exchanges (entrance/expulsion) driven by the bilayer oxidation or reduction. The result is a cooperative actuation; the bending amplitude described by the asymmetric bilayer muscle is one order of magnitude larger than those attained from each of the conducting polymer/tape muscles. The cooperative actuation almost eliminates creeping effects. A large dynamical hysteresis persists, which can be attributed to an irreversible reaction of the organic acid components at high overpotentials.

  11. 离子液体[Bmim]BF4合成反应后的纯化工艺%The purification process of ionic liquid [Bmim]BF4 after synthesis

    Institute of Scientific and Technical Information of China (English)

    王国平; 刘培元; 方伟慧

    2008-01-01

    ;考察了离子液体[Bmim]BF4(四氟硼酸1-丁基-3-甲基咪唑)合成反应后纯化步骤中CH2Cl2用量、H2O用量及不同萃取水洗方式等因素对[Bmim]BF4得率的影响,得到了纯化时合理的CH2Cl2用量及H2O用量,质量比为:CH2Cl2:H2O:[Bmim]BF4粗品=7:3:10,其中H2O采用多次加入方式进行萃取水洗效果较好、离子液体的得率较高,纯化后[Bmim]BF4得率约为93.15%.

  12. Effect of ionic liquid [BMIM][PF6] on asymmetric reduction of ethyl 2-oxo-4-phenylbutyrate by Saccharomyces cerevisiae.

    Science.gov (United States)

    Shi, Yu-Gang; Fang, Yun; Ren, Yue-Ping; Wu, Hong-Ping; Guan, Hui-Lei

    2008-11-01

    The effect of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) on the asymmetric reduction of ethyl 2-oxo-4-phenylbutyrate (EOPB) to synthesize optical active ethyl 2-hydroxy-4-phenylbutyrate (EHPB) catalyzed by Saccharomyces cerevisiae was investigated. (R)-EHPB [70.4%, e.e.(R)] is obtained using ethyl ether or benzene as the solvent. The main product is (S)-EHPB [27.7%, e.e.(S)] in [BMIM][PF6]. However, in ionic liquid-water (10:1, v/v) biphasic system, the enantioselectivity of the reduction is shifted towards (R)-side, and e.e.(R) is increased from 6.6 to 82.5% with the addition of ethanol (1%, v/v). The effect of the use of [BMIM][PF6] as an additive in relatively small amounts on the reduction was also studied. We find that there is a decline in the enantioselectivity of the reduction in benzene. In addition, a decrease in the conversion of EOPB and the yield of EHPB with increasing [BMIM][PF6] concentrations occurs in either organic solvent-water biphasic systems or benzene.

  13. Direct electrochemistry of horseradish peroxidase on Nafion/[bmim]PF(6)/agarose composite film modified glassy carbon electrode.

    Science.gov (United States)

    Fan, Da-He; Sun, Jun-Yong; Huang, Ke-Jing

    2010-03-01

    A new strategy to construct electrochemical biosensor for direct electrochemistry of horseradish peroxidase (HRP) on glassy carbon electrode (GCE) based on Nafion, agarose hydrogel and hydrophobic room-temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF(6)) composite as sensing platform has been described. [bmim]PF(6) has good conductivity and wide electrochemical windows and agarose can maintain biological activity well. Nafion/[bmim]PF(6)/agarose composite combines the advantages of [bmim]PF(6) and agarose. Electrochemical impedance spectroscopy (EIS), ultraviolet visible spectroscopy (UV-vis), fourier transform infrared (FT-IR) spectroscopy and cyclic voltammetry (CV) were used to characterize the composite film, showing that the composite film could be effectively constructed on the GCE surface and greatly enhance the electron transfer between HRP and electrode. The factors influencing the performance of the resulting biosensor were studied in detail. The biosensor responded to H(2)O(2) in the linear range from 2x10(-6) to 1.6x10(-4)M with a detection limit of 1.2x10(-7)M (based on the S/N=3). The studied biosensor exhibited good accuracy and high sensitivity. Moreover, the proposed method was economical and efficient.

  14. Ultrafast gigantic photo-response in (EDO-TTF)2PF6 initiated by 10-fs laser pulses

    Science.gov (United States)

    Itatani, Jiro; Rini, Matteo; Cavalleri, Andrea; Onda, Ken; Ishikawa, Tadahiko; Koshihara, Shin-ya; Shao, Xiangfeng; Yamochi, Hideki; Saito, Gunzi; Shoenlein, Robert W.

    We photo-excited a charge-ordered organic salt (EDO-TTF)2PF6 with sub-10-fs optical pulses. The photo-induced metallic phase appeared within 80-fs after pumping, characterized by large changes in reflectivity (ΔR/R˜0.8) followed by strong coherent phonon modulation

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

    Directory of Open Access Journals (Sweden)

    Aparecido Nivaldo Módenes

    2013-04-01

    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.

  16. Synthesis and Physicochemical Properties of Ionic Liquids [Bmim]Br and [Bmim]PF6%离子液体[Bmim]Br和[Bmim]PF6的合成及其物化性质研究

    Institute of Scientific and Technical Information of China (English)

    张楠; 邓天龙; 刘明明; 高道林

    2014-01-01

    Ionic liquids 1-butyl-3-methylimidazolium bromide([Bmim]Br)and 1-butyl-3-methylimidazolium hexafluoro-phosphate([Bmim]PF6)were synthesized by using ultrasonic-assisted method. The factors affecting the productivity of [Bmim]Br including reaction time,frequency,the mole ratio of reactants as well as the productivity of [Bmim]PF6,including reacting time and mass ratio of solvent to [Bmim]Br were systematically investigated. The results show that the yield of [Bmim]Br was 98.88% under the optimal synthetic conditions of reaction time of 50,min,frequency 20,Hz and mole ratio 1.1,and the yield of [Bmim]PF6,was 86.54% with reaction time of 50,min,frequency 20,Hz and mass ratio of solvent to [Bmim]Br 1.5. In addition,the structure of [Bmim]Br was characterized by infrared spectra,UV absorption spectra,and NMR spectra;[Bmim]PF6,was characterized by infrared spectra and UV absorption spectra with antithesis. The contents of water and its corresponding physicochemical properties including density and refractive index between 10,℃and 30,℃were also measured.%采用超声波辅助法合成离子液体1-丁基-3-甲基咪唑溴盐([Bmim]Br)和1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6),研究了超声处理时间、超声频率和原料物质的量比对[Bmim]Br 产率的影响,以及超声处理时间、超声频率和溶剂与[Bmim]Br 的质量比对[Bmim]PF6产率的影响.结果表明:超声处理时间、超声频率、原料溴代正丁烷与 N-甲基咪唑物质的量比分别为50,min、20,Hz、1.1时,[Bmim]Br 产率可达到98.88%;在超声处理时间、超声频率、溶剂与[Bmim]Br的质量比分别为50,min、20,Hz和1.5时,[Bmim]PF6产率可达到86.54%.采用红外光谱、紫外吸收光谱和核磁共振氢谱对[Bmim]Br 进行结构表征,同时采用对比法,利用红外光谱、紫外吸收光谱对[Bmim]PF6进行表征,并分别测定了[Bmim]Br和[Bmim]PF6的含水量及其在10~30,℃下的密度和折光率与温度的关系.

  17. Computational Studies of [Bmim][PF6]/n-Alcohol Interfaces with Many-Body Potentials

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Tsun-Mei; Dang, Liem X.

    2014-09-04

    In this paper, we present the results from molecular-dynamics simulations of the equilibrium properties of liquid/liquid interfaces of room temperature ionic liquid [bmim][PF6] and simple alcohols (i.e., methanol, 1-butanol, and 1-hexanol) at room temperature. Polarizable potential models are employed to describe the interactions among species. Results from our simulations show stable interfaces between the ionic liquid and n-alcohols, and we found that the interfacial widths decrease from methanol to 1-butanol systems, and then increase for 1-hexanol interfaces. Angular distribution analysis reveals that the interface induces a strong orientational order of [bmim] and n-alcohol molecules near the interface, with [bmim] extending its butyl group into the alcohol phase while the alcohol has the OH group pointing into the ion liquid region, which is consistent with the recent sum-frequency-generation experiments. We found the interface to have a significant influence on the dynamics of ionic liquids and n-alcohols. The orientational autocorrelation functions illustrate that [bmim] rotate more freely near the interface than in the bulk, while the rotation of n-alcohol is hindered at the interface. Additionally, the time scale associated with the diffusion along the interfacial direction is found to be faster for [bmim] but slowed down for n-alcohols approaching the interface. We also calculate the dipole moment of n-alcohols as a function of the distance normal to the interface. We found that, even though methanol and 1-butanol have different dipole moments in bulk phase, they reach a similar value at the interface. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for the Department of Energy by Battelle. The calculations were carried out using computer resources provided by the

  18. Computational studies of [bmim][PF6]/n-alcohol interfaces with many-body potentials.

    Science.gov (United States)

    Chang, Tsun-Mei; Dang, Liem X

    2014-09-04

    In this paper, we present the results from molecular dynamics simulations of the equilibrium properties of liquid/liquid interfaces of room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and simple alcohols (i.e., methanol, 1-butanol, and 1-hexanol) at room temperature. Polarizable potential models are employed to describe the interactions among species. Results from our simulations show stable interfaces between the ionic liquid and n-alcohols, and we found that the interfacial widths decrease from methanol to 1-butanol systems and then increase for 1-hexanol interfaces. Angular distribution analysis reveals that the interface induces a strong orientational order of [bmim] and n-alcohol molecules near the interface, with [bmim] extending its butyl group into the alcohol phase, whereas the alcohol has the OH group pointing into the ionic liquid region, which is consistent with the recent sum-frequency-generation experiments. We found the interface to have a significant influence on the dynamics of ionic liquids and n-alcohols. The orientational autocorrelation functions illustrate that [bmim] rotates more freely near the interface than in the bulk, whereas the rotation of n-alcohol is hindered at the interface. Additionally, the time scale associated with the diffusion along the interfacial direction is found to be faster for [bmim] but slowed down for n-alcohols approaching the interface. We also calculate the dipole moment of n-alcohols as a function of the distance normal to the interface. We found that, even though methanol and 1-butanol have different dipole moments in bulk phase, they reach a similar value at the interface.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-10

    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.

  20. Density Functional Theoretical Study of Polynitrogen Compounds N+5Y- (Y=B(CF3)4, BF4, PFe and B(N3)4)

    Institute of Scientific and Technical Information of China (English)

    廉鹏; 来蔚鹏; 常海波; 李亚南; 李辉; 杨威; 王友兵; 王伯周; 薛永强

    2012-01-01

    The structures and the stabilities of polynitrogen compounds N+5Y^- [Y=B(CF3)4, BF4, PF6, and B(N3)4], as the potential high energy density compounds, have been investigated at the B3LYP/6-31G(d,p) and B3LYP/6-311 +G(d,p) levels. On the basis of our geometry optimization calculations, the structural properties of the N+5Y^- compounds are discussed, and it is found that the combination of the N+ cation and the Y- anions leads to dis- tortion of the structures of the Y anions. Based on the TS calculations for the N2-10ss dissociations of the N+Y- compounds, the stabilities of these compounds are discussed, and the following conclusion can be drawn that among the four compounds, N+B(CF3)4 is the most stable one and N+B(N3)7 is the most unstable, and the relative stability of these compounds is always consistent using different basis sets. From these discussions, it is re- vealed that there are close correlations between the stuctrual distortions of the Y-anions and the stabilities of the N+Y- compounds, and between the nitrogen content in the compounds and the stabilities of the N+5Y^- compounds.

  1. 离子液体[BMIM]PF6的制备及其在萃取中的应用%Preparation of Ionic Liquids -[BMIM]PF6 and Application in the Extraction

    Institute of Scientific and Technical Information of China (English)

    严永新

    2009-01-01

    Mn3+/Mn2+间接电合成对甲氧基苯甲醛的反应中,为了防止残留有机物污染电极,降低电流效率,用离子液体[BMIM]PF6对化学反应液进行萃取,与有机溶剂苯萃取效果进行比较,并讨论酸度、温度对其萃取效果的影响,结果表明:用离子液体[BMIM]PF6萃取效果优于苯,pH值为1、温度为30 ℃时,萃取效果好.

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

    Institute of Scientific and Technical Information of China (English)

    郑建华; 申书昌

    2015-01-01

    A kind of Silicone modified ionic liquid 1-ethyl-3-( 3-chloropropyl ) three hydroxy silane six benzimidazole fluorophosphate([SOeBim][PF6])was synthesized using 1-ethyl benzimidazole(3-chloropropyl) trimethoxysilane and six fluorine potassium phosphate as raw meterials,the structure and the stability of it were analyzed.[SOeBim][PF6] stationary liquid with silica hydroxyl on the surface of quartz reacted by chemical bonding method , the opening capillary column was prepared by this method . The separating characteristic of the chromatography column was investigated by benzene mixtures and alcohol mixtures respectively.%以1-乙基苯并咪唑、(γ-氯丙基)三甲氧基硅烷和六氟磷酸钾为原料,合成了一种硅氧烷改性的离子液体1-乙基-3-(γ-氯丙基)三羟基硅烷苯并咪唑六氟磷酸盐([SOeBim][PF6]),并对其结构及稳定性进行了分析。将[SOeBim][PF6]固定液用化学键合的方法与石英表面的硅羟基反应,制成开口毛细管色谱柱。通过对苯类混合物和醇类混合物进行分离,考察了其分离性能。

  3. Highly selective CO2 adsorption accompanied with low-energy regeneration in a two-dimensional Cu(II) porous coordination polymer with inorganic fluorinated PF6(-) anions.

    Science.gov (United States)

    Noro, Shin-ichiro; Hijikata, Yuh; Inukai, Munehiro; Fukushima, Tomohiro; Horike, Satoshi; Higuchi, Masakazu; Kitagawa, Susumu; Akutagawa, Tomoyuki; Nakamura, Takayoshi

    2013-01-01

    High selectivity and low-energy regeneration for adsorption of CO(2) gas were achieved concurrently in a two-dimensional Cu(II) porous coordination polymer, [Cu(PF(6))(2)(4,4'-bpy)(2)](n) (4,4'-bpy = 4,4'-bipyridine), containing inorganic fluorinated PF(6)(-) anions that can act as moderate interaction sites for CO(2) molecules.

  4. [Bmim]BF4-H2O体系超额摩尔体积测定及关联%Measurement and Correlation of Excess Molar Volume for the [Bmim]BF4-H2O System

    Institute of Scientific and Technical Information of China (English)

    方伟慧; 林金清; 王国平; 金春英

    2010-01-01

    合成并表征离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4),测定[Bmim]BF4-H2O二元混合物在不同温度下的密度值和超额摩尔体积.结果表明,在所有组成范围内,体系的超额摩尔体积都为正值,且不同温度下的等温线都存在一极大值点;同时,所有等温线的极值点所对应的H2O的摩尔分数基本上在50%左右.不同温度下超额摩尔集体的变化趋势相似,而在组成相同的情况下,随着温度的增加,超额摩尔体积变大.采用Redlich-Kister方程对[Bmim]BF4-H2O的超额摩尔体积进行关联,最大标准偏差为1.32%.

  5. Cycle stability of the electrochemical capacitors patterned with vertically aligned carbon nanotubes in an LiPF6-based electrolyte

    Science.gov (United States)

    Chiou, Yi-Deng; Tsai, Dah-Shyang; Lam, Hoa Hung; Chang, Chuan-Hua; Lee, Kuei-Yi; Huang, Ying-Sheng

    2013-08-01

    The miniature ultracapacitors, with interdigitated electrodes of vertically aligned carbon nanotubes (VACNTs) and an inter-electrode gap of 20 μm, have been prepared in the LiPF6 organic electrolyte with and without PVdF-HFP gel. PVdF-HFP between two opposing electrodes enhances the device reliability, but lessens its power performance because of the extra diffusion resistance. Also noteworthy are the gel influences on the cycle stability. When the applied voltage is 2.0 or 2.5 V, both the LiPF6 and the gel capacitors exhibit excellent stability, typified by a retention ratio of >=95% after 10 000 cycles. Their coulombic efficiencies quickly rise up, and hold steady at 100%. Nonetheless, when the applied voltage is 3.5 or 4.0 V, the cycle stability deteriorates, since the negative electrode potential descends below 0.9 V (vs. Li), leading to electrolyte decomposition and SEI formation. For the LiPF6 capacitor, its retention ratio could be around 60% after 10 000 cycles and the coulombic efficiency of 100% is difficult to reach throughout its cycle life. On the other hand, the gel capacitor cycles energy with a much higher retention ratio, >80% after 10 000 cycles, and a better coulombic efficiency, even though electrolyte decomposition still occurs. We attribute the superior stability of the gel capacitor to its extra diffusion resistance which slows down the performance deterioration.

  6. Asymmetric Glyoxylate-Ene Reactions Catalyzed by Chiral Pd(II Complexes in the Ionic Liquid [bmim][PF6

    Directory of Open Access Journals (Sweden)

    Nan Sun

    2007-06-01

    Full Text Available The room temperature ionic liquid [bmim][PF6] was employed as the reactionmedium in the asymmetric glyoxylate-ene reaction of α-methyl styrene (4a with ethylglyoxylate using chiral palladium(II complexes as the catalysts. [Pd(S-BINAP(3,5-CF3-PhCN2](SbF62 (1b showed the highest catalytic activity. Under the reaction conditionsof 40 oC, 0.5 h, and 1b/4a molar ratio of 0.05, ethyl α-hydroxy-4-phenyl-4-pentenoate wasobtained in excellent chemical yield (94 % with high enantioselectivity (70 %. Otherα-hydroxy esters can also be obtained in high chemical yields and enantioselectitiesthrough the glyoxylate-ene reactions of alkenes with glyoxylates catalyzed by 1b in[bmim][PF6]. Moreover, the ionic liquid [bmim][PF6] which contained the palladium(IIcomplex could be recycled and reused several times without significant loss of the catalyticactivity.

  7. Luminescent molecular Ag-S nanocluster [Ag(62)S(13)(SBu(t))(32)](BF(4))(4).

    Science.gov (United States)

    Li, Gen; Lei, Zhen; Wang, Quan-Ming

    2010-12-22

    The first observation of luminescence from a structurally well-defined Ag(2)S molecular nanocluster is reported. Reaction of AgSBu(t)/AgBF(4) with N(2)H(4) in methanol affords the tetracationic cluster [Ag(62)S(13)(SBu(t))(32)](BF(4))(4), which has a core-shell configuration. The 14 silver(I) centers of the [Ag(14)S(13)] core are in a face-centered cubic arrangement with each edge bridged by a S(2-) ligand; the core is further connected to the [Ag(48)(SBu(t))(32)] shell via both Ag-S bonds and Ag···Ag interactions. This novel cluster displays intense red emission in both the solid state and solution at room temperature.

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

    DEFF Research Database (Denmark)

    Mortensen, Kell; Engler, E. M.

    1984-01-01

    The conductivity σ and the thermoelectric power S have been studied experimentally on the organic conductors bis-tetramethyltetraselenafulvalenium hexafluorophosphide [(TMTSF)2PF6] and bis-tetramethyltetrathiafulvalenium hexafluorophosphide [(TMTTF)2PF6] and their solid solutions: (TMTSF1-xTMTTFx)2......PF6. Dramatic effects are seen in σ already when dilute concentrations of TMTTF molecules are introduced in the TMTSF chains, and for x=0.1, σ shows generally activated behavior. The thermopower, on the contrary, remains basically unaffected for x at least as large as 0.25. These unusual findings...

  9. Excitation photon energy dependence of photo-induced phase transition in (EDO-TTF)2PF6

    Science.gov (United States)

    Ogihara, S.; Onda, K.; Shimizu, M.; Ishikawa, T.; Okimoto, Y.; Shao, X. F.; Nakano, Y.; Yamochi, H.; Saito, G.; Koshihara, S.

    2009-02-01

    The conducting charge transfer complex (EDO-TTF)2PF6 has two types of charge transfer bands in the low temperature insulator phase: CT1 at 0.56 eV and CT2 at 1.38 eV. We excited these bands independently with a tunable ultrashort pulse laser and studied the difference of the photo-induced phases by measuring change in reflectivity spectrum over a wide photon energy range. As a result, we found that both the photo-induced phases by CT1 and CT2 excitation are the same except for their photo-conversion efficiencies

  10. Ultrafast photo-induced metal insulator transition in 1/4 filled organic crystal (EDO-TTF)2PF6

    Science.gov (United States)

    Chollet, Matthieu; Guerin, Laurent; Uchida, Naoki; Fukaya, Souichi; Shimoda, Hiroaki; Ishikawa, Tadahiko; Matsuda, Kazunari; Hasegawa, Takumi; Ota, Akira; Yamochi, Hideki; Saito, Gunzi; Tazaki, Ryoko; Adachi, Shin-ichi; Koshihara, Shin-ya

    2005-01-01

    We report that the 1/4 filled A2B salt (EDO-TTF)2PF6 developed as a candidate for organic superconductor unexpectedly shows highly sensitive and ultra-fast photo-induced phase transition (PIPT) from insulator (I) to metal (M). We show the results of time resolved experiments performed on this crystal. A large reflectivity change in the near infrared region (1.2-2 eV), which occurs within 2 ps for weak excitation intensity, has been observed. We also observed coherent vibrations in the dynamical process of this transition.

  11. Purification of crude LiPF6 by organic solvent%用有机溶剂提纯六氟磷酸锂粗品

    Institute of Scientific and Technical Information of China (English)

    陈俊彩; 张志业; 王辛龙; 杨林; 傅玉信

    2012-01-01

    Ethyl ether with non-toxicity and non-corrosiveness was used instead of HF as a purification solvent of crude LiPF6. LiPF6 was purified by extraction and recrystallization method. The purifying process was with low energy consumption and didn' t have pollution to environment and production. The synthesized and purified IiPF6 was characterized by infrared spectrometry and X-ray diffraction (XRD). Chloride ion,undissolved solid and the residual ether in the product were also determinated. Additionally,the effect of residual ether on the first charge-discharge performance of Li-ion batteries based electrolyte containing IiPF6 was studied. The result showed that the purity of purified LiPF6 reached 99. 98% ,and it was superior to that of the commercial LiPF6. The ether residuum didn' t have adverse effects on the first charge-discharge performance of Li-ion batteries.%本文用乙醚作为纯化溶剂,采用有机溶剂重结晶并辅以洗涤萃取等方法来提纯六氟磷酸锂(LiPF6)粗品.工艺操作条件温和、能耗低、原材料无毒无HF腐蚀、简便易得,是一条绿色工艺纯化路线.经红外光谱、X射线粉末衍射对提纯后的晶体LiPF6进行结构确认和物相分析,对最终产品LiPF6中氯离子(Clˉ)、乙二醇二甲醚(DME)不溶物和乙醚残留量进行检测分析,还探讨了残留的乙醚对锂离子二次电池首次充放电性能的影响.结果表明:LiPF6粗品经乙醚提纯后纯度达到99.98%,优于商用LiPF6;产品中微量乙醚残留不会对锂离子二次电池首次充放电性能造成不良影响.

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

    Indian Academy of Sciences (India)

    S Rajendran; T Uma

    2000-02-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    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.

  14. Synthesis and Crystal Structure of [CpRu(η5-C5H5)(dppc)Cl][PF6

    Institute of Scientific and Technical Information of China (English)

    WU Xiang-Hua; YU Guang-Ao; MENG Xiang-Gao; CHEN Yan; REN Yong; LIU Sheng-Hua

    2006-01-01

    The title complex [Ru(η5-C5H5)(dppc)Cl][PF6] has been synthesized by the reaction of [Ru(η5-C5H5)(PPh3)2Cl] with [dppc][PF6] (1,1'-bis(diphenylphosphino)cobaltocenium hexaflurophospate) in CH2Cl2, and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 15.754(8), b =13.704(7), c=19.120(10) (A),β=106.148(9)°, V=3965(4) (A)3, Z=4, C40H35Cl3CoF6P3Ru, Mr=988.94, Dc=1.657 g/cm3, F(000) = 1984 and μ(MoKα) = 1.181 mm-1. The final R = 0.0425 and wR = 0.1001 for 7002 independent reflections. The title complex shows a mononuclear Ru(Ⅱ)capped by an η5-Cp ring, a chelating η2-dppc and a terminal chloride to assume a three-legged piano-stool configuration.

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

    Indian Academy of Sciences (India)

    B L Bhargava; M Saharay; S Balasubramanian

    2008-06-01

    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.

  16. Laser photolysis study of anthraquinone in binary mixtures ofionic liquid [bmim][PF6] and organic solvent

    Directory of Open Access Journals (Sweden)

    Side Yao

    2006-12-01

    Full Text Available Photochemical properties of the ionic liquid (RTIL 1-butyl-3-methylimidazoliumhexafluorophosphate [bmim][PF6] and its binary mixed solutions with organic solvent(DMF and MeCN were investigated by laser photolysis at an excitation wavelength of 355nm, using anthraquinone (AQ as a probe molecule. It was indicated that the triplet excitedstate of AQ (3AQ* can abstract hydrogen from [bmim][PF6]. Moreover, along with thechange of the ratio of RTIL and organic solvent, the reaction rate constant changes regularly.Critical points were observed at volume fraction VRTIL = 0.2 for RTIL/MeCN and VRTIL =0.05 for RTIL/DMF. For both systems, before the critical point, the rate constant increasesrapidly with increasing VRTIL; however, it decreases obviously with VRTIL after the criticalpoint. We conclude that the concentration dependence is dominant at lower VRTIL, while theviscosity and phase transformation are dominant at higher VRTIL for the effect of ionic liquidon the decay of rate constant.

  17. [Bmim]PF6离子液体中微波辅助制备纳米TiO2/PMMA及其光催化活性

    Institute of Scientific and Technical Information of China (English)

    杨艳琼; 毕先钧

    2010-01-01

    微波加热法合成[Bmim]PR离子液体,以该离子液体为反应介质,在微波辐射条件下制备纳米TiO2/PMMA复合材料,并在高压汞灯下用甲基橙溶液对其进行光催化降解性能测试,并用XRD、IR、SEM、TG和BET等对该复合材料的结构进行测试和表征。结果表明,制备TiO2/PMMA复合材料的最佳条件:[Bmim]PF62.0mL,钛酸丁酯与甲基丙烯酸甲酯的体积比为3.4:1.0,微波辐射功率700W,反应温度80℃,反应时间35min。用[Bmim]PF6离子液体作反应介质,制备的TiO2/PMMA复合材料不需高温焙烧就表现出极高的光催化活性,对甲基橙降解率在1h可达到99.2%,活性明显优于用[Bmim]BF4离子液体作反应介质时所制备的同种材料的活性。

  18. Strong substrate-stabilizing effect of a water-miscible ionic liquid [BMIM][BF(4)] in the catalysis of horseradish peroxidase.

    Science.gov (United States)

    Hong, Eun Sik; Kwon, O Yul; Ryu, Keungarp

    2008-03-01

    The effects of a water-miscible ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]), on both thermodynamics and kinetic mechanism of the horseradish peroxidase (HRP)-catalyzed oxidation of guaiacol (2-methoxyphenol) by H(2)O(2) were investigated. The ionic liquid stabilized the ground state of guaiacol by causing an 8-fold increase of K(m) from 3 to 23 mM upon the addition of 25% (v/v) [BMIM][BF(4)]. In addition, the effect of [BMIM][BF(4)] in decreasing the k(cat) value of HRP catalysis was described by a non-competitive inhibition mechanism. The value of the inhibition constant of [BMIM][BF(4)] was 2.9 M indicating that the ionic liquid plays the role of a weak non-competitive inhibitor for HRP catalysis.

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

    Directory of Open Access Journals (Sweden)

    S. K. Chaurasia

    2015-07-01

    Full Text Available 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 PF 6 - 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.

  20. Room temperature ionic liquid in confined media: a temperature dependence solvation study in [bmim][BF4]/BHDC/benzene reverse micelles.

    Science.gov (United States)

    Pramanik, Rajib; Ghatak, Chiranjib; Rao, Vishal Govind; Sarkar, Souravi; Sarkar, Nilmoni

    2011-05-19

    In this work, we reported a detailed study of the solvation dynamics of coumarin-480 in [bmim][BF(4)]/BHDC/benzene reverse micelles (RMs) with varying [bmim][BF(4)]/BHDC molar ratio (R) 1.00, 1.25, 1.50, and also study the solvation dynamics at five different temperatures from 15 to 35 °C RMs at [bmim][BF(4)]/BHDC molar ratio 1.25 for the first time. The average solvation time constant becomes slightly faster with the increase in R values at a temperature 25 °C. The solvation dynamics of the RMs with R value 1.25 becomes faster with the increase in temperature. We have also investigated temperature-dependent solvation dynamics in neat [bmim][BF(4)]. The solvation dynamics in neat [bmim][BF(4)] has a substantial temperature effect but for the [bmim][BF(4)]/BHDC/benzene RMs the temperature effect on the solvation dynamics is not that significant. Time-resolved fluorescence anisotropy studies reveal a decrease in the rotational restriction on the probe with increasing temperature. Wobbling-in-cone analysis of the anisotropy data also supports this finding.

  1. Dynamics of NH3 ligands and ClO4- anions in the phase transition in [Cd(NH3)6](ClO4)2 studied by x-ray powder diffraction, neutron scattering methods and infrared spectroscopy

    Science.gov (United States)

    Hetmańczyk, Łukasz; Hetmańczyk, Joanna

    2017-02-01

    Phase transition, reorientational dynamics of NH3 ligands and ClO4- anions and crystal structure changes were investigated using x-ray powder diffraction (XRPD), neutron powder diffraction (NPD), quasi-elastic neutron scattering (QENS) and Fourier transform infrared spectroscopy (FT-IR). Most measurements were carried out in the temperature range 9-300 K. The diffraction techniques revealed that NH3 ligands and ClO4- anions are orientationally disordered at room temperature. During the cooling process, the high temperature cubic phase transforms into a lower symmetry phase (most probably of monoclinic structure). The QENS results confirm that NH3 ligands perform picoseconds reorientational motions both in the high and low temperature phases. This motion is almost unaffected by the observed phase transition (Tc=138.9 K on heating) and can be well described assuming the three fold jump model. On the other hand, the band shape analysis performed for the IR band connected with ClO4- internal vibration mode δd(OClO)E at 461 cm-1 clearly shows that ClO4- anions reorientate quickly in the high temperature phase, but that motion begins slowing down in the vicinity of the phase transition. Below 150 K the exponential reorientation relaxation term vanishes and only the vibrational relaxation term is present; small discontinuity is also visible. Moreover, below the phase transition temperature Tc splitting of the infrared absorption bands connected with some NH3 internal vibrations is observed.

  2. Inter-layer charge disproportionation in the dual-layer organic metal (tTTF-I)2ClO4 with unsymmetrical I***O halogen bond interactions.

    OpenAIRE

    Shin, Kyoung-Soon; Jeannin, Olivier; Brezgunova, Mariya; Dahaoui, Slimane; Aubert, Emmanuel; Espinosa, Enrique; Auban-Senzier, Pascale; Świetlik, Roman; Frąckowiak, Arkadiusz; Fourmigué, Marc

    2014-01-01

    Accepted 19 Nov 2013; International audience; A mixed-valence salt of tTTF-I with ClO4(-), formulated as (tTTF-I)2ClO4, is characterized by the presence of two crystallographically independent donor molecules, segregated in different layers and linked together through I***O interactions with the ClO4(-) anion disordered at room temperature. The tTTF-I donor molecule was prepared by metallation of tTTF (trimethylene tetrathiafulvalene) followed by reaction with iodine to afford the mono and di...

  3. Partial Dissolution of Charge Order Phase Observed in β-(BEDT-TTF)2PF6 Single Crystal Field Effect Transistor.

    Science.gov (United States)

    Sakai, Masatoshi; Moritoshi, Norifumi; Kuniyoshi, Shigekazu; Yamauchi, Hiroshi; Kudo, Kazuhiro; Masu, Hyuma

    2016-04-01

    The effect of an applied gate electric field on the charge-order phase in β-(BEDT-TTF)2PF6 single-crystal field-effect transistor structure was observed at around room temperature by technical improvement with respect to sample preparation and electrical measurements. A relatively slight but systematic increase of the electrical conductance induced by the applied gate electric field and its temperature dependence was observed at around the metal-insulator transition temperature (TMI). The temperature dependence of the modulated electrical conductance demonstrated that TMI was shifted toward the lower side by application of a gate electric field, which corresponds to partial dissolution of the charge-order phase. The thickness of the partially dissolved charge order region was estimated to be several score times larger than the charge accumulation region.

  4. Ultrafast infrared spectroscopic study of the photo-induced phase transition in (EDO-TTF)2PF6

    Science.gov (United States)

    Onda, Ken; Ishikawa, Tadahiko; Chollet, Matthieu; Shao, Xiangfeng; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-ya

    2005-01-01

    We have measured ultrafast reflectivity changes of (EDO-TTF)2PF6 in the infrared region (0.51 eV - 1.03 eV) after excitation with a 1.58 eV photon in order to reveal the mechanism of ultrafast photo-induced insulator-to-metal phase transition. We found that the temporal profiles of reflectivity change have two components: a faster component within 3 ps associated with a 1-ps or 0.5-ps period oscillation and a slower component lasting over hundreds of a picosecond. In addition, we found that the sign of a reflectivity change is often different from that expected from the thermally induced phase transition. These results indicate that the PIPT takes place via a complicated process due to strong electron and phonon coupling.

  5. Anomalous photo-induced response by double-pulse excitation in the organic conductor (EDO-TTF)2PF6

    Science.gov (United States)

    Onda, Ken; Ogihara, Sho; Ishikawa, Tadahiko; Okimoto, Yoichi; Shao, Xiangfeng; Nakano, Yoshiaki; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-ya

    2009-02-01

    We measured ultrafast reflectivity changes induced by double-pulse excitation in the organic conductor (EDO-TTF)2PF6. Using double-pulse excitation with a relatively high intensity, the sign of reflectivity change became reversed at around 0.8 ps and subsequently the reflectivity change reverted to that of the normal photo-induced state after about 1 ps. Using a optically phase-locked double-pulse with low intensity, we found that the temporal profile excited by an in-phase double-pulse differs from that by an out-of-phase double-pulse despite the time difference between the double-pulses being only 1.31 fs. This was true even when there is almost no overlap between each pulse in the double-pulse. These results indicate that the photo-response in this material to double-pulse excitation differs greatly from the linear sum of the responses to single pulses.

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

    Science.gov (United States)

    Cheng, Ping; Liu, Chuan; Yang, Yongpeng; Huang, Shiping

    2015-05-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

    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.

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

    Science.gov (United States)

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

    2016-06-01

    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.

  9. Effect of Hydrogen Reduction of Silver Ions on the Performance and Structure of New Solid Polymer Electrolyte PEI/Pebax2533/AgBF4 Composite Membranes

    Institute of Scientific and Technical Information of China (English)

    WANG Yanbei; REN Jizhong; LI Hui; DENG Maicun

    2013-01-01

    In this paper,the effect of hydrogen reduction of silver ions on the performance and structure of new solid polymer electrolyte polyetherimide (PEI)/Pebax2533 (Polynylon12/tetramethylene oxide block copolymer,PA12-PTMO)/AgBF4 composite membranes is investigated.For PEI/Pebax2533/AgBF4 composite membranes prepared with different AgBF4 concentration,the permeances of propylene and ethylene increase with the increase of AgBF4 concentration due to the carrier-facilitated transport,resulting in a high selectivity.But for propylene/propane mixture,the mixed-gas selectivity is lower than its ideal selectivity.The hydrogen reduction strongly influences the membrane performance,which causes the decrease of propylene permeance and the increase of propane permeance.With the increase of hydrogen reduction time,the membranes show a clearly color change from white to brow0n,yielding a great selectivity loss.The data of X-ray diffraction and FT-IR prove that silver ions are reduced to Ag after hydrogen reduction,and aggregated on the surface of PEI/Pebax2533/AgBF4 composite membranes.

  10. Radioactive iodide (131 I-) excretion profiles in response to potassium iodide (KI) and ammonium perchlorate (NH4ClO4) prophylaxis.

    Science.gov (United States)

    Harris, Curtis; Dallas, Cham; Rollor, Edward; White, Catherine; Blount, Benjamin; Valentin-Blasini, Liza; Fisher, Jeffrey

    2012-08-01

    Radioactive iodide ((131)I-) protection studies have focused primarily on the thyroid gland and disturbances in the hypothalamic-pituitary-thyroid axis. The objective of the current study was to establish (131)I- urinary excretion profiles for saline, and the thyroid protectants, potassium iodide (KI) and ammonium perchlorate over a 75 hour time-course. Rats were administered (131)I- and 3 hours later dosed with either saline, 30 mg/kg of NH(4)ClO(4) or 30 mg/kg of KI. Urinalysis of the first 36 hours of the time-course revealed that NH(4)ClO(4) treated animals excreted significantly more (131)I- compared with KI and saline treatments. A second study followed the same protocol, but thyroxine (T(4)) was administered daily over a 3 day period. During the first 6-12 hour after (131)I- dosing, rats administered NH(4)ClO(4) excreted significantly more (131)I- than the other treatment groups. T(4) treatment resulted in increased retention of radioiodide in the thyroid gland 75 hour after (131)I- administration. We speculate that the T(4) treatment related reduction in serum TSH caused a decrease synthesis and secretion of thyroid hormones resulting in greater residual radioiodide in the thyroid gland. Our findings suggest that ammonium perchlorate treatment accelerates the elimination rate of radioiodide within the first 24 to 36 hours and thus may be more effective at reducing harmful exposure to (131)I- compared to KI treatment for repeated dosing situations. Repeated dosing studies are needed to compare the effectiveness of these treatments to reduce the radioactive iodide burden of the thyroid gland.

  11. 阴离子表面活性剂SDS与离子液体[bmim][PF6]的相互作用研究%Study on Interaction Between 1-Butyl-3-methylimidazolium Hexafluorophosphate([bmim][PF6])and Anionic Surfactant Sodium Dodecyl Sulfate(SDS)

    Institute of Scientific and Technical Information of China (English)

    杨明桃; 边峰; 刘雪锋; 方云

    2008-01-01

    采用IHNMR、荧光发射光谱以及UV光谱研究了阴离子表面活性荆SDS与离子液体[bmim][PF6]的相互作用.结果表明,SDS胶束对[bmim][PF6]固有近紫外吸收和荧光发射具有显著敏化作用.IHNMR分析结果表明,[bmim][PF6]在SDS胶束中的增溶部位为SDS胶束的栅栏层,[bmim][PF6]渗入SDS胶束栅栏层的最大深度为SDS分子的C3亚甲基附近.

  12. Application of the Bahe's pseudolattice-theory to water-1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)) mixtures at 298.15K Part I. Autoprotolysis constants.

    Science.gov (United States)

    Bou Malham, I; Letellier, P; Turmine, M

    2007-04-15

    The autoprotolysis constants (K(s)) of water - 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)) mixtures were determined at 298K over the composition range of 0 to 77.43vol.% bmimBF(4) using potentiometric method with a glass electrode. A slight increase in the autoprotolysis constant was observed when the salt was added to the water. The value of the ionic product of the medium then decreases as the bmimBF(4) content increases from about 20vol.%. The acid-base properties of these media were perfectly described by Bahe's approaches that were completed by Varela et al. concerning structured electrolyte solutions with large short-range interactions.

  13. Molecular dynamics simulation of the electrochemical interface between a graphite surface and the ionic liquid [BMIM][PF6].

    Science.gov (United States)

    Kislenko, Sergey A; Samoylov, Igor S; Amirov, Ravil H

    2009-07-21

    The structure of the electrical double layer in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) near a basal plane of graphite was investigated by molecular dynamics simulation. The calculations were performed both for an uncharged graphite surface and for positively and negatively charged ones. It is found that near an uncharged surface the ionic liquid structure differs from its bulk structure and represents a well-ordered region, extending over approximately 20 A from the surface. Three dense layers of ca 5 A thick are clearly observed at the interface, composed of negative ions and positively charged rings. It is established that in the first adsorption layer the imidazolium ring in the [BMIM]+ cation tends to be arranged in parallel to the graphite surface at a distance of 3.5 A. The [PF6]- anion is oriented in such a way that the phosphorus atom is at a distance of 4.1 A from the surface and triplets of fluorine atoms form two planes parallel to the graphite surface. Ions adsorbed at the uncharged surface are arranged in a highly defective 2D hexagonal lattice and the corresponding lattice spacing is approximately four times larger than that of the graphene substrate. The influence of the electrode potential on the distribution of electrolyte ions and their orientation has also been investigated. Increase in the electrode potential induces broadening of the angle distribution of adsorbed rings and a shift of the most probable tilt angle towards bigger values. It was shown that there are no adsorbed anions on the negatively charged surface (sigma = -8.2 microC cm(-2)), but the surface concentration of adsorbed cations on the positively charged surface (sigma = +8.2 microC cm(-2)) has a nonzero value. In addition, the influence of the surface charge (+/- sigma) on the volume charge density and electric potential profiles in an electrolyte was studied. The differences in the cation and anion structure result in the fact that the

  14. 月桂酸淀粉酯在[ BMIM ] BF4离子液体中的酶法合成%Synthesis of laurate starch through lipase-catalyzed reaction in [ BMIM] BF4 ionic liquid

    Institute of Scientific and Technical Information of China (English)

    袁久刚; 向中林; 范雪荣; 王强; 姚金龙; 唐文君; 于拥军

    2016-01-01

    为了改善淀粉的疏水性能,采用固定化脂肪酶CALB在[ BMIM] BF4离子液体中对淀粉进行了月桂酸酯化改性。首先,对反应后得到的产物结构进行了核磁分析,结果显示月桂酸在脂肪酶的催化作用下成功对淀粉进行了改性。其次,研究了不同因素对产物取代度的影响,结果表明月桂酸淀粉酯的较优制备条件为:脂肪酶用量0.2 g、月桂酸/AGU摩尔比=3∶1、反应温度60℃、反应时间4 h。最后,对月桂酸接枝后淀粉的疏水性能进行了测试,结果显示淀粉的润湿接触角明显提高,而且随着取代度的增加,疏水性也越高。%In order to improve the hydrophobilicity of raw starch , lauric acid was grafted on starch through CALB lipase-catalyzed reac-tion in [BMIM]BF4ionic liquid.Firstly, the structure of modified starch was tested with 1H NMR, it showed that the lauric acid was successfully grafted on starch .Secondly , the effect of different reaction conditions on the DS values of modified starch was studied in detail.Results showed that a better synthesis condition for laurate starch was as follows:lipase dosage 0.2 g, lauric acid/AGU=3:1, temperature 60℃,time 4 h.Finally, the hydrophobilicity of modified starch was tested through water contact angle .Results showed that the hydrophobicity of modified starch was significantly improved and increased with DS values .

  15. In situ observation of multiple phase transitions in low-melting ionic liquid [BMIM][BF4] under high pressure up to 30 GPa.

    Science.gov (United States)

    Su, Lei; Zhu, Xiang; Wang, Zheng; Cheng, Xuerui; Wang, Yongqiang; Yuan, Chaosheng; Chen, Zhenping; Ma, Chunli; Li, Fangfei; Zhou, Qiang; Cui, Qiliang

    2012-02-23

    In situ characterization of phase transitions and direct microscopic observations of a low-melting ionic liquid, 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF(4)]), has been performed in detail by Raman spectroscopy. Compression of [BMIM][BF(4)] was measured under hydrostatic pressure up to ~30.0 GPa at room temperature by using a high-pressure diamond anvil cell. With pressure increasing, the characteristic bands of [BMIM][BF(4)] displayed nonmonotonic pressure-induced frequency shifts, and it is found to undergo four successive phase transitions at around 2.25, 6.10, 14.00, and 21.26 GPa. Especially, above a pressure of 21.26 GPa, luminescence of the sample occurs, which is connected with the most significant phase transition at around this pressure. It was indicated that the structure change under high pressure might be associated with a conformational change in the butyl chain. Upon releasing pressure, the spectrum was not recovered under a pressure up to 1.16 GPa, thereby indicating that this high-pressure phase remains stable over a large pressure range between 30 and 1.16 GPa in low-melting ionic liquid [BMIM][BF(4)]. Although the sample was kept under the normal pressure for 24 h, the spectrum was recovered, and it showed that the phase transition of [BMIM][BF(4)] was reversible. In other words, such a low-melting ionic liquid [BMIM][BF(4)] remains stable even after being treated under so a high pressure of up to 30 GPa.

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

    Directory of Open Access Journals (Sweden)

    Floyd A. Beckford

    2010-01-01

    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.

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

    Science.gov (United States)

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

    2015-05-01

    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.

  18. Influence of temperature on the structure and dynamics of the [BMIM][PF(6)] ionic liquid/graphite interface.

    Science.gov (United States)

    Kislenko, Sergey A; Amirov, Ravil H; Samoylov, Igor S

    2010-10-07

    The influence of temperature on the structure and dynamics of the [BMIM][PF(6)] ionic liquid/graphite interface has been investigated by molecular dynamics simulations. The performed simulations cover a 100 K wide temperature interval, ranging from 300 K to 400 K. It was shown that the magnitudes of density peaks of anions in the vicinity of the surface decrease with increasing temperature while in the case of cations anomalous temperature behaviour of the density profile is observed: the magnitude of the second peak of cations increases with the increase of temperature. To characterize interface dynamics the local self-diffusion coefficients D(x) of ions in the normal direction to the surface and the residence time of ions in the first and second interfacial layer have been estimated. It was shown that the local self-diffusion coefficients in the vicinity of the surface correlate with the local ion density; the maxima of the function D(x)(x) for the cations (anions) coincide with the regions of reduced cation (anion) density and vice versa. Finally, the influence of temperature on the screening potential in the vicinity of a charged graphite surface has been studied. It was shown that the increase of temperature from 300 K to 400 K induces the decrease of the potential drop across the interface that implies the increase of the capacitance of the electrical double layer.

  19. The photo-induced phase and coherent phonon in the organic conductor (EDO-TTF)2PF6

    Science.gov (United States)

    Onda, Ken; Ogihara, Sho; Ishikawa, Tadahiko; Okimoto, Yoichi; Shao, Xiangfeng; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-ya

    2008-06-01

    We have investigated the nature of the photo-induced state and coherent phonon in the conducting charge transfer complex (EDO-TTF)2PF6 by measuring the ultrafast reflectivity change over a wide photon energy range from 0.069 eV (18 µm) to 2.1 eV (580 nm). The photo-induced spectra just after photo-excitation indicate that the photo-induced phase is similar to but clearly different from that in a thermally induced metal phase though they are the same for general photo-induced phase transition. The temporal profiles at each probe photon energy are accompanied by extraordinarily large amplitude oscillation originating from coherent phonon generation. The period of the coherent phonon depends discretely on the probe photon energy, while the generation efficiency of both the photo-induced phase and coherent photon reaches a maximum when the peak top of a charge transfer band is excited. These results are probably attributable to the strong electron-vibration coupling in this complex.

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

    Science.gov (United States)

    Hofmann, Andreas; Hanemann, Thomas

    2015-12-01

    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.

  1. Periodic Hartree-Fock and hybrid density functional calculations on the metallic and the insulating phase of (EDO-TTF)(2)PF6

    NARCIS (Netherlands)

    Linker, Gerrit-Jan; Loosdrecht , van Paul H.M.; van Duijnen, Piet Th.; Broer, Ria

    2015-01-01

    The insulating and conducting phases of (EDO-TTF)(2)PF6 were studied by all electron, periodic Hartre-Fock and hybrid density functional calculations. Electronic properties, such as the electronic band structure, the density of states and the Fermi surface are discussed in relation to the metal-insu

  2. Strong Electron Correlation in the High-Temperature Phase of (EDO-TTF)2PF6 as a Quasi-One-Dimensional Molecular Conductor

    Science.gov (United States)

    Iwano, Kaoru; Shimoi, Yukihiro

    2010-10-01

    We focus on the electronic property of the high-temperature phase of (EDO-TTF)2PF6. Applying a cluster-based density-functional theory (DFT) calculation augmented by a self-consistent environment, we recognize a strong electron-electron repulsion in a dimer-Mott-type ground state. On the basis of this ground state, we obtain an absorption spectrum that takes a form of a single peak in the mid-infrared (mid-IR) region. We next analyze a Hubbard model with alternate transfers, of which the values are determined by the DFT calculations. The obtained absorption peak energy is comparable to the mid-IR peak energy observed in the experiment. Finally, we also investigate other one-dimensional conductors, (TMTSF)2PF6 and (TMTTF)2PF6, which are known as correlated metals, and conclude that (EDO-TTF)2PF6 also falls in this category, in spite of its unique (0110)-type charge ordering observed in the low-temperature phase.

  3. Comparison of ab initio molecular properties of EDO-TTF with the properties of the (EDO-TTF)(2)PF6 crystal

    NARCIS (Netherlands)

    Linker, Gerrit-Jan; van Loosdrecht, Paul H. M.; van Duijnen, Piet; Broer, Ria

    2010-01-01

    We performed ab initio quantum chemical calculations for the geometrical and electronic structure of the EDO-TTF (ethylenedioxy-tetrathiafulvalene) molecule using HF, CASSCF and DFT methods. We compare these in vacuo results with the properties of the (EDO-TTF)(2)PF6 crystal at near room temperature

  4. Pressure effects on the HS --> LS relaxation in [Zn1 - xFex(6-mepy)3tren](PF6)2

    Science.gov (United States)

    Wang, Wei; Chan, I. Y.; Schenker, Sabine; Hauser, Andreas

    1997-03-01

    Laser flash photolysis experiments were performed on the mixed crystal [Zn1-xFex(6-mepy)3tren](PF6)2 (x=0.00025) at 10 K in the pressure range between 1 bar and 20 kbar. An external pressure of 20 kbar accelerates the low-temperature tunneling process by almost eight orders of magnitude.

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

    Science.gov (United States)

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

    2016-04-14

    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.

  6. Further investigation of the intermolecular interactions and component distributions in a [Bmim][BF4]-based polystyrene composite membranes using two-dimensional correlation infrared spectroscopy.

    Science.gov (United States)

    Shi, Jingya; Wu, Peiyi; Yan, Feng

    2010-07-06

    The intermolecular interaction and distribution of components in [Bmim][BF(4)]-based polystyrene composite membrane which is composed of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]), poly(1-(2-methyl acryloyloxyundecyl)-3-methylimidazolium bromide) (poly(MAUM-Br)) and polystyrene is investigated by in situ Fourier transform infrared spectroscopy (FTIR) and two-dimensional correlation infrared spectroscopy (2DIR) in this study. A proposed model about the structure of this composite material is presented, and a sketch map about the local distributions of components is provided. In this model, alkyl chains in [Bmim][BF(4)], poly(MAUM-Br), and polystyrene in this system were supposed to form a polymeric network through aggregation or copolymerization. Cations of ionic liquids separate into the polymer network, while anions are kept mainly through the Coulomb force and partially by the hydrogen bonding between cations and anions. To support this model, FTIR has provided some hints on the pi-pi interaction existing in this complex material between the imidazole ring of ionic liquids and the benzene ring of polystyrene, based on the discovery of the shifts of IR absorption bands assigned to the C-C stretching vibrational mode. The sequential order of the responses from different chemical groups toward the variation of temperature is calculated by 2DIR, and the results suggest how different components distributed in this [Bmim][BF(4)]-based polystyrene composite membrane.

  7. Inhibiting effect of [HOEmim][BF4] and [Amim]Cl ionic liquids on the cross-linking reaction of bituminous coal

    Institute of Scientific and Technical Information of China (English)

    Wang Lanyun; Xu Yongliang; Wang Shaokun; Song Zhipeng

    2016-01-01

    In order to reduce the hazard of coal spontaneous combustion, the cross-linking reaction between O-containing functional groups of coal should be inhibited. So the inhibitory effect of an ionic liquid (IL) on the cross-linking reaction was studied. The O-containing functional groups change the weight loss and H2O, CO2, CO yields of bituminous coal before and after [HOEmim][BF4] and [Amim]Cl pre-treatment and were detected by Fourier Transform Infrared spectroscopy (FTIR) and Thermo Gravimetric (TG) anal-ysis. The results show that [Amim]Cl has a weaker ability to inhibit the cross-linking reaction of bitumi-nous coal compared to [HOEmim][BF4]. Besides, based on Quantum Chemistry calculation, it was found that the different inhibiting effects of [HOEmim][BF4] and [Amim]Cl are greatly related to their anions and the H linked with C2 atom on the imidazole ring. The H-donor ability of coal will be enhanced by [HOEmim][BF4] leading to a weaker cross-linking reaction of coal.

  8. Molecular dynamics simulations of the aqueous interface with the [BMI][PF6] ionic liquid: Comparison of different solvent models.

    Science.gov (United States)

    Chevrot, G; Schurhammer, R; Wipff, G

    2006-09-28

    We report a Molecular Dynamics (MD) study of the interface between water and the hygroscopic room temperature Ionic Liquid "IL" [BMI][PF6] (1-butyl-3-methyl-imidazolium hexafluorophosphate), comparing the TIP3P, SPC/E and TIP5P models for water and two IL models where the ions are +/-1 or +/-0.9 charged. A recent MD study (A. Chaumont, R. Schurhammer and G. Wipff, J. Phys. Chem. B, 2005, 109, 18964) showed that using TIP3P water in conjunction with the IL(+/-1) model led to water-IL mixing without forming an interface, whereas a biphasic system could be obtained with the IL(+/-0.9) model. With the TIP5P and SPC/E models, the juxtaposed aqueous and IL phases are found to remain distinct for at least 20 ns. The resulting IL humidity, exaggerated with the IL(+/-1) model, is in better agreement with experiment using the IL(+/-0.9) model. We also report demixing simulations on the "randomly mixed" liquids, using the IL(+/-0.9) model for the ionic liquid. With the three tested water models, the phases separate very slowly ( approximately 20 ns or more) compared to "classical" chloroform-water mixtures (less than 1 ns), leading to biphasic systems similar to those obtained after equilibration of the juxtaposed liquids. The characteristics of the interface (size, polarity, ion orientation, electrostatic potential) are compared with the different models. Possible reasons why, among the three tested water models, the widely-used TIP3P model exaggerates the inter-solvent mixing, are analyzed. The difficulty in computationally and experimentally equilibrating water-IL mixtures is attributed to the slow dynamics and micro-heterogeneity of the IL and to the different states of water in the IL phase.

  9. Synthesis of ionic liquids [bmim]BF4 and its impact on the antistatic property of polyester fabric%离子液体[bmim]BF4的合成及其对涤纶织物抗静电性能的影响

    Institute of Scientific and Technical Information of China (English)

    郑小佳

    2013-01-01

    研究了离子液体[bmim]BF4的合成,采用IR、1HNMR进行结构表征;分析了离子液体用量、轧余率、焙烘温度对涤纶织物抗静电性能的影响。结果表明:成功合成离子液体[bmim]BF4;[bmim]BF4用量25 g/L、轧余率80%、焙烘温度170℃时,整理的涤纶织物具有较好的抗静电性能,但耐洗性较差。通过TiO2/SiO2水溶胶进行后处理可以提高其耐洗性。%The synthesis of ionic liquids [bmim]BF4 was investigated and the structure of product was characterized by IR and 1HNMR. The effects of the dosage of ionic liquids [bmim]BF4, wet pickup and the cur-ing temperature on the antistatic property of polyester fabric were discussed. The results showed that the ion-ic liquids [bmim]BF4 was successful y synthesized. The finished polyester fabric had good antistatic properties when the dosage of [bmim]BF4 was 25 g/L, wet pickup was 80% and the curing temperature was 170 ℃, however, the durability was poor. The durability could be improved by the treatment of TiO2/SiO2 hydrosol.

  10. Density-of-state oscillation of quasiparticle excitation in the spin density wave phase of (TMTSF)2ClO4.

    Science.gov (United States)

    Uji, S; Kimata, M; Moriyama, S; Yamada, J; Graf, D; Brooks, J S

    2010-12-31

    Systematic measurements of the magnetocaloric effect, heat capacity, and magnetic torque under a high magnetic field up to 35 T are performed in the spin density wave (SDW) phase of a quasi-one-dimensional organic conductor (TMTSF)2ClO4. In the SDW phase above 26 T, where the quantum Hall effect is broken, rapid oscillations (ROs) in these thermodynamic quantities are observed, which provides clear evidence of the density-of-state (DOS) oscillation near the Fermi level. The resistance is semiconducting and the heat capacity divided by temperature is extrapolated to zero at 0 K in the SDW phase, showing that all the energy bands are gapped, and there is no DOS at the Fermi level. The results show that the ROs are ascribed to the DOS oscillation of the quasiparticle excitation.

  11. Magnetic susceptibility and Mössbauer studies of [FeX3](ClO4)2.H2O with X = bpz, bpy, phen or tpy

    Science.gov (United States)

    Ho, J. C.; Hamdeh, H. H.; Kirgan, R.; Rillema, D. P.

    2008-03-01

    Magnetic studies have been made on several tris-chelated iron complex compounds [FeX3](ClO4)2.H2O with aromatic nitrogen heterocycle ligands X = bpz (2,2'-bipyrazine), bpy (2,2'-bipyridine), phen (1,10-phenanthroline) or tpy (2,2':6,2''-terpyridine). SQUID data (2-300 K and 0.01-1 T) yielded small effective magnetic moments, which are characteristic of low-spin Fe(II), in agreement with the isomer shift and quadrupole splitting values from Mössbauer measurements (4-300 K, 0-5 T). Meanwhile, apart from the expected diamagnetism, a positive term of temperature-independent paramagnetic susceptibility prevails in most cases.

  12. Superconducting gap function in the organic superconductor (TMTSF)2ClO4 with anion ordering; First-principles calculations and quasiclassical analysis for angle-resolved heat capacity

    Science.gov (United States)

    Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko

    2011-03-01

    We calculate angle-dependent heat capacity in a low magnetic field range on the basis of the Kramer-Pesch approximation together with an electronic structure obtained by first-principles calculations to determine a superconducting gap function of (TMTSF)2ClO4 through its comparisons with experiments. The present comparative studies reveal that a nodal d-wave gap function consistently explains the experimental results for (TMTSF)2ClO4. It is especially emphasized that the observed unusual axis asymmetry of the angle dependence eliminates the possibility of s-wave and nodeless d-wave functions. It is also found that the directional ordering of ClO4 anions does not have any significant effects on the Fermi surface structure contrary to the previous modelings since the two Fermi surfaces obtained by the band calculations almost cross within the present full accuracy in first-principles calculations.

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

    Institute of Scientific and Technical Information of China (English)

    乔燕; 闫方友; 夏淑倩; 马沛生

    2013-01-01

    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.

  14. Synthesis and structures of novel octadecanuclear clusters [Cu12RE6(μ3-OH)24(pyb)12(H2O)18(μ12-ClO4)]17+(RE=Sm, Eu)

    Institute of Scientific and Technical Information of China (English)

    陈小明; 吴玉銮; 王如骥

    1996-01-01

    The novel octadecanudear Cu-RE cluster haw been isolated from the reaction system of aqueous Cu2+-RE3+-pyb (RE=Sm, Eu; pyb=pyridine betaine) and characterized by single-crystal structural analysis. The results show that the clusters comprise a [Cu12RE6(μ3-OH)24(μ12-ClO4)]17+ octahedral core, which encapsulates a ClO4- ion and has 18 water molecules and 12 bridging pyb carboxylato ligands as external ligands.

  15. Ultrafast Gigantic Photo-Response in Charge-Ordered Organic Salt (EDO-TTF)2PF6 on 10-fs time scales

    Science.gov (United States)

    Itatani, J.; Rini, M.; Cavalleri, A.; Onda, K.; Ishikawa, T.; Ogihara, S.; Koshihara, S.; Shao, X. F.; Nakano, Y.; Yamochi, H.; Saito, G.; Schoenlein, R. W.

    The initial dynamics of photo-induced phase transition in charge-ordered organic salt (EDO-TTF)2PF6 was investigated using 10-fs near-infrared laser pulses. We observed sub-20-fs gigantic photo-responses (|∆R/R|>100%) due to intra-molecular vibration and a clear signature of a structural bottleneck (~50 fs) for the first time.

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

    Science.gov (United States)

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

    2015-10-05

    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.

  17. The catalytic efficiency of lipase in a novel water-in-[Bmim][PF6] microemulsion stabilized by both AOT and Triton X-100.

    Science.gov (United States)

    Xue, Luyan; Li, Ying; Zou, Feixue; Lu, Lu; Zhao, Yin; Huang, Xirong; Qu, Yinbo

    2012-04-01

    In the water-in-[Bmim][PF(6)] microemulsion stabilized by both AOT and Triton X-100, the lipase-catalyzed hydrolysis of 4-nitrophenyl butyrate (p-NPB) was investigated to evaluate the catalytic efficiency of lipase in this novel microemulsion. The structural parameters of the microemulsion and the conditions of the enzymatic reaction affect the catalytic activity of lipase, especially the concentration of Tris-HCl buffer. Under optimum conditions, the catalytic activity of lipase in the present microemulsion is much higher than that in H(2)O saturated [Bmim][PF(6)]. When the partitioning of the substrate in the microemulsion is taken into account, the catalytic efficiency of lipase in this novel microemulsion is 14.3 times that in H(2)O saturated [Bmim][PF(6)] due to the significant decrease of the Michaelis constant in the microemulsion. Due to the large interface, high water activity, and probably the activating effect of the imidazolium cation in the water pool, the present microemulsion is demonstrated to be a promising medium for the lipase-catalyzed hydrolytic reaction. To demonstrate an important biocatalytic application in the IL-based microemulsion, the lipase-catalyzed synthesis of the flavoring agent benzyl acetate via transesterification of vinyl acetate with benzyl alcohol was also studied in the medium. Due to the high dispersion of lipase, large interface and removal of the byproduct, a maximum yield of 94% was obtained, indicating that the novel microemulsion is really important and useful.

  18. Synthesis of Polypyrrole Inverse Opal in [bmim]PF6- Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2013-01-01

    Full Text Available Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered polypyrrole (PPy inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF6. PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that the PF6- anions kept dedoping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. Although PF6- anions also kept dedoping from the PPy inverse opals, the PO43- anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours.

  19. Molecular dynamics simulation of the interfacial structure of [C(n)mim][PF6] adsorbed on a graphite surface: effects of temperature and alkyl chain length.

    Science.gov (United States)

    Dou, Q; Sha, M L; Fu, H Y; Wu, G Z

    2011-05-01

    The structures and diffusion behaviors of a series of ionic liquids [C(n)mim][PF(6)] (n = 1, 4, 8 and 12) on a graphite surface have been investigated by means of molecular dynamics simulation. It was found that three or four ordering layers of ionic liquids were formed near the graphite surface, and this layering structure was stable over the temperature range investigated. At the liquid/vacuum interface, the ionic liquid with a butyl chain had a monolayer ordering surface, while [C(8)mim][PF(6)] and [C(12)mim][PF(6)] exhibited a bilayer ordering with a polar domain sandwiched between two orientational nonpolar domains. More impressively, the simulated results showed that for the ionic liquids with alkyl chains longer than C(4), the adjacent alkyl chains in the whole film tended to be parallel to each other, with the imidazolium rings packed closely together. This indicated that the ionic liquids have a better regulated short-range structure than was previously expected. It was also found that both in the bottom layer and in the bulk region, the diffusion of the alkyl chains was much faster than that of the polar groups. However, as the alkyl chain length increased, the charge delocalization in the cation and the enhanced van der Waals interaction between the nonpolar groups contributed by reducing this difference in the diffusivity of major groups.

  20. Self-assembled histidine acid phosphatase nanocapsules in ionic liquid [BMIM][BF4] as functional templates for hollow metal nanoparticles.

    Science.gov (United States)

    Soni, Sarvesh K; Selvakannan, P R; Bhargava, Suresh K; Bansal, Vipul

    2012-07-17

    We report the biomacromolecular self-assembly of histidine acid phosphatase (HAP), an enzyme of significant biomedical and industrial importance, in the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]). The spontaneous self-assembly of HAP enzyme in [BMIM][BF(4)] results in the formation of HAP nanocapsules. The HAP enzyme molecules were found to retain their enzymatic activity after the self-assembly process, which enabled us to utilize self-assembled HAP capsules as self-catalyzing templates for the synthesis of a range of hollow metal nanoparticles (Au, Ag, Pd, and Ni) without employing any additional reducing agent. The hollow metal nanospheres with HAP encapsulated within their cavity were found to retain enzymatic activity for at least up to four cycles, as demonstrated in the case of Au-coated HAP capsules as the model system.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

    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.

  2. Insight into the intermolecular interactions in [Bmim]BF4/[Amim]Cl-ethanol-water mixtures by near-infrared spectroscopy.

    Science.gov (United States)

    Wu, Bo; Zhang, Yumei; Wang, Huaping

    2009-09-10

    In this contribution, we examined the effect of ethanol on the structural organization of aqueous solution of ionic liquids (ILs) using the near-infrared (NIR) technique and two-dimensional (2D) correlation spectra. The ILs used here are 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF(4)) and 1-allyl-3-methylimidazolium chloride ([Amim]Cl). It was easily found, from the distinct change tendency of NIR spectra for their aqueous solution, that the added ethanol exerted a different effect on the solution structure of [Bmim]BF(4) and [Amim]Cl. For [Amim]Cl/H(2)O, it was deduced that ethanol molecules prefer to compete with water by interacting with imidazolium C(2)-H rather than C(4,5)-H groups, accompanied by the formation of C(2)-H...O interactions with ethanol molecules, while ethanol molecules do not interact specifically with any imidazolium C-H groups for [Bmim]BF(4). Furthermore, it was shown that the nonpolar tail of [Amim]Cl is more sensitive to the decrease of polarity or dielectric constant of solvents than its polar head, whereas the converse is true for [Bmim]BF(4). However, for both ILs, ethanol molecules were capable of changing the interaction between cations and water, anions and water by introduction of C-H...O interactions with cations, as well as the strong hydrogen-bond interactions between the anions and the hydroxyls of the ethanol. This information is suggestive for recycling the hydrophilic ILs by distillation from their aqueous diluted solutions, as well as for purifying hygroscopic ILs.

  3. Facilitated Transport of Ethylene in Poly (Amide 12-Block Tetramethylenoxide) Copolymer/AgBF4 Membranes Containing Silver (I) and Copper (I) Ions as Carriers

    Science.gov (United States)

    Ben Hamouda, Sofiane; Trong Nguyen, Quang; Langevin, Dominique; Roudesli, Sadok

    Metal-incorporated poly(amide 12-block-tetramethylenoxide) (PA12-co-PTMO) copolymer was used for studying facilitated transport of olefines through new composite membranes. The metals incorporated were silver {Ag(I)} and copper {Cu(I)}. Tests were carried out at room temperature (25±2°C) to determine the selectivity and permeability of these membranes to ethylene and ethane gas. The membranes prepared by mixing in solution the copolymer with silver (AgBF4) or copper (CuBF4) salt show a ethylene/ethane selectivity much higher than that of pure PA12-co-PTMO. The membranes were also characterized by Fourier Transform Infra Red (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) in order to understand the structural feature responsible for the observed behaviour. The IRFT spectrum indicate that Ag+ and Cu+ ions are developing interactions with the copolymer. The permeation results obtained with copper containing membranes show that CuBF4 salt introduction in the copolymer tends to reduce ethane permeability. This phenomenon is explained by a diminution of the free volume caused by a decrease of the interchain distance due to the formation of metal ions-polymer matrix complexes. At the same time, for ethylene, the decrease in permeability observed at low salt content is recouped rapidly, when the salt content increases, by a dramatic increase of the permeability which attains 10 times that of the pure PA12-co-PTMO. This behaviour is attributed to the facilitated transport mechanism of the ethylene molecules able to develop specific interactions with the incorporated metal ions. It results from these two antagonistic phenomena a multiplication by 18 of the ethylene/ethane selectivity of the pure copolymer when the CuBF4 content of the composite attains 60%.

  4. Reactive-Atom Scattering from Liquid Crystals at the Liquid-Vacuum Interface: [C12mim][BF4] and 4-Cyano-4'-Octylbiphenyl (8CB).

    Science.gov (United States)

    Purcell, Simon M; Tesa-Serrate, Maria A; Marshall, Brooks C; Bruce, Duncan W; D'Andrea, Lucía; Costen, Matthew L; Slattery, John M; Smoll, Eric J; Minton, Timothy K; McKendrick, Kenneth G

    2016-10-04

    Two complementary approaches were used to study the liquid-vacuum interface of the liquid-crystalline ionic liquid 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C12mim][BF4]) in the smectic A (SmA) and isotropic phases. O atoms with two distinct incident translational energies were scattered from the surface of [C12mim][BF4]. Angle-dependent time-of-flight distributions and OH yields, respectively, were recorded from high- and low-energy O atoms. There were no significant changes in the measurements using either approach, nor the properties derived from them, accompanying the transition from the SmA to the isotropic phase. This indicates that the surface structure of [C12mim][BF4] remains essentially unchanged across the phase boundary, implying that the bulk order and surface structure are not strongly correlated for this material. This effect is ascribed to the strong propensity for the outer surfaces of ionic liquids to be dominated by alkyl chains, over an underlying layer rich in anions and cation head groups, whether or not the bulk material is a liquid crystal. In a comparative study, the OH yield from the surface of the liquid crystal, 8CB, was found to be affected by the bulk order, showing a surprising step increase at the SmA-nematic transition temperature, whose origin is the subject of speculation.

  5. 沙丁胺醇在离子液体[BnMIM]PF6修饰碳糊电极上的电催化氧化及电分析方法%Electrocatalytic Oxidation of Salbutamol at a [BnMIM]PF6 Modified Carbon Paste Electrode and Its Electrochemical Determination

    Institute of Scientific and Technical Information of China (English)

    吴锐; 马少宁; 张艳梅; 高作宁

    2013-01-01

    The electrocatalytic oxidation and electrochemical kinetic of Salbutamol (SAL) were investigated at a 1-Benzyl-3-Methylimidazole hexafluorophosphate([BnMIM]PF6) modified carbon paste electrode([BnMIM]PF6/CPE).The experimental results showed that the [BnMIM]PF6/CPE showed an excellent electrocatalytic activity toward SAL.The reaction rate constant for catalytic oxidation k was obtained as (2.10± 0.05) × 103 (mol· L-1)-1 · s-1 by chronoamperometry(CA).The catalytic oxidation peak current of SAL and its concentration had a good linear relationship in the range of 6.0× 10-7-1.0×10-3 mol· L-1,with a detection limit of 3.7 × 10-8 mol· L 1 (S/N=3) obtained by differential pulse voltammetry (DPV).The proposed method has been successfully applied in the electrochemical quantitative determination of SAL content in the commercial inhaled salbutamol solution.%研究了沙丁胺醇(Salbutamol,SAL)在离子液体1-苄基-3-甲基咪唑六氟磷酸盐([BnMIM]PF6)修饰碳糊电极([BnMIM]PF6/CPE)上的电催化氧化行为和电化学动力学性质.实验结果表明,[BnMIM]PF6/CPE对SAL的电化学氧化具有良好的催化作用.用计时电流法(CA)测定了SAL在[BnMIM] PF6/CPE上的电催化氧化反应速率常数k为(2.10±0.05)×103(mol·L-1)1·s-1.用微分脉冲伏安法(DPV)测得催化氧化峰电流与SAL的浓度在6.0×10-7~1.0×10-3mol· L-1范围内呈良好线性关系,检测限(S/N=3)为3.27×10-8 mol·L-1,同时运用该方法对吸入用沙丁胺醇溶液中的SAL含量进行了电化学定量测定.

  6. From molecule to bulk material: optical properties of hydrogen-bonded dimers [C12H12N4O2AgPF6]2 and [C28H28N6O3AgPF6]2 depend on the arrangement of the oxime moieties.

    Science.gov (United States)

    Cheng, Wen-Dan; Wu, Dong-Sheng; Shen, Juan; Huang, Shu-Ping; Xie, Zhi; Zhang, Hao; Gong, Ya-Jing

    2007-01-01

    The dependence of the optical properties of [C(12)H(12)N(4)O(2)AgPF(6)](2) (dimer-1) and [C(28)H(28)N(6)O(3)AgPF(6)](2) (dimer-2) on the arrangement of the oxime moieties in the molecule and in bulk crystals was investigated by means of time-dependent density functional theory. Dimer-1 with simple pyridine oxime ligands and a wavy arrangement has a smaller dipole moment and larger transition energy between the two states, and thus smaller third-order polarizabilities and two-photon absorption cross sections. Dimer-2 with extended pyridine oxime ligands and a ladder arrangement has a larger dipole moment and smaller transition energy between the two states, and thus larger third-order polarizabilities and two-photon absorption cross sections. The lowest energy absorption band is red-shifted for dimer-2 as compared with dimer-1, due to more pronounced pi-pi delocalization interactions and weaker hydrogen bonding in dimer-2. The electronic absorption spectra, frequency-dependent third-order polarizabilities, and two-photon absorption cross sections involve significant contributions from charge transfers from pi/pi* orbitals of the pyridine oxime ligands but no contribution from PF(6) (-) ions or H(2)O molecules in the wavelength range studied for the monomers and dimers of the C(12)H(12)N(4)O(2)AgPF(6) and C(28)H(28)N(6)O(3)AgPF(6) molecules. The third-order susceptibilities and two-photon absorption coefficients of bulk solids were estimated on the basis of the optical properties of the corresponding dimers, and the bulk material constructed from dimer-2 has the larger optical parameters of the two.

  7. Preparation of Fatty Acid Methyl Ester from Soybean Oil Catalyzed by Ionic Liquid [BMIM]BF4%离子液体([BMIM]BF4)催化大豆油酯交换制备脂肪酸甲酯

    Institute of Scientific and Technical Information of China (English)

    纪俊敏; 杨国龙; 毕艳兰; 景彦荣; 武冬晓

    2010-01-01

    考察了以离子液体(1-丁基-3-甲基咪唑四氟硼酸盐,[BMIM]BF4)在催化大豆油和甲醇酯化反应中的催化活性,结果表明:[BMIM]BF4对大豆油酯交换反应具有一定的催化活性,产物与离子液体易分离.当[BMIM]BF4的用量为大豆油质量的1%、甲醇与大豆油物质的量比为6 :1、反应温度69 ℃、反应时间4 h,酯交换反应的转化率可达到96%以上.反应结束后离子液体与酯化产物成两相,而且在同样的反应条件下,[BMIM]BF4可重复使用3次,仍有较高的催化活性.

  8. H2O-CH2Cl2-[Bmim]BF4体系的液液相平衡测定及其关联%Measurement and Correlation of Liquid-Liquid Equilibrium Data for H2O-CH2Cl2-[Bmim]BF4 System

    Institute of Scientific and Technical Information of China (English)

    林金清; 王国平; 方伟慧; 林晶; 金春英

    2009-01-01

    采用两步法合成了离子液体[Bmim]BF4,并利用红外光谱、核磁共振、元素分析等手段对所合成的产物进行表征和分析.利用浊点法测定了常压30℃下H2O-CH2Cl2-[Bmim]BF4体系的饱和溶解度曲线和密度曲线并进行了关联,还进一步采用浊点-密度法测定该体系的液液相平衡数据.由实验数结果可以看出:该体系上相以H2O为主,CH2Cl2、 [Bmim]BF4的含量很少,下相则以 [Bmim]BF4、CH2Cl2为主,H2O的含量很少;随着体系中CH2Cl2含量的增加上相中 [Bmim]BF4的含量从0.1665下降到0.1032.由此可见在纯化离子液体[Bmim]BF4时适当地增加CH2Cl2的用量可以减少[Bmim]BF4的损失.采用Othmer-Tobias和Bancroft经验方程对液液相平衡数据进行关联,关联结果不理想;采用Othmer-Tobias经验方程+溶解度方程法对其关联,最大相对误差为4.43%,最大平均相对误差为3.03%,关联精度较高.

  9. Synthesis and Crystal Structure of Dinuclear Cadmium Complex [Cd2(phen)4(fca)2](ClO4)2·(H2O)2

    Institute of Scientific and Technical Information of China (English)

    YANG Jia-Xiang; ZHANG Ze; WU Jie-Ying; TIAN Yu-Peng; DU Peng; LIU Qing-Liang; FUN Hoong Kun; C. Suchada

    2003-01-01

    A novel complex [Cd2(phen)4(fca)2](ClO4)2((H2O)2 (fca = dianion of 3-ferrocenyl- 2-crotonic acid, phen = 1,10-phenanthroline) has been synthesized and characterized by X-ray single-crystal structure analysis. It crystallizes in triclinic system, space group Pī with a = 11.6297(5), b = 12.5165(5), c = 13.8986(6) A, α = 63.345(1), β = 87.747(1), γ = 71.862(1)°, V = 1706.20(1) A3, Z = 1, Dc = 1.673 g/cm3, F(000) = 868 and μ(MoKα) = 1.185 mm-1 (λ = 0.71073 A). R = 0.0800 and Wr = 0.1793 for 7653 observed reflections (I > 2σ(I)). The structure consists of a dinuclear cation [Cd2(phen)4(fca)2]2+, two discrete perchlorate anions and two water molecules. The cationic part of the complex shows a tetrametallic core in which two fca groups act as the (O, O') bridging ligands between two cadmium(Ⅱ) ions with a distorted octahedral environment. The Cd…Cd intradimer distance is 4.128 A.

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

    Science.gov (United States)

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

    2016-09-01

    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.

  11. Synthesis and Crystal Structure of a [Cu(HTren)Cl2]ClO4·H2O Complex (Tren = Tris(2-aminoethyl)amine)

    Institute of Scientific and Technical Information of China (English)

    NIU De-Zhong; MA Heng-Jun; GAO Feng; LU Zai-Sheng; CHEN Jiu-Tong

    2006-01-01

    The title complex [Cu(HTren)Cl2]ClO4·H2O (Tren = tris(2-aminoethyl)amine) was crystal (CuC6H21Cl3N4O5) is of triclinic, space group P-1, with a = 8.2689(2), b = 8.4503(3), c=11.6801(4)(A), a = 96.9350(10), β= 108.2440(10), γ = 90.7550(10)°, V= 768.32(4)(A)3, Z= 2, Mr=399.16, Dc= 1.725 g/cm3,μ= 1.962 mm-1, F(000) = 410, T= 293(2) K, the final R = 0.0479 and wR = 0.1339 for 2659 observed reflections with I > 2σ(I). X-ray single-crystal structure analysis reveals that the copper(Ⅱ) atom adopts a slightly distorted square-pyramidal geometry. The distances between Cu and N atoms (N(1), N(2), N(3)) range from 1.975(4) to 2.116(3)(A). The bond lengths of Cu-Cl(1) and Cu-Cl(2) are 2.309(10) and 2.591(10) (A), respectively. The whole crystal presents a three-dimensional network structure by hydrogen bonds.

  12. Liquid/liquid interface layering of 1-butanol and [bmim]PF6 ionic liquid: a nonlinear vibrational spectroscopy and molecular dynamics simulation study.

    Science.gov (United States)

    Iwahashi, Takashi; Ishiyama, Tatsuya; Sakai, Yasunari; Morita, Akihiro; Kim, Doseok; Ouchi, Yukio

    2015-10-14

    IR-visible sum-frequency generation (IV-SFG) vibrational spectroscopy and a molecular dynamics (MD) simulation were used to study the local layering order at the interface of 1-butanol-d9 and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6), a room-temperature ionic liquid (RTIL). The presence of a local non-polar layer at the interface of the two polar liquids was successfully demonstrated. In the SFG spectra of 1-butanol-d9, we observed significant reduction and enhancement in the strength of the CD3 symmetric stretching (r(+)) mode and the antisymmetric stretching (r(-)) mode peaks, respectively. The results can be well explained by the presence of an oppositely oriented quasi-bilayer structure of butanol molecules, where the bottom layer is strongly bound by hydrogen-bonding with the PF6(-) anion. MD simulations reveal that the hydrogen-bonding of butanol with the PF6(-) anion causes the preferential orientation of the butanols; the restriction on the rotational distribution of the terminal methyl group along their C3 axis enhances the r(-) mode. As for the [bmim](+) cations, the SFG spectra taken within the CH stretch region indicate that the butyl chain of [bmim](+) points away from the bulk RTIL phase to the butanol phase at the interface. Combining the SFG spectroscopy and MD simulation results, we propose an interfacial model structure of layering, in which the butyl chains of the butanol molecules form a non-polar interfacial layer with the butyl chains of the [bmim](+) cations at the interface.

  13. Cyclic voitammetry, convolutive voltammetry, chrono-potentiometry and digital simulation studies of [Pt(C≡C tol)_2(dppm)_2Ir(CO)_2]~+PF_6~- complex

    Institute of Scientific and Technical Information of China (English)

    El-Hallag S Ibrahim

    2009-01-01

    The electrochemical behaviour of the heterobimetallic complex [Pt(C≡C tol)_2(dppm)_2-Ir(CO)_2]~+PF_6~-was studied via cyclic voltammetry, convolutive voltammetry and chronopotentiometry at glassy carbon electrode in dichloromethane solution. The electrochemical parameters calculated from experimental data were tested and confirmed by matching the experimental cyclic voltammograms with the simu-lated data. It was found that convolutive voltammetry provided higher sensitivity, better resolution and more accurate method for determination of the electrochemical parameters than ordinary cyclic volt-ammetry.

  14. DFT calculations for the high-temperature structure of (EDO-TTF)2PF6: Identification of an electronic molecular dimer

    Science.gov (United States)

    Iwano, Kaoru; Shimoi, Yukihiro

    2009-02-01

    Density-functional theory (DFT) calculations are performed based on the high-temperature structure of (EDO-TTF)2PF6, a quasi-one-dimensional molecular compound that shows both thermal and photoinduced phase transitions. In this structure, the EDO-TTF molecules are one-dimensionally aligned, accompanied with weak dimerization. Contrary to a common sense, our DFT calculations reveal that the pair having a shorter mutual distance has a weaker intermolecular coupling than the pair with a longer one; the latter is appropriate to be called an electronic dimer. We also estimate the corresponding transfer energies and discuss their relevance to spin correlations and optical excitations.

  15. Phase transition in (EDO-TTF)2PF6: domain growth in the thermal hysteresis and ultra-fast photoinduced effects

    Science.gov (United States)

    Guérin, L.; Glijer, D.; Moisan, N.; Lorenc, M.; Buron-LeCointe, M.; Collet, E.; Cailleau, H.; Ota, A.; Saito, G.; Shao, X.; Yamochi, H.; Chollet, M.; Onda, K.; Ishikawa, T.; Koshihara, S.

    2005-01-01

    The first order phase transition between the metal (M) and insulating (I) phases of the molecular compound (EDO-TTF)2PF6 is investigated by single crystal x-ray diffraction. The coexistence of the insulating and metallic phases and the growth of the domains in the thermal hysteresis are clearly observed during the phase transition. We also present ultra-fast optical experiments using a nitrogen gas flow cryostat. A change of the reflectivity in the photoinduced phase was observed just after excitation. We will also discuss the influence of the excitation light polarisation on the efficiency of the photo-induced I-M phase transition.

  16. Photoinduced Change in the Charge Order Pattern in the Quarter-Filled Organic Conductor (EDO-TTF)2PF6 with a Strong Electron-Phonon Interaction

    Science.gov (United States)

    Onda, Ken; Ogihara, Sho; Yonemitsu, Kenji; Maeshima, Nobuya; Ishikawa, Tadahiko; Okimoto, Yoichi; Shao, Xiangfeng; Nakano, Yoshiaki; Yamochi, Hideki; Saito, Gunzi; Koshihara, Shin-Ya

    2008-08-01

    The quasistable state in the photoinduced phase transition for the quasi-one-dimensional quarter-filled organic conductor (EDO-TTF)2PF6 has been examined by ultrafast reflective measurements and time-dependent model calculations incorporating both electron-electron and electron-phonon interactions. The transient optical conductivity spectrum over a wide probe photon-energy range revealed that photoexcitation induced a new type of charge-disproportionate state. Additionally, coherent and incoherent oscillations dependent on probe photon energies were found, as predicted by the calculation.

  17. Comparison of ab initio molecular properties of EDO-TTF with the properties of the (EDO-TTF) 2PF 6 crystal

    Science.gov (United States)

    Linker, Gerrit-Jan; Loosdrecht, Paul H. M. van; Duijnen, Piet van; Broer, Ria

    2010-03-01

    We performed ab initio quantum chemical calculations for the geometrical and electronic structure of the EDO-TTF (ethylenedioxy-tetrathiafulvalene) molecule using HF, CASSCF and DFT methods. We compare these in vacuo results with the properties of the (EDO-TTF) 2PF 6 crystal at near room temperature. We demonstrate that, by bending and charging the molecule in vacuum, the deformation that is thought to be the origin of charge ordering in this material is an inherent property of the EDO-TTF molecule. We further show that deformations can be readily made at ambient temperatures.

  18. A molecular dynamics simulation of the structure of ionic liquid (BMIM+/PF6-)/rutile (110) interface

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The interfacial structure between the room-temperature ionic liquid, 1-butyl-3-methyl-imidazolium hexafluorophosphate (BMIM+/PF6-) and rutile (110) surface is simulated by classical molecular dynam-ics simulation, aiming to model a crucial constituent of the electrolyte/semiconductor interface. The simulation results show several enhanced layers forming in the interfacial region, especially for the anions. A well ordered double layering structure of the ions is also observed in the interfacial region. The cations are found to organize themselves in a parallel alignment with respect to the TiO2 slab, with an obvious elongation of the side chains.

  19. 离子液体[bmim][BF4]对联苯甲酰光化学反应影响的瞬态吸收光谱%Transient Absorption Spectroscopy of the Effects of the Ionic Liquid [bmim][BF4] on the Photochemical Reactions of Benzil

    Institute of Scientific and Technical Information of China (English)

    朱光来; 吴国忠; 崔执凤; 许新胜

    2011-01-01

    Using benzil (BZ) as a probe molecule, the photochemical properties of the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) and its binary mixed solutions with acetonitrile (MeCN) were investigated by nanosecond laser photolysis.We found that the decay of the triplet excited state of benzil (3BZ*) in a N2-saturated solution followed mono-exponential kinetics.Along with the increase in the volume fraction (VIL) of [bmim][BF4]in the mixed solvents, the absorption peak of 3BZ* did not change.However, the effect of different VIL values on the photoinduced electron transfer process in the mixture of [bmim][BF4]/MeCN was obvious.Moreover, the apparent rate constant (kgr) of the formed radical decreased obviously with an increase in VIL.When the ratio of [bmim][BF4]was sufficiently high, the electron transfer reaction between 3BZ* and triethylamine or N,N,N',N' -tetramethyl-p-phenylenediamine was retarded.%利用纳秒级激光光解瞬态吸收光谱研究了联苯甲酰(BZ)在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([bmim][BF4])与乙腈(MeCN)混合体系中的光化学反应行为.考察了探针分子BZ存在下[bmim][BF4]/MeCN比例对体系中化学反应动力学的影响.实验发现:在N2饱和条件下,BZ溶液经激光辐照后产生的激发三线态3BZ遵循一级反应动力学规律衰减.离子液体(IL)相对比例增加对3BZ瞬态吸收峰的位置和强度没有产生明显影响.但离子液体体积分数ViL的变化对[bmim][BF4]/MeCN混合溶剂中光诱导电子转移的影响却非常显著,总体上电子转移产生的自由基的表观生成速率常数kgr随[bmim][BF4]的VIL增大而减小.在[bmim]BF4]比例足够大的情况下,3BZ与三乙胺或四甲基对苯二胺之间的电子转移被抑制.

  20. 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.

    Science.gov (United States)

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

    2007-06-14

    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 400 ps and 1.10 ns.

  1. 草酰胺桥联异三核配合物Cu(NiL)2(ClO4)2的合成、光谱表征和晶体结构%Synthesis,Spectroscopic Characterization and Crystal Structure of A Novel Oxamido-Bridged Trinuclear Complex Cu(NiL)2(ClO4)2

    Institute of Scientific and Technical Information of China (English)

    周旭光; 王圆方; 李容芳; 王庆伦; 杨光明; 廖代正

    2004-01-01

    A novel oxamido-bridged trinuclear complex Cu(NiL)2(ClO4)2 (where H2L=2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,3-dien) has been synthesized and characterized by elemental analysis, IR spectrum,UV-Visible spectrum and single crystal X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n. The lattice parameters are: a=1.0524(6) nm, b=1.182 1(6) nm, c=1.586 2(9) nm, β=91.657(9)°, and V=1.972 6(19) nm3, Z=2. The results show that the coordination geometry around copper(Ⅱ) in the title complex is hexa-coordinated octahedron.

  2. In Situ AFM Imaging of Microstructural Changes Associated with The Spin Transition in [Fe(Htrz2(Trz](Bf4 Nanoparticles

    Directory of Open Access Journals (Sweden)

    María D. Manrique-Juárez

    2016-06-01

    Full Text Available Topographic images of [Fe(Htrz2(trz](BF4 nanoparticles were acquired across the first-order spin transition using variable-temperature atomic force microscopy (AFM in amplitude modulation mode. These studies revealed a complex morphology of the particles consisting of aggregates of small nanocrystals, which expand, separate and re-aggregate due to the mechanical stress during the spin-state switching events. Both reversible (prompt or slow recovery and irreversible effects (fatigue on the particle morphology were evidenced and correlated with the spin crossover properties.

  3. A Novel and Efficient Process for Preparation of 2,4-Diphenyl-4-methyl-1-pentene in Br(o)nsted Acidic Ionic Liquid [Hmim]+BF4-

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng-Rong; DU Ji-Yan; YANG Fan; ZOU Gang; TANG Jie

    2005-01-01

    Highly selective dimerization of α-methylstyrene (AMS) was effected using a Bronsted acidic ionic liquid,[Hmim]+BF-4, as solvent as well as catalyst, providing the industrial high-value olefin, 2,4-diphenyl-4-methyl-1-pentene (1-PT). The desired dimer 1-PT could be obtained in 90% yield at 96% conversion in the dimerization of AMS under optimized conditions. Features of the procedure include use of readily available ionic liquid-catalyst,exclusion of volatile organic solvents, higher selectivity and efficiency for 1-PT.

  4. Mechanical exfoliation of graphite in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) providing graphene nanoplatelets that exhibit enhanced electrocatalysis

    Science.gov (United States)

    Hayes, William Ignatius; Lubarsky, Gennady; Li, Meixian; Papakonstantinou, Pagona

    2014-12-01

    A novel production method for graphene nanoplatelets (GPs) with enhanced electrocatalytic behaviour is presented. GPs show improvement in their oxygen reduction reaction (ORR) catalysis after prolonging the grinding of graphite in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6). Nitrogen doping of the GPs has inferred a further increase in ORR. The ORR onset potential, cathodic current magnitude and electron transfer efficiency have all improved as a direct consequence of increasing the graphite grinding duration from 30 min to 4 h. Atomic force microscopy has confirmed a decrease in the GP diameter and height as the grinding increases. Raman spectroscopy indicates a higher level of defects present after prolonging the graphite grinding in BMIM-PF6, most likely a result of the increased edge plane exposure. This increased edge plane appears to promote a higher level of nitrogen incorporation as the graphite grinding duration increases, as confirmed by X-ray photoelectron spectroscopy analysis. The stability of the cathodic current assessed by chronoamperometry analysis is higher for the GP and nitrogen doped graphene nanoplatelet (N-GP) samples than the platinum on carbon black (Pt/C). This study presents a novel process for the production of nitrogen doped graphene nanoplatelets, constituting a strategy for the up-scaled production of electrocatalysts.

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

    Science.gov (United States)

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

    2012-11-15

    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.

  6. Structural and dynamic features of Candida rugosa lipase 1 in water, octane, toluene, and ionic liquids BMIM-PF6 and BMIM-NO3.

    Science.gov (United States)

    Burney, Patrick R; Pfaendtner, Jim

    2013-03-07

    Ionic liquids (ILs) and organic chemicals can be used as solvents in biochemical reactions to influence the structural and dynamic features of the enzyme, sometimes detrimentally. In this work we report the results for molecular dynamics simulations of Candida rugosa lipase (CRL) in ILs BMIM-PF6 and BMIM-NO3, as well as organic solvents toluene and octane in an effort to explore the role of solvent on the structure and dynamics of an enzyme known to be active in many nonaqueous media. Simulations of CRL in water were also included for comparison, bringing the aggregate simulation time to over 2.8 μs. At both 310 and 375 K the ILs significantly dampen protein dynamics and trap the system near its starting structure. Structural changes in the enzyme follow the viscosity of the solvent, with the enzyme deviating from its initial structure the most in water and the least in BMIM-PF6. Interactions between the enzyme surface and the solvent in the IL simulations show that contacts are dominated by the IL anion, which is ascribed to a broader spatial distribution of positively charged protein residues and reduced mobility of the cation due to the size of the imadazolium ring.

  7. Evaluation of potassium iodide (KI) and ammonium perchlorate (NH4ClO4) to ameliorate 131I- exposure in the rat.

    Science.gov (United States)

    Harris, C A; Fisher, J W; Rollor, E A; Ferguson, D C; Blount, B C; Valentin-Blasini, L; Taylor, M A; Dallas, C E

    2009-01-01

    Nuclear reactor accidents and the threat of nuclear terrorism have heightened the concern for adverse health risks associated with radiation poisoning. Potassium iodide (KI) is the only pharmaceutical intervention that is currently approved by the Food and Drug Administration for treating (131)I(-) exposure, a common radioactive fission product. Though effective, KI administration needs to occur prior to or as soon as possible (within a few hours) after radioactive exposure to maximize the radioprotective benefits of KI. During the Chernobyl nuclear reactor accident, KI was not administered soon enough after radiation poisoning occurred to thousands of people. The delay in administration of KI resulted in an increased incidence of childhood thyroid cancer. Perchlorate (ClO(4)(-)) was suggested as another pharmaceutical radioprotectant for 131I- poisoning because of its ability to block thyroidal uptake of iodide and discharge free iodide from the thyroid gland. The objective of this study was to compare the ability of KI and ammonium perchlorate to reduce thyroid gland exposure to radioactive iodide (131I-). Rats were dosed with 131I- tracer and 0.5 and 3 h later dosed orally with 30 mg/kg of either ammonium perchlorate or KI. Compared to controls, both anion treatments reduced thyroid gland exposure to 131I- equally, with a reduction ranging from 65 to 77%. Ammonium perchlorate was more effective than stable iodide for whole-body radioprotectant effectiveness. KI-treated animals excreted only 30% of the (131)I(-) in urine after 15 h, compared to 47% in ammonium perchlorate-treated rats. Taken together, data suggest that KI and ammonium perchlorate are both able to reduce thyroid gland exposure to 131I- up to 3 h after exposure to 131I-. Ammonium perchlorate may offer an advantage over KI because of its ability to clear 131I- from the body.

  8. Synthesis, Characterization, and Catalytic Hydrogenation Activity of New N-Acyl-Benzotriazole Rh(I and Ru(III Complexes in [bmim][BF4

    Directory of Open Access Journals (Sweden)

    Hakan Ünver

    2016-09-01

    Full Text Available The hydrogenation activity of new N-acyl-benzotriazole Rh(I and Ru(III complexes in ionic liquid media is reported in this study. Both complexes were completely soluble in 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4], and they were able to catalyze the hydrogenation of styrene and 1-octene. While ethylbenzene conversion in styrene hydrogenation reached 84% when the Ru complex was used, 100% conversion was obtained with the Rh complex at 393 K in 6 h. Additionally, total conversion in 1-octene hydrogenation reached 100% with the Rh complex in [bmim][BF4] media. The hydrogenation of styrene and 1-octene in dimethyl sulfoxide (DMSO and toluene was also studied to compare the solvent effect on catalytic system. The effect of some catalytic parameters such as temperature, H2 (g pressure, and catalyst amount on the conversion was examined, and it was found that the conversion increased parallel to the increasing temperature and H2 pressure. The recyclability of catalysts was also investigated, and it was revealed that the Rh complex in particular maintained the activity for at least 10 cycles.

  9. 在盐酸溶液中[HMIM ]BF4对70高碳钢的缓蚀作用和吸附行为%Inhibition Property and Adsorption Behavior of [ HMIM] BF4 on 70 High-carbon Steel in HCl Solution

    Institute of Scientific and Technical Information of China (English)

    王威淳

    2016-01-01

    合成了咪唑类离子液体1-己基-3-甲基咪唑四氟硼酸盐([HMIM]BF4),采用失重法与电化学方法研究了在1 mol/L HCl溶液中对高碳钢(70钢)的缓蚀性能、吸附行为及缓蚀机理。结果表明,[ HMIM] BF4具有明显的缓蚀作用,属于混合型缓蚀剂,缓蚀效率随着浓度的增加而增大,随着温度升高而下降。该离子液体在碳钢表面的吸附反应为自发放热过程,且该吸附符合Langmuir吸附等温式,属于同时具有物理吸附和化学吸附的混合吸附。%Imidazole ionic liquid 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM]BF4) was synthesized. Using weight loss method and electrochemical methods , inhibition properties , adsorption behavior and inhibition mechanism of 70 high-carbon steel in 1 mol/L HCl solution were studied .The results showed that [ HMIM ] BF4 had significant inhibition effect , belonged to mixed inhibitor , inhibition efficiency increased with increasing concentration , decreased with increasing temperature . The adsorption reaction of ionic liquid on steel surface was a spontaneous exothermic process , and the adsorption isotherm comply Langmuir belonged simultaneously with mixed physical adsorption and chemical adsorption .

  10. Inter-layer charge disproportionation in the dual-layer organic metal (tTTF-I)2ClO4 with unsymmetrical I···O halogen bond interactions.

    Science.gov (United States)

    Shin, Kyoung-Soon; Jeannin, Olivier; Brezgunova, Mariya; Dahaoui, Slimane; Aubert, Emmanuel; Espinosa, Enrique; Auban-Senzier, Pascale; Świetlik, Roman; Frąckowiak, Arkadiusz; Fourmigué, Marc

    2014-04-14

    A mixed-valence salt of tTTF-I with ClO4(-), formulated as (tTTF-I)2ClO4, is characterized by the presence of two crystallographically independent donor molecules, segregated in different layers and linked together through I···O interactions with the ClO4(-) anion disordered at room temperature. The tTTF-I donor molecule was prepared by metallation of tTTF (trimethylene tetrathiafulvalene) followed by reaction with iodine to afford the mono and diiodo derivatives tTTF-I and tTTFI2, respectively. The crystal structure of the latter neutral tTTFI2 shows the occurrence of strong type II, II halogen bond interactions. Band structure calculations of the dual-layer structure of the 2 : 1 salt (tTTF-I)2ClO4 show co-existence of both 1D open and 2D closed Fermi surfaces. The salt undergoes a metal-insulator phase transition at T(MI) = 90 K, associated with an electronic dimensionality decrease, since already at 100 K, the 2D part of the Fermi surface transforms into 1D corrugated planes. High resolution X-ray investigations performed at 100 K, combined with multipolar refinements, indicate an approximately equivalent +0.5e charge in both donor molecules, as also deduced from the intramolecular bond distances. On the other hand, Raman spectroscopic investigations show that at ambient temperature the charge is actually distributed non-uniformly in conducting layers of tTTF-I molecules, with the identification of molecules with charges +1, +0.5, 0e, while at low temperature the charge distribution becomes essentially uniform (+0.5e), as confirmed from the X-ray high resolution data. These apparently contradictory behaviors are actually a consequence of a partial electron transfer between the two independent slabs to reach a common Fermi level in the metallic phase.

  11. Synthesis and Crystal Structure of [NiL2(H2O)2](ClO4)2L=MBPT=4-p-methylphenyl-3,5-bis-(pyridin-2-yl)-1,2,4-triazole

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Nickel (II) complex, [Ni(MBPT)2(H2O)2](ClO4)2 (MBPT=4-p-methylphenyl-3,5-bis-(pyridin-2-yl)-1,2,4-triazole), was synthesized and its crystal structure determined by X-ray diffraction methods.The complex adopts a distorted octahedral environment made up of two bidentate chelating MBPT ligands in the equatorial plane and two water molecules filling the axial positions.

  12. Studies on extraction of nickel and cadmium ions in used batteries with ionic liquid [ Emim ] PF6- phenanthroline%离子液体[Emim]PF6-邻菲咯琳萃取回收废旧电池中镐、镍离子的研究

    Institute of Scientific and Technical Information of China (English)

    廖芳丽; 王永生; 郑汉锐

    2011-01-01

    The extraction of nickel and cadmium in waste nickel-cadmium battery with hydrophobic ionic liquid [ Emim] PF6- phenanthroline was studied. The effects of the oscillation duration、 temperature、 the balance aqueous phase acidity and the extractant quantity on the extraction of nickel and cadmium were examined, respectively. The result showed that nickel and cadmium ions in waste nickel-cadmium battery could be extracted nicely in extraction system of 4. 0 mL of 4g/L phenanthroline-3.0 mL of[ Emim ] PF6, in an aqueous phase of pH 5.91, at a, temperature of 80℃ for 20 min of oscillation duration. The effect of back-extraction of used [ Emim ] PF6 under different oscillation duration and acidic media was also researched, and it was found that the nickel and cadmium ions could be well back extracted in 1.0 mol/L hydrochloric acid medium when oscillation duration was one hour.%研究了疏水性离子液体[Emim] PF_6-邻菲咯琳萃取体系对废旧镍镉电池中镉、镍离子的萃取性能,考察了振荡时间、温度、平衡水相酸度和萃取剂用量时萃取性能的影响.在水相pH值为5.91、温度为80℃时,4.0mL4g/L的邻菲咯琳与3.0mL离子液[Emim] PF_6组成的萃取体系时废旧电池液中镉、镍离子萃取效果良好.同时研究了废旧离子液在不同时间及酸度下的反萃效果,在浓度为1.0mol/L的盐酸介质中反萃1h,镉、镍离子能较好地被反萃.

  13. Electrocatalytic oxidation and its electrochemical determination of quinine sulfate at SDBS - [bupy] PF_6 modified carbon paste electrode%硫酸奎宁在SDBS-[bupy]PF_6修饰碳糊电极上的电催化氧化及电分析方法

    Institute of Scientific and Technical Information of China (English)

    刘立红; 高作宁

    2010-01-01

    目的:研究了硫酸奎宁(quinine sulfate,QS)在十二烷基苯磺酸钠(sodium dodecyl benzenesulfonate,SDBS)自组装膜与离子液体N-丁基吡啶六氟磷酸盐([bupy]PF_6)复合修饰碳糊电极(SDBS-[bupy]PF_6/CPE)上的电化学行为和电化学动力学性质,建立了QS电化学定量测定方法.方法:循环伏安法(CV),计时电流法(CA),计时库仑法(CC),方波伏安法(SWV)以及电化学交流阻抗法(EIS).结果:在SDBS-[bupy]PF_6/CPE上,QS发生了受扩散控制的不可逆电化学氧化过程.测得QS在SDBS-[bupy]PF_6/CPE上的电极反应过程动力学参数.用SWV法测得QS氧化峰电流与其浓度在5.0 ×10~(-6)~1.0×10~(-4)mol·L~(-1)和1.0×10~(-4)~1.0×10~(-3)mol·L~(-1)呈线性关系,检测限为3.5×10~(-7)mol·L~(-1).采用本方法对市售二盐酸奎宁注射液进行了电化学定量测定,RSD在1.3%~3.4%之间,加标回收率在98.0%~103%之间.结论:SDBS-[bupy]PF_6/CPE对QS电化学氧化具有良好的催化作用,该方法可用于市售奎宁类药物含量的电化学定量测定,方法操作简单,测定结果令人满意.

  14. Temperature-dependent interactions and disorder in the spin-transition compound [Fe(II)(L)2][ClO4]2.C7H8 through structural, calorimetric, magnetic, photomagnetic, and diffuse reflectance investigations.

    Science.gov (United States)

    Mishra, Vibha; Mukherjee, Rabindranath; Linares, Jorge; Balde, Chérif; Desplanches, Cédric; Létard, Jean-François; Collet, Eric; Toupet, Loic; Castro, Miguel; Varret, François

    2008-09-01

    The title compound [Fe (II)(L) 2][ClO 4] 2.C 7H 8 (L = 2-[3-(2'-pyridyl)pyrazol-1-ylmethyl]pyridine) has been isolated while attempting to grow single crystals of the spin-transition (continuous-type) compound [Fe (II)(L) 2][ClO 4] 2, published earlier ( Dalton Trans. 2003, 3392-3397). Magnetic susceptibility measurements, as well as Mossbauer and calorimetric investigations on polycrystalline samples of [Fe(L) 2][ClO 4] 2.C 7H 8 revealed the occurrence of an abrupt HS ( (5) T 2) LS ( (1) A 1) transition with steep and narrow (2 K) hysteresis at approximately 232 K. The photomagnetic properties exhibit features typical for a broad distribution of activation energies, with relaxation curves in the shape of stretched exponentials. We performed a crystal structure determination of the compound at 120, 240, and 270 K. A noteworthy temperature-dependent behavior of the structural parameters was observed, in terms of disorder of both the anions and solvent molecules, leading to a strong thermal dependence of the strength and dimensionality of the interaction network. Additional data were obtained by diffuse reflectance measurements. We model and discuss the antagonistic effects of interactions and disorder by using a two-level cooperative mean-field approach which includes a distribution of barrier energies at the microscopic scale.

  15. 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

    Science.gov (United States)

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

    2016-05-01

    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.

  16. Volumetric and viscosity properties of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid in methanol%[Bmim]BF4离子液体在甲醇中的体积和黏度性质

    Institute of Scientific and Technical Information of China (English)

    李诗琴; 周贤丰; 许映杰

    2013-01-01

    在298.15 K和常压下,测定了1-丁基-3-甲基咪唑四氟硼酸([Bmim] BF4)离子液体+甲醇体系的密度和黏度.由密度计算了体系的表观摩尔体积,并采用Redlich-Mayer方程关联了体系的表观摩尔体积与组成的关系,得到了[Bmim]BF4在甲醇中的标准偏摩尔体积.由Jones-Dole方程对体系的黏度随组成的变化进行了拟合,获得了[Bmim] BF4在甲醇中的黏度B系数.结果表明:[Bmim] BF4+甲醇体系的表观摩尔体积和黏度均随[Bmim] BF4浓度的增加而增加,[Bmim] BF4在甲醇中的标准偏摩尔体积和黏度B系数分别为155.72×10-6m3/mol和0.282 9.%Densities and viscosities of l-butyl-3-methylimi-dazolium tetrafluoroborate ionic liquid ( [ Bmim ] BF4 ) with methanol were measured at 298. 15 K and atmospheric pressure. Apparent molar volumes, Vf of the above-mentioned mixture were determined from the experimental densities. Standard partial molar volume , Vo/f of [ Bmim] BF4 in methanol was estimated by the Redlich-Mayer equation. The achieved viscosities were used to calculate the viscosity B-coefficient of [ Bmim ] BF4 in methanol through Jones-Dole equation. The results indicate that the apparent molar volumes and viscosities increase with increasing of ionic liquid concentration. Standard partial molar volume and viscosity B-coefficient of [Bmim] BF4 in methanol is 155.72 ?10-6 m3 穖ol-1 and 0.282 9,respectively.

  17. Copper triflate-mediated synthesis of 1,3,5-triarylpyrazoles in [bmim][PF6] ionic liquid and evaluation of their anticancer activities.

    Science.gov (United States)

    Rao, V Kameshwara; Tiwari, Rakesh; Chhikara, Bhupender S; Shirazi, Amir Nasrolahi; Parang, Keykavous; Kumar, Anil

    2013-09-21

    A simple, efficient, and environment friendly protocol for the synthesis of 1,3,5-triarylpyrazole and 1,3,5-triarylpyrazolines in [bimm][PF6] ionic liquid mediated by Cu(OTf)2 is described. The reaction protocol gave 1,3,5-triarylpyrazoles in good to high yields (71-84%) via a one-pot addition-cyclocondensation between chalcones and arylhydrazines, and oxidative aromatization without requirement for an additional oxidizing reagent. The catalyst can be reused up to four cycles without much loss in the catalytic activity. The pyrazoles (4a-o) and pyrazolines (3a-n) were evaluated for antiproliferative activity in SK-OV-3, HT-29, and HeLa human cancer cells lines. Among all compounds, 3b inhibited cell proliferation of HeLa cells by 80% at a concentration of 50 μM.

  18. Li2SO4-Li2O-P2O5 ionic glass dispersed with [Bmim] [PF6] ionic liquid: Electrical transport and thermal stability investigations

    Science.gov (United States)

    Rathore, Munesh; Dalvi, Anshuman; Kumar, Anil

    2014-04-01

    A fast ionic composite is prepared by dispersion of Ionic liquid [Bmim][PF6] in Li2SO4-Li2O-P2O5 glass matrix by mixing and through grinding. Amorphous/glassy nature of the samples is confirmed by X-Ray diffraction (XRD). Surprisingly, the electrical conductivity of the samples is found to be increasing by ˜ 2 orders of magnitude and exhibits typical Arrhenius behavior with low activation energy. DC polarization and impedance spectroscopy measurements suggest that samples are essentially ionic in nature. The conductivity isotherms were also obtained at different temperatures (T < 100 °C) and found to be appreciably stable at least for ˜ 10 days.

  19. Ultrafast and large reflectivity change by ultraviolet excitation of the metallic phase in the organic conductor (EDO-TTF)2PF6

    Science.gov (United States)

    Onda, K.; Shimizu, M.; Sakaguchi, F.; Ogihara, S.; Ishikawa, T.; Okimoto, Y.; Koshihara, S.; Shao, X. F.; Nakano, Y.; Yamochi, H.; Saito, G.

    2010-06-01

    We examined the ultrafast response of the metallic high-temperature phase in the conducting charge transfer complex (EDO-TTF)2PF6. A large reflectivity change of approximately 10% was observed when the intra-molecular band was excited by a weak 3.1 eV ultraviolet light pulse. The lifetimes of the photo-induced states were 0.2 and 0.7 ps in the Drude-like band and the intra-molecular band, respectively. Measurement of the photo-induced spectrum just after photo-excitation and simulation using the Drude model revealed that the electronically excited EDO-TTF molecules shortened the relaxation time of conduction electrons and reduced the reflectivity of the Drude-like band.

  20. Lithium ethylene dicarbonate identified as the primary product of chemical and electrochemical reduction of EC in 1.2 M LiPF6/EC:EMC electrolyte.

    Science.gov (United States)

    Zhuang, Guorong V; Xu, Kang; Yang, Hui; Jow, T Richard; Ross, Philip N

    2005-09-22

    Lithium ethylene dicarbonate ((CH2OCO2Li)2) was chemically synthesized and its Fourier transform infrared (FTIR) spectrum was obtained and compared with that of surface films formed on Ni after cyclic voltammetry (CV) in 1.2 M lithium hexafluorophosphate (LiPF6)/ethylene carbonate (EC):ethyl methyl carbonate (EMC) (3:7, w/w) electrolyte and on metallic lithium cleaved in-situ in the same electrolyte. By comparison of IR experimental spectra with that of the synthesized compound, we established that the title compound is the predominant surface species in both instances. Detailed analysis of the IR spectrum utilizing quantum chemical (Hartree-Fock) calculations indicates that intermolecular association through O...Li...O interactions is very important in this compound. It is likely that the title compound in the passivation layer has a highly associated structure, but the exact intermolecular conformation could not be established on the basis of analysis of the IR spectrum.

  1. Preparation and evaluation of modified composition for lyophilized kits of [Cu(MIBI4]BF4 for [99mTc] technetium labeling

    Directory of Open Access Journals (Sweden)

    Marisa de Jesus de C. Lima

    2005-10-01

    Full Text Available The [Cu(MIBI4]BF4 complex was synthesized and different formulations for lyophilized kits that could be cost-effectively used with different routines in nuclear medicine laboratories were investigated. In one preparation the kit components were kept similar to the Cardiolite® , except that the SnCl2.2H2O concentration was increased to 0.150 mg. In a second formulation, component concentrations were reduced to 1/5 of the original value and the SnCl2.2H2O concentration was adjusted to 0.04 mg. These products were labeled with maximum activities of 55.5 GBq and 8.14 GBq, respectively, and have shown an average radiochemical purity of 95 %. Biodistribution of the products was assessed by dissection in mice and in rabbits, and did not show any statistical difference when compared to Cardiolite®. In the synthesis of [Cu(MIBI4]BF4 a new procedure was introduced for the synthesis of N-(2-methyl-propenyl-formamide, with the use of microwave radiation as heat source. This modification reduced the reaction time to 25 seconds, while maintaining a yield of 68%.Neste trabalho são apresentados dados relativos a síntese do complexo [Cu(MIBI4]BF4 e à utilização do mesmo para produção de kit liofilizado para obtenção do radiofármaco [[99mTc](MIBI6]+. No processo de síntese foi utilizado radiação de microondas como fonte de aquecimento em uma etapa do processo, permitindo que a reação fosse executada em 25 segundos, obtendo rendimento de 68 %. Na preparação dos kits liofilizados, um deles denominado FULL, nos quais a quantidade dos componentes foi mantida igual ao produto comercial Cardiolite®, e outro denominado FRACTION, nos quais as quantidades foram reduzidas a 1/5 do total, foram adicionadas quantidades extras de SnCl2.2H2O. Deste modo, tornou-se possível marcar os kits liofilizados com atividades máximas de 55,5 GBq e 8,14 GBq, respectivamente. A biodistribuição dos produtos marcados, em camundongos e coelhos, não mostrou diferen

  2. Computational and Experimental Investigation of Li-doped Ionic Liquid Electrolytes: [pyr14][tfsi], [pyr13][fsi], and [EMIM][BF4

    Science.gov (United States)

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

    2014-01-01

    We employ molecular dynamics (MD) simulation and experiment to investigate the structure, thermodynamics, and transport of 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 mole fraction (0.05 xLi+ 0.33) and temperature (298 K T 393 K). Structurally, Li+ is shown to be solvated by three anion neigh- bors 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. Pulsed field gradient spin-echo NMR measurements of diffusion and electrochemical impedance spectroscopy measurements of ionic conductivity are made for the neat ionic liquids as well as 0.5 molal solutions of Li-salt in the ionic liquids. Bulk ionic liquid properties (density, diffusion, viscosity, and ionic conductivity) are obtained with MD and show excellent agreement with experiment. While the diffusion exhibits a systematic decrease with increasing xLi+, the contribution of Li+ to ionic conductivity increases until reach- ing 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. Our transport results also demonstrate the necessity of long MD simulation runs ( 200 ns) required to converge transport properties at room T. The differences in Li+ transport are reflected in the residence times of Li+ with the anions (Li), 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, to comment on the relative kinetics of Li+ transport in each liquid, we find that while the net motion of Li+ with its solvation shell (vehicular) significantly contributes to net diffusion in all liquids, the importance of

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

    Science.gov (United States)

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

    2008-04-10

    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.

  4. Mechanochemical effect in the iron(III) spin crossover complex [Fe(3-MeO-salenEt2]PF6 as studied by heat capacity calorimetry.

    Science.gov (United States)

    Sorai, Michio; Burriel, Ramón; Westrum, Edgar F; Hendrickson, David N

    2008-04-10

    Magnetic and thermal properties of the iron(III) spin crossover complex [Fe(3MeO-salenEt)(2)]PF(6) are very sensitive to mechanochemical perturbations. Heat capacities for unperturbed and differently perturbed samples were precisely determined by adiabatic calorimetry at temperatures in the 10-300 K range. The unperturbed compound shows a cooperative spin crossover transition at 162.31 K, presenting a hysteresis of 2.8 K. The anomalous enthalpy and entropy contents of the transition were evaluated to be Delta(trs)H = 5.94 kJ mol(-1) and Delta(trs)S = 36.7 J K(-1) mol(-1), respectively. By mechanochemical treatments, (1) the phase transition temperature was lowered by 1.14 K, (2) the enthalpy and entropy gains at the phase transition due to the spin crossover phenomenon were diminished to Delta(trs)H = 4.94 kJ mol(-1) and Delta(trs)S = 31.1 J K(-1) mol(-1), and (3) the lattice heat capacities were larger than those of the unperturbed sample over the whole temperature range. In spite of different mechanical perturbations (grinding with a mortar and pestle and grinding in a ball-mill), two sets of heat capacity measurements provided basically the same results. The mechanochemical perturbation exerts its effect more strongly on the low-spin state than on the high-spin state. It shows a substantial increase of the number of iron(III) ions in the high-spin state below the transition temperature. The heat capacities of the diamagnetic cobalt(III) analogue [Co(3MeO-salenEt)(2)]PF(6) also were measured. The lattice heat capacity of the iron compounds has been estimated from either the measurements on the cobalt complex using a corresponding states law or the effective frequency distribution method. These estimations have been used for the evaluation of the transition anomaly.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-10

    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.

  6. Single-Walled Carbon Nanotubes in Highly Viscous Media: A Comparison between the Dispersive Agents [BMIM][BF4 ], L121, and Triton X-100.

    Science.gov (United States)

    Gasbarri, Carla; Croce, Fausto; Meschini, Ida; Bowen, Christopher H; Marinelli, Lisa; Di Stefano, Antonio; Angelini, Guido

    2016-01-11

    Dispersions of single-walled carbon nanotubes (SWNTs) have been prepared by using the room-temperature ionic liquid [BMIM][BF4 ] (1-butyl-3-methylimidazolium tetrafluoroborate), the triblock copolymer Pluronic L121 [poly(ethylene oxide)5 -poly(propylene oxide)68 -poly(ethylene oxide)5 ] and the non-ionic surfactant Triton X-100 (TX100) in the pure state. The size of the SWNTs aggregates and the dispersion degree in the three viscous systems depend on the sonication time, as highlighted by UV/Vis/NIR spectroscopy and optical microscopy analysis. A nonlinear increase in conductivity can be observed as a function of the SWNTs loading, as suggested by electrochemical impedance spectroscopy. The generation of a three-dimensional network of SWNTs showing a viscoelastic gel-like behavior above a critical percolation concentration has been found at 25 °C in all the investigated systems by oscillatory rheology measurements.

  7. Recent Advances in the Application of SelectfluorTMF-TEDA-BF4 as a Versatile Mediator or Catalyst in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Stojan Stavber

    2011-07-01

    Full Text Available SelectfluorTM F-TEDA-BF4 (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo [2.2.2]octane bis(tetrafluoroborate is not only one of the most efficient and popular reagents for electrophilic fluorination, but as a strong oxidant is also a convenient mediator or catalyst of several “fluorine-free” functionalizations of organic compounds. Its applications as a mediator in transformations of oxidizable functional groups or gold-catalyzed C-C and C-heteroatom oxidative coupling reactions, a catalyst in formation of various heterocyclic rings, a reagent or catalyst of various functionalizations of electron-rich organic compounds (iodination, bromination, chlorination, nitration, thiocyanation, sulfenylation, alkylation, alkoxylation, a catalyst of one-pot-multi-component coupling reactions, a catalyst of regioselective ring opening of epoxides, a deprotection reagent for various protecting groups, and a mediator for stereoselective rearrangement processes of bicyclic compounds are reviewed and discussed.

  8. 应用滤纸接触法甄别[BMIM]PF6对赤子爱胜蚓的急性毒性效应%Application of Filter Paper Contact Method for Acute Toxicity Identification of [BMIM]PF6 on Eisenia Foetida

    Institute of Scientific and Technical Information of China (English)

    杨蕾; 阮键鸿; 周超; 刘扣

    2012-01-01

    In the study, fiber paper contact method was used to identity acute toxicRies of one kind of imidazolium ionic tiquid 1-butyl-3-methylimidazoIium hexafluorophosphate ([BMIM]PF6) as exposure and Eisenia foetida were used as model animals. The death rates were tested under different exposure concentrations in 60 h, 72 h and 84 h. It was found that there was a positive correlation between death rates and exposure levels. Although [BMIM]PF6, was considered to be a new type green solvent, further studies about its toxicities and ecological effects should be done because of its environmental risks.%文章选用咪唑类离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PFe)作为目标污染物,采用赤于爱胜蚓作为受试动物,应用滤纸接触法,通过测试不同暴露浓度下蚯蚓在60h、72h和84h时的死亡率,研究其对受试动物的急性毒性效应。实验发现,[BMIM]PF6虽然是新型绿色溶剂.但其仍存在一定程度的环境璺眸,带要笋基事性和生态效应做进一步研究。

  9. Synthesis, Crystal Structure and Electrochemical Properties of Complex [Ru2 (μ-O2CCH3)4 (H2O)2] PF6%配合物[Ru2(μ-O2CCH3)4(H2O)2]PF6的合成、表征及电化学性质

    Institute of Scientific and Technical Information of China (English)

    严生虎; 姜冬明; 张跃; 刘建武; 沈介发

    2011-01-01

    The title compound, [Ru2 (μ-O2CCH3)4 (H2O)2] PF6, was prepared by treating Ru2 (O2 CCH3)4C1 with methanol aqueous solution at the presence of Ag2SO4 and NH4PF6 through coordinating process. The compound was characterized by elemental analysis, IR spectra, cyclic voltammetry and X-ray single crystal structure analysis. The result reveals that the compound crystallizes in the monoclinic system with space group at C2/c, and a =1. 9 52 3 (9) nm, b = 1. 2 83 0 (6) nm, c =0. 846 8 (4) nm, β=93. 11 (10) and Z = 4. Thermogravimetric analysis was carried out to study the mechanism of thermal decomposition of the complex. The electrochemical property of ruthenium complex were studied by means of cyclic voltametry, the results show that electron transfer between Ru (II) and Ru (III) in electrolysis is quasi-reversible process.%[Ru2(μ-O2CCH3)4(H2O)2]PF6是以Ru2( O2CCH3)4Cl为前体配合物,在甲醇水(体积比7 ∶ 1)溶液中用Ag2SO4和NH4PF6进行脱氯配位反应而得.用元素分析、红外光谱、热重分析、循环伏安、X-衍射单晶结构分析等对其进行表征.晶体结构表明,标题化合物的晶体属单斜晶系,空间群为C2/c,晶胞参数为a=1.9 523 (9) nm,b=1.2830 (6) nm,c=0.8468 (4) nm,β=93.11 (10)°,Z=4.通过热失重分析研究配合物的热分解机理.用循环伏安法对其电化学性质进行表征,结果为一对准可逆的氧化还原峰,表明该配合物的中心金属2价钌原子Ru (Ⅱ)与3价钌原子Ru (Ⅲ)之间存在电子转移.

  10. Monodisperse Ru Nanoparticles in [Bmim]BF4:Preparation and Application in Benzene Selective Hydrogenation%离子液体[Bmim]BF4中单分散Ru纳米粒子的制备及选择加氢性能

    Institute of Scientific and Technical Information of China (English)

    魏珺芳; 王延吉; 励娟; 薛伟

    2011-01-01

    The monodisperse Ru nanoparticles were prepared by chemical reduction method in 1-butyl-3-methyl limidizaolium tetrafluoroborate ([BMim]BF4). The prepared Ru nanoparticles were characterized by XRD as hexagonal close packed structure and no diffraction peak from oxidation products. TEM analysis of these nanoparticles shows that the monodisperse Ru nanoparticles prepared by positive dripping method disperse in the ionic liquids with diameter less than 5 nm. The Ru nanoparticles prepared by reverse dripping method agglomerate with diameter more than 10 nm. FTIR results indicate that a physically absorbed layer of ionic liquid is evident on the surface of Ru nanoparticles. TG results indicate that the ionic liquid serves not only as a protective agent or stabilizing agent to inhibit the aggregation of Ru nanoparticles, but also a modification agent adsorbed on the Ru nanoparticles. Results of benzene selective hydrogenation show that benzene conversion is relatively high in the reaction system with water, however the selectivity of cyclohexene is low, only 14.5% at 27.3% benzene conversion in the same system.%采用化学还原法在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMim]BF4)中制备了单分散纳米金属Ru粒子.采用X射线衍射(XRD)、透射电镜(TEM)、傅里叶红外光谱(FTTR)及热重(TG)对所制备样品的形貌和结构进行了表征.XRD表征结果显示:在[BMim]BF4中制备的Ru具有六方紧密堆积结构,无氧化物峰出现;TEM结果显示:采用正滴法制备的Ru纳米粒子为球形颗粒,呈现良好的单分散状态,粒径分布窄,为2~5 nm,而采用反滴法制备的Ru纳米粒子则发生了严重的团聚,团聚体粒径大于10 nm;FTIR表征表明:Ru纳米粒子表面存在[BMjm]BF4液体层,分析二者之间存在较强的物理吸附作用,[BMim]BF4在Ru纳米粒子的制备中起到了修饰剂和保护剂的双重作用,这一推论通过TG分析得到了进一步验证.将分散于[BMim]BF4的Ru纳

  11. Measurement and modeling of the molar heat capacity of the dicationic ionic liquid [ C4 (MIM) 2 ] [ PF6 ] 2%双阳离子型离子液体[C4(MIM)2][PF6]2的比热容测定及其模型化

    Institute of Scientific and Technical Information of China (English)

    杨许召; 王军; 孙新科

    2011-01-01

    利用差示扫描量热计(DSC)测定了双阳离子型离子液体1,1'-(丁烷-1,4-二基)-双(3-甲基-1H-咪唑鎓-1-基)双六氟磷酸盐([C4(MIM)2][PF6]2)在293.15~513.15 K温区内的摩尔比热容.结果表明,在293.15~363.15 K和398.15~513.15 K温区内,该化合物无相变及其他热异常现象发生,比热容随温度变化符合二次方程.在363.15~398.15 K温区内,该物质发生固-液熔化相变,其熔化温度、熔化焓及熔化熵分别为384.71 K、28.243kJ/mol和73.414 J/(K·mol).根据热力学函数关系式,计算出[C4(MIM)2][PF6]:相对于标准参考温度298.15K的热力学函数值.采用基团贡献法对液相区的热容进行了估算,结果表明,估算值与实验值符合很好.%The molar heat capacity of the dicationic ionic liquid 1, 1 '-( butane-l, 4-diyl)-bis(3-methyl-1 H- imidazolium-l-yl) dihexafluorophosphate ( [C4 (MIM)2 ] [ PF6 ]2 ) has been measured using a differential scanning calorimeter (DSC) at temperatures from 293. 15 K to 513. 15 K. No phase transition or other thermal anomaly was observed in the temperature ranges 293.15 -363.15 K and 398.15 -513.15 K, in which the molar heat capacities were fitted to two polynomials. The melting point, molar enthalpy and entropy of fusion were determined to be 384.71 K, 28.243 kJ/mol and 73.414 J/( K· mol), respectively. The thermodynamic functions of [ C4 ( MIM ) 2 ] [ PF6 ] 2 relative to the reference temperature 298. 15 K were derived based on the heat capacity data. A group contribution method was used to calculate the molar heat capacity of [ C4 ( MIM )2 ] [ PF6 ]2 in the liquid region. The results showed that the calculated values are in good agreement with the experimental values.

  12. Interaction of Lambda- and Delta-[Ru(bpy)2(pbmz)](PF6)2 with the oligonucleotide duplex d(CGCGAATTCGCG)2.

    Science.gov (United States)

    Papakyriakou, Athanasios; Malandrinos, Gerasimos; Garoufis, Achilleas

    2006-11-01

    The interaction of the enantiomeric complexes Lambda- and Delta-[Ru(bpy)(2)(pbmz)](PF(6))(2) (bpy=2,2'-bipyridine, pbmz=2-(2'-pyridyl)benzimidazole) with the DNA duplex d(CGCGAATTCGCG)(2) was investigated by means of 2D NMR techniques. The synthesis of the enantiomers was based on the optically pure complexes Lambda- and Delta-[Ru(bpy)(2)(py)(2)](2+) and were characterized by CD and NMR spectroscopy. NMR data indicate that both enantiomers bind weakly to the oligonucleotide, approaching from the minor groove at the centre of the helix. The perturbation of the B-DNA conformation is minor with an apparent absence of enantioselectivity. Molecular modelling calculations in conjunction with the NOE data support the suggestion that more than one binding modes are present. The imidazole amine group of the pbmz ligand is probably hydrogen bonded to the DNA phosphodiesteric backbone at the AATT step, and this may provide an explanation for the diminished enantioselectivity observed.

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

    Science.gov (United States)

    Sharma, Anirban; Ghorai, Pradip Kr.

    2016-03-01

    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.

  14. Sodium-ion-conducting polymer nanocomposite electrolyte of TiO2/PEO/PAN complexed with NaPF6

    Science.gov (United States)

    Bhatt, Chandni; Swaroop, Ram; Sharma, Parul Kumar; Sharma, A. L.

    2016-05-01

    A free standing transparent film of solid state polymer electrolyte based on PEO/PAN+NaPF6 with different compositions of nano sized TiO2 in weight percent (x = 0, 1, 2, 5, 10, 15, 20) is synthesized by using standard solution cast technique. The homogeneous surface of above polymer composition is examined by FESEM. The microscopic interaction among polymer, salt and nanoceramic filler has been analyzed by Fourier Transformed Infra-Red (FTIR) spectroscopy. The reduction of ion pair formation in polymeric separator is clearly observed on addition of nanofiller in the polymer salt complex film. Electrical conductivity has been recorded of the prepared polymeric separator which is of the order of ˜10-4 Scm-1 after addition of nanofiller (15% wt/wt) which support the FTIR results. Electrochemical potential window has been observed of the order of ˜6V by the cyclic voltammetry results. The observed data of the prepared separator are at par with the desirable value for device applications

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

    Institute of Scientific and Technical Information of China (English)

    李宝龙; 曹正白; 王寿武; 徐正; 郁开北

    2002-01-01

    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.

  16. Two-phase Beckmann Rearrangement of Cyclohexanone Oxime for Preparing ε-Caprolactam in [bmim] [BF4] Ionic Liquids Using PCl3 as Catalyst%[bmim][BF4]离子液体中PCl3催化的液相贝克曼重排

    Institute of Scientific and Technical Information of China (English)

    张伟; 吴巍; 张树忠; 闵恩泽

    2004-01-01

    在1-丁基-3-甲基咪唑四氟硼酸盐([bmim][BF4])与甲苯组成的两相体系中,以三氯化磷(PCl3)为催化剂,实现了由环己酮肟制备己内酰胺的液相贝克曼重排反应,两相体系有利于反应控制和体系取热.研究了环己酮肟用量、PCl3用量、反应时间和反应温度对重排效果的影响.优化反应条件为:2 ml[bmim][BF4],5 ml甲苯,0.3 ml PCl3,5 ml 2 mol/L环己酮肟-甲苯溶液,90℃,反应时间10~30 min.此时,环己酮肟转化率达98.96%,生成己内酰胺的选择性达87.30%,PCl3催化转化数达2.88.生成的大部分己内酰胺在离子液体相.

  17. [C4mim][BF4]与乙醇胺和N,N-二甲基乙醇胺混合体系的密度、黏度和电导率%Densities,Viscosities and Electrical Conductivities of [C4mim][BF4],MEA and DMEA

    Institute of Scientific and Technical Information of China (English)

    耿彦芳; 刘鑫; 虞大红; 彭昌军; 刘洪来

    2009-01-01

    分别采用比重瓶、乌氏黏度计和电导率仪测定了1-丁基-3-甲基咪唑四氟硼酸盐([C4mim][BF4])+乙醇胺(MEA)和[C4mim][BF4]+N,N-二甲基乙醇胺(DMEA)两种二元混合物在283.15~323.15 K时的密度、黏度和电导率.用Redlich-Kister方程关联并计算了混合体系的过量摩尔体积和黏度偏差.通过电导率的实验结果计算得到了混合体系的摩尔电导率,证明有机溶剂摩尔含量对混合体系摩尔电导率的贡献符合Walden规则.

  18. L-Proline Catalyzed Michael Additions of Thiophenols to α,β-Unsaturated Compounds, Particularly α-Enones, in the Ionic Liquid [bmim]PF6

    Directory of Open Access Journals (Sweden)

    Stefan Toma

    2006-03-01

    Full Text Available L-Proline catalyzed additions of 13 different thiols to 11 different α-enoneMichael acceptors in [bmim] PF6 are reported. Reasonable to high yields of the reactionproducts were isolated in most cases.

  19. Thermal stability, complexing behavior, and ionic transport of polymeric gel membranes based on polymer PVdF-HFP and ionic liquid, [BMIM][BF4].

    Science.gov (United States)

    Shalu; Chaurasia, S K; Singh, R K; Chandra, S

    2013-01-24

    PVdF-HFP + IL(1-butyl-3-methylimidazolium tetrafluoroborate; [BMIM][BF(4)]) polymeric gel membranes containing different amounts of ionic liquid have been synthesized and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared (FTIR), differential scanning calorimetry, thermogravimetric analysis (TGA), and complex impedance spectroscopic techniques. Incorporation of IL in PVdF-HFP polymer changes different physicochemical properties such as melting temperature (T(m)), thermal stability, structural morphology, amorphicity, and ionic transport. It is shown by FTIR, TGA (also first derivative of TGA, "DTGA") that IL partly complexes with the polymer PVdF-HFP and partly remains dispersed in the matrix. The ionic conductivity of polymeric gel membranes has been found to increase with increasing concentration of IL and attains a maximum value of 1.6 × 10(-2) S·cm(-1) for polymer gel membrane containing 90 wt % IL at room temperature. Interestingly, the values of conductivity of membranes with 80 and 90 wt % of IL were higher than that of pure IL (100 wt %). The polymer chain breathing model has been suggested to explain it. The variation of ionic conductivity with temperature of these gel polymeric membranes follows Arrhenius type thermally activated behavior.

  20. Using hydrophilic ionic liquid, [bmim]BF4-ethylene glycol system as a novel media for the rapid synthesis of copper nanoparticles.

    Directory of Open Access Journals (Sweden)

    Manika Dewan

    Full Text Available In this work, we present a novel method for the synthesis of copper nanoparticles. We utilize the charge compensatory effect of ionic liquid [bmim]BF(4 in conjunction with ethylene glycol for providing electro-steric stabilization to copper nanoparticles prepared from copper sulphate using hydrazine hydrate as a reducing agent. The formed copper nanoparticles showed extended stability over a period of one year. Copper nanoparticles thus prepared were characterized by powder X-ray diffraction measurements (pXRD, transmission electron microscopy (TEM and quasi elastic light scattering (QELS techniques. Powder X-ray diffraction (pXRD analysis revealed relevant Bragg's reflection for crystal structure of copper. Powder X-ray diffraction plots also revealed no oxidized material of copper nanoparticles. TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical applications of copper nanoparticles include uses in conductive films, lubrication and nanofluids. Currently efforts are under way in our laboratory for using these nanoparticles as catalysts for a variety of organic reactions.

  1. Using hydrophilic ionic liquid, [bmim]BF4-ethylene glycol system as a novel media for the rapid synthesis of copper nanoparticles.

    Science.gov (United States)

    Dewan, Manika; Kumar, Ajeet; Saxena, Amit; De, Arnab; Mozumdar, Subho

    2012-01-01

    In this work, we present a novel method for the synthesis of copper nanoparticles. We utilize the charge compensatory effect of ionic liquid [bmim]BF(4) in conjunction with ethylene glycol for providing electro-steric stabilization to copper nanoparticles prepared from copper sulphate using hydrazine hydrate as a reducing agent. The formed copper nanoparticles showed extended stability over a period of one year. Copper nanoparticles thus prepared were characterized by powder X-ray diffraction measurements (pXRD), transmission electron microscopy (TEM) and quasi elastic light scattering (QELS) techniques. Powder X-ray diffraction (pXRD) analysis revealed relevant Bragg's reflection for crystal structure of copper. Powder X-ray diffraction plots also revealed no oxidized material of copper nanoparticles. TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical applications of copper nanoparticles include uses in conductive films, lubrication and nanofluids. Currently efforts are under way in our laboratory for using these nanoparticles as catalysts for a variety of organic reactions.

  2. 高压下NH4ClO4结构、电子及弹性性质的第一性原理研究%First principles investigations of structural, electronic and elastic prop erties of ammonium p erchlorate under high pressures

    Institute of Scientific and Technical Information of China (English)

    刘博; 王煊军; 卜晓宇

    2016-01-01

    Ammonium perchlorate (NH4ClO4) is a highly energetic oxidizer widely used in solid propellants and explosives. Under extreme pressure conditions, significant changes are observed in the structures and properties of NH4ClO4. How-ever, many studies of structural transformations of NH4 ClO4 under high pressures have not formed a more consistent conclusion. In this study, the structural, electronic, and elastic properties of NH4ClO4 are investigated by first-principles calculations based on the density functional theory with dispersion correction (DFT-D) method in a range of 0–15 GPa. The unit cell volume and lattice parameters are optimized by GGA/PBE-TS, which leads to good agreement with the experimental structure parameters at 0 GPa, suggesting the reliability of the present calculation method. The calculated P-V data are fitted to the third-order Birch-Murnaghan equation of state, and the result provides better agreement with experimental result than other calculations for the unit cell with a volume V0 and bulk moduli B0 and B′. The comprehensive analyses of the lattice parameters, bond lengths, and hydrogen bonds under high pressure indicate that three structural transformations occur in NH4ClO4 at 1 GPa, 4 GPa, and 9 GPa. With increasing pressure, hydrogen bonding interaction gradually increases, and intra- and intermolecular hydrogen bonds are present in crystals. Results obtained from the band structures and state densities under high pressure indicate that NH4ClO4 exhibits good insu-lating properties. Valence band shifts towards low energy, conduction band shifts towards high energy, and electronic localization is enhanced. The charge density differences and Mulliken charge populations at different pressures reveal that the covalent interaction between the N—H and Cl—O bonds increases, and the ionicity of crystal decreases. The band gaps in different structural transition regions exhibit different linear increase trends with increasing pressure. The calculated elastic constants of NH4ClO4 satisfy elastic stability criteria of orthorhombic systems at pressures ranging from 0 GPa to 15 GPa, indicating that NH4ClO4 is mechanically stable. The bulk modulus, shear modulus, and Young’s modulus are estimated by the Voigt-Reuss-Hill approach. The Cauchy pressures and B/G values indicate that NH4ClO4 exhibits ductility, attributed to the fact that NH4ClO4 is an ionic crystal, and ionic bonds are non-directional bonds;hence, NH4ClO4 is ductile and can be easily bended or reshaped. The results indicate that the ductility properties of NH4ClO4 increase with increasing pressure. All calculated properties are in excellent agreement with the available ex-perimental results. These results will not only help to understand the structural transformations of NH4ClO4 under high pressures but also provide an important theoretical reference for the safe application of NH4ClO4 in solid propellants and explosives.

  3. Lanthanide Complex[Xd(dpdo)4(H2O)3][ClO4]3·4.5H2O·dpdo Containing Framework Based on 4,4′—Dipyradine—Dioxide

    Institute of Scientific and Technical Information of China (English)

    马宝清; 孙豪岭; 等

    2002-01-01

    A novel lanthanide coordination polymer formulated as [Nd(dpdo)4(H2O)3][ClO4]4·4.5H2O·dpdo1(dpdo=4,4′-dipyrazine-dioxide)was synthesized and structurally characterized.The Nd3+ions are bridged by dpdo ligands in a cis-mode to form a zigzag chain along[001]direction.Meanwhile,each Nd3+ion is coordinated with three terminal dpdo molecules.One of them is overlapped with the bridging one throughπ-πstackings,and the orher wto are bound to the opposite directions of the bridging ones,producing a ribbon-like motif with rectangular cavity,These adjacent ribbons are connected thorough inter-molecularπ-πstackings to give parquet-like architecture with a large rectangular channel(1.108nm×1.660nm)in which the crystal lattice water molecules and ClO-4anions are included.Thermalanalysis shows that the solvate dpdo and water molecules can be removed at lower temperature,while coordinated dpdo molecules are lost simultaneously at higher temperature.

  4. Electrochemical behaviors of Fenbendazole at graphene and[ Bupy] PF6 modified carbon paste electrode and its electrochemical determination%芬苯达唑在石墨烯与[ Bupy ] PF6复合修饰碳糊电极上的电化学性质及电分析方法研究

    Institute of Scientific and Technical Information of China (English)

    田碧桃; 李金来; 王维; 犹卫; 彭娟; 高作宁

    2015-01-01

    本文研究了芬苯达唑( Fenbendazole,FBZ)在石墨烯( RGO)与离子液体( N-丁基吡啶六氟磷酸盐)复合修饰碳糊电极上的电催化氧化及电化学动力学性质。同时用CC法(计时库仑法)、计时电流法( CA)测定FBZ在RGO-[ Bupy] PF6/CPE上的电极反应动力学参数,并用方波伏安法( SWV)测定FBZ氧化峰电流( Ip )与其浓度c在4.0×10-8~1.0×10-5mol·L-1范围内呈良好线性关系,线性回归方程为Ip(μA)=1.471+5220.78c (10-3mol·L-1),R=0.9995,检测限(S/N=3)为1.4×10-9mol·L-1,在此基础上用SWV法对FBZ片剂中FBZ含量进行了电化学定量测定,RSD在0.2%~0.9%之间,回收率在99.0%~101.4%之间。%Objective:Electrocatalytic oxidation and its electrochemical kinetics of fenbendazole( FBZ) were investigated by Cyclic voltammetry(CV)method at carbon paste electrode(CPE)which modified by graphene(RGO)and [Bupy]PF6. The experiment re-sults indicated that FBZ electrochemical behaviors exhibits an irreversible electrochemical oxidation progress at RGO-[ Bupy] PF6/CPE,The electrochemical kinetic parameters were determined by chronocoulometry ( CC) and chronoamperometry ( CA) at RGO-[ Bupy] PF6/CPE. The oxidation peak current of FBZ versus its concentration had a good linear relationship in the concentration range of 4. 0 × 10-8 ~1. 0 × 10-5 mol·L-1and the detection limit(S/N=3)was 1. 4 × 10-9mol·L-1 by square wave voltammetric (SWV)method. The equation of linear regression was Ip(μA)=1. 471+5220. 78c(10-3mol·L-1),R=0. 9995,Also the proposed method have been applied in electrochemical quantitative determination of FBZ content in commercial tablet samples,with their rel-ative standard deviations of 0. 2% ~0. 9%and recoveries of 99. 0% ~101. 4%.

  5. The self-assembled Ru(bpy)3(PF6)2 nanoparticle on polystyrene microfibers and its application for ECL sensing.

    Science.gov (United States)

    Luo, Jiaojiao; Zhou, Cuisong; Shi, Yalin; Zhang, Lei; Xiao, Dan

    2013-10-21

    Ruthenium nanoparticle tris(2,2'-bipyridyl)ruthenium(II) bis(hexafluorophosphate) (Ru(bpy)3(PF6)2, RuNP) was self-assembled on polystyrene (PS) electrospun microfibers. The formation of RuNP is attributed to the sulfonated PS (SPS) microfibers' high adsorptive capability of 94% for Ru(bpy)3(2+), as well as the strong interaction between the Ru(bpy)3(2+) and ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, BMIMPF6). The RuNP/SPS microfibers exhibited an enhanced electrochemiluminescence (ECL) emission, 2.3 times higher than that from Ru(bpy)3(2+)/SPS microfibers and 6.6 times higher than that from Ru(bpy)3(2+)/SPS continuous thin films. It is worthy of note that, as a result of the hydrophobic nature of the RuNP, the transfer of water-insoluble α-naphthol is accelerated, and thus the α-naphthol ECL quenching efficiency is enhanced. An ECL sensor based on the RuNP/SPS microfibers was fabricated and used to detect low concentrations of α-naphthol. The detection limit was of 1.0 nM (S/N > 3), and the linear response ranged from 0 to 18 μM. This sensor has been successfully applied to measure the α-naphthol content in pesticide carbaryl samples. Our work provides a very simple and cost-effective method to fabricate RuNP on polymer microfibers with great potential in the field of chemo/biosensors.

  6. Interfacial Design of Ternary Mixed Matrix Membranes Containing Pebax 1657/Silver-Nanopowder/[BMIM][BF4] for Improved CO2 Separation Performance.

    Science.gov (United States)

    Ghasemi Estahbanati, Ehsan; Omidkhah, Mohammadreza; Ebadi Amooghin, Abtin

    2017-03-08

    In this research, Pebax1657 as an organic phase and silver nanoparticles as an inorganic phase were used for preparation of binary mixed matrix membranes (MMMs). Silver nanoparticles as a filler could enter the polymer chains and enhance the gas permeability by increasing the fractional free volume of membranes. Afterward, ternary MMMs were fabricated by addition of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid, in order to have better polymer/filler adhesion and eliminate interfacial defects and nonselective voids. In addition, positively polarized silver nanoparticles in the presence of the IL could interact with PEO segment of the polymer and increase the CO2 affinity of membranes, which results in increasing the CO2/light gases permselectivity of MMMs. Gas permeation properties of MMMs were studied at a temperature of 35 °C and operating pressures from 2 to 10 bar. Moreover, fabricated membranes were characterized by fourier transform infrared-attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). The analysis revealed that there is a proper adhesion between positively charged surface of nanoparticles and the polymer, and both filler and IL decrease the crystallinity of the membranes, which could enhance the polar gas transport properties. Gas permeation results showed significant enhancement in CO2 permeability (325 Barrer) for binary membrane (Pebax 1657/1%Ag) at 35 °C and 10 bar. Moreover, ternary MMM (Pebax 1657/0.5%Ag/50%IL) encountered significant increase in both permeability and selectivity in comparison with neat membrane. Indeed, the CO2 permeability increased from 110 Barrer to 180 (about 64%). Moreover, the related CO2/CH4 and CO2/N2 selectivities were increased from 20.8 to 61.0 (more than 193%) and from 78.6 to 187.5 (about 139%), respectively.

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

    Science.gov (United States)

    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

    2016-01-01

    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.

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

    Science.gov (United States)

    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

    2016-06-01

    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 (<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.

  9. Optical characterization of 2 kF bond-charge-density wave in quasi-one-dimensional 3 /4 -filled (EDO-TTF)2 X ( X= PF6 and AsF6 )

    Science.gov (United States)

    Drozdova, Olga; Yakushi, Kyuya; Yamamoto, Kaoru; Ota, Akira; Yamochi, Hideki; Saito, Gunzi; Tashiro, Hidenori; Tanner, David B.

    2004-08-01

    We present the electronic and vibrational spectra of quasi-one-dimensional (3)/(4) -filled (EDO-TTF)2X ( EDO-TTF=ethylenedioxy-tetrathiafulvalene , X=PF6 and AsF6 ) above and below the metal-insulator phase transition ( TMI=280K for the PF6 salt and 268K for the AsF6 salt). For the low-temperature insulating phase, the pattern of both bond and charge order was identified. Almost all charge density is localized on the strongly bound central pair of 0110 tetramer giving rise to a characteristic spectrum of electronic excitations. Infrared spectra along the stacking axis show evidence of strong electron-molecular vibration coupling between the charge transfer band within the pair and some specific intramolecular vibrations. This charge order is assisted by a molecular deformation.

  10. Measurement and estimation of heat capacity of dicationic ionic liquid [C3 ( MIM)2][PF6]2%双阳离子型离子液体[C3(MIM)2][PF6]2的热容测定及估算

    Institute of Scientific and Technical Information of China (English)

    杨许召; 王军; 孙新科

    2011-01-01

    利用差示扫描热量计(DSC)测定了双阳离子型离子液体1,1′-(丙烷-1,3-二基)-双(3-甲基-1H-咪唑鎓-1-基)双六氟磷酸盐([C3(MIM)2][PF6]2)在293.15-543.15 K温区内的摩尔热容.实验结果表明:在293.15-403.15 K和433.15-543.15 K温区内,该化合物无相变及其他热异常现象发生,将实验数据拟合得到了该化合物热容随温度变化的多项式方程.其熔化温度、熔化焓及熔化熵分别为416.83 K,38.256 kJ/mol和91.778 J/(K·mol).由热容数据计算出其在固相区和液相区相对于标准参考温度298.15 K的热力学函数值.采用基团贡献法对433.15-543.15 K温区的热容进行了估算,为该离子液体的工业应用提供了热力学基础数据.%The molar heat capacity of dicationic ionic liquid 1, 1'-( propane-1, 3-diyl)-bis (3-methyl-1Himidazolium-1-yl) dihexafluorophosphate ( [C3 ( MIM )2][PF6]2 ) was measured with differential scanning calorimeter(DSC) at 293.15-543.15 K.The results show that no phase transition or other thermal anomaly is observed in the range of 293.15-403.15 K and 433.15-543.15 K, in which the molar heat capacities are fitted to polynomials.The fusing temperature, molar enthalpy and entropy of fusion are 416.83 K, 38.256 kJ/mol and 91.778 J/(K· mol), respectively.The thermodynamic functions relative to the standard reference temperature 298.15 K were derived based on the heat capacity data.A group contribution method was used to calculate its molar heat capacity from 433.15 to 543.15 K.The basic data are helpful for its industrial application.

  11. The role of carboxylato ligand dissociation in the oxidation of chrysin with H2O2 catalysed by [Mn-2 (III, IV)(mu-CH3COO)(mu-O)(2)(Me(4)dtne)](PF6)(2)

    NARCIS (Netherlands)

    Abdolahzadeh, Shaghayegh; Boyle, Nicola M.; Hoogendijk, M. Lisa; Hage, Ronald; de Boer, Johannes W.; Browne, Wesley R.

    2014-01-01

    The aqueous and non-aqueous chemistry of the complex [Mn-2 (III,IV)(mu-CH3COO)(mu-O)(2)(Me(4)dtne)](PF6)(2) (where Me(4)dtne = 1,2-bis(4,7-dimethyl- 1,4,7-triazacyclonon-1-yl) ethane), which has been demonstrated as an exceptionally active catalyst in the bleaching of raw cotton and especially wood

  12. 甲苯/TX-100/1-丁基-3-甲基咪唑六氟磷酸盐微乳液的相结构研究%Phase structure of toluene/TX-100/[bmim][PF6] microemulsions

    Institute of Scientific and Technical Information of China (English)

    雷达; 范芳; 严建芳

    2007-01-01

    在25 ℃时用相态观察法研究了甲苯/TX-100/[bmim][PF6]三元体系的相结构,结果表明此体系存在单相微乳液区和两相区.用电导法和渗滤器模型进一步确定了甲苯/TX-100/[bmim][PF6]单相微乳液区的微结构,表明了在甲苯/TX-100/[bmim][PF6]单相微乳液区内包括[bmim][PF6]/甲苯、双连续相、甲苯/[bmim][PF6]3种微结构.

  13. Highly efficient extraction and oxidative desulfurization system using Na7H2LaW10O36⋅32 H2O in [bmim]BF4 at room temperature.

    Science.gov (United States)

    Xu, Junhua; Zhao, Shen; Chen, Wei; Wang, Miao; Song, Yu-Fei

    2012-04-10

    Highly efficient, deep desulfurization of model oil containing dibenzothiophene (DBT), benzothiophene (BT), or 4,6-dimethyldibenzothiophene (4,6-DMDBT) has been achieved under mild conditions by using an extraction and catalytic oxidative desulfurization system (ECODS) in which a lanthanide-containing polyoxometalate Na(7)H(2)LnW(10)O(36)⋅32 H(2)O (LnW(10); Ln = Eu, La) acts as catalyst, [bmim]BF(4) (bmim = 1-butyl-3-methylimidazolium) as extractant, and H(2)O(2) as oxidant. Sulfur removal follows the order DBT>4,6-DMDBT>BT at 30 °C. DBT can be completely oxidized to the corresponding sulfone in 25 min under mild conditions, and the LaW(10)/[bmim]BF(4) system could be recycled for ten times with only slight decrease in activity. Thus, LaW(10) in [bmim]BF(4) is one of the most efficient systems for desulfurization using ionic liquids as extractant reported so far.

  14. Anion effects in the scattering of CO2 from the room-temperature ionic liquids [bmim][BF4] and [bmim][Tf2N]: insights from quantum mechanics/molecular mechanics trajectories.

    Science.gov (United States)

    Li, Xiaohu; Schatz, George C; Nesbitt, David J

    2012-03-22

    Quantum mechanics/molecular mechanics (QM/MM) molecular dynamics simulations have been carried out to model the scattering of hyperthermal (15 kcal/mol) CO(2) on the surfaces of two common imidazolium based room-temperature ionic liquids (RTILs) [bmim][BF4] and [bmim][Tf2N]. Good agreement was achieved in comparison with experiment. The [bmim][BF4] surface is found to be more absorptive of CO(2) than [bmim][Tf2N], which leads to greater loss in translational energy and less rotational excitation of CO(2)'s that scatter from [bmim][BF4]. These differences are found to result from a interplay of differences in the structure of the interface and the strength of interactions that depend on anion identity. Our results also suggest that CO(2) interacts strongly with ionic species on the RTIL surfaces due to the large induced dipole moments on CO(2) during the collisions. The inclusion of electronic polarization is critical in determining the final rotational excitation of CO(2) compared to results from an MM model with fixed charge.

  15. Desulfurization of Diesel Fuel by Extraction with [BF4]- -based Ionic Liquids%四氟硼酸盐类离子液体对典型柴油的萃取脱硫研究

    Institute of Scientific and Technical Information of China (English)

    褚雪梅; 胡玉峰; 李吉广; 梁倩卿; 刘艳升; 张先明; 彭效明; 岳文佳

    2008-01-01

    The extractive removal of sulfur compounds (S-compounds) from Dongying and Liaohe diesel fuels with [BF4]--based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 : 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels.

  16. Thermochemistry on the Complex of Erbium Perchlorate with L-α-Glutamic Acid [Er2(L-Glu)2(H2O)6](ClO4)4·6H2O(s)

    Institute of Scientific and Technical Information of China (English)

    DI, You-Ying; ZHANG, Jian; TAN, Zhi-Cheng

    2007-01-01

    A coordination compound of erbium perchlorate with L-α-glutamic acid, [Er2(Glu)2(H2O)6](ClO4)4·6H2O(s),was synthesized. By chemical analysis, elemental analysis, FTIR, TG/DTG, and comparison with relevant literatures, its chemical composition and structure were established. The mechanism of thermal decomposition of the complex was deduced on the basis of the TG/DTG analysis. Low-temperature heat capacities were measured by a precision automated adiabatic calorimeter from 78 to 318 K. An endothermic peak in the heat capacity curve was observed over the temperature region of 290-318 K, which was ascribed to a solid-to-solid phase transition. The temperature Ttrans, the enthalpy △transHm and the entropy △transSm of the phase transition for the compound were determined to be: (308.73±0.45) K, (10.49±0.05) kJ·mol-1 and (33.9±0.2) J·K-1·mol-1. Polynomial equation of heat capacities as a function of the temperature in the region of 78-290 K was fitted by the least square method.Standard molar enthalpies of dissolution of the mixture [2ErCl3·6H2O(s)+2L-Glu(s)+6NaClO4·H2O(s)] and the mixture { [Er2(Glu)2(H2O)6](ClO4)4·6H2O(s)+6NaCl(s)} in 100 mL of 2 mol·dm-3 HClO4 as calorimetric solvent,and {2HClO4(l)} in the solution A'at T=298.15 K were measured to be, △dHm,1=(31.552±0.026) kJ·mol-1,△dHm,2=(41.302±0.034) kJ·mol-1, and △dHm,3 = (14.986 ± 0.064) kJ·mol-1, respectively. In accordance with Hess law, the standard molar enthalpy of formation of the complex was determined as △fH(-)m = -(7551.0± 2.4) kJ· mol -1 by using an isoperibol solution-reaction calorimeter and designing a thermochemical cycle.

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

    Science.gov (United States)

    Timm, Matthew J; Matta, Chérif F

    2014-12-01

    Argon tetroxide (ArO4) is the last member of the N=50 e(-) isoelectronic and isosteric series of ions: SiO4(4-), PO4(3-), SO4(2-), and ClO4(-). A high level computational study demonstrated that while ArO4 is kinetically stable it has a considerable positive enthalpy of formation (of ~298kcal/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 (38)Cl to the stable rare argon isotope (38)Ar 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((3)P) from which the predicted barrier to dissociation is ca. 22kcal/mol and the exothermic reaction energy is ca. 28kcal/mol [(U)MP2/6-311+G(d)].

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

    Science.gov (United States)

    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

    2016-01-01

    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 (<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.

  19. Analysis of antibacterial activity and mechanism of polypyridyl ruthenium complex%多吡啶钌配合物[(Phen)2 Ru(dppz)](PF6)2的抗菌活性及机制研究

    Institute of Scientific and Technical Information of China (English)

    刘汉杰; 付彬; 付爱玲; 付琛

    2016-01-01

    目的:研究多吡啶钌配合物[(Phen)2Ru(dppz)]( PF6)2的抗菌活性,并进一步探讨其作用机制。方法采用最小抑菌浓度( MIC)以及最小杀菌浓度( MBC),测定无机配合物[( Phen)2 Ru( dppz)]( PF6)2的抗菌活性。为了阐明其抗菌机制,首先利用配合物自身荧光特性和核酸染料对DNA的竞争性结合所导致的荧光强度变化,以确定配合物与DNA的结合能力;然后通过DNA凝胶电泳,检测配合物与细菌基因组DNA结合后产生的效果以检测抗菌活性的机制。结果多吡啶钌配合物[(Phen)2Ru(dppz)](PF6)2对大肠杆菌以及金黄色葡萄球菌具有较强的抗菌活性,最小抑菌浓度达0.2~0.4 g·L-1。荧光检测显示,配合物能够与细菌DNA发生结合,以此为基础,配合物能够干扰细菌的转录过程,抑制细菌生长。结论本研究证明了多吡啶钌配合物[( Phen)2 Ru( dppz)]( PF6)2的抗菌活性及作用机制,为其进一步开发奠定了基础。%Aim To analyze the antibiotic activity and mechanism of a polypyridyl ruthenium complex. Meth-ods The antibacterial activity of [ ( Phen ) 2 Ru ( dp-pz) ] ( PF6 ) 2 was determined by MIC and MBC value. Based on a fluorescent activity of this complex, the flu-orescent emission spectra was used to analyze the com-bination of complex to DNA. Then the competition combination was analyzed between complex and Gold View to DNA. Lastly, gel electrophoresis of DNA was applied to detect the combination situation between complex and DNA. Results This kind of polypyridyl ruthenium complex showed a significant antibacterial activity with a minimum antibacterial conentration of 0. 2~0. 4 g · L-1 . That was caused by the combina-tion and distortion of DNA due to the activity of this complex. Conclusion The antibacterial activity and the mechanism of antibacterial activity about [ ( Phen) 2 Ru( dppz) ] ( PF6 ) 2 are confirmed in this re-search, which provides a good foundation for the

  20. Assembly of a new family of mercury(II) zwitterionic thiolate complexes from a preformed compound [Hg(Tab)2](PF6)2 [Tab = 4-(trimethylammonio)benzenethiolate].

    Science.gov (United States)

    Chen, Jin-Xiang; Zhang, Wen-Hua; Tang, Xiao-Yan; Ren, Zhi-Gang; Zhang, Yong; Lang, Jian-Ping

    2006-03-20

    Reactions of Hg(OAc)2 with 2 equiv of TabHPF6 [TabH = 4-(trimethylammonio)benzenethiol] in MeCN/MeOH afforded a mononuclear linear complex [Hg(Tab)2](PF6)2 (1). By using 1 as a precursor, a new family of mercury(II) zwitterionic thiolate complexes, [Hg2(Tab)6](PF6)4.2MeCN (2.2MeCN), [Hg(Tab)2(SCN)](PF6) (3), [Hg(Tab)2(SCN)2] (4), [Hg(Tab)I2] (5), {[Hg(Tab)2]4[HgI2][Hg2I6]}(PF6)2(NO3)4 (6), [Hg(Tab)2][HgI4] (7), [Hg(Tab)2][HgCl2(SCN)2] (8), [Tab-Tab]2[Hg3Cl10] (9), and [Hg2(Tab)6]3(PF6)Cl11 (10), were prepared and characterized by elemental analysis, IR spectra, UV-vis spectra, 1H NMR, and single-crystal X-ray crystallography. The [Hg2(Tab)6]4+ tetracation of 2 or 10 contains an asymmetrical Hg2S2 rhomb with an inversion center lying on the midpoint of the Hg...Hg line. The Hg atom of the [Hg(Tab)2]2+ dication of 3 is coordinated to one SCN-, forming a rare T-shaped coordination geometry, while in 4, the Hg atom of [Hg(Tab)2]2+ is coordinated to two SCN-, forming a seesaw-shaped coordination geometry. Through weak secondary Hg...S coordinations, each cation in 3 is further linked to afford a one-dimensional zigzag chain. The trigonal [Hg(Tab)I2] molecules in 5 are held together by weak secondary Hg...I and Hg...S interactions, forming a one-dimensional chain structure. In 6, the four [Hg(Tab)2]2+ dications, one HgI2 molecule, one [Hg2I6]2- dianion, one PF6-, and four NO3- anions are interconnected by complicated secondary Hg...I and Hg...O interactions, forming a scolopendra-like chain structure. The secondary Hg...I interactions, [Hg(Tab)2]2+ and [HgI4]2- in 7, are combined to generate a one-dimensional chain structure, while [Hg(Tab)2]2+ and [HgCl2(SCN)2]2- in 8 are interconnected by secondary Hg...N interactions to form a one-dimensional zigzag chain structure. Compound 9 consists of two [Tab-Tab]2+ dications and one [Hg3Cl10]4- tetraanion. The facile approach to the construction of 2-8 and 10 from 1 may be applicable to the mimicking of a coordination sphere of

  1. Solvato-polymorph of [(η6-C6H6)RuCl (L)]PF6 (L = (2,6-dimethyl-phenyl-pyridin-2-yl methylene amine)

    Science.gov (United States)

    Gichumbi, Joel M.; Friedrich, Holger B.; Omondi, Bernard

    2016-06-01

    A half-sandwich complex salt of ruthenium containing the Schiff base ligand, 2, 6-dimethyl-N-(pyridin-2-ylmethylene)aniline has been synthesized and structurally characterized. The complex salt 1, [(η6-C6H6)RuCl(C5H4NCHdbnd N(2,6-(CH3)2C6H3)]PF6 was obtained from the reaction of the ruthenium arene precursor, [(η6- C6H6)Ru(μ-Cl)Cl]2 with the Schiff base in a 1:2 ratio followed by treatment with NH4PF6. Its acetone solvate 2, [(η6-C6H6)RuCl(C5H4NCHdbnd N (2, 6- (CH3)2C6H3)]PF6. (CH3)2CO was obtained by recrystallization of 1 from a solution of hexane and acetone. 1 and 2 crystallize in the monoclinic P21/c and P21/n space groups as blocks and as prisms respectively. The ruthenium centers in 1 and 2 are coordinated to the bidentate Schiff base, to a chloride atom, and to the arene ring to give a pseudo-octahedral geometry around them. The whole arrangement is referred to as the familiar three-legged piano stool in which the Schiff base and the Cl atom serve as the base while the arene ring serve as the apex of the stool. Polymorph 2 has an acetone molecule in the asymmetric unit. Of interest is the similar behavior of the solvate on heating which shows the crystals shuttering at about 531.6 and 523.4 K for 1 and 2 respectively.

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

    Institute of Scientific and Technical Information of China (English)

    WU XinMin; LI Wei; TAN ZhiCheng; QU SongSheng

    2009-01-01

    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.

  3. Synthesis and X-ray structure of nickel(II) benzylpiperazine-dithiocarbamate complex [Ni(bpdtc)(PPh3)2]ClO4·PPh3

    Science.gov (United States)

    Trávníček, Zdeněk; Štarha, Pavel; Pastorek, Richard

    2013-10-01

    A mixed-ligand nickel(II) dithiocarbamate complex of the composition [Ni(bpdtc)(PPh3)2]ClO4·PPh3 was synthesized, characterized (elemental analysis, UV-Vis, IR and NMR spectroscopy and molar conductivity measurements) and its X-ray structure was determined. The three ligands are arranged in a distorted square-planar geometry (an S2P2 donor set), with the bond lengths and angles within the vicinity of the central atom as follows: Nisbnd P = 2.2150(6) and 2.2529(6) Å, Nisbnd S = 2.2267(6) and 2.2129(6) Å, Psbnd Nisbnd P = 105.11(2)°, Ssbnd Nisbnd S = 78.26(2)°. The Psbnd Nisbnd P angle of the studied complex falls outside the interval of 98.37-102.92° determined for thirteen formerly reported structural analogues involving the [Ni(ndtc)(PPh3)2]+ moiety with a combination of dithiocarbamate (ndtc) and triphenylphosphine (PPh3) ligands. In the crystal, the complex cations, perchlorate anions and PPh3 molecules of crystallization are linked through intramolecular Csbnd H⋯O and Csbnd H⋯π and intermolecular Csbnd H⋯O, Csbnd H⋯C and Csbnd H⋯π contacts to a three-dimensional architecture.

  4. Synthesis and Crystal Structure of Complex {[Cu(N-men)2(cda)2]·[Cu(N-men)2]((ClO4)2}(N-men = N-Methylethylenediamine,cda = Carbamyldicyanomethanide Anion)

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Mononuclear complex {[Cu(N-men)2(cda)2]([Cu(N-men)2]((ClO4)2} was synthesized by sodium carbamyldicyanomethanide Na(cda), N-methylethylenediamine and hydrate copper perchlorate. The crystal belongs to the triclinic system, space group P ī with a = 7.229(2), b = 8.114(2), c = 15.936(4) (A), α = 80.511(4), β = 78.993(4), γ= 72.118(4)o, V = 867.6(3)(A)3, Z = 1, C20H44Cl2Cu2N14O10, Mr = 838.68, Dc = 1.605 g/cm3, F(000) = 434 and μ = 1.449 mm-1. The structure was refined to R = 0.0480 and wR = 0.1289 for 2503 observed reflections (I > 2σ(I)). In the complex there exist two kinds of coordination models for Cu (Ⅱ) ions. One is that the Cu (Ⅱ) ion is coordinated by four nitrogen atoms which are from two N-men molecules, and a slightly distorted square planar coordinate environment is formed around the Cu (Ⅱ) ion; the other is that the Cu (Ⅱ) ion is coordinated by six nitrogen atoms, of which four are from two N-men molecules and the left from nitrile groups, resulting in a distorted octahedron around the Cu (Ⅱ) ion. The deposition number of the crystal at CCDC is 161868.

  5. Synthesis, crystal structure and properties of binuclear manganese complex [(bipy)2Mn2(μ-O)(μ-Ac)2(H2O)2](ClO4)2

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Binuclear manganese complex [(bipy)2Mn2(μ-O)(μ-Ac)2(H2O)2](ClO4)2 was synthesized by the reaction of MnAc3·2H2O with 2,2′- -bipyridine in the HAc-NaAc buffer (pH = 4.0). X-ray diffraction result for the single crystal shows that the crystal is monoclinic, space group C2/C, with a = 3.408 2(7), b = 0.864 4(2), c = 2.174 9(4) nm, β=105.2°,V =6.186(2) nm3, Z = 8. There are two very strong peaks of UV-Vis spectrum in the range of 400-600 nm, which are similar to those of Mn catalase and Mn ribonuleotide reductase extracted from organisms. Cyclic voltammogram shows that the complex in CH3CN undergoes quasi-reversible one-electron reduction and oxidation at E1/2=1.15 V.

  6. An Efficient and Green One-pot Synthesis of 12-Aryl-8,9,10,12-tetra hyd robenzo[a]xanthen-11 -one Deriva- tives Promoted by Sulfamic Acid in [BMIM]BF4 Ionic Liquid

    Institute of Scientific and Technical Information of China (English)

    Zang, Hongjun; Zhang, Yong; Cheng, Bowen; Zhang, Weiwei; Xu, Xianlin; Ren, Yuanlin

    2012-01-01

    An efficient and green procedure for the synthesis of novel 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen- 11- one derivatives has been described through one-pot condensation of 2-naphthol, arylaldehyde and 5,5-dimethyl- cyclohexane-l,3-dione in the presence of sulfamic acid (NH2SO3H) in ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4). These reactions proceed with good yields under short reaction time. Furthermore, the green catalytic system can be recycled specific times with no decreases in yields and reaction rates.

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

    Directory of Open Access Journals (Sweden)

    Monika Bakierska

    2016-01-01

    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.

  8. 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.

    Science.gov (United States)

    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

    2016-08-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Yutaka Nishio

    2012-11-01

    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.

  10. Synthesis, structure and gas-phase reactivity of the mixed silver hydride borohydride nanocluster [Ag3(μ3-H)(μ3-BH4)L(Ph)3]BF4 (L(Ph) = bis(diphenylphosphino)methane).

    Science.gov (United States)

    Zavras, Athanasios; Ariafard, Alireza; Khairallah, George N; White, Jonathan M; Mulder, Roger J; Canty, Allan J; O'Hair, Richard A J

    2015-11-21

    Borohydrides react with silver salts to give products that span multiple scales ranging from discrete mononuclear compounds through to silver nanoparticles and colloids. The cluster cations [Ag3(H)(BH4)L3](+) are observed upon electrospray ionization mass spectrometry of solutions containing sodium borohydride, silver(I) tetrafluoroborate and bis(dimethylphosphino)methane (L(Me)) or bis(diphenylphosphino)methane (L(Ph)). By adding NaBH4 to an acetonitrile solution of AgBF4 and L(Ph), cooled to ca. -10 °C, we have been able to isolate the first mixed silver hydride borohydride nanocluster, [Ag3(μ3-H)(μ3-BH4)L(Ph)3]BF4, and structurally characterise it via X-ray crystallography. Combined gas-phase experiments (L(Me) and L(Ph)) and DFT calculations (L(Me)) reveal how loss of a ligand from the cationic complexes [Ag3(H)(BH4)L3](+) provides a change in geometry that facilitates subsequent loss of BH3 to produce the dihydride clusters, [Ag3(H)2Ln](+) (n = 1 and 2). Together with the results of previous studies (Girod et al., Chem. - Eur. J., 2014, 20, 16626), this provides a direct link between mixed silver hydride/borohydride nanoclusters, silver hydride nanoclusters, and silver nanoclusters.

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

    Directory of Open Access Journals (Sweden)

    Maritana Farias

    2012-01-01

    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.

  12. Large electric-potential bias in an EDO-TTF tetramer as a major mechanism of charge ordering observed in its PF6 salt: A density functional theory study

    Science.gov (United States)

    Iwano, Kaoru; Shimoi, Yukihiro

    2008-02-01

    Based on density functional theory, we investigate the electronic structures of an organic molecular solid, (EDO-TTF)2PF6 (EDO-TTF=ethylendioxy-tetrathiafulvalene) , which is known to have a so-called charge-ordered state below a critical temperature. While it has been thought that the origins of the charge ordering are molecular deformations, we find that an electric potential bias within a tetramer of EDO-TTF molecules is close to 1eV , originating from long-range Coulombic interactions with surrounding molecules, and that it is essential in reproducing the actual degree of charge ordering. We also calculate optical conductivity spectra and find a good consistency with experimental results.

  13. Determination of the molecular structure of the short-lived light-induced high-spin state in the spin-crossover compound [Fe(6-mepy)3tren](PF6)2

    Science.gov (United States)

    Chakraborty, Pradip; Tissot, Antoine; Peterhans, Lisa; Guénée, Laure; Besnard, Céline; Pattison, Philip; Hauser, Andreas

    2013-06-01

    In the spin-crossover compound [Fe(6-mepy)3tren](PF6)2, (6-mepy)3tren = tris{4-[(6-methyl)-2-pyridyl]-3-aza-butenyl}amine, the high-spin state can be populated as a metastable state below the thermal transition temperature via irradiation into the metal to the ligand charge-transfer absorption band of the low-spin species. At 10 K, the lifetime of this metastable state is only 1 s. Despite this, it is possible to determine an accurate excited state structure by following the evolution of relevant structural parameters by synchrotron x-ray diffraction under continuous irradiation with increasing intensity. The difference in metal-ligand bond length between the high-spin and the low-spin states is found to be 0.192 Å, obtained from an analysis of the experimental data using the mean-field approximation to model cooperative effects.

  14. Impact of the electrochemical porosity and chemical composition on the lithium ion exchange behavior of polypyrroles (ClO4-, TOS-, TFSI-) prepared electrochemically in propylene carbonate. comparative EQCM, EIS and CV studies.

    Science.gov (United States)

    Dziewoński, Paweł Marek; Grzeszczuk, Maria

    2010-06-03

    Conditions of electrodeposition, i.e. a potential window of the process, addition of water, the current density, and morphology of substrate electrodes (Pt, Pt/TiO(2), Au), were shown to influence strongly ion-exchange properties of polypyrrole (PPy) synthesized in propylene carbonate (PC), doped with ClO(4)(-) or p-toluenesulfonate (TOS(-)). "Electrochemical porosity" and redox activity of PPy films were compared to the characteristics of poly(3,4-ethylenedioxythiophene) (PEDOT). A molecular indicator of the PPy film structure packing was bis(trifluoromethylsulfonyl)imide anion (TFSI(-)). Ion-exchange properties of PPy were found to be almost independent of chemical composition of the polymer, described in the literature as PPy(I), PPy(II), PPy(III). Instead, micro- and nanoscopic morphology of the polymer film and a molecular level packing of the polymer chains as well as the counterion nature are of the foremost importance. The polymer film structure/properties are shown to change upon prolonged redox/ionic stimulations. Lithium exchange between PPy films and contacting phases (PC electrolyte, TiO(2)) proceeds in addition to the anion exchange, the latter being a dominant process under conditions of the reversible electrochemical p-doping of PPy, although diffusion coefficients of PC solvated lithium ions in PPy are higher than diffusion coefficients of perchlorate, p-toluenesulfonate or bis(trifluoromethylsulfonyl)imide anions. The highest flux of Li(+) ions into/out of the PPy phase takes place about -1.0 V vs Ag/Ag(+) which is clearly evidenced by the cathodic/anodic CV peaks. Cation transport phenomena can be analyzed independently from anion transport when observed at a longer time scale (low values of potential scan rate) as each prevails at different redox states of the polymer. However, in a shorter time scale (v > or = 10 mV s(-1)), the opposite fluxes of cations and anions were observed to interfere. Furthermore, a net uptake of propylene carbonate by the as grown PPy film occurs at initial cycles of the cation uptake causing irreversible swelling of the polymer phase. Mechanisms of the redox process and accompanying mass transport involving PPy films were investigated using comparatively three techniques: cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and electrochemical quartz crystal microbalance (EQCM).

  15. 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

    Institute of Scientific and Technical Information of China (English)

    谢宇轩; 关翔宇; 王阳; 王鹤立

    2014-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-01

    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. What determines the rate of excited-state intramolecular electron-transfer reaction of 4-(N,N'-dimethylamino)benzonitrile in room temperature ionic liquids? A study in [bmim][PF6].

    Science.gov (United States)

    Santhosh, Kotni; Samanta, Anunay

    2012-05-14

    The kinetics of excited-state intramolecular electron-transfer reaction and dynamics of solvation of the intramolecular charge transfer (ICT) state of 4-(N,N'-dimethylamino)benzonitrile (DMABN) was studied in 1-butyl-3-methylimidazloium hexafluorophosphate, [bmim][PF(6)], by monitoring the dual fluorescence of the system. The picosecond time-resolved emission spectra (TRES) of DMABN exhibit decay of the locally excited (LE) emission intensity and shift of the ICT emission peak position with time, thus capturing the kinetics of evolution of the ICT state from the LE state and solvent relaxation of the ICT state. These results show that the LE→ICT transformation rate is determined not by the slow dynamics of solvation in ionic liquid, but is controlled mainly by the rate of structural reorganization of the molecule, which accompanies the electron-transfer process in this polar viscous medium. Even though both solvent reorganization around photo-excited DMABN and structural rearrangement of the molecule are dependent on the viscosity of the medium, it is the latter process that contributes to the viscosity dependence of the LE→ICT transformation.

  18. 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

    Institute of Scientific and Technical Information of China (English)

    耿彦芳; 王腾芳; 虞大红; 彭昌军; 刘洪来; 胡英

    2008-01-01

    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.

  19. Preparation and Performances of Room Molten Salt as Electrolyte in Carbon-carbon Capacitor Based on LiPFe and Trifluoroacetamide%LiPF6/三氟乙酰胺室温熔盐的制备及在碳-碳电容器中的性能

    Institute of Scientific and Technical Information of China (English)

    左晓希; 李奇; 刘建生; 肖信; 范成杰; 南俊民

    2012-01-01

    利用LiPF6和三氟乙酰胺为前驱物,制备了低共熔温度约为-62℃的室温熔盐,并测试了该熔盐作为碳-碳电化学电容器(EDLCs)电解液时的性能。其中,使用差示扫描量热法(DSC)和红外光谱法(FTIR)分析了不同LiPF6和三氟乙酰胺配比熔盐的热稳定性,拟制了该二元组分的共熔相图,认为LiPF6和三氟乙酰胺极性基团间的氢键作用促成了室温熔盐的形成。循环伏安(CV)、交流阻抗(EIS)和电导等测定结果表明,所制备的LiPF6/三氟乙酰胺电解液的室温电导率为1.30mS/cm,电化学窗口大于5.6V,大于60℃的使用温度,作为电解液可满足碳-碳EDLCs的使用要求。%A novel room molten salt with an eutectic temperature of about -62℃ is prepared using LiPF6 and trifluoroacetamide as precursors. And then its performances are evaluated in carbon-carbon electrochemical double layer capacitor (EDLC) as electrolyte. The thermal properties of the complex electrolyte with different molar ratios are characterized and then the liquid-solid phase diagram is presented by using differential scanning calorimeter (DSC) and Fourier transform infrared spectroscopy (FTIR). The hydrogen bonding interaction between LiPF6 and trifluoroacetamide molecules is attributed to the formation of the as-prepared molten salt. In addition, the results of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and conductance tests show that the as-prepared LiPF6/trifluoroacetamide electrolyte has a maximum conductance at room temperature, i.e. 1.30 mS/cm, a stable electrochemical window of ca. 5.6 V, an applicable temperature of more than 60℃, suggesting it is a promising electrolyte candidate for carbon-carbon EDLCs.

  20. Synthesis, Crystal Structures and Properties of Tetrametallic Complexes: [M2(phen)4(FCA)2](ClO4)2o(H2O)2 (M=Zn or Co, phen= 1,10-phenanthroline, FCA =anion of 3-ferrocenyl-2-crotonic acid)

    Institute of Scientific and Technical Information of China (English)

    YANG Jia-Xiang; HU Zhang-Jun; ZHANG Ze; TIAN Yu-Peng; LIU Qing-Liang; CHANTRAPROMMA Suchada; FUN Hoong-Kun

    2005-01-01

    Two new complexes [Zn2(phen)4(FCA)2](ClO4)2·(H2O)2 (1) and [Co2(phen)4 (FCA)2](ClO4)2·(H2O)2 (2) (FCA =anion of 3-ferrocenyl-2-crotonic acid, phen= 1,10-phenanthroline) have been synthesized, and characterized by elemental analysis, IR, UV-Vis spectra, thermal analyses, and single-crystal X-ray diffraction. Two M(Ⅱ) (M=Zn or Co) ions are bridged by two FCA anions with syn-anti bridging ligands, leading to dimeric cores,[M2(phen)4(FCA)2]2+, and each M(Ⅱ) ion is six-coordinated in a distorted octahedral geometry by two chelate phen ligands and two μ2-carboxylate oxygen atoms from two FCA groups. The M(Ⅱ)…M(Ⅱ) intradimer distances are 0.4391 and 0.4462 nm in 1 and 2, respectively. Electrochemical properties of the complexes have been discussed.

  1. 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

    Directory of Open Access Journals (Sweden)

    Marcio Wilker Soares Campelo

    2011-01-01

    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

  2. Solvent-dependent dihydrogen/dihydride stability for [Mo(CO)(Cp*)H(2)(PMe(3))(2)](+)[BF(4)](-) determined by multiple solvent...anion...cation non-covalent interactions.

    Science.gov (United States)

    Dub, Pavel A; Belkova, Natalia V; Filippov, Oleg A; Daran, Jean-Claude; Epstein, Lina M; Lledós, Agustí; Shubina, Elena S; Poli, Rinaldo

    2010-01-04

    Low-temperature (200 K) protonation of [Mo(CO)(Cp*)H(PMe(3))(2)] (1) by Et(2)OHBF(4) gives a different result depending on a subtle solvent change: The dihydrogen complex [Mo(CO)(Cp*)(eta(2)-H(2))(PMe(3))(2)](+) (2) is obtained in THF, whereas the tautomeric classical dihydride [Mo(CO)(Cp*)(H)(2)(PMe(3))(2)](+) (3) is the only observable product in dichloromethane. Both products were fully characterised (nu(CO) IR; (1)H, (31)P, (13)C NMR spectroscopies) at low temperature; they lose H(2) upon warming to 230 K at approximately the same rate (ca. 10(-3) s(-1)), with no detection of the non-classical form in CD(2)Cl(2), to generate [Mo(CO)(Cp*)(FBF(3))(PMe(3))(2)] (4). The latter also slowly decomposes at ambient temperature. One of the decomposition products was crystallised and identified by X-ray crystallography as [Mo(CO)(Cp*)(FHFBF(3))(PMe(3))(2)] (5), which features a neutral HF ligand coordinated to the transition metal through the F atom and to the BF(4) (-) anion through a hydrogen bond. The reason for the switch in relative stability between 2 and 3 was probed by DFT calculations based on the B3LYP and M05-2X functionals, with inclusion of anion and solvent effects by the conductor-like polarisable continuum model and by explicit consideration of the solvent molecules. Calculations at the MP4(SDQ) and CCSD(T) levels were also carried out for calibration. The calculations reveal the key role of non-covalent anion-solvent interactions, which modulate the anion-cation interaction ultimately altering the energetic balance between the two isomeric forms.

  3. Renewable-surface sol-gel derived carbon ceramic electrode fabricated by [Ru(bpy)(tpy)Cl]PF6 and its application as an amperometric sensor for sulfide and sulfur oxoanions.

    Science.gov (United States)

    Salimi, Abdollah; Pourbeyram, Sima; Amini, Mohamad Kazem

    2002-12-01

    A highly sensitive and fast responding sensor for the determination of thiosulfate, sulfite, sulfide and dithionite is described. It consists of a chemically modified carbon ceramic composite electrode (CCE) containing [Ru(bpy)(tpy)Cl]PF6 complex that was constructed by the sol-gel technique. A reversible redox couple of Ru(II)/Ru(III) was observed as a solute in acetonitrile solution and as a component of carbon based conducting composite electrode. Electrochemical behavior and stability of modified CCE were investigated by cyclic voltametry, the apparent electron transfer rate constant (kappa(S)) and transfer coefficient (a) were determined by cyclic voltametry which were about 28 s(-1) and 0.43 respectively. Electrocatalytic oxidation of S(2-), SO3(2-), S2O4(2-) and S2O3(2-) were effective at the modified electrode at significantly reduced overpotentials and in the pH range 1-11. Optimum pH values for amperometric detection of thiosulfate, dithionite, sulfide and sulfite are 7, 9, 2 and 2. Under the optimized conditions the calibration curves are linear in the concentration ranges 1-500, 3-80, 2-90 and 1-100 microM for S2O3(2-), SO3(2-), S2- and S2O4(2-) determination. The detection limit (signal to noise is 3) and sensitivity are 0.5 and 12, 2.8 and 6, 1.6 and 8, and 0.65 microM and 80 nA microM(-1) for thiosulfate, sulfite, sulfide and dithionite detection. The modified carbon ceramic electrode doped with Ru-complex shows good reproducibility, a short response time (t 6 month) and especially good surface renewability by simple mechanical polishing (RSD for eight successive polishing is 2%). The advantages of this sulfur compound amperometric detector based on ruthenium doped CCE are high sensitivity, inherent stability at a broader pH range, excellent catalytic activity, less expense and simplicity of preparation in comparison with recently published papers. This sensor can be used as a chromatographic detector for analysis of sulfur derivatives.

  4. Thermal Behavior and Decomposition Kinetics of the Complexes of CuX2 (X=NO3, Br, Cl and ClO4) with 3,3′-Dimethyl-1-(1 H-1,2,4-triazol-1-yl)-2-butanone

    Institute of Scientific and Technical Information of China (English)

    LU,Zhen-Rong(陆振荣); DING,Yuan-Chen(丁元晨); XU,Ying(徐颖); LI,Bao-Long(李宝龙); ZHANG,Yong(张勇)

    2004-01-01

    The thermal behaviors of the complexes of Cu(DMTZB)4X2 (DMTZB =3,3′-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone, X=NO3 or ClO4) and Cu(DMTZB)2X2 (X = Br or C1) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC, EDS and elemental analysis techniques. The results showed that their decomposition proceeded in three different ways mainly depending on the anions in the molecules. The heat effect associated with the decomposition step of DMTZB molecules was also different. The decomposition mechanisms and the kinetic parameters of DMTZB were determined and calculated by jointly using four methods, which showed that its pyrolysis was controlled by D3 mechanism but with different activation energies and pre-exponential factors for different complexes.

  5. 高氯酸碳酰肼盐与硝酸碳酰肼盐系列化合物的晶格能与感度性能关系%Relationship between Lattice Energy and Sensitivity of [M(CHZ)3](NO3)2 and [M(CHZ)3](ClO4)2 (M=Mn, Zn, Ni)

    Institute of Scientific and Technical Information of China (English)

    郑秋雨; 乔小晶; 邵风雷; 张建国; 杨利

    2009-01-01

    为了研究晶格能与感度之间的关系,采用微热量计测定了[M(CHZ)3](NO3)2和[M(CHZ)3](ClO4)2 (M=Mn, Zn, Ni)在去离子水中的溶解焓并计算出它们的标准摩尔溶解焓,根据卡普廷斯基经验公式计算了它们的晶格能,得出配阳离子半径[M(CHZ)3]2+ (M=Mn, Zn, Ni)分别为2.12(A), 1.89(A)和2.70(A);讨论了晶格能与机械感度之间的关系: 相同外阴离子系列中配合物的晶格能越大,感度越小,并且高氯酸碳酰肼盐要比相应的硝酸碳酰肼盐的晶格能低,感度最高的为[Ni(CHZ)3](ClO4)2,最钝感的为[Zn(CHZ)3](NO3)2.%The standard molar enthalpies of series of energetic coordination compounds solution with carbohydrazide as ligand and nitrate or perchlorate as anion in deionized water were measured by a Setaram C80II microcalorimeter at 298.15 K. Based on these values, their lattice energy were calculated through Kapustinkii formula, meanwhile the thermochemistry radius of [M(CHZ)3]2+ (M=Mn, Zn, Ni) was gained. The relationship between lattice energy and impact sensitivity or friction sensitivity was discussed. Results show that the lattice energy of perchlorate are smaller than their corresponding nitrate, thus the perchlorate are more sensitive.

  6. 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

    Institute of Scientific and Technical Information of China (English)

    许映杰; 黄钗英; 李浩然

    2011-01-01

    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

  7. Ring-strain release in neutral and dicationic 7,8,17,18-tetrabromo-5,10,15,20-tetraphenylporphyrin: crystal structures of C44H26Br4N4 and C44H28Br4N42+·2ClO4−·3CH2Cl2

    Directory of Open Access Journals (Sweden)

    W. Robert Scheidt

    2016-06-01

    Full Text Available Two porphyrin complexes were studied to determine the effects of protonation on ring deformation within the porphyrin. The porphyrin 7,8,17,18-tetrabromo-5,10,15,20-tetraphenylporphyrin, C44H26Br4N4, was selected because the neutral species is readily doubly protonated to yield a dication, which was crystallized here with perchlorate counter-ions as a dichloromethane trisolvate, C44H28Br4N42+·2ClO4−·3CH2Cl2. The centrosymmetric neutral species is observed to have a mild `ruffling' of the pyrrole rings and is essentially planar throughout; intramolecular N—H...N hydrogen bonds occur. In contrast, the dication exhibits considerable deformation, with the pyrrole rings oriented well out of the plane of the porphyrin, resulting in a `saddle' conformation of the ring. The charged species forms N—H...O hydrogen bonds to the perchlorate anions, which lie above and below the plane of the porphyrin ring. Distortions to the planarity of the pyrrole rings in both cases are very minor. The characterization of the neutral species represents a low-temperature redetermination of the previous room-temperature analyses [Zou et al. (1995. Acta Cryst. C51, 760–761; Rayati et al. (2008. Polyhedron, pp. 2285–2290], which showed disorder and physically unrealistic displacement parameters.

  8. Crystal structure of paddle-wheel sandwich-type [Cu2{(CH3)2CO}{μ-Fe(η(5)-C5H4C N)2}3](BF4)2·(CH3)2CO.

    Science.gov (United States)

    Strehler, Frank; Korb, Marcus; Lang, Heinrich

    2015-02-01

    The mol-ecular structure of (acetone-κO)tris-(μ-ferrocene-1,1'-dicarbo-nitrile-κ(2) N:N')dicopper(I) bis-(tetra-fluorido-borate) acetone monosolvate, [Cu2Fe3(C6H4N)6(C3H6O)](BF4)2·C3H6O, consists of two Cu(I) ions bridged by a ferrocene-1,1'-dicarbo-nitrile moiety in a paddle-wheel-architectured sandwich complex with two BF4 (-) units as counter-ions. One of the latter is equally disordered over two sets of sites. The two Cu(I) ions are complexed in a trigonal-planar manner by three nitrile N-donor atoms. Further inter-actions by the O atom of an acetone mol-ecule to one of the Cu(I) atoms and a weak η(2),π-inter-action of two atoms of a cyclo-penta-dienyl ring to the other Cu(I) atom complete a distorted trigonal-pyramidal environment for each of the metal ions. A further acetone mol-ecule is also present as a solvent mol-ecule. The crystal packing is consolidated by several π-π inter-actions.

  9. Scan Rate Dependent Spin Crossover Iron(II) Complex with Two Different Relaxations and Thermal Hysteresis fac-[Fe(II)(HL(n-Pr))3]Cl·PF6 (HL(n-Pr) = 2-Methylimidazol-4-yl-methylideneamino-n-propyl).

    Science.gov (United States)

    Fujinami, Takeshi; Nishi, Koshiro; Hamada, Daisuke; Murakami, Keishiro; Matsumoto, Naohide; Iijima, Seiichiro; Kojima, Masaaki; Sunatsuki, Yukinari

    2015-08-03

    Solvent-free spin crossover Fe(II) complex fac-[Fe(II)(HL(n-Pr))3]Cl·PF6 was prepared, where HL(n-Pr) denotes 2-methylimidazol-4-yl-methylideneamino-n-propyl. The magnetic susceptibility measurements at scan rate of 0.5 K min(-1) showed two successive spin transition processes consisting of the first spin transition T1 centered at 122 K (T1↑ = 127.1 K, T1↓ = 115.8 K) and the second spin transition T2 centered at ca. 105 K (T2↑ = 115.8 K, T2↓ = 97.2 K). The magnetic susceptibility measurements at the scan rate of 2.0, 1.0, 0.5, 0.25, and 0.1 K min(-1) showed two scan speed dependent spin transitions, while the Mössbauer spectra detected only the first spin transition T1. The crystal structures were determined at 160, 143, 120, 110, 95 K in the cooling mode, and 110, 120, and 130 K in the warming mode so as to follow the spin transition process of high-spin HS → HS(T1) → HS(T2) → low-spin LS → LS(T2) → LS(T1) → HS. The crystal structures at all temperatures have a triclinic space group P1̅ with Z = 2. The complex-cation has an octahedral N6 coordination geometry with three bidentate ligands and assume a facial-isomer with Δ- and Λ-enantimorphs. Three imidazole groups of fac-[Fe(II)(HL(n-Pr))3](2+) are hydrogen-bonded to three Cl(-) ions. The 3:3 NH(imidazole)···Cl(-) hydrogen-bonds form a stepwise ladder assembly structure, which is maintained during the spin transition process. The spin transition process is related to the structural changes of the FeN6 coordination environment, the order-disorder of PF6(-) anion, and the conformation change of n-propyl groups. The Fe-N bond distance in the HS state is longer by 0.2 Å than that in the LS state. Disorder of PF6(-) anion is not observed in the LS state but in the HS state. The conformational changes of n-propyl groups are found in the spin transition processes except for HS → HS(T1) → HS(T2).

  10. N-Doped TiO2 Nanotube Arrays: Synthesis by Anodization in an Ionic Liquid ([BMIM]BF4) and Assessment of Photocatalytic Property%离子液体辅助阳极氧化法制备N掺杂TiO2纳米管阵列及其光催化性能研究

    Institute of Scientific and Technical Information of China (English)

    于滢慧; 姜艳丽; 田玫; 杨丽娟; 闫慧君; 盛双

    2016-01-01

    以HF水溶液为电解液,离子液体(1-丁基-3-甲基咪唑四氟硼酸盐[BMIM]BF4)为N源,采用阳极氧化法制备N掺杂TiO2纳米管阵列.通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子谱(XPS)、傅里叶变换红外光谱(FT-IR)和紫外-可见漫反射光谱(DRS)对N掺杂TiO2纳米管阵列的表面形貌、晶型和氮元素的掺杂方式进行分析.以球形氙灯为光源,亚甲基蓝溶液为目标降解物测试N掺杂TiO2纳米管阵列的光催化活性.结果表明,N掺杂TiO2纳米管阵列对亚甲基蓝溶液的降解率明显高于未掺杂的TiO2纳米管阵列.这是因为N掺杂后不仅使TiO2禁带宽度变窄,并且N掺杂进入TiO2晶格中形成O-Ti-N键和Ti-O-N键,使氧空位数量增加,从而使其光催化活性提高.%N-doped TiO2 nanotube (NT) arrays were prepared by anodization in electrolytes containing HF,ionic liquid 1-n-butyl-3-methyl-imidazolium tetrafluoroborate ([BMIM]BF4) and water.The ionic liquid,[BMIM]BF4,was used as the nitrogen source.The surface morphology and the composition of samples were characterized by scanning electron microscopy (SEM),X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),Fourier transform infrared spectroscopy (FT-IR) and UV-Vis diffuse reflectance spectra (DRS).The photocatalytic activities of samples were investigated by the degradation of methylene blue (MB) under spherical xenon lamp.The results show that the degradation rate of MB over N-doped TiO2 NT arrays is obviously higher than that over undoped TiO2 NT arrays.The above results are caused by the increased oxygen vacancies and the decreased band gap.

  11. H(+)/AuPPh(3)(+) Exchange for the Hydride Complexes CpMoH(CO)(2)(L) (L = PMe(3), PPh(3), CO). Formation and Structure of [Cp(CO)(2)(PMe(3))Mo(AuPPh(3))(2)](+)[BF(4)](-).

    Science.gov (United States)

    Galassi, Rossana; Poli, Rinaldo; Quadrelli, E. Alessandra; Fettinger, James C.

    1997-07-02

    The reaction of CpMoH(CO)(2)L with AuPPh(3)(+)BF(4)(-) in THF at -40 degrees C proceeds directly to the MoAu(2) cluster compounds [CpMo(CO)(2)L(AuPPh(3))(2)](+)BF(4)(-) (L = PMe(3) (1), PPh(3) (2)) with release of protons. A 1:1 reaction leaves 50% of the starting hydride unreacted. At lower temperature, however, the formation of a [CpMo(CO)(2)(PMe(3))(&mgr;-H)(AuPPh(3))](+) intermediate is observed. This compound evolves to the cation of 1 and CpMoH(CO)(2)(PMe(3)) upon warming and is deprotonated by 2,6-lutidine to afford CpMo(CO)(2)(PMe(3))(AuPPh(3)). The X-ray structure of 1 can be described as a four-legged piano stool with the PMe(3) and the "eta(2)-(AuPPh(3))(2)" ligands occupying relative trans positions. [Cp(CO)(2)(PMe(3))Mo(AuPPh(3))(2)](+)[BF(4)](-) (M(r) = 1298.41): monoclinic, space group P2(1)/n, a = 18.1457(13) Å, b = 9.7811(7) Å, c = 26.096(2) Å, beta = 105.086(5) degrees, V = 4472.0(5) Å(3), Z = 4. The reaction of CpMoH(CO)(2)(PMe(3)) with 3 equiv of AuPPh(3)(+) affords a MoAu(3) cluster, [CpMo(CO)(2)(PMe(3))(AuPPh(3))(3)](2+) (3), in good yields under kinetically controlled conditions. Under thermodynamically controlled conditions, 3 dissociates extensively into 1 and free AuPPh(3)(+). It is proposed that the hydride ligand helps build higher nuclearity Mo-Au clusters. The difference in reaction pathways for the interaction of AuPPh(3)(+) with CpMoH(CO)(2)L when L = PR(3) or CO and for the interaction of CpMoH(CO)(2)(PMe(3)) with E(+) when E = H, Ph(3)C or AuPPh(3) is discussed. The lower acidity and greater aurophilicity of the [CpMo(CO)(2)L(&mgr;-H)(AuPPh(3))](+) intermediate when L = PMe(3) favor attack by AuPPh(3)(+) before deprotonation.

  12. Efeito protetor do complexo de rutÃnio (II) (cis-[RuCl(qui)(bpy)2]PF6) contra lesÃo gÃstrica induzida por naproxeno: possÃvel papel regulador da enzima guanilato ciclase solÃvel

    OpenAIRE

    Antonio Ãder Enzo Albuquerque Teixeira

    2015-01-01

    IntroduÃÃo: Os AINEs sÃo um dos principais agentes que contribuem para a patogÃnese da Ãlcera gastrintestinal e representam um importante fator etiolÃgico por serem comumente utilizados na prÃtica clÃnica. Objetivo: Avaliar o efeito protetor do complexo de rutÃnio (II) (cis-[RuCl(qui)(bpy)2]PF6), contra a lesÃo gÃstrica induzida por naproxeno (NPX) em camundongos. MÃtodos: Foram utilizados camundongos Swiss (18-22g). Mensuramos os nÃveis de GMPc incubando amostras de tecidos gÃstricos com DMS...

  13. Two Cobalt(Ⅱ) Complexes Derived from the Hydrolysis Product of Di-Schiff Base Ligand N,N'-Bis-(1-benzimidazo-2-ylethylidene)-ethane-1,2-diamine: Preparation,Characterization and Crystal Structure of the 6-Coordinate Species [CoL2]X·H2O (X = ClO4-,NO3-)

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The reactions of Co(CIO4)2.6H2O and Co(NO3)2·6H2O with the di-Schiff base ligand N,N'-bis-(1-benzimidazo-2-yl-ethylidene)-ethane-1,2-diamine (LA) in ethanol have been investigated.The reactions of LA with excess amount of cobalt salts yield the six-coordinate complexes [CoL2](CIO4)2·H2O 1 and [CoL2](NO3)2·H2O 2 as isolatable products (L = N-(1-benzimidazo-2-yl-ethylidene)-ethane-1,2-diamine), where L is a tri-dentate mono-Schiff base ligand, resulting from the hydrolysis of the precursor di-Schiff base LA.Both complexes were characterized by X-ray crystallography.Crystal data for complex 1: monoclinic, space group P21/c, a = 11.9214(10), b = 23.5828(17), c = 14.0387(12)(A), β= 135.219[4]°,C22H30CI2CoN9O9,Mr = 680.37, V = 2780.1(4)(A)3, Z = 4, Dc = 1.625 g/cm3,μ(MoKa) = 0.876 mm-1, F(000) = 1404,the final R = 0.0725 and wR = 0.1530 for 5726 observed reflections (I>2σ(I)).Crystal data for complex 2: monoclinic, space group P21/c, a = 18.2162(16), b = 10.0610(6), c = 18.593(2)(A),β=130.099(3)°, C22H30CoN10O7, Mr = 605.49, V = 2606.5(4)(A)3, Z = 4, Dc = 1.543 g/cm3,μ(MoKα)= 0.722 mm-1, F(000) = 1260, the final R = 0.0619 and wR = 0.1429 for 5194 observed reflections (I > 2σ(I)).X-ray diffraction analysis reveals that each cobalt atom in the two complexes is chelated by six nitrogen atoms from two tridentate iigands L, exhibiting a slightly distorted octahedral coordination sphere.In both complexes, the strong hydrogen-bonding interactions between the lattice waters and N-H groups of the ligands result in 1D chains which are further connected by ClO4- (or NO3-) groups to form a 3D framework.In complex 2, the strong π-π interactions increase the stability of the structure.

  14. 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

    Institute of Scientific and Technical Information of China (English)

    陈金燕; 邹树平; 何冬梅; 杨晓刚; 李春

    2011-01-01

    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

  15. 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

    Institute of Scientific and Technical Information of China (English)

    王良; 李清; 闫永胜; 崔运成

    2011-01-01

    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.

  16. Sulfur-containing trinuclear arene ruthenium clusters

    OpenAIRE

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

    2006-01-01

    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...

  17. 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).

    Science.gov (United States)

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

    2015-12-01

    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.

  18. 镍-多吡啶配合物[Ni(dmbpy)3](H2O)(ClO4)2的合成、晶体结构及与DNA相互作用研究%Synthesis, crystal structure and DNA-binding studies of a new polypyridyl nickel complex [Ni (dmbpy) 3] (H2O) (ClO4) 2

    Institute of Scientific and Technical Information of China (English)

    张万举; 王芳; 杨水彬

    2013-01-01

    A new polypyridyl nickel complex [Ni(dmbpy)3] (H2 O) (ClO4)2 (dmbpy=4,4′-dimethyl-2,2′-bipyridine) has been synthesized and characterized by single-crystal Xray diffraction method.It crystallizes in the triclinic system,space group P-1,with a =11.192(13) (A),b=14.444(18) (A),c=14.468(18) (A),α=84.86(2)°,β=76.691(19)°,γ=68.24(2)°,V=2114(4) (A)3 and Z=2.The molecular structure of the complex consists of a mononuclear nickel(Ⅱ) complex cation,two perchlorate anions and one water molecule.Each of the three dmbpy molecules chelates to the nickel(Ⅱ) atom in the usual bidentate mode and the nickel(Ⅱ) atom is six-coordinated in a distorted octahedral geometry.The binding studies of the complex with calf thymus DNA (CT DNA) have been explored by electronic absorption titration and fluorescence quenching experiments.The experimental results suggest that the complex bind to CT-DNA through two models:electrostatic and intercalatively binding.%合成了一个镍—多吡啶配合物[Ni(dmbpy)3](H2O)(ClO4)2(dmbpy=4,4′-二甲基2,2′-联吡啶),并通过室温挥发法培养了该配合物的单晶.单晶X-衍射结果表明,该配合物属三斜晶系,P-1空间群,主要晶体学参数为:a=11.192(13)(A),b=14.444(18)(A),c=14.468(18)(A),α=84.86(2)°,β=76.691(19)°,y=68.24(2)°,V=2114(4)(A)3,Z=2.配合物分子由1个单核镍阳离子单元[Ni(dmbpy)3]2+、2个高氯酸根阴离子和1个水分子组成,配合物中镍原子的配位环境为六配位的八面体构型,3个dmbpy分子以双齿形式和1个镍原子配位.通过紫外光谱和荧光光谱研究了该配合物与小牛胸腺DNA(CT-DNA)的相互作用,结果表明该配合物与CT-DNA之间存在静电和插入两种作用模式.

  19. Facile coupling of propargylic, allylic and benzylic alcohols with allylsilane and alkynylsilane, and their deoxygenation with Et3SiH, catalyzed by Bi(OTf)3 in [BMIM][BF4] ionic liquid (IL), with recycling and reuse of the IL.

    Science.gov (United States)

    Kumar, G G K S Narayana; Laali, Kenneth K

    2012-09-28

    Allyltrimethylsilane (allyl-TMS) reacts with propargylic alcohols 1a-1d in the presence of 10% Bi(OTf)(3) in [BMIM][BF(4)] solvent to furnish the corresponding 1,5-enynes in respectable isolated yields (87-93%) at room temperature. The utility of Bi(OTf)(3) as a superior catalyst was demonstrated in a survey study on coupling of allyl-TMS with employing several metallic triflates (Bi, Ln, Al, Yb) as well as, B(C(6)F(5))(3), Zn(NTf(2))(2) and Bi(NO(3))(3)·5H(2)O. Coupling of cyclopropyl substituted propargylic alcohol with allyl-TMS gave the skeletally intact 1,5-enyne and a ring opened derivative as a mixture. Coupling of propargylic/allylic alcohol with allyl-TMS resulted in allylation at both benzylic (2 isomers) and propargylic positions, as major and minor products respectively. The scope of this methodology for allylation of a series of allylic and benzylic alcohols was explored. Chemoselective reduction of a host of propargylic, propagylic/allylic, bis-allylic, allylic, and benzylic alcohols with Et(3)SiH was achieved in high yields with short reaction times. The same approach was successfully applied to couple representative propargylic and allylic alcohols with 1-phenyl-2-trimethylsilylacetylene. The recovery and reuse of the ionic liquid (IL) was gauged in a case study with minimal decrease in isolated yields after six cycles.

  20. 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

    Indian Academy of Sciences (India)

    R Lalrempuia; Patrick J Carroll; Mohan Rao Kollipara

    2004-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    Renqing Lü; Zuogang Cao; Guoping Shen

    2007-01-01

    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.

  2. N-(trifluoromethylsulfonyl)aryloxytrifluoromethylsulfoximines [ArO-SO(CF3)=NTf] and N-aryltriflimides Ar-N(Tf)2 by thermal and photolytic dediazoniation of [ArN2][BF4] in [BMIM][Tf2N] ionic liquid: exploiting the ambident nucleophilic character of a "nonnucleophilic" anion.

    Science.gov (United States)

    Laali, Kenneth K; Okazaki, Takao; Bunge, Scott D

    2007-08-31

    Arenediazonium tetrafluoroborate salts undergo metathesis on immobilization in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonato)amide [BMIM][Tf(2)N]. The "noncoordinating", "nonnucleophilic" [Tf(2)N] anion acts as an ambident nucleophile toward the aryl cations, formed via thermal dediazoniation, to give predominantly the oxy anion quenching products [ArO-SO(CF(3))=NTf], with minimal formation of ArN(Tf)(2), irrespective of the nature of the substituent(s) on the ArN(2)+. Strong preference for the formation of oxygen trapping products did not change under photolytic conditions, where dediazoniation occurs at room temperature. A minimal amount of the Schiemann product ArF is also formed in both thermal and photolytic dediazoniation, depending on the substituent(s). Progress of dediazoniation in the IL (both thermal and photolytic) and the evolution of the products were directly monitored by (1)H and (19)F NMR. According to DFT (Density Functional Theory) calculations, PhN(Tf)(2) is more stable than PhO-SO(CF(3))=NTf by 15-17 kcal/mol, depending on the basis set. Inclusion of solvation effects (PCM, with acetone and with CH(2)ClCH(2)Cl as solvent) did not change this preference. The [ArN(2)][BF(4)] dediazoniation in [BMIM][Tf(2)N] resulted in synthesis and characterization of a series of hitherto unknown [ArO-SO(CF(3))=NTf] compounds. The X-ray structure of MesO-SO(CF(3))=NTf (Mes = mesityl) is reported. On the basis of extraction studies, suitable solvent systems have been identified that remove the products without dissolving [BMIM][NTf(2)], thus overcoming product recovery difficulties typically associated with the use of this IL.

  3. Organic Synthesis in Ionic Liquids: Condensation of 3-Methyl-1-phenyl-5-pyrazolone with Carbonyl Compounds Catalyzed by Ethylenediammonium Diacetate(EDDA)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An efficient and environmental benign method is reported for the condensation of 3-methyl-1-phenyl-5-pyrazolone with carbonyl compounds in ionic liquids [Bmim]BF4 and [Bmim]PF6 catalyzed by ethylenediammonium diacetate.

  4. All-trans-[ClRu(II)(py)4(NC)Ru(II)(py)4(CN)Ru(II)(py)4(NO)](PF6)4: a redox-active 2-donor/1-acceptor system based on the electrophilic {RuNO}6 motif.

    Science.gov (United States)

    De Candia, Ariel G; Singh, Priti; Kaim, Wolfgang; Slep, Leonardo D

    2009-01-19

    The new linear homotrinuclear compound trans-[ClRu(II)(py)(4)(NC)Ru(II)(py)(4)(CN)Ru(II)(py)(4)(NO)](PF(6))(4) was prepared by reaction between the nitro complex trans-[(NC)Ru(II)(py)(4)(CN)Ru(II)(py)(4)(NO(2))](+) and the solvento complex obtained by reaction between [ClRu(II)(py)(4)(NO)](3+) and N(3)(-) in acetone. The trans-[ClRu(II)(py)(4) (NC)Ru(II)(py)(4)(CN)Ru(II)(py)(4)(NO)](4+) ion (I) has been characterized by (1)H NMR and IR spectroscopy (nu(NO) = 1919 cm(-1)). This species displays intense electronic absorptions in the visible region which can be assigned to donor-acceptor charge-transfer transitions (DACT) involving {RuNO}(6)-centered acceptor orbitals and donor orbitals located on the two different neighboring metal centers at ca. 6.7 and 12.6 A distance from the metal in the {RuNO}(6) fragment. Addition of OH(-) to I generated the nitro complex with a second-order rate constant of (12.5 +/- 0.2) x 10(3) M(-1) s(-1) (25 degrees C). Cyclic voltammetry experiments complemented by spectroelectrochemistry in the UV-vis-NIR region reveal that I can be reversibly reduced at 0.49 or 0.20 V vs AgCl/Ag for acetonitrile and water, respectively, and oxidized at 0.71 or 0.57 V vs AgCl/Ag. The spectroscopic and spectroelectrochemical information (UV-vis-NIR, X-band EPR) supplemented with electronic structure computation (DFT) reveals that the one-electron reduction is centered on the nitrosyl moiety to yield a {RuNO}(7) species, while oxidation occurs on the chlororuthenium side of the molecule. Both processes yield significant changes of the electronic spectra which are discussed in parallel with the electronic structure picture as obtained by DFT.

  5. 1D and 2D assembly structures by imidazole···chloride hydrogen bonds of iron(II) complexes [Fe(II)(HL(n-Pr))3]Cl·Y (HL(n-Pr) = 2-methylimidazol-4-yl-methylideneamino-n-propyl; Y = AsF6, BF4) and their spin states.

    Science.gov (United States)

    Fujinami, Takeshi; Nishi, Koshiro; Matsumoto, Naohide; Iijima, Seiichiro; Halcrow, Malcolm A; Sunatsuki, Yukinari; Kojima, Masaaki

    2011-12-07

    Two Fe(II) complexes fac-[Fe(II)(HL(n-Pr))(3)]Cl·Y (Y = AsF(6) (1) and BF(4) (2)) were synthesized, where HL(n-Pr) is 2-methylimidazole-4-yl-methylideneamino-n-propyl. Each complex-cation has the same octahedral N(6) geometry coordinated by three bidentate ligands and assumes facial-isomerism, fac-[Fe(II)(HL(n-Pr))(3)](2+) with Δ- and Λ-enantiomorphs. Three imidazole groups per Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) are hydrogen-bonded to three Cl(-) ions or, from the viewpoint of the Cl(-) ion, one Cl(-) ion is hydrogen-bonded to three neighbouring fac-[Fe(II)(HL(n-Pr))(3)](2+) cations. The 3 : 3 NH···Cl(-) hydrogen bonds between Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) and Cl(-) generate two kinds of assembly structures. The directions of the 3 : 3 NH···Cl(-) hydrogen bonds and hence the resulting assembly structures are determined by the size of the anion Y, though Y is not involved into the network structure and just accommodated in the cavity. Compound 1 has a 1D ladder structure giving a larger cavity, in which the Δ- and Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) enantiomorphs are bridged by two NH···Cl(-) hydrogen bonds. Compound 2 has a 2D network structure with a net unit of a cyclic trimer of {fac-[Fe(II)(HL(n-Pr))(3)](2+)···Cl(-)}(3) giving a smaller cavity, in which Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) species with the same chirality are linked by NH···Cl(-) hydrogen bonds to give a homochiral 2D network structure. Magnetic susceptibility and Mössbauer spectral measurements demonstrated that compound 1 showed an abrupt one-step spin crossover with 4.0 K thermal hysteresis of T(c↓) = 125.5 K and T(c↑) = 129.5 K and compound 2 showed no spin transition and stayed in the high-spin state over the 5-300 K temperature range.

  6. 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

    Institute of Scientific and Technical Information of China (English)

    吕仁庆; 林进; 曲占庆

    2012-01-01

    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

  7. Spectroscopic studies on Solvatochromism of mixed-chelate copper(II) complexes using MLR technique.

    Science.gov (United States)

    Golchoubian, Hamid; Moayyedi, Golasa; Fazilati, Hakimeh

    2012-01-01

    Mixed-chelate copper(II) complexes with a general formula [Cu(acac)(diamine)]X where acac=acetylacetonate ion, diamine=N,N-dimethyl,N'-benzyl-1,2-diaminoethane and X=BPh(4)(-), PF(6)(-), ClO(4)(-) and BF(4)(-) have been prepared. The complexes were characterized on the basis of elemental analysis, molar conductance, UV-vis and IR spectroscopies. The complexes are solvatochromic and their solvatochromism were investigated by visible spectroscopy. All complexes demonstrated the positive solvatochromism and among the complexes [Cu(acac)(diamine)]BPh(4)·H(2)O showed the highest Δν(max) value. To explore the mechanism of interaction between solvent molecules and the complexes, different solvent parameters such as DN, AN, α and β using multiple linear regression (MLR) method were employed. The statistical results suggested that the DN parameter of the solvent plays a dominate contribution to the shift of the d-d absorption band of the complexes.

  8. 烷氧基和酚氧基取代的茂铁盐阳离子光引发剂的合成和表征%Synthesis and Characterization of Alkoxy and Phenoxy-substituted Ferrocenium Salt Cationic Photoinitiators

    Institute of Scientific and Technical Information of China (English)

    王涛; 万平玉; 马丽君

    2006-01-01

    Alkyl-substituted ferrocenium salts have limited solubility in epoxy oligomers and produce poisonous arene by photolysis. Herein, the synthesis and photoactivity of several alkoxy-substituted ferrocenium salts as long-wavelength UV light photoinitiators have been reported. [Cyclopendadien-Fe-anisole]PF6, [Cyclopendadien-Fe-anisole]BF4, [Cyclopendadien-Fe-diphenylether]PF6, [Cyclopendadien-Fe-diphenylether]BF4. and [Cyclopendadien-Fe-diethoxybenzene] PF6 for polymerization of epoxy resin were prepared through the ligand exchange reaction between one ring of ferrocene and aromatic ether. They all display good solubility and photoinitiating activities in epoxy resins.

  9. EFFECT OF WATER ON THE CONDUCTIVITY OF PPQ (ClO4) COMPLEX

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chi; LU Fengcai

    1993-01-01

    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.

  10. Solid-state materials for anion sensing in aqueous solution: highly selective colorimetric and luminescence-based detection of perchlorate using a platinum(II) salt.

    Science.gov (United States)

    Taylor, Stephen D; Howard, Whitney; Kaval, Necati; Hart, Robert; Krause, Jeanette A; Connick, William B

    2010-02-21

    The PF(6)(-) salt of a platinum(II) complex changes from yellow to red and becomes intensely luminescent upon exposure to aqueous ClO(4)(-). The response is remarkably selective. Spectroscopic changes are consistent with anion exchange resulting in shortening of the intramolecular PtPt distances between the square planar cations.

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

    DEFF Research Database (Denmark)

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

    1985-01-01

    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...

  12. Electroanalytical determination of trace chloride in room-temperature ionic liquids.

    Science.gov (United States)

    Villagrán, Constanza; Banks, Craig E; Hardacre, Christopher; Compton, Richard G

    2004-04-01

    The electroanalytical quantification of chloride in [C4mim][BF4], [C4mim][NTf2], and [C4mim][PF6] ionic liquids has been explored using linear sweep and square wave voltammetry. Cathodic stripping voltammetry at a silver disk electrode is found to be the most sensitive. The methodology is based on first holding the potential of the electrode at +2.0 V (vs Ag wire), to accumulate silver chloride at the electrode. On applying a cathodic scan, a stripping wave is observed corresponding to the reduction of the silver chloride. This stripping protocol was found to detect ppb levels of chloride in [C4mim][BF4], [C4mim][NTf2], and [C4mim][PF6]. Although other methods for chloride have been reported for [BF4](-)- and [PF6](-)-based ionic liquids, no methods have been reported for [NTf2](-) ionic liquids.

  13. Photo-induced spin transition of Iron(III) compounds with pi-pi intermolecular interactions.

    Science.gov (United States)

    Hayami, Shinya; Hiki, Kenji; Kawahara, Takayoshi; Maeda, Yonezo; Urakami, Daisuke; Inoue, Katsuya; Ohama, Mitsuo; Kawata, Satoshi; Sato, Osamu

    2009-01-01

    Iron(III) spin-crossover compounds [Fe(pap)(2)]ClO(4) (1), [Fe(pap)(2)]BF(4) (2), [Fe(pap)(2)]PF(6) (3), [Fe(qsal)(2)]NCS (4), and [Fe(qsal)(2)]NCSe (5) (Hpap=2-(2-pyridylmethyleneamino)phenol and Hqsal=2-[(8-quinolinylimino)methyl]phenol) were prepared and their spin-transition properties investigated by magnetic susceptibility and Mössbauer spectroscopy measurements. The iron(III) compounds exhibited spin transition with thermal hysteresis. Single crystals of the iron(III) compounds were obtained as suitable solvent adducts for X-ray analysis, and structures in high-spin (HS) and low-spin (LS) states were revealed. Light-induced excited-spin-state trapping (LIESST) effects of the iron(III) compounds were induced by light irradiation at 532 nm for 1-3 and at 800 nm for 4 and 5. The activation energy E(a) and the low-temperature tunneling rate k(HL)(T-->0) of iron(III) LIESST compound 1 were estimated to be 1079 cm(-1) and 2.4x10(-8) s(-1), respectively, by HS-->LS relaxation experiments. The Huang-Rhys factor S of 1 was also estimated to be 50, which was similar to that expected for iron(II) complexes. It is thought that the slow relaxation in iron(III) systems is achieved by the large structural distortion between HS and LS states. Introduction of strong intermolecular interactions, such as pi-pi stacking, can also play an important role in the relaxation behavior, because it can enhance the structural distortion of the LIESST complex.

  14. Stability Study of the Cu(MIBI)4BF4By HPLC

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    3.StabilityStudyoftheCu(MIBI).BF.byHPLCChenSuzhen ̄(99)Tc ̄m-MIBIimagingagentofmyocardialperfusionispreparedfromaSn(Ⅱ)-Cu(MIBI)...

  15. Electrochemical properties of room temperature ionic liquids incorporating BF4- and TFSI- anions as green electrolytes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhengxi; GAO Xuhui; YANG Li

    2005-01-01

    Two series of room temperature ionic liquids, 1-alkyl-3-methylimidazolium tetrafluoroborate and 1-alkyl- 3-methylimidazolium bis(trifluoromethylsulfonyl)imide (n = 2―4) as electrolytes were prepared and fundamental electrochemical properties of the neat ionic liquids and those mixed with an organic solvent (EC-DMC-DEC, 1:1:1, mass ratio) were investigated. It was found that the Arrhenius equation is approximately fit for the relationship between conductivity and temperature for neat ionic liquids within lower temperature range (298―323 K). The VTF interpretation describes the conductivity temperature dependence for the ionic liquids containing tetrafluoroborate anion more accurately than those containing bis(trifluoromethylsulfon- yl)imide anion within wider temperature range. The potential windows are approximately 4.0 V for all these ionic liquids. Conductivities of the mixed electrolytes show a maximum value as the solution concentrations increase.

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    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.

  17. Multi-dimensional transition-metal coordination polymers of 4,4'-bipyridine-N,N'-dioxide: 1D chains and 2D sheets.

    Science.gov (United States)

    Jia, Junhua; Blake, Alexander J; Champness, Neil R; Hubberstey, Peter; Wilson, Claire; Schröder, Martin

    2008-10-06

    Reaction of 4,4'-bipyridine -N, N' -dioxide (L) with a variety of transition-metal salts in MeOH affords a range of coordination polymer products. For the complexes [FeCl 3(mu-L)] infinity, 1, and ([Cu(L) 2(OHMe) 2(mu-L)].2PF 6. n(solv)) infinity, 2, 1D chain structures are observed, whereas ([Mn(mu-L) 3].2ClO 4) infinity, 3, and ([Cu(mu-L) 3].2BF 4) infinity, 4, both show 2D sheet architectures incorporating an unusual 3 (6)- hxl topology. The more common 4 (4)- sql topology is observed in [Cd(ONO 2) 2(mu-L) 2] infinity, 5, ([Cu(OHMe) 2(mu-L) 2].2ZrF 5) infinity, 6, ([Cu(L) 2(mu-L) 2].2EF 6) infinity ( 7 E = P; 8 E = Sb), and ([Et 4N][Cu(OHMe) 0.5(mu-L) 2(mu-FSiF 4F) 0.5].2SbF 6. n(solv)) infinity, 9. In 6, the [ZrF 5] (-) anion, formed in situ from [ZrF 6] (2-), forms 1D anionic chains ([ZrF 5] (-)) infinity of vertex-linked octahedra, and these chains thread through a pair of inclined polycatenated ([Cu(OHMe) 2(mu-L) 2] (2+)) infinity 4 (4)- sql grids to give a rare example of a triply intertwined coordination polymer. 9 also shows a 3D matrix structure with 4 (4)- sql sheets of stoichiometry ([Cu(L) 2] (2+)) infinity coordinatively linked by bridging [SiF 6] (2-) anions to give a structure of 5-c 4 (4).6 (6)- sqp topology. The mononuclear [Cu(L) 6].2BF 4 ( 10) and [Cd(L) 6].2NO 3 ( 11) and binuclear complexes [(Cu(L)(OH 2)) 2(mu-L) 2)].2SiF 6. n(solv), 12, are also reported. The majority of the coordination polymers are free of solvent and are nonporous. Thermal treatment of materials that do contain solvent results in structural disintegration of the complex structures giving no permanent porosity.

  18. Binding energies of CO2 with some ionic liquids

    Science.gov (United States)

    Eucker, William; Bendler, John

    2007-03-01

    Room temperature ionic liquids (RTILs), a novel class of materials with negligible vapor pressures and potentiality as benign solvents, may be an ideal chemical for carbon dioxide (CO2) gas sequestration. Ab initio computational modeling was used to investigate the molecular interactions of simple RTIL anions hexafluorophosphate (PF6^-) and tetrafluoroborate (BF4^-) with CO2. Electronic potential energy surface (PES) scans of a comprehensive sampling of 1:1 anion-CO2 orientations were computed using Spartan '02 with Dunning's correlation consistent basis sets. Qualitatively, the PES scans yielded deeper, more numerous and radially closer active sites surrounding BF4^- anion as compared with the PF6^- anion. Quantitatively, the binding energies of 17.87 kJ/mol and 25.24 kJ/mol were extracted from the identified global energy minima for the PF6^- and BF4^- systems, respectively. The smaller BF4^- anion was concluded to bind more strongly to the CO2. However, literature-reported experimental Henry's law constants for CO2 dissolved in imidizolium based RTILs show greater gas solvation in the PF6^- system. The discrepancy between the energetics calculation results and the experimental solvation data will be discussed.

  19. Lamellar Phases Formed in Brij 97/Water/Ionic Liquids%Brij 97/H2O/离子液体体系层状液晶的研究

    Institute of Scientific and Technical Information of China (English)

    王仲妮; 孟琳; 周武; 丁兆云; 李干佐; 张高勇

    2007-01-01

    利用小角X射线散射和小幅振荡实验研究了Brij 97/H2O/ bmim-BF4 和 Brij 97/H2O / bmim-PF6 体系层状液晶的微观结构和动态流变性质.结果表明两层状液晶体系分别表现gel-like 和fluid-like 的动态流变行为,而且 bmim-PF6 和 bmim-BF4增溶在液晶结构的不同位置.%Microstructure and dynamic rheological properties of lamellar liquid crystals formed in Brij 97/water/ bmim-BF4 and Brij 97/water/ bmim-PF6 systems were investigated by means of SAXS and small amplitude oscillatory shear measurements. It is shown that two systems exhibit gel-like and fluid-like rheograms respectively, along with the different locations of bmim-PF6 and bmim-BF4 penetrating through the lamellar phase.

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

    CERN Document Server

    Srivastava, Ambrish Kumar

    2016-01-01

    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...

  1. Cationic ring-opening polymerization of 3,3-bis(chloromethyl)oxacyclobutane in ionic liquids

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cationic ring-opening polymerization of 3,3-bis(chloromethyl)oxacyclobutane catalyzed by BF3·OEt2 was carried out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO/BF3·OEt2 on the molecular weights and yield of PBCMO were investigated. The polymerization in ionic liquids proceed to high conversions, although molecular weights are limited, similar to polymerization in organic solvent such as CH2C12. Follow a viewpoint of green chemistry,we feel ionic liquid [bmim]BF4 is superior to [bmim]PF6. Extracting [bmim]PF6 from the product using organic solvent as extractant limits its advantage as a green reaction media.

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

    Science.gov (United States)

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

    2014-11-01

    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.

  3. Bonding properties of PEO-LiClO4 and Al%PEO-LiClO4与 Al 的键合性能

    Institute of Scientific and Technical Information of China (English)

    吴常雄; 刘翠荣; 吴志生; 阴旭

    2015-01-01

    To improve the packaging quality of the micro-electro-mechanical systems (MEMS),the solid polymer electrolyte (PEO-LiClO4 )was designed as a new material to bond with anode Al.The application of polymer solid electrolyte in anodic bond-ing package was mainly due to its ionic conductivity.FTIR,XRD,super depth of field optical microscopy and SEM were used to investigate the conductive mechanism of PEO-LiClO4 ,the effects of adding different lithium salts on its electrical conductivity, and the combination of bonding interface.The results show that compared with the LiPF6 and LiBF4 ,reactions between LiClO4 and PEO are more likely to weaken the complex structure and make it much looser;with the action of a strong electrostatic field, the diffusion and migration of lithium ions can be promoted.The conductive mechanism of PEO-LiClO4 lies in that the Li+is first-ly dissociated with ClO-4 and then forms complexation with C—O;the transition layers formed by a chemical reaction at the bond-ing interface is the key for the bonding of PEO-LiClO4 and aluminum.%为了提高微机电系统(MEMS)的封装质量,设计了应用高分子固体电解质(PEO-LiClO4)作为新材料并与 Al 进行阳极键合。高分子固体电解质能用于阳极键合封装主要是因为它具有离子导电性。采用红外光谱(FTIR)、X 射线衍射(XRD)、超景深光学显微镜观察、扫描电子显微镜(SEM)等方法研究了 PEO-LiClO4的导电机理,加入不同锂盐对其导电性的影响及其键合界面的结合情况。结果表明:相对于 LiPF6和 LiBF4,LiClO4与 PEO 发生的反应更容易削弱络合结构,使络合结构松散,在强静电场的作用下,促进了锂离子的扩散和迁移;PEO-LiClO4的导电机理是 Li+先与 ClO-4离解,然后与 C—O 产生络合;键合界面发生化学反应形成的过渡层是 PEO-LiClO4与 Al 能够键合的关键。

  4. Identity of Passive Film Formed on Aluminum in Li-ion BatteryElectrolytes with LiPF6

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xueyuan; Devine, T.M.

    2006-09-01

    The passive film that forms on aluminum in 1:1 ethylene carbonate + ethylmethyl carbonate with 1.2M LiPF{sub 6} and 1:1 ethylene carbonate + dimethyl carbonate with 1.0M LiPF{sub 6} was investigated by a combination of electrochemical quartz crystal microbalance measurements (EQCM), electrochemical impedance spectroscopy (EIS), and x-ray photoelectron spectroscopy. During anodic polarization of aluminum a film of AlF{sub 3} forms on top of the air-formed oxide, creating a duplex, or two-layered film. The thickness of the AlF{sub 3} increases with the applied potential. Independent measurements of film thickness by EQCM and EIS indicate that at a potential of 5.5V vs. Li/Li{sup +}, the thickness of the AlF{sub 3} is approximately 1 nm.

  5. Entropic evidence for cooperation of multiple instabilities upon a metal-insulator transition in (EDO-TTF) 2PF 6

    Science.gov (United States)

    Saito, Kazuya; Ikeuchi, Satoaki; Ota, Akira; Yamochi, Hideki; Saito, Gunzi

    2005-01-01

    The entropy of the peculiar metal-insulator transition of the title compound was measured and analyzed, resulting in the conclusions that the mechanism of this transition is the catastrophic cooperation of multiple instabilities: Peierls instability, charge order and anion ordering.

  6. Catalytic Epoxidation of a Technical Mixture of Methyl Oleate and Methyl Linoleate in Ionic Liquids Using MoO(O22•2QOH (QOH = 8-quinilinol as Catalyst and NaHCO3 as co-Catalyst

    Directory of Open Access Journals (Sweden)

    Chuan-Lei Fan

    2009-08-01

    Full Text Available The oxo-diperoxo molybdenum(VI complex MoO(O22•2QOH (QOH = 8-quinilinol was prepared and characterized by elemental analysis, IR and UV-Vis spectra. The ionic liquids (ILs [bmim][BF4], [hydemim][BF4], and [bmim][PF6] were characterized by 1H-NMR and UV-Vis spectra. The epoxidation of a technical mixture of methyl oleate and methyl linoleate with H2O2, in [bmim][BF4], [hydemim][BF4] and [bmim][PF6], catalyzed by MoO(O22•2QOH (QOH = 8-quinilinol and with NaHCO3 as co-catalyst has been studied for the first time. It was found that high conversions of methyl oleate and methyl linoleate to their respective oxidation products, as well as the total selectivity of their oxidation products to oxirane in [hydemim][BF4] were obtained. Also, the IL phases containing the Mo(VI catalyst can be readily recycled by washing with diethyl ether and drying, and the Mo(VI catalyst can be reused at least five times.

  7. 水、空气稳定型离子液体应用研究进展

    Institute of Scientific and Technical Information of China (English)

    冯鹏棉

    2011-01-01

    近年来新发现的对水、空气稳定的离子液体,因其具有A1C13型离子液体无法比拟的优点而引起了人们广泛的重视.本文综述了ZnC12/[emim]C1,[emim]BF4,[bmim]BF4,[bmim]PF6,[SMP]Tf2N,[bmim]Tf2N等新型离子液体的应用进展情况.

  8. Efficient Copper-bisisoquinoline-based Catalysts for Selective Aerobic Oxidation of Alcohols to Aldehydes and Ketones

    Directory of Open Access Journals (Sweden)

    Zaher M. A. Judeh

    2007-06-01

    Full Text Available The selective oxidation of alcohols with molecular oxygen was efficientlycompleted in high conversion and selectivity using copper-bisisoquinoline-based catalystsunder mild reaction condition. The effects of various parameters such as reactiontemperature, reaction time, oxidant, ligands, etc, were studied. Solvent effect has been aswell studied in ionic liquids [bmim]PF6, [omim]BF4 and [hmim]BF4, comparing totraditional volatile organic solvent. The use of ionic liquids was found to enhance thecatalytic properties of the catalysts used.

  9. Dinuclear Metallacycles with Single M-X-M Bridges (X = Cl(-), Br(-); M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)): Strong Antiferromagnetic Superexchange Interactions.

    Science.gov (United States)

    Reger, Daniel L; Pascui, Andrea E; Foley, Elizabeth A; Smith, Mark D; Jezierska, Julia; Wojciechowska, Agnieszka; Stoian, Sebastian A; Ozarowski, Andrew

    2017-03-06

    A series of monochloride-bridged, dinuclear metallacycles of the general formula [M2(μ-Cl)(μ-L)2](ClO4)3 have been prepared using the third-generation, ditopic bis(pyrazolyl)methane ligands L = m-bis[bis(1-pyrazolyl)methyl]benzene (Lm), M = Cu(II), Zn(II), and L = m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*), M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II). These complexes were synthesized from the direct reactions of M(ClO4)2·6H2O, MCl2, and the ligand, Lm or Lm*, in the appropriate stoichiometric amounts. Three analogous complexes of the formula [M2(μ-Cl)(μ-L)2](BF4)3, L = Lm, M = Cu(II), and L = Lm*, M = Co(II), Cu(II), were prepared from the reaction of [M2(μ-F)(μ-L)2](BF4)3 and (CH3)3SiCl. The bromide-bridged complex [Cu2(μ-Br)(μ-Lm*)2](ClO4)3 was prepared by the first method. Three acyclic complexes, [Co2(μ-Lm)μ-Cl4], [Co2(μ-Lm*)Cl4], and [Co2(μ-Lm*)Br4], were also prepared. The structures of all [M2(μ-X)(μ-L)2](3+) (X = Cl(-), Br(-)) complexes have two ditopic bis(pyrazolyl)methane ligands bridging two metals in a metallacyclic arrangement. The fifth coordination site of the distorted trigonal bipyramidal metal centers is filled by a bridging halide ligand that has an unusual linear or nearly linear M-X-M angle. The NMR spectra of [Zn2(μ-Cl)(μ-Lm*)2](ClO4)3 and especially [Cd2(μ-Cl)(μ-Lm*)2](ClO4)3 demonstrate that the metallacycle structure is maintained in solution. Solid state magnetic susceptibility data for the copper(II) compounds show very strong antiferromagnetic exchange interactions, with -J values of 536 cm(-1) for [Cu2(μ-Cl)(μ-Lm)2](ClO4)3·xCH3CN, 720 cm(-1) for [Cu2(μ-Cl)(μ-Lm*)2](ClO4)3, and 945 cm(-1) for [Cu2(μ-Br)(μ-Lm*)2](ClO4)3·2CH3CN. Smaller but still substantial antiferromagnetic interactions are observed with other first row transition metals, with -J values of 98 cm(-1) for [Ni2(μ-Cl)(μ-Lm*)2](ClO4)3, 55 cm(-1) for [Co2(μ-Cl)(μ-Lm*)2](ClO4)3, and 34 cm(-1) for [Fe2(μ-Cl)(μ-Lm*)2](ClO4

  10. Solute recovery from ionic liquids: a conceptual design study for recovery of styrene monomer from [4-mebupy][BF4

    NARCIS (Netherlands)

    Jongmans, M.T.G.; Trampe, J.; Schuur, B.; Haan, de A.B.

    2013-01-01

    Extractive distillation using ionic liquids (ILs) is a promising technology to separate the close-boiling mixture ethylbenzene/styrene. A proper solvent regeneration is crucial to obtain a technical and economic feasible process. In this work, several regeneration technologies were studied to recove

  11. Brij97/H2O/离子液体体系层状液晶的研究

    Institute of Scientific and Technical Information of China (English)

    王仲妮; 孟琳; 周武; 丁兆云; 李干佐; 张高勇

    2007-01-01

    利用小角X射线散射和小幅振荡实验研究了Brij97/H2O/bmim-BF4和Brij97/H2O/bmim-PF6体系层状液晶的微观结构和动态流变性质。结果表明两层状液晶体系分别表现gel-like和fluid-like的动态流变行为,而且bmim-PF6和bmim—BFd增溶在液晶结构的不同位置。

  12. Probing the Interaction of Ionic Liquids with CO2: A Raman Spectroscopy and Ab Initio Study

    Science.gov (United States)

    2008-05-05

    N N + [emim]+ 1-ethyl-3-dimethylimidazolium cation N N + [ bmim ]+ 1-butyl-3-methylimidazolium cation Figure 3: Common IL Ions...Select Solvents Solvent CO2 Solubility (g/L) CO2/N2 Selectivity Ratio MEA 6.63 (20) No Data [ bmim ][Tf2N] 3.61 (18) 22.3 (18) [ bmim ][PF6] 3.43... bmim ][BF4] 1-butyl-3-methylimidazolium tetrafluoroborate [ bmim ][PF6] 1-butyl-3-methyl-imidazolium hexafluorophosphate [ bmim ][Tf2N] 1-butyl-3

  13. Azido- and chlorido-cobalt complex as carrier-prototypes for antitumoral prodrugs.

    Science.gov (United States)

    Pires, Bianca M; Giacomin, Letícia C; Castro, Frederico A V; Cavalcanti, Amanda dos S; Pereira, Marcos D; Bortoluzzi, Adailton J; Faria, Roberto B; Scarpellini, Marciela

    2016-04-01

    Cobalt(III) complexes are well-suited systems for cytotoxic drug release under hypoxic conditions. Here, we investigate the effect of cytotoxic azide release by cobalt-containing carrier-prototypes for antitumoral prodrugs. In addition, we study the species formed after reduction of Co(3+) → Co(2+) in the proposed models for these prodrugs. Three new complexes, [Co(III)(L)(N3)2]BF4(1), [{Co(II)(L)(N3)}2](ClO4)2(2), and [Co(II)(L)Cl]PF6(3), L=[(bis(1-methylimidazol-2-yl)methyl)(2-(pyridyl-2-yl)ethyl)amine], were synthesized and studied by several spectroscopic, spectrometric, electrochemical, and crystallographic methods. Reactivity and spectroscopic data reveal that complex 1 is able to release N3(-) either after reduction with ascorbic acid, or by ambient light irradiation, in aqueous phosphate buffer (pH6.2, 7.0 and 7.4) and acetonitrile solutions. The antitumoral activities of compounds 1-3 were tested in normoxia on MCF-7 (human breast adenocarcinoma), PC-3 (human prostate) and A-549 (human lung adenocarcinoma epithelial) cell lines, after 24h of exposure. Either complexes or NaN3 presented IC50 values higher than 200 μM, showing lower cytotoxicity than the clinical standard antitumoral complex cisplatin, under the same conditions. Complexes 1-3 were also evaluated in hypoxia on A-549 and results indicate high IC50 data (>200 μM) after 24h of exposure. However, an increase of cancer cell susceptibility to 1 and 2 was observed at 300 μM. Regarding complex 3, no cytotoxic activity was observed in the same conditions. The data presented here indicate that the tridentate ligand L is able to stabilize both oxidation states of cobalt (+3 and +2). In addition, the cobalt(III) complex generates the low cytotoxic cobalt(II) species after reduction, which supports their use as as carrier prototypes for antitumoral prodrugs.

  14. Organic-inorganic hybrid solar cells via electropolymerization

    Science.gov (United States)

    Feng, Wenchun

    Integrating polymers with inorganic nanostructures is difficult due to wetting and surface energy considerations. We developed an electropolymerization method to grow conformal polymers on high aspect ratio nanostructures. Our method is shown to improve the polymer filling rate inside the nanostructures and can be used in the development of efficient hybrid solar cells. As an example, we have studied the hybrid system of electropolymerized polythiophene (e-PT) on a variety of conductive (Au and ITO) and semiconductive substrates (Si, Ge, ZnO). In particular, e-PT/ZnO hybrid structure can be further developed into organic photovoltaics (OPV). Although unsubstituted PT is not the ideal polymer material for high efficiency solar cells, it is an excellent choice for studying basic bonding and morphology in hybrid structures. We find that e-PT is covalently bound to the polar ZnO planar substrate via a Zn-S bond, adopting an upright geometry. By contrast, no strong covalent bonding was observed between e-PT and ZnO nanorods that consist of non-polar ZnO surfaces predominantly. Energy level alignment at interfaces is critical for fundamental understanding and optimization of OPV as band offsets of the donor and acceptor materials largely determine the open circuit voltage (Voc) of the device. Using ultraviolet photoemission spectroscopy (UPS) and inverse photoemission spectroscopy (IPS), we examined the correlation between energy alignment and photovoltaic properties of a model hybrid solar cell structure incorporating undoped electrodeposited polythiophene (e-PT) films on ZnO planar substrates. The electrolyte anion (BF4-, PF6 -, ClO4- or CF3SO3 -) used in the electrodeposition solution was found to exert a strong influence on the neutral e-PT film morphology and adhesion, the band alignment at the interface, and ultimately the photovoltaic behavior. The interfacial dipole lowers polythiophene energy levels, increasing the theoretical and actual Voc in polythiophene

  15. Layering of [BMIM]+-based ionic liquids at a charged sapphire interface.

    Science.gov (United States)

    Mezger, Markus; Schramm, Sebastian; Schröder, Heiko; Reichert, Harald; Deutsch, Moshe; De Souza, Emerson J; Okasinski, John S; Ocko, Benjamin M; Honkimäki, Veijo; Dosch, Helmut

    2009-09-07

    The structure of two model room temperature ionic liquids, [BMIM](+)[PF(6)](-) and [BMIM](+)[BF(4)](-), near the solid/liquid interface with charged Al(2)O(3)(0001) (sapphire) was determined with subnanometer resolution by high energy (72.5 keV) x-ray reflectivity. [BMIM](+)[PF(6)](-) exhibits alternately charged, exponentially decaying, near-surface layering. By contrast, the smaller-anion compound, [BMIM](+)[BF(4)](-), shows only a single layer of enhanced electron density at the interface. The different layering behaviors, and their characteristic length scales, correspond well to the different bulk diffraction patterns, also measured in this study. Complementary measurements of the surface and interface energies showed no significant different between the two RTILs. The combined bulk-interface results support the conclusion that the interfacial ordering is dominated by the same electrostatic ion-ion interactions dominating the bulk correlations, with hydrogen bonding and dispersion interactions playing only a minor role.

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

    Directory of Open Access Journals (Sweden)

    Nur Liyana Sakinah Johari

    2014-09-01

    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].

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

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

    @@ 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.

  18. Mechanistic insights into acetophenone transfer hydrogenation catalyzed by half-sandwich ruthenium(II) complexes containing 2-(diphenylphosphanyl)aniline - a combined experimental and theoretical study

    NARCIS (Netherlands)

    A. Bacchi; M. Balordi; R. Cammi; L. Elviri; C. Pelizzi; F. Picchioni; V. Verdolino; K. Goubitz; R. Peschar; P. Pelagatti

    2008-01-01

    Several new half-sandwich ruthenium(II) complexes containing 2-(diphenyphosphanyl)aniline (PNH2) of formula {Ru[(kappa P-2,N)PNH2](p-cymene)Cl}Y [Y = Cl (1a), PF6 (1b), BF4 (1c), BPh4 (1d), TfO (1e)] were synthesized and fully characterized both in solution (H-1 NMR and P-31{H-1) NMR spectroscopy) a

  19. Alkylphosphate-based nonflammable gel electrolyte for LiMn 2O 4 positive electrode in lithium-ion battery

    Science.gov (United States)

    Yoshimoto, Nobuko; Gotoh, Daisuke; Egashira, Minato; Morita, Masayuki

    Polymeric gel containing alkylphosphate has been examined as nonflammable gel electrolyte for LiMn 2O 4 positive electrode of lithium-ion battery (LIB). The gel was composed of a polymer matrix of poly(vinylidenefluoride- co-hexafluoropropylene) (PVdF-HFP) and a liquid component consisting of ternary solvent of trimethyl phosphate (TMP) mixed with ethylene carbonate (EC) and diethyl carbonate (DEC) that dissolves lithium salt (LiPF 6 or LiBF 4). The gel composition of 0.8 M (mol dm -3) LiX (X = PF 6 and BF 4) dissolved in EC + DEC + TMP (55:25:20) with PVdF-HFP showed excellent nonflammable characteristics and high ionic conductivity of ca. 3.1 mS cm -1 at room temperature (20 °C). The charge-discharge cycling test of LiMn 2O 4 positive electrode gave good reversibility with high capacitance in the gel electrolyte. With respect to the electrolyte salt, LiBF 4 was better than LiPF 6 due to its thermal stability during the gel preparation.

  20. Metal-organic framework supported ionic liquid membranes for CO2 capture: anion effects.

    Science.gov (United States)

    Gupta, Krishna M; Chen, Yifei; Hu, Zhongqiao; Jiang, Jianwen

    2012-04-28

    IRMOF-1 supported ionic liquid (IL) membranes are investigated for CO(2) capture by atomistic simulation. The ILs consist of identical cation 1-n-butyl-3-methylimidazolium [BMIM](+), but four different anions, namely hexafluorophosphate [PF(6)](-), tetrafluoroborate [BF(4)](-), bis(trifluoromethylsulfonyl)imide [Tf(2)N](-), and thiocyanate [SCN](-). As compared with the cation, the anion has a stronger interaction with IRMOF-1 and a more ordered structure in IRMOF-1. The small anions [PF(6)](-), [BF(4)](-), and [SCN](-) prefer to locate near to the metal-cluster, particularly the quasi-spherical [PF(6)](-) and [BF(4)](-). In contrast, the bulky and chain-like [BMIM](+) and [Tf(2)N](-) reside near the phenyl ring. Among the four anions, [Tf(2)N](-) has the weakest interaction with IRMOF-1 and thus the strongest interaction with [BMIM](+). With increasing the weight ratio of IL to IRMOF-1 (W(IL/IRMOF-1)), the selectivity of CO(2)/N(2) at infinite dilution is enhanced. At a given W(IL/IRMOF-1), the selectivity increases as [Tf(2)N](-) membrane with W(IL/IRMOF-1) = 1, [SCN](-) is identified to be the most favorable site for CO(2) adsorption. [BMIM][SCN]/IRMOF-1 outperforms polymer membranes and polymer-supported ILs in CO(2) permeability, and its performance surpasses Robeson's upper bound. This simulation study reveals that the anion has strong effects on the microscopic properties of ILs and suggests that MOF-supported ILs are potentially intriguing for CO(2) capture.

  1. Synthesis and structures of cyclic gold complexes containing diphosphine ligands and luminescent properties of the high nuclearity species.

    Science.gov (United States)

    Bhargava, Suresh; Kitadai, Kunihiko; Masashi, Takahashi; Drumm, Daniel W; Russo, Salvy P; Yam, Vivian Wing-Wah; Lee, Terence Kwok-Ming; Wagler, Jörg; Mirzadeh, Nedaossadat

    2012-04-28

    A mixture of cyclic gold(I) complexes [Au(2)(μ-cis-dppen)(2)]X(2) (X = OTf 1, PF(6)3) and [Au(cis-dppen)(2)]X (X = OTf 2, PF(6)4) is obtained from the reaction of [Au(tht)(2)]X (tht = tetrahydrothiophene) with one equivalent of cis-dppen [dppen = 1,2-bis(diphenylphosphino)ethylene]. The analogous reaction with trans-dppen or dppa [dppa = bis(diphenylphosphino)acetylene] affords the cyclic trinuclear [Au(3)(μ-trans-dppen)(3)]X(3) (X = OTf 11, PF(6)12) and tetranuclear [Au(4)(μ-dppa)(4)]X(4) (X = OTf 13, PF(6)14, ClO(4)15) gold complexes, respectively. Recrystallization of 15 from CH(2)Cl(2)/MeOH yielded a crystal of the octanuclear gold cluster [Au(8)Cl(2)(μ-dppa)(4)](ClO(4))(2)16. Attempts to prepare dicationic binuclear gold(II) species from the reaction of a mixture of 3 and 4 with halogens gave a mixture of products, the components of which confirmed to be acyclic binuclear gold(I) [Au(2)X(2)(cis-dppen)] (X = I 5, Br 7) and cyclic mononuclear gold(III) [AuX(2)(cis-dppen)]PF(6) (X = I 6, Br 8) complexes. Complexes 11-14 reveal weak emission in butyronitrile glass at 77 K, but they are non-emissive at room temperature. Ab initio modelling was performed to determine the charge state of the gold atoms involved. Extensive structural comparisons were made to experimental data to benchmark these calculations and rationalize the conformations.

  2. Ce(IV)- and light-driven water oxidation by [Ru(terpy)(pic)3]2+ analogues: catalytic and mechanistic studies.

    Science.gov (United States)

    Duan, Lele; Xu, Yunhua; Tong, Lianpeng; Sun, Licheng

    2011-02-18

    A series of mononuclear ruthenium polypyridyl complexes [Ru(Mebimpy)(pic)(3)](PF(6))(2) (2; Mebimpy = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; pic = 4-picoline), Ru(bimpy)(pic)(3) (3; H(2)bimpy = 2,6-bis(benzimidazol-2-yl)pyridine), trans-[Ru(terpy)(pic)(2)Cl](PF(6)) (4; terpy = 2,2';6',2"-terpyridine), and trans-[Ru(terpy)(pic)(2)(OH(2))](ClO(4))(2) (5) are synthesized and characterized as analogues of the known Ru complex, [Ru(terpy)(pic)(3)](PF(6))(2) (1). The effect of the ligands on electronic and catalytic properties is studied and discussed. The negatively charged ligand, bimpy(2-), has a remarkable influence on the electrochemical events due to its strong electron-donating ability. The performance in light- and Ce(IV)-driven (Ce(IV) = Ce(NH(4))(2)(NO(3))(6)) water oxidation is successfully demonstrated. We propose that ligand exchange between pic and H(2)O occurs to form the real catalyst, a Ru-aqua complex. The synthesis and testing of trans-[Ru(terpy)(pic)(2)(OH(2))](ClO(4))(2) (5) confirmed our proposal. In addition, complex 5 possesses the best catalytic activity among these five complexes.

  3. CO2 adsorption property of 1-butyl-3-methyl imidazolium ionic liquid impregnated silica gel%1-丁基-3-甲基咪唑离子液体浸渍硅胶吸附CO2的研究

    Institute of Scientific and Technical Information of China (English)

    辛丰; 朱佳媚; 张虎; 何凯歌

    2011-01-01

    采用浸渍法将1-丁基-3-甲基咪唑四氟硼酸([BMIM]BF4)和1-丁基-3-甲基咪唑六氟磷酸([BMIM]PF6)离子液体负载在A型硅胶上,并对负载样品进行了FTIR和CO2吸附表征.研究了不同阴离子种类、离子液体负载量、孔径分布等对CO2吸附性能的影响.结果表明:浸渍法制备的硅胶固载离子液体具有发达的微孔结构,且在0.4 ~ 0.8 nm有连续的分布;对于硅胶负载[BMIM]PF6,离子液体用量对CO2吸附能力的影响并不十分显著;硅胶负载[BMIM]PF6比[BMIM]BF4具有更好的CO2吸附性能,在273 K、0.1 MPa时,浸渍[BMIM]PF6样品的CO2吸附量达到3.68wt%.

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

    Science.gov (United States)

    Kruk, D.; Meier, R.; Rachocki, A.; Korpała, A.; Singh, R. K.; Rössler, E. A.

    2014-06-01

    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.

  5. Solvent control: dinuclear versus tetranuclear complexes of a bis-tetradentate pyrimidine-based ligand.

    Science.gov (United States)

    Gobeze, Worku A; Milway, Victoria A; Moubaraki, Boujemaa; Murray, Keith S; Brooker, Sally

    2012-08-28

    A new bis-tetradentate acyclic amine ligand L(Et) has been synthesized from 4,6-bis(aminomethyl)-2-phenylpyrimidine and 2-vinylpyridine. Dinuclear complexes, Mn(II)(2)L(Et)(MeCN)(H(2)O)(3)(ClO(4))(4) (1), Fe(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (2), Co(II)(2)L(Et)(H(2)O)(3)(MeCN)(2)(BF(4))(4) (3), Ni(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (4), Ni(II)(2)L(Et)(H(2)O)(4)(ClO(4))(4)·8H(2)O (4'), Cu(II)(2)L(Et)(BF(4))(4)·MeCN (5), Zn(II)(2)L(Et)(BF(4))(2)(BF(4))(2)·½MeCN (6), were obtained from 1 : 2 reactions of L(Et) and the appropriate metal salts in MeCN, whereas in MeOH tetranuclear complexes, Mn(II)(4)(L(Et))(2)(OH)(4)(ClO(4))(4) (7), Fe(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·5/2H(2)O (8), Co(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (9), Ni(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·4H(2)O (10), Cu(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (11) and Zn(II)(4)(L(Et))(2)(F)(4)(BF(4))(4) (12), result. Six complexes have been structurally characterized: in all cases each L(Et) is bis-tetradentate and provides a pyrimidine bridge between two metal centres. As originally anticipated, complexes 1, 4' and 6 are dinuclear, while 9, 10 and 12 are revealed to be tetranuclear, with two M(2)(L(Et))(4+) moieties bridged by two pairs of fluoride anions. Weak to moderate antiferromagnetic coupling between the metal centres is a feature of complexes 2, 3, 4, 8, 9 and 10. The dinuclear complexes 1-6 undergo multiple, mostly irreversible, redox processes. However, the pyrimidine-based dicopper(II) complex 5 undergoes a two electron quasi-reversible reduction, Cu(II)(2)→ Cu(I)(2), and this occurs at a more positive potential [E(m) = +0.11 V (E(pc) = -0.03 and E(pa) = +0.26 V) vs. 0.01 M AgNO(3)/Ag] than for either of the dicopper(II) complexes of the analogous pyrazine-based ligands.

  6. Detailed magnetic study on the formato-bridged MOFs with anion-tunable magnetic properties

    Institute of Scientific and Technical Information of China (English)

    WANG XinYi; WANG ZheMing; GAO Song

    2012-01-01

    Detailed studies of the structures,magnetic properties and photodimerization of a series of formato-bridged MOFs with the general formula M2(HCOO)3(4,4'-bpe)3(H20)3(X)(4,4'-bpe =4,4'-bipyridylethylene,M =Mn(l-X-),X- =CIO-4,NO-3,BF-4,I-,Br-; M =Co(2-X-),X- =CIO-4,NO-3; M =Zn(3-X-),X- =NO-3)were reported.Careful magnetic measurements on an oriented single crystal of 1-ClO-4 determined the spin-flop magnetic phase diagram and some intrinsic parameters,such as the intralayer coupling J,the anisotropy field HA and the exchange field HE.Different anions can remarkably tune the magnetic properties of l-X-,especially the critical fields of the spin-flop transition.Compound 2-ClO-4 remained paramagnetic down to 2 K.

  7. Reversible supra-channel effects: 3D kagome structure and catalysis via a molecular array of 1D coordination polymers.

    Science.gov (United States)

    Lee, Haeri; Noh, Tae Hwan; Jung, Ok-Sang

    2013-10-14

    Self-assembly of CuX2 (X(-) = ClO4(-) and BF4(-)) with 2,3-bis(nicotinoyloxy)naphthalene yields a 1D loop-chain skeleton. The loop-chains form an ensemble constituting a unique 3D kagome-type structure with both hexagonal and trigonal supra-channels. The unprecedented supra-channel effects on the catalytic oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylbenzoquinone were investigated.

  8. Phase Transitions and Water Dynamics of [Mn(H2O)6](ClO4 )2 Studied by Differential Scanning Calorimetry and Neutron Scattering Methods

    Science.gov (United States)

    Mikuli, E.; Migdał-Mikuli, A.; Natkaniec, I.; Mayer, J.

    2000-10-01

    DSC measurements performed at 95 -290 K have shown that [Mn(H 2 O) 6 ](CIO 4) 2 possesses, besides a high-temperature phase, existing above 323 K, four low-temperature solid phases. The inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) pat-terns registered at 20 -290 K have supported the DSC results and provided evidence that the investigated substance possesses even more than five solid phases. The IINS spectra have shown that in the room-temperature phase, water molecules perform fast stochastic reorientation at the picosecond scale. The orientational disorder characteristic for the room-temperature phase can be easily overcooled and frozen. Even by relatively slow cooling at ca. 40 K/hour a metastable, orientational (protonic) glass phase is formed below ca. 160 K. Below ca. 100 K, a structural phase transition was observed by the NPD, however the IINS spectra indicate existence of the pure ordered low-temperature phase only after annealing the sample for a few hours at 100 K. On heating, a structural phase transition takes place at ca. 120 K, and at ca. 225 K water molecules begin fast reorientation.

  9. 40 CFR 721.8350 - 2-Propenoic acid, 7-oxa-bi-cy-clo[4.1.0]hept-3-ylmethyl ester.

    Science.gov (United States)

    2010-07-01

    ...-3-ylmethyl ester. 721.8350 Section 721.8350 Protection of Environment ENVIRONMENTAL PROTECTION... ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance 2-propenoic acid, 7-oxabicyclo hept-3-ylmethyl ester (PMN P-89-31) is subject to reporting...

  10. Separation of CO2 and H2 Mixed Gas with Ionic liquid Membrane%离子液膜分离CO2、H2混合气体研究

    Institute of Scientific and Technical Information of China (English)

    仲惟

    2016-01-01

    Ionic liquid [BMIM]Cl and NaBF4 was selected to synthesize [BMIM]BF4 in methanol. After OH anion exchange resin exchange, ionic liquid [BMIM]Cl was neutralized with formic acid to prepare [BMIM] HCOO. Three kinds of polymer film PVDF, PAN and PS, and four kinds of ionic liquid [BMIM] BF4, HCOO [BMIM], [BMIM] PF6 and [BMIM] CH3COO were chosed to prepare 12 kinds of supported liquid membranes. At 30℃, 40℃ and 50℃, the CO2and H2single gas permeability of 12 kinds of liquid film were test. The results showed: at 30℃, the CO2 and H2 separation performance of [BMIM] BF4 polysulfone membrane was good, separation factor was more than 14; separation factor of [BMIM] PF6 type polyacrylonitrile membrane was more than 12 at 30℃; the separation factor of [BMIM] PF6 type polyvinylidene fluoride membrane was more than 5 at 30℃. So these three kinds of ionic liquid film had a certain separation degree for CO2 and H2 gas mixture at 30℃.%选用离子液体[BMIM]Cl与NaBF4在甲醇中反应制得[BMIM]BF4,离子液体[BMIM]Cl经OH型阴离子交换树脂交换后再与甲酸进行中和制得[BMIM]HCOO。分别选用3种聚合物薄膜PVDF、PAN和PS,使其与4种离子液体[BMIM] BF4、[BMIM]HCOO、[BMIM]PF6和[BMIM]CH3COO共制成12种支撑液膜。在30℃、40℃和50℃时分别进行12种液膜的CO2、H2单一气体渗透性测试。结果显示,[BMIM]BF4型聚砜膜在30℃时对CO2与H2分离性能较好,分离系数达14以上;[BMIM]PF6型聚丙烯腈膜在30℃时分离系数达12以上;[BMIM]PF6型聚偏氟乙烯膜在30℃时分离系数达到5以上。因此这3种离子液膜在30℃时可对CO2、H2混合气体进行一定程度的分离。

  11. Conductivity anisotropy helps to reveal the microscopic structure of a density wave at imperfect nesting

    Science.gov (United States)

    Grigoriev, P. D.; Kostenko, S. S.

    2015-03-01

    Superconductivity or metallic state may coexist with density wave ordering at imperfect nesting of the Fermi surface. In addition to the macroscopic spatial phase separation, there are, at least, two possible microscopic structures of such coexistence: (i) the soliton-wall phase and (ii) the ungapped Fermi-surface pockets. We show that the conductivity anisotropy allows us to distinguish these two microscopic density-wave structures. The results obtained may help to analyze the experimental observations in layered organic metals (TMTSF)2PF6, (TMTSF)2ClO4, α-(BEDT-TTF)2KHg(SCN)4 and in other compounds.

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

    Institute of Scientific and Technical Information of China (English)

    岳贵宽; 吕兴梅; 朱艳丽; 王慧; 张香平; 张锁江

    2008-01-01

    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.

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

    Science.gov (United States)

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

    2015-01-01

    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.

  14. Ionic liquids as additive in thin layer chromatography on separation of amino acids%离子液体作薄层色谱添加剂对氨基酸分离的研究

    Institute of Scientific and Technical Information of China (English)

    刘建平; 何丽君

    2011-01-01

    The separation of two alkaline amino acids ( argi-nine and lysine) was performed using 1-butyl-3-methylimid-azolium tetrafluoroborate ionic liquid ( [ Bmim ] BF4 ) as the eluent additives in thin layer chromatography. The addition of ionic liquid improved the separation the free silanol group markedly. The retardation factor ( R1) of the analytes firstly increased and then remained constant with the increase of the concentration of ionic liquids. In addition,the comparison results showed that the inhibition effect of [ Bmim ] PF6 for free silanol group was more effective than that of [ Bmim] BF4.%将1-丁基-3-甲基咪唑基四氟硼酸盐([Bmim]BF4)离子液体作为薄层色谱展开剂添加剂,讨论了[Bmim]BF4浓度对精氨酸和赖氨酸两种碱性氨基酸分离的影响.结果表明:添加离子液体能有效改善碱性氨基酸的展开效果,而且分析物的Rf值随离子液体浓度的增加而增加,浓度增加到一定后Rf保持不变.另外,比较了[Bmim]PF6和[Bmim]BF4两种离子液体对自由硅羟基抑制作用的效果,前者对自由硅羟基的抑制作用比后者更有效.

  15. Molecular Interactions of the Difluoro(oxalato)borate Anion and Its Application for Lithium Ion Battery Electrolytes

    Science.gov (United States)

    Allen, Joshua Lee

    scattering activities of the coordinated and uncoordinated solvent bands. In this study, correction factors are identified through joint quantum chemistry (QC) and experimental analysis techniques that enable the accurate analysis of EC and PC-based mixtures with lithium salts. From this analysis, the ionic association strength of the DFOB. anion was determined and compared to various lithium salt anions (PF6 --, TFSI--, BOB--, ClO 4 --, BF4--, CF 3SO3--, CF3CO2 --). Understanding the ionic association (Li+...anion) and ion solvation (Li+...solvent) interactions is crucial for an informed design process (i.e., electrolytes-on-demand) if these interactions can be directly linked to the physical and electrochemical properties of electrolyte mixtures. Thus, the solvation behavior of carbonate and lactone-based electrolytes with three lithium salts (LiBF4, LiDFOB and LiBOB) was investigated. Based upon the analysis of the solution structure of these mixtures, the electrolyte transport properties (viscosity and conductivity) were readily explainable. A direct link was therefore made between the solution structure of the electrolyte mixtures and the physicochemical properties they possess. LiDFOB has proven to be a highly versatile lithium salt, displaying many favorable battery properties including the formation of amorphous mixtures (even in mixtures with EC), relatively high ionic conductivity, and favorable electrode passivation layer properties when mixed with appropriate electrolyte solvents. Thus, alternative applications of the DFOB- anion have been explored, such as its use as an ionic liquid (IL) anion. N-Alkyl- N-methylpyrrolidinium difluoro(oxalato)borate (PY1RDFOB) ILs have been synthesized and characterized. These ILs are liquid at room temperature and have favorable Al corrosion properties, as well as a large electrochemical stability window. The present study provides a useful set of tools for scrutinizing a new electrolyte material; from the initial synthesis and

  16. Proposed kinetic mechanism of biodiesel production through lipase catalysed interesterification with a methyl acetate acyl acceptor and ionic liquid BMIM PF6 co-solvent

    Energy Technology Data Exchange (ETDEWEB)

    Ruzich, Nicholas Ivan; Bassi, A.S.

    2011-02-15

    As the depletion of fossil resources continues, the demand for environmentally friendly sources of energy as biodiesel is increasing. Biodiesel is the resulting fatty acid methyl ester (FAME) from an esterification reaction. To enhance this reaction lipase catalysts and ionic liquids can also used. The aim of this study was to develop a kinetic model of this reaction and to determine the effect of ionic liquids. The esterification reaction was conducted in a jacketed reactor under constant temperature in presence of ionic liquid and with the use of lipase to start the reaction; samples were analyzed with a high-performance liquid chromatography. A kinetic model was developed and results indicated that ionic liquids tend to limit mass transfer and thus reduce initial reaction rates; the authors proposed to increase the flow rate of the reaction mixture to overcome this issue. This study successfully investigated the reaction of lipase-catalyzed biodiesel production and developed its kinetic model.

  17. Magnetic Interactions through Fluoride: Magnetic and Spectroscopic Characterization of Discrete, Linearly Bridged Mn-2(III)(mu-F)F-4(Me(3)tacn)(2) (PF6)

    DEFF Research Database (Denmark)

    Pedersen, K. S.; Sigrist, M.; Weihe, H.;

    2014-01-01

    The nature of the magnetic interaction through fluoride in a simple, dinuclear manganese(III) complex (1), bridged by a single fluoride ion in a perfectly linear fashion, is established by experiment and density functional theory. The magnitude of the antiferromagnetic exchange interaction...... and the manganese(III) zero-field-splitting parameters are unambiguously determined by inelastic neutron scattering to yield J = 33.0(2) cm(-1) ((H) over cap = J (S-1) over cap.(S-2) over cap Hamiltonian definition) and single-ion D = -4.0(1) cm(-1). Additionally, high-field, high-frequency electron paramagnetic...... resonance and magnetic measurements support the parameter values and resolve vertical bar E vertical bar approximate to 0.04 cm(-1). The exchange coupling constant (J) is 1 order of magnitude smaller than that found in comparable systems with linear oxide bridging but comparable to typical magnitudes...

  18. Laser Photolysis Studies on Pyrene in Ionic Liquids and Conventional Solvents%芘在离子液体及常规溶剂中的激光闪光光解研究

    Institute of Scientific and Technical Information of China (English)

    付海英; 邢兆国; 吴国忠

    2011-01-01

    利用纳秒级时间分辨激光光解装置,以Nd:YAG激光器三倍频后的355 nm激光作为激发光源,研究了芘在常规溶剂乙腈、丙酮、环己烷、1-丁基-3-甲基咪唑六氟磷酸离子液体([Bmim][PF6])、N-丁基吡啶四氟硼酸离子液体([BuPy][BF4])以及三乙基庚基铵双三氟甲磺酰亚胺(R4NNTf2)的瞬态光解行为,比较了芘在各类体系中的瞬态光谱及反应动力学行为.研究表明芘在离子液体中各类瞬态物种的寿命均较常规溶剂延长,且反应速率常数随着离子液体的类型的变化而不同.与[Bmim][PF6]和R4NNTf2相比,[BuPy][BF4]最为活泼,认为主要是由于[BuPy][BF4]自身参加了反应.%The photochemistry of pyrene in conventional solvents (acetone, acetonitrile, cyclohexane) and ionic liquids [Bmim][PF6 ], [BuPy][BF4 ], R4 NNTf2 was investigated by time-resolved laser photolytic techniques. The transient absorption spectra of the excited pyrene and other radical species were compared. The absorption hand of pyrene cation radical was observed in the acetone, acetronitrile and pyridiniurn ionic liquid [BuPy][BF4 ] systems. Only excited triplet pyrene was observed in cyclohexane and [Bmim][PF6 ] and R4 NNTf2. The result demonstrates that there was an interaction between pyrene and solvents, and the pyrene cation radical was formed by electron transfer from the excited state of pyrene to acetonitrile, acetone and [BuPy][BF4 ].The possible mechanisms of the six systerna were suggested.

  19. Anion-solvent dependence of bistability in a family of meridional N-donor-ligand-containing iron(II) spin crossover complexes.

    Science.gov (United States)

    Leita, Ben A; Neville, Suzanne M; Halder, Gregory J; Moubaraki, Boujemaa; Kepert, Cameron J; Létard, Jean-François; Murray, Keith S

    2007-10-15

    Five mononuclear spin crossover iron(II) bis-meridional ligand complexes of the general formula [Fe(L)(2)](X)(2).solvent, have been synthesized, where X = BF(4)- or ClO(4)-; L = 2-(1-pyridin-2-ylmethyl-1H-pyrazol-3-yl)-pyrazine (picpzpz) or 2-(3-(2-pyridyl)pyrazol-1-ylmethyl)pyridine) (picpypz); solvent = MeOH or EtOH. The magnetic and structural consequences of systematic variation of meridional ligand, solvent, and anion, including a desolvated species, have been investigated. The complex [Fe(picpzpz)(2)](BF(4))(2).MeOH, 1.MeOH, displays several unique properties including a two-step spin transition with a gradual higher-temperature step ((1)T(1/2) = 197 K) and an abrupt low-temperature step with hysteresis ((2)T(1/2) = 91/98 K) and a metastable intermediate spin state below 70 K with quench-cooling. Removal of the solvent methanol results in the loss of the abrupt step and associated hysteresis (T(1/2) = 150 K). The complexes [Fe(picpzpz)(2)](BF(4))(2).EtOH (1.EtOH), [Fe(picpzpz)(2)](ClO(4))(2).MeOH (2.MeOH), [Fe(picpzpz)(2)](ClO(4))(2).EtOH (2.EtOH), and [Fe(picpypz)(2)](BF(4))(2).MeOH (3.MeOH) all show gradual one-step spin transitions with T(1/2) values in the range 210-250 K. Photomagnetic LIESST measurements on 1.MeOH reveal a near-quantitative excitation of high-spin sites and a unique two-step relaxation process related to the two-step thermal spin transition ((1)T(LIESST) = 49 K and (2)T(LIESST) = 70 K). The structural consequences of the unusual spin transition displayed by 1.MeOH have been investigated by single-crystal X-ray diffraction structural analyses between 25 and 293 K. Detailed characterization of the unit cell parameter evolution vs temperature reflects both the gradual high-temperature step and abrupt low-temperature step, including the thermal hysteresis, observed magnetically.

  20. The horizontal transfer of antibiotic resistance genes is enhanced by ionic liquid with different structure of varying alkyl chain length

    Directory of Open Access Journals (Sweden)

    Qing eWang

    2015-08-01

    Full Text Available Antibiotic resistance genes (ARGs have become a global health concern. In our previous study, an ionic liquid (IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6] had been proven to facilitate the dissemination of ARGs in the environment. However, enhanced alkyl group chain length or the substitution of alkyl groups with the cation ring corresponded with increased antimicrobial effects. In this study, we investigated how different structures of ILs with 4, 6 and 8 C atoms in the longer alkyl chain on the imidazolium cations facilitated the dissemination of ARGs. The promotion of plasmid RP4 transfer frequency decreased with [CnMIM][BF4] increasing the alkyl chain length from 4 carbon atoms to 8 carbon atoms on the imidazolium cations, which is observed with [BMIM][BF4] (n=4, 5.9 fold> HMIM][BF4] (n=6, 2.2 fold> [OMIM][BF4] (n=8, 1.7 fold. This illustrates that [CnMIM][BF4] with increasing the alkyl chain length exert decreasing ability in facilitating plasmid RP4 horizontal transfer, which is possibly related to IL-structure dependent toxicity. The IL-structure dependent plasmid RP4 transfer frequency was attributable to bacterial cell membrane permeability weaken with increasing alkyl chain length of [CnMIM][PF4], which was evidenced by flow cytometry (FCM. In freshwater microcosm, [CnMIm][BF4] promoted the relative abundance of the sulI and intI genes for 4.6 folds, aphA and traF for 5.2 folds higher than the untreated groups, promoting the propagation of ARGs in the aquatic environment. This is the first report that ILs with different structure of varying alkyl chain length facilitate horizontal transfer of plasmid RP4 which is widely distributed in the environment, and thus add the adverse effects of the environmental risk of ILs.

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

    @@ 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.

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

    Institute of Scientific and Technical Information of China (English)

    ZHU Jiqin; YU Yanmei; CHEN Jian; FEI Weiyang

    2007-01-01

    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.

  3. Bis-heteroleptic ruthenium(II) complex of a triazole ligand as a selective probe for phosphates.

    Science.gov (United States)

    Chowdhury, Bijit; Khatua, Snehadrinarayan; Dutta, Ranjan; Chakraborty, Sourav; Ghosh, Pradyut

    2014-08-04

    A new bis-heteroleptic ruthenium(II) complex (1) of 2-(1-methyl-1H-1,2,3-triazol-4-yl) pyridine (L) ligand was extensively explored for anion sensing studies. 1[PF6]2 shows selective sensing of dihydrogen phosphate (H2PO4(-))/hydrogen pyrophosphate (HP2O7(3-)) among halides, HCO3(-), AcO(-), NO3(-), ClO4(-), HSO4(-), OH(-), BzO(-), H2PO4(-), and HP2O7(3-) in acetonitrile. Enhancement of emission intensity of 1[PF6]2 along with a 10 nm red shift of the emission maximum is observed in the presence of H2PO4(-)/HP2O7(3-) selectively. The photoluminescence (PL) titration experiment of 1[PF6]2 results in binding constants (K(a)) of 5.28 × 10(4) M(-1) and 4.67 × 10(4) M(-1) for H2PO4(-) and HP2O7(3-), respectively, which is in good agreement with the Ka values obtained from UV-vis titration experiments (2.97 × 10(4) M(-1) and 2.45 × 10(4) M(-1) for H2PO4(-) and HP2O7(3-), respectively). High selectivity of 1[PF6]2 toward these two anions in acetonitrile is further confirmed by PL intensity measurement of 1[PF6]2 upon addition of these two anions in the presence of a large excess of other competitive anions. Further, considerable changes in the lifetime (τ) as well as in the decay pattern of 1[PF6]2 in the presence of H2PO4(-)/HP2O7(3-) among all tested anions support the selective binding property of 1[PF6]2 toward these two anions. Significant downfield shift of the triazole -CH proton of 1[PF6]2 with 1 equiv of H2PO4(-) (Δδ = 0.26 ppm) and HP2O7(3-) (Δδ = 0.23 ppm) in deuterated dimethyl sulfoxide proclaim binding mechanism via C-H···anion interaction in solution state. Finally, single-crystal X-ray structural analysis confirms the first example of dihydrogen pyrophosphate (H2P2O7(2-)) recognition via solitary C-H···anion interactions.

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

    Science.gov (United States)

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

    2014-11-01

    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]-.

  5. 咪唑类离子液体的合成和光谱表征%Synthesis and Spectroscopic Characterization of N, N'-dialkylimidazolium-based Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    卢泽湘; 袁霞; 吴剑; 王良芥; 罗和安

    2005-01-01

    以N-甲基咪唑为原料合成了离子液体氯化1-丁基-3-甲基咪唑盐([BMIm]Cl)1-丁基-3-甲基咪唑氟硼酸盐([BMIm]BF4)、1-丁基-3-甲基咪唑六氟磷酸盐([BMIm]PF6),并对合成的产物作了紫外光谱、红外光谱、核磁共振的结构表征.

  6. C18:1 Methyl ester metathesis in [bmim][X] type ionic liquids.

    Science.gov (United States)

    Thomas, Priya A; Marvey, Bassie B

    2009-11-18

    The efficacy of [bmim][X] ionic liquids (ILs) (X = PF(6) (-), BF(4) (-) and NTf(2) (-)) as reaction media for methyl oleate metathesis was compared with that of conventional organic solvents (PhCl, PhMe, DCM and DCE) using the well-defined first and second generation Grubbs precatalysts, RuCl(2)(PCy(3))(L)(=CHPh) (L = PCy(3) or H(2)IMes). Best catalytic performance, with excellent selectivity (>98%) at moderate reaction temperatures, was achieved in [bmim][X] ILs compared to conventional solvents. The effects of anion, reaction temperature, solvent polarity, solvent viscosity, and ligand-anion interaction on the reaction are also addressed.

  7. Synthesis, bonding, and reactivity of a cerium(IV) fluoride complex.

    Science.gov (United States)

    Williams, Ursula J; Robinson, Jerome R; Lewis, Andrew J; Carroll, Patrick J; Walsh, Patrick J; Schelter, Eric J

    2014-01-06

    Oxidation of Ce[N(SiMe3)2]3 in the presence of PF6(-) or BF4(-) afforded isolation of CeF[N(SiMe3)2]3. Structural and electrochemical characterization shows that this compound is in its tetravalent oxidation state and contains a terminal fluoride ligand. Spectroscopy and density functional theory have been used to characterize the Ce-F bond as ionic, which is reinforced by an initial reactivity study that demonstrates the nucleophilicity of the fluoride ligand.

  8. Influence of 15-crown-5 additive to a liquid electrolyte on the performance of Li/CFx - Systems at temperatures up to -50 °C

    Science.gov (United States)

    Ignatova, A. A.; Yarmolenko, O. V.; Tulibaeva, G. Z.; Shestakov, A. F.; Fateev, S. A.

    2016-03-01

    The additive of 15-crown-5 for liquid electrolyte for primary Li/CFx cells is proposed. In their presence the cells with 1 M LiBF4 in GBL and 1 M LiPF6 in EC/DMC/EMC are workable at low temperatures. Their discharge capacities are 140 and 110 mAh g-1 at -45 ÷ -50 °C respectively. The 15-crown-5 additive probably is adsorbed on electrodes surfaces and form Li+ conducting layers. This mechanism approved by quantum-chemical modeling.

  9. Photochemical oxidation of water and reduction of polyoxometalate anions at interfaces of water with ionic liquids or diethylether

    OpenAIRE

    Bernardini, Gianluca; Wedd, Anthony G.; Zhao, Chuan; Bond, Alan M.

    2012-01-01

    Photoreduction of [P2W18O62]6-, [S2Mo18O62]4-, and [S2W18O62]4- polyoxometalate anions (POMs) and oxidation of water occurs when water–ionic liquid and water–diethylether interfaces are irradiated with white light (275–750 nm) or sunlight. The ionic liquids (ILs) employed were aprotic ([Bmim]X; Bmim = (1-butyl-3-methylimidazolium,X = BF4,PF6) and protic (DEAS = diethanolamine hydrogen sulphate; DEAP = diethanolamine hydrogen phosphate). Photochemical formation of reduced POMs at both thermody...

  10. Enzymatic Synthesis of Esculin Ester in Ionic Liquids Buffered with Organic Solvents

    DEFF Research Database (Denmark)

    Hu, Yifan; Guo, Zheng; Lue, Bena-Marie

    2009-01-01

    The enzymatic esterification of esculin catalyzed by Candida antarctica lipase B (Novozym 435) was carried out in ionic liquid (IL)-organic solvent mixed systems in comparison with individual systems. The reaction behaviors in IL-organic solvents were systemically evaluated using acetone as a model...... in IL-acetone mixtures made it possible to improve the solubility of esculin while the effects of ILs on lipase activity were minimized. Following the benignity of ILs to lipase activity, the anions of ILs were ranked in the order as [Tf2N](-) > [PF6](-) > [BF4](-) > [CF3SO3](-) > [C4F9SO3](-) > [TAF...

  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

    Energy Technology Data Exchange (ETDEWEB)

    Moosbauer, Dominik Johann

    2010-11-09

    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. Slow relaxation of the magnetization observed in an antiferromagnetically ordered phase for SCM-based two-dimensional layered compounds.

    Science.gov (United States)

    Kagesawa, Koichi; Nishimura, Yuki; Yoshida, Hiroki; Breedlove, Brian K; Yamashita, Masahiro; Miyasaka, Hitoshi

    2017-03-07

    Two-dimensional layered compounds with different counteranions, [{Mn(salen)}4C6](BF4)2·2(CH3OH) (1) and [{Mn(salen)}4C6](PF6)2·2(CH3OH) (2) (salen(2-) = N,N'-bis(salicylideneiminato), C6(2-) = C6H12(COO)2(2-)), were synthesized by assembling [Mn(salen)(H2O)]X (X(-) = BF4(-) and PF6(-)) and C6H12(CO2(-))2 (C6(2-)) in a methanol/2-propanol medium. The compounds have similar structures, which are composed of Mn(salen) out-of-plane dimers bridged by μ(4)-type C6(2-) ions, forming a brick-wall-type network of [-{Mn2}-OCO-] chains alternately connected via C6H12 linkers of C6(2-) moieties. The counteranions for 1 and 2, i.e., BF4(-) and PF6(-), respectively, are located between layers. Since the size of BF4(-) is smaller than that of PF6(-), intra-layer inter-chain and inter-plane nearest-neighbor MnMn distances are shorter in 1 than in 2. The zigzag chain moiety of [-{Mn2}-OCO-] leads to a canted S = 2 spin arrangement with ferromagnetic coupling in the Mn(III) out-of-plane dimer moiety and antiferromagnetic coupling through -OCO- bridges. Due to strong uniaxial anisotropy of the Mn(III) ion, the [-{Mn2}-OCO-] chains could behave as a single-chain magnet (SCM), which exhibits slow relaxation of magnetization at low temperatures. Nevertheless, these compounds fall into an antiferromagnetic ground state at higher temperatures of TN = 4.6 and 3.8 K for 1 and 2, respectively, than active temperatures for SCM behavior. The spin flip field at 1.8 K is 2.7 and 1.8 kOe for 1 and 2, respectively, which is attributed to the inter-chain interactions tuned by the size of the counteranions. The relaxation times of magnetization become longer at the boundary between the antiferromagnetic phase and the paramagnetic phase.

  13. Preparation and Characterization of New Type Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new type of ionic liquids containing cation of diacetone acrylamide [or N-(1,1- bismethyl-3-oxo-butyl)acrylamide] and anions such as CH3COO-(Ac), CF3COO(-(TF), BF4-(BF), PF6-(PF), HSO4-(SO) and Cl-(Cl) were prepared by normal neutralization.The obtained ionic liquids were identified by FT-IR and 1H NMR spectroscopy.However, their properties such as melting point, conductivity, viscosity etc.were determined.

  14. Measurement and Correlation of the Ionic Conductivity of Ionic Liquid-Molecular Solvent Solutions

    Institute of Scientific and Technical Information of China (English)

    LI,Wen-Jing; HAN,Bu-Xing; TAO,Ran-Ting; ZHANG,Zhao-Fu; ZHANG,Jian-Ling

    2007-01-01

    The ionic conductivity of the solutions formed from 1-n-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) or 1-n-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) and different molecular solvents (MSs) were measured at 298.15 K. The molar conductivity of the ionic liquids (ILs) increased dramatically with increasing concentration of the MSs. It was found that the molar conductivity of the IL in the solutions studied in this work could be well correlated by the molar conductivity of the neat ILs and the dielectric constant and molar volume of the MSs.

  15. Metathesis of Fatty Acid Ester Derivatives in 1,1-Dialkyl and 1,2,3-Trialkyl Imidazolium Type Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Priya A. Thomas

    2011-06-01

    Full Text Available The self-metathesis of methyl oleate and methyl ricinoleate was carried out in the presence of ruthenium alkylidene catalysts 1–4 in [bmim] and [bdmim][X] type ionic liquids (RTILs (X = PF6−, BF4– and NTf2− using the gas chromatographic technique. Best catalytic performance was obtained in [bdmim][X] type ionic liquids when compared with [bmim][X] type ionic liquids. Catalyst recycling studies were also carried out in the room temperature ionic liquids (RTILs with catalysts 1–4 in order to explore their possible industrial application.

  16. Metathesis of fatty acid ester derivatives in 1,1-dialkyl and 1,2,3-trialkyl imidazolium type ionic liquids.

    Science.gov (United States)

    Thomas, Priya A; Marvey, Bassie B; Ebenso, Eno E

    2011-01-01

    The self-metathesis of methyl oleate and methyl ricinoleate was carried out in the presence of ruthenium alkylidene catalysts 1-4 in [bmim] and [bdmim][X] type ionic liquids (RTILs) (X = PF(6) (-), BF(4) (-) and NTf(2) (-)) using the gas chromatographic technique. Best catalytic performance was obtained in [bdmim][X] type ionic liquids when compared with [bmim][X] type ionic liquids. Catalyst recycling studies were also carried out in the room temperature ionic liquids (RTILs) with catalysts 1-4 in order to explore their possible industrial application.

  17. 离子液体-CmimPF6分离提纯虾、蟹壳中壳聚糖的研究%Study on Chitosan of Shrimp and Crab Shell by Extracting with Ionic Liquid - CmimPF6

    Institute of Scientific and Technical Information of China (English)

    陶海霞; 廖芳丽; 车剑锋

    2009-01-01

    利用离子液的强溶解性,对虾、蟹粉中的壳聚糖进行分离提纯,与传统方法比较,其提取工艺简单,产率高.而且其它各项综合性能指标均优,离子液体可回收,并减少环境污染.

  18. Antiferromagnetically Coupled Dimeric Dodecacopper Supramolecular Architectures of Macrocyclic Ligands with a Symmetrical μ6-BO3(3-) Central Moiety.

    Science.gov (United States)

    Tandon, Santokh S; Bunge, Scott D; Toth, Sara A; Sanchiz, Joaquin; Thompson, Laurence K; Shelley, Jacob T

    2015-07-20

    Reactions between 2,6-diformyl-4-alkyl(R)-phenol (R = CH3 or C(CH3)3) and 1,3-diamino-2-hydroxypropane (1,3-DAP) in the presence of copper(II) salts (Cu(BF4)2·6H2O, Cu(ClO4)2·6H2O/H3BO3/Ar) and triethylamine (TEA) in a single pot result in self-assembly of dimeric dodecacopper supramolecular architectures of 30-membered hexatopic macrocyclic ligands (H6L4 and H6L5) with unique and fascinating structures having the BO3(3-) anion as the central species bonded to all six copper centers in a symmetrical fashion (μ6-BO3(3-)). A number of closely related macrocyclic hexacopper complexes are reported: {[Cu6(L4)(μ6-BO3)(μ-H2O)(C3H7NO)2(BF4)][BF4]2·3C3H7NO}2 (1) (DMF = C3H7NO), {[Cu6(L4)(μ6-BO3)(μ-C3H7NO)3][ClO4]3·3C3H7NO}2 (2), {[Cu6(L5)(μ6-BO3)(μ-OH)(H2O)3(C3H7NO)][BF4]2·6C3H7NO·4C2H5OH·2H2O}2 (3), {[Cu6(L5)(μ6-BO3)(μ-CH3OH)(CH3OH)2][ClO4]3·10H2O}2 (4), and {[Cu6(L5)(μ6-BO3)(μ-CH3CO2)(μ-CH3O)(CH3OH)][BF4]·13CH3OH·8H2O}2 (5). A polymeric side product {[Cu2(H2L2)(CH3OH)(BF4)][BF4]}n (6), involving a 2 + 2 macrocyclic ligand, was also isolated and structurally characterized. Complex 6 involves dinuclear copper(II) units linked through BF4(-) anions to form a novel 1D single-chain polymeric coordination compound. This appears to be the first report in which a central BO3(3-) species is linked to six copper(II) ions held together by a single macrocyclic ligand through three μ1,1-O(BO3(3-)) and three μ1,3-O(BO3(3-)) bridges. In complexes 1-5 the BO3(3-) is present in the center of the macrocyclic cavity and is bonded to all six metal centers arranged in a benzene-like hexagonal array. In the hexagonal array there are alternate double (μ-alkoxide and μ1,3-O(BO3(3-))) and (μ-phenoxide and μ1,1-O(BO3(3-))) bridges between the Cu(II) centers. The symmetrical hexa-bridging nature of μ6-BO3(3-) is unprecedented in transition metal complex chemistry, and along with alkoxide and phenoxide bridges in the equatorial plane provides effective pathways for an

  19. Ultrasonicwave-assisted extraction of lycopene from fresh tomato with ionic liquid%离子液体在番茄红素提取中的应用研究

    Institute of Scientific and Technical Information of China (English)

    崔萌; 胡乐根; 马停停; 蔡明建; 王秀阁

    2012-01-01

    以1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4)、1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6)、1-乙基-3-甲基咪唑四氟硼酸盐([Emim]BF4)、1-乙基-3-甲基溴盐([Emim]Br)、1-丁基-3-甲基咪唑硫酸一氢盐([Bmim]HSO4)离子液体为萃取剂,并用超声波辅助萃取新鲜番茄中的番茄红素.对离子液体超声波辅助萃取新鲜番茄中的番茄红素的条件进行了优化,优化后的提取条件为:以[Bmim]BF4为萃取溶剂,离子液体浓度:V乙醇/V[Bmim]BF4=3,在固定超声温度为40℃,超声萃取时间10min,超声波功率380W,料液比1:5 (g/mL)时,效果最佳.%Applying the ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborat ([ Bmim] BF4 ) , 1-butyl-3-methylimidazolium hexafluorophosphate( [Bmim]PF6) ,1-ethyl-3-methylimidazolium tetrafluoroborat( [Emim] BF4) ,1-butyl-3-methylimidazolium bro-mide( [Emim]Br) ,and 1-butyl-3-methylimizolium hydrosulfate( [Bmim]HSO4)as solvents,the ultrasonicwave-assisted solvent extraction of lycopene from fresh tomato were investigated, and the influences of extraction parameters on the extraction yield were discussed. The optimal operating conditions for ultrasonicwave-assisted extraction of lycopene with ionic liquid as solvent was obtained as follows;the suitable solvent used was[Bmim]BF4 with concentration of Vethanol/V[Bmin]BF = 3, ultrasonic temperature was fixed to ,the ultrasonic extraction time was 10 min and the ultrasonicwave power was 380 W.then the extraction effect was excellent

  20. Biocatalytic Synthesis of Salidroside by β-Glucosidase in Ionic Liquids%离子液体中β-葡萄糖苷酶生物催化合成红景天甙

    Institute of Scientific and Technical Information of China (English)

    王梦亮; 郭春侠

    2011-01-01

    比较了聚乙二醇修饰的β-葡萄糖苷酶在三种离子液体([bmim]PF6,[bmim]BF4,[bmim]Tf2N)及两种常用有机溶剂(1,4-二氧六环、正己烷)中的催化性能,确定了适宜的反应介质;考察了底物浓度、温度、体系含水量和反应时间等因素对β-葡萄糖苷酶催化合成红景天甙反应的影响.结果表明,在最佳反应介质[bmim]PF6存在下,底物酪醇浓度为70 mmol/L,体系含水量2%,于50℃,反应24 h时,高达88.5%的酪醇转化为红景天甙(即61.93 mmol/L).与有机溶剂相比,以[bmim]PF6为反应介质对酶促合成红景天甙的反应过程具有明显的强化作用.%β-Glucosidase modified with polyethylene glycol (PEG) was used as catalyst for the synthesis of salidroside from tyrosol and D-glucose, and its catalytic activity in three ionic liquids, [bmim]PF6, [bmim]BF4, and [bmim]Tf2N, and two common organic solvents, 1,4-dioxane and n-hexane, was measured. Ionic liquid [bmim]PF6 was the optimal reaction medium, and different reaction conditions were optimized in it. A yield of 88.5% (product content of 61.93 mmol/L) was obtained under the conditions of H2O content of 2%, temperature of 50 ℃, tyrosol content of 70 mmol/L, D-glucose/tyrosol molar ratio of 2, and reaction time of 24 h. The results suggest that both the modification with PEG and using ionic liquid [bmim]PF6 as reaction medium have obvious promoting effects on the enzymatic synthesis of salidroside.

  1. Anion Complexes with Tetrazine-Based Ligands: Formation of Strong Anion-π Interactions in Solution and in the Solid State.

    Science.gov (United States)

    Savastano, Matteo; Bazzicalupi, Carla; Giorgi, Claudia; García-Gallarín, Celeste; López de la Torre, Maria Dolores; Pichierri, Fabio; Bianchi, Antonio; Melguizo, Manuel

    2016-08-15

    Ligands L1 and L2, consisting of a tetrazine ring decorated with two morpholine pendants of different lengths, show peculiar anion-binding behaviors. In several cases, even the neutral ligands, in addition to their protonated HL(+) and H2L(2+) (L = L1 and L2) forms, bind anions such as F(-), NO3(-), PF6(-), ClO4(-), and SO4(2-) to form stable complexes in water. The crystal structures of H2L1(PF6)2·2H2O, H2L1(ClO4)2·2H2O, H2L2(NO3)2, H2L2(PF6)2·H2O, and H2L2(ClO4)2·H2O show that anion-π interactions are pivotal for the formation of these complexes, although other weak forces may contribute to their stability. Complex stability constants were determined by means of potentiometric titration in aqueous solution at 298.1 K, while dissection of the free-energy change of association (ΔG°) into its enthalpic (ΔH°) and entropic (TΔS°) components was accomplished by means of isothermal titration calorimetry measurements. Stability constants are poorly regulated by anion-ligand charge-charge attraction. Thermodynamic data show that the formation of complexes with neutral ligands, which are principally stabilized by anion-π interactions, is enthalpically favorable (-ΔG°, 11.1-17.5 kJ/mol; ΔH°, -2.3 to -0.5 kJ/mol; TΔS°, 9.0-17.0 kJ/mol), while for charged ligands, enthalpy changes are mostly unfavorable. Complexation reactions are invariably promoted by large and favorable entropic contributions. The importance of desolvation phenomena manifested by such thermodynamic data was confirmed by the hydrodynamic results obtained by means of diffusion NMR spectroscopy. In the case of L2, complexation equilibria were also studied in a 80:20 (v/v) water/ethanol mixture. In this mixed solvent of lower dielectric constant than water, the stability of anion complexes decreases, relative to water. Solvation effects, mostly involving the ligand, are thought to be responsible for this peculiar behavior.

  2. 离子液体/有机两相催化新进展%Recent Advances in Ionic liquid -organic Biphasic Catalysis

    Institute of Scientific and Technical Information of China (English)

    焦国柱

    2012-01-01

    综述了近年来离子液体/有机两相均相催化的研究进展,重点介绍了基于氟硼酸根(BF4-)或氟磷酸根(PF6-)的咪唑类离子液体在均相催化加氢、氢甲酰化、齐聚、Heck反应中的应用,并对离子液体/有机两相催化工业应用的前景进行了探讨。%The development of ionic liquid - organic two - phasic catalysis was summerized, the applications of imid- azole class ionic liquid based were introduced with emphasis based on the fluoboric acid anion ( BF4- ) or the hexafluoro- phosphoric acid anion (PF6- ) in homogeneous catalysis hydrogenation, hydroformylation, oligomerization, Heek reaction, and the future applications of ionic liquid - organic biphasic catalysis in chemical industry were commented.

  3. Research progress on application of ionic liquid-organic biphasic catalysis%离子液体/有机两相催化应用研究进展

    Institute of Scientific and Technical Information of China (English)

    李玉成; 王恒生; 程艳婷; 郭振美

    2011-01-01

    作者就近年来离子液体/有机两相催化在加氢、氢甲酰化、齐聚、Heck反应和羰基化反应中的研究进展进行了综述,重点介绍了基于氟硼酸根(BF4-)或氟磷酸根(PF6 -)的咪唑类离子液体在均相催化反应中的应用,并对离子液体/有机两相催化工业应用的前景进行了探讨.%This paper described the development of ionic liquid-organic biphasic catalysis in hydrogena-tion,hydroformylation,oligomerization, Heck reaction and carbonylation,introduced emphatically the applications of imidazole class ionic liquid based on the fluoboric acid anion (BF4- ) or the hexafluoro-phosphoric acid anion (PF6- ) in the homogeneous catalysis,and commented the future applications of ionic liquid-organic biphasic catalysis in chemical industry.

  4. Synthesis of phosphinoferrocene amides and thioamides from carbamoyl chlorides and the structural chemistry of Group 11 metal complexes with these mixed-donor ligands.

    Science.gov (United States)

    Fernandes, Tiago A; Solařová, Hana; Císařová, Ivana; Uhlík, Filip; Štícha, Martin; Štěpnička, Petr

    2015-02-21

    The reaction of in situ generated 1'-(diphenylphosphino)-1-lithioferrocene with carbamoyl chlorides, ClC(E)NMe2, affords the corresponding (thio)amides, Ph2PfcC(E)NMe2 (E = O (), S (); fc = ferrocene-1,1'-diyl). These compounds as well as their analogues, Ph2PfcC(O)NHMe () and Ph2PfcC(O)NH2 (), prepared from 1'-(diphenylphosphino)ferrocene-1-carboxylic acid (Hdpf) were studied as ligands for the Group 11 metal ions. In the reactions with [Cu(MeCN)4][BF4], the amides give rise to bis-chelate complexes of the type [Cu(L-κ(2)O,P)2][BF4]. Similar products, [Ag(L-κ(2)O,P)2]ClO4, are obtained from silver(i) perchlorate and , or . In contrast, the reaction of AgClO4 with produces a unique molecular dimer [Ag()(ClO4-κO)]2, where the metal centres are bridged by the sulfur atoms of the P,S-chelating thioamides. The reactions of with [AuCl(tht)] (tht = tetrahydrothiophene) afford the expected gold(i)-phosphine complexes, [AuCl(L-κP)], containing uncoordinated (thio)amide moieties. Hemilabile coordination of the phosphinoamide ligands in complexes with the soft Group 11 metal ions is established by the crystal structure of a solvento complex, [Cu(-κ(2)O,P)(-κP)(CHCl3-κCl)][BF4], which was isolated serendipitously during an attempted crystallisation of [Cu(-κ(2)O,P)2][BF4]. All of the compounds are characterised by spectroscopic methods, and the structures of several representatives of both the free phosphinoamides and their complexes are determined by X-ray diffraction analysis and further studied by DFT calculations and cyclic voltammetry.

  5. Ion aggregation in high salt solutions. VI. Spectral graph analysis of chaotropic ion aggregates

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-11-01

    Carrying out molecular dynamics simulations and graph theoretical analyses of high salt solutions, and comparing numerically calculated vibrational spectroscopic properties of water with femtosecond IR pump-probe experimental data, we have recently found that ions in high salt solutions can form two morphologically different ion aggregate structures. In the cases of NaCl solutions, Na+ and Cl- tend to form compact cluster-like ion aggregate in high NaCl solutions. In contrast, K+ and SCN- form spatially extended network-like ion aggregates that also exhibit a percolating network behavior. Interestingly, a variety of graph theoretical properties of ion network in high KSCN solutions were found to be very similar to those of water H-bonding network. It was shown that spatially extended ion networks in high KSCN solutions are completely intertwined with water H-bonding networks, which might be the key to understand the high solubility of thiocyanate salts in water. Here, we further consider two salts that have been extensively studied experimentally by using femtosecond IR pump-probe technique, which are NaClO4 and NaBF4. Note that ClO4 - and BF4 - are well-known chaotropic ions that have been believed to behave as water structure breaker. To understand how such chaotropic ions affect water H-bonding structure, we carried out spectral graph analyses of molecular dynamics simulation data of these aqueous solutions. Graph spectra and degree distribution of ion aggregates formed in high NaBF4 and NaClO4 solutions show that these chaotropic anions also have a strong propensity to form ion networks. The fact that salts containing chaotropic ions like SCN-, BF4 - , and ClO4 - have very high solubility limits in water could then be related to our observation that these chaotropic anions with counter cations in high salt solutions are capable of forming intricate ion networks intertwined with water H-bonding networks. We anticipate that the present graph theoretical analysis

  6. 离子液体对β-糖苷酶催化合成红景天苷的影响%Ionic Liquid Effects on the Activity of β-Glycosidase for the Synthesis of Salidroside in Co-solvent Systems

    Institute of Scientific and Technical Information of China (English)

    毕艳红; 王朝宇; 茅燕勇; 郑尚永; 张海江; 时号

    2012-01-01

    研究了混合溶剂体系中阴离子分别为BF4-,PF6-,Cl-,Br-和r的14种离子液体对来源于黑布林糖苷酶催化合成红景天苷反应的影响.结果表明,在最佳反应条件下,β-糖苷酶的反应初速度和红景天苷的产率分别为3.3mmol/(L·h)和24.5%.离子液体咪唑阳离子的烷基链长(C2~C10)对β-糖苷酶的活性影响较大,当烷基链长为C6时,糖苷酶表现出较高的催化活性.%The preparation of salidroside was successfully carried out in fourteen ionic liquids (ILs)-containing systems using β-glycosidase from black plum seeds for the first time.The optimum conditions were determined for C6Mlm·BF4,pH,phosphate buffer content,and molar ratio of tyrosol to D-glucose to be 1% (v/v),5.9,20% (v/v),and 8∶1,under which the initial reaction rate and yield were 3.3 mmol/(L·h) and 24.5%,respectively.Moreover,the effects of 1-alkylimidazolium-based ILs possessing different alkyl chain lengths from C2 to C10 and a variety of anions including BF-4,PF-6,Cl-,Br-,and I- on enzyme activity in co-solvent systems were investigated.The results indicate that the optimal chain length of the alkyl substituent on the imidazolium ring of the cation was C6.

  7. Charge-assisted triel bonding interactions in solid state chemistry: A combined computational and crystallographic study

    Science.gov (United States)

    Bauzá, Antonio; García-Llinás, Xavier; Frontera, Antonio

    2016-12-01

    A combined energetic and geometric study of a series of triel bond complexes involving haloborane salts has been carried out at the M06-2X/def2-QZVPD level of theory. We have used 1-(dihaloboranyl)pyridin-1-ium compounds Py+BX2 (X = Cl, Br and I) as triel bond donors and Cl-, Br-, HCO2-, BF4- and ClO4- as electron donor moieties. In addition we have used Bader's theory of 'atoms in molecules' to further characterize the noncovalent interactions described herein. Finally, several examples were retrieved from the CSD (Cambridge Structural Database) in order to provide experimental support to the results presented in this work.

  8. Predicting the partitioning of biological compounds between room-temperature ionic liquids and water by means of the solvation-parameter model.

    Science.gov (United States)

    Padró, Juan M; Ponzinibbio, Agustín; Mesa, Leidy B Agudelo; Reta, Mario

    2011-03-01

    The partition coefficients, P(IL/w), for different probe molecules as well as for compounds of biological interest between the room-temperature ionic liquids (RTILs) 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF(6)], 1-hexyl-3-methylimidazolium hexafluorophosphate, [HMIM][PF(6)], 1-octyl-3-methylimidazolium tetrafluoroborate, [OMIM][BF(4)] and water were accurately measured. [BMIM][PF(6)] and [OMIM][BF(4)] were synthesized by adapting a procedure from the literature to a simpler, single-vessel and faster methodology, with a much lesser consumption of organic solvent. We employed the solvation-parameter model to elucidate the general chemical interactions involved in RTIL/water partitioning. With this purpose, we have selected different solute descriptor parameters that measure polarity, polarizability, hydrogen-bond-donor and hydrogen-bond-acceptor interactions, and cavity formation for a set of specifically selected probe molecules (the training set). The obtained multiparametric equations were used to predict the partition coefficients for compounds not present in the training set (the test set), most being of biological interest. Partial solubility of the ionic liquid in water (and water into the ionic liquid) was taken into account to explain the obtained results. This fact has not been deeply considered up to date. Solute descriptors were obtained from the literature, when available, or else calculated through commercial software. An excellent agreement between calculated and experimental log P(IL/w) values was obtained, which demonstrated that the resulting multiparametric equations are robust and allow predicting partitioning for any organic molecule in the biphasic systems studied.

  9. Synthesis of Nano-sized Yttria via a Sol-Gel Process Based on Hydrated Yttrium Nitrate and Ethylene Glycol and Its Catalytic Performance for Thermal Decomposition of NH4 ClO4

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nano-sized yttria particles were synthesized via a non-aqueous sol-gel process based on hydrated yttrium nitrate and ethylene glycol. The effects of the molar ratio of ethylene glycol to yttrium ion and calcination temperature on crystallite size of the products were studied. The catalytic performance of the as-prepared yttria for the ammonium perchlorate (AP) decomposition was investigated by differential scanning calorimetry (DSC). The results indicate that the nano-sized cubic yttria particles with less than 20 nm in average crystallite size can be obtained after 2 h reflux at 70 ℃, dried at 90 ℃, forming xerogel, and followed by annealing of xerogel for 2 h, and that the addition of the nano-sized yttria to AP incorporates two small exothermic peaks of AP in the temperature ranges of 310 ~ 350 ℃ and 400 ~ 470 ℃ into a strong exothermic peak of AP and increases the apparent decomposition heat from 515 to over 1110 J·g-1. It is also clear that the temperature of AP decomposition exothermic peak decreases and the apparent decomposition heat of AP increases with the increase of the amount of nano-sized yttria. The fact that the addition of the 5 % nano-sized yttria to AP decreases the temperature of AP exothermic peak to 337.7 ℃ by reduction of 114.6 ℃ and increases the apparent decomposition heat from 515 to 1240 J·g-1, reveals that nano-sized yttria shows strong catalytic property for AP thermal decomposition.

  10. Synthesis and Structure of a NovelTetranuclear Erbium( Ⅲ) Complex with α-Alanine [Er4(Hala)6·(μ3-OH)4(H2O)8](ClO4)8·3H2O

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The title complex was synthesized in an aqueous solution and its crystal structure was determined by X-ray diffraction. The crystal crystallizes in a triclinic system, space group P1 with a=1.306 3(2) nm, b=1.319 4(4) nm, c=1.950 2(4) nm, α=90.597(14)°, β=93.998(11)°, γ=94.093(13)°, V=3.344 1(12) nm3, Z=2, the final R indices are R1=0.065 4, wR2=0.126 2 respectively. The complex contains a novel tetranuclear cluster cation with four Er3+ ions connected by four μ3-OH ions and six bridging carboxyl groups. Each erbium ion is coordinated by three μ3-OH, three carboxylic oxygen atoms from three α-alanine and two oxygen atoms from water molecules, forming a square-antiprismatic coordination polyhedron.

  11. A kinetic model for photoswitching of magnetism in the high spin molecule [Mo(IV)(CN)2(CN-Cu(II)(tren))6](ClO4)8.

    Science.gov (United States)

    Raghunathan, Rajamani; Ramasesha, S; Mathonière, Corine; Marvaud, Valérie

    2008-09-21

    The heptanuclear complex [Mo(IV)(CN)2(CN-CuL)6]8+ switches from a paramagnetic dark state corresponding to six spin-1/2 Cu(II) ions to a predominantly high spin S = 3 state, on prolonged irradiation with 406 nm laser radiation at low temperature. The system returns to a paramagnetic state on warming to room temperature. The temperature dependence of the chiMT vs. T curve depends upon duration of irradiation. An earlier microscopic model showed that the excitation cross sections in different spin manifolds are similar in magnitude and that photomagnetism is not due to preferential excitation to the S = 3 state. In this paper, we attribute photomagnetism to a long lived S = 3 charge transfer excited state for which there appears to be sufficient experimental evidence. Based on this postulate, we model the photomagnetism by employing a kinetic model which includes internal conversions and intersystem crossings. The key feature of the model is the assumption of the existence of two kinds of S = 3 states: one of which has no direct pathway for internal conversion and the other characterized by slow kinetics for internal conversion to the low-energy states. The trapped S = 3 state can decay via a thermally activated barrier to the other S = 3 state. The experimental chiMT vs. T for two different irradiation times are fitted using Arrhenius dependence of the rate constants in the model.

  12. A kinetic model for photoswitching of magnetism in the high spin molecule [Mo(iv)(CN)2(CN Cu(ii)(tren))6](ClO4)8

    Science.gov (United States)

    Raghunathan, Rajamani; Ramasesha, S.; Mathonière, Corine; Marvaud, Valérie

    The heptanuclear complex [Mo(IV)(CN)2(CN-CuL)6]8+ exhibits photomagnetism. An earlier microscopic model showed that the transition dipole moments for excitation in different spin manifolds are similar in magnitude. In this paper, we attribute photomagnetism to the long lived S=3 charge transfer excited state for which there appears to be sufficient experimental evidence. We model the photomagnetism by employing a kinetic model which includes internal conversions and intersystem crossings. The key feature of the model is assumption of the existence of two kinds of S=3 states: one which has no direct pathway for internal conversion and the other characterized by slow kinetics for internal conversion to the low-energy states. The trapped S=3 state can decay via a thermally activated barrier to the other S=3 state. The experimental temperature dependence of magnetization plot is fitted using rate constants with Arrhenius dependence. The two different experimental cMT vs. T curves obtained with different irradiation times are fitted with our model. Our studies show that the photomagnetism in these systems is governed by kinetics and not due to differences in oscillator strengths for excitation of the different spin states.

  13. Synthesis, structural characterization, and benzyl alcohol oxidation activity of mononuclear manganese(II) complex with 2,2'-bipyridine: [Mn(bipy)2(ClO4)2

    OpenAIRE

    KANİ, İbrahim; KURTÇA, Mehmet

    2012-01-01

    A manganese(II) complex of 2,2'-bipyridine (bipy) was synthesized and characterized by X-ray diffraction, IR, and UV-vis spectroscopy. The activity of the complex was tested for oxidation of benzyl alcohols using t-BuOOH as an oxidant in organic solvents and in an organic/water biphasic system (hexane/H2O, toluene/H2O). The effect of solvent, temperature, oxidant, and some additives (KBr, N(C4H9)Br, and N-bromosuccinimide) on the oxidation of benzyl alcohol is reported. The res...

  14. Novel superconducting phenomena in quasi-one-dimensional Bechgaard salts

    Science.gov (United States)

    Jerome, Denis; Yonezawa, Shingo

    2016-03-01

    It is the saturation of the transition temperature Tc in the range of 24 K for known materials in the late sixties that triggered the search for additional materials offering new coupling mechanisms leading in turn to higher Tc's. As a result of this stimulation, superconductivity in organic matter was discovered in tetramethyl-tetraselenafulvalene-hexafluorophosphate, (TMTSF)2PF6, in 1979, in the laboratory founded at Orsay by Professor Friedel and his colleagues in 1962. Although this conductor is a prototype example for low-dimensional physics, we mostly focus in this article on the superconducting phase of the ambient-pressure superconductor (TMTSF)2ClO4, which has been studied most intensively among the TMTSF salts. We shall present a series of experimental results supporting nodal d-wave symmetry for the superconducting gap in these prototypical quasi-one-dimensional conductors. xml:lang="fr"

  15. Permeability and Selectivity of Sulfur Dioxide and Carbon Dioxide in Supported Ionic Liquid Membranes%二氧化硫和二氧化碳在离子液体支撑液膜中的渗透率和选择性

    Institute of Scientific and Technical Information of China (English)

    江滢滢; 吴有庭; 王文婷; 李磊; 周政; 张志炳

    2009-01-01

    Permeabilities and selectivities of gases such as carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen (N2) and methane (CH4) in six imidazolium-based ionic liquids ([emim][BF4], [bmim][BF4], [bmim][PF6], [hmim][BF4], [bmim][Tf2N] and [emim][CF3SO3]) supported on polyethersulfone microfiltration membranes are investigated in a single gas feed system using nitrogen as the environment and reference component at temperature from 25 to 45℃ and pressure of N2 from 100 to 400 kPa. It is found that SO2 has the highest permeability in the tested supported ionic liquid membranes, being an order of magnitude higher than that of CO2, and about 2 to 3 or-ders of magnitude larger than those of N2 and CH4. The observed selectivity of SO2 over the two ordinary gas components is also striking. It is shown experimentally that the dissolution and transport of gas components in the supported ionic liquid membranes, as well as the nature of ionic liquids play important roles in the gas permeation. A nonlinear increase of permeation rate with temperature and operation pressure is also observed for all sample gases. By considering the factors that influence the permeabilities and selectivities of CO2 and SO2, it is expected to develop an optimal supported ionic liquid membrane technology for the isolation of acidic gases in the near future.

  16. Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO2 Separation from CH4 and N2

    Directory of Open Access Journals (Sweden)

    Ksenia V. Otvagina

    2016-06-01

    Full Text Available CO2 separation was found to be facilitated by transport membranes based on novel chitosan (CS–poly(styrene (PS and chitosan (CS–poly(acrylonitrile (PAN copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF4], [bmim][PF6], and [bmim][Tf2N] (IL. CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75–104 MPa for CS-PAN and 69–75 MPa for CS-PS. Ionic liquid (IL doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO2 permeability 400 Barrers belongs to CS-b-PS/[bmim][BF4]. The highest selectivity α (CO2/N2 = 15.5 was achieved for CS-b-PAN/[bmim][BF4]. The operational temperature of the membranes is under 220 °C.

  17. MD simulations of the formation of stable clusters in mixtures of alkaline salts and imidazolium-based ionic liquids.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; Bouzón-Capelo, Silvia; Pérez-Rodríguez, Martín; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

    2013-03-21

    Structural and dynamical properties of room-temperature ionic liquids containing the cation 1-butyl-3-methylimidazolium ([BMIM](+)) and three different anions (hexafluorophosphate, [PF6](-), tetrafluoroborate, [BF4](-), and bis(trifluoromethylsulfonyl)imide, [NTf2](-)) doped with several molar fractions of lithium salts with a common anion at 298.15 K and 1 atm were investigated by means of molecular dynamics simulations. The effect of the size of the salt cation was also analyzed by comparing these results with those for mixtures of [BMIM][PF6] with NaPF6. Lithium/sodium solvation and ionic mobilities were analyzed via the study of radial distribution functions, coordination numbers, cage autocorrelation functions, mean-square displacements (including the analysis of both ballistic and diffusive regimes), self-diffusion coefficients of all the ionic species, velocity and current autocorrelation functions, and ionic conductivity in all the ionic liquid/salt systems. We found that lithium and sodium cations are strongly coordinated in two different positions with the anion present in the mixture. Moreover, [Li](+) and [Na](+) cations were found to form bonded-like, long-lived aggregates with the anions in their first solvation shell, which act as very stable kinetic entities within which a marked rattling motion of salt ions takes place. With very long MD simulation runs, this phenomenon is proved to be on the basis of the decrease of self-diffusion coefficients and ionic conductivities previously reported in experimental and computational results.

  18. Anion-Directed Copper(II) Metallocages, Coordination Chain, and Complex Double Salt: Structures, Magnetic Properties, EPR Spectra, and Density Functional Study.

    Science.gov (United States)

    Wu, Jing-Yun; Zhong, Ming-Shiou; Chiang, Ming-Hsi; Bhattacharya, Dibyendu; Lee, Yen-Wei; Lai, Long-Li

    2016-05-17

    A series of Cu(II) metallo-assemblies showing anion-directed structural variations, including five metallocages [(G(n-) )⊂{Cu2 (Hdpma)4 }]((8-n)+) (A(-) )8-n (G(n-) =NO3 (-) , ClO4 (-) , SiF6 (2-) , BF4 (-) , SO4 (2-) ; A(-) =NO3 (-) , ClO4 (-) , BF4 (-) , CH3 SO4 (-) ; Hdpma=bis(3-pyridylmethyl)ammonium cation), a complex double salt, namely, (H3 dpma)4 (CuCl4 )5 Cl2 , and a coordination chain, namely, [Cu2 (dpma)(OAc)4 ], are reported. The influence of the anion can be explained by its coordinating ability, the affinity of which for the Cu(II) center interferes significantly with metallocage formation, and its shape, which offers host-guest recognition ability to engage in weak metal-anion coordination and hydrogen bonding to the organic ligand, which are responsible for metallocage templation. EPR studies of these metallocages in the powder phase at room temperature and 77 K showed a trend of the g values (g|| >2.10>g⊥ >2.00) indicating a dx2-y2 -based ground state with square-pyramidal geometry for the Cu(II) centers. The magnetism of these metallocages can be interpreted as the result of a combination of relatively small magnetic coupling integrals and a substantial contribution of temperature-independent paramagnetism (TIP). The weak magnetic interaction is corroborated by the results of DFT calculations and the EPR spectra. Availability of the low-lying state for spin population was confirmed by a magnetization study, which revealed a magnetic moment approaching 2Nβ, which would explain the presence of the larger TIP term.

  19. Interaction of anions with substituted buckybowls. The anion's nature and solvent effects.

    Science.gov (United States)

    Campo-Cacharrón, Alba; Cabaleiro-Lago, Enrique M; González-Veloso, Iván; Rodríguez-Otero, Jesús

    2014-08-07

    Complexes formed by CN-substituted corannulene and sumanene with monovalent anions have been computationally studied to evaluate the effect of anion's nature and solvent upon the interaction. The results indicate that the most stable complex arrangement corresponds in all cases to the anion located by the center of the concave face of the bowl. All complexes are remarkably stable in the gas phase, with interaction energies ranging from -47 to -24 kcal/mol depending on the anion and the bowl considered. The order of stability for the different anion complexes in the gas phase is CO2H(-) > Cl(-) > Br(-) > NO3(-) ≫ ClO4(-) > BF4(-). Regarding the bowl employed, the intensity of the interaction is largest with the sumanene derivative substituted in the C-H aromatic groups. The weakest interactions are obtained with the sumanene derivative substituted in the CH2 groups, whereas complexes with the corannulene derivative give intermediate values. NO3(-) is oriented parallel to the bowl in the most stable complexes, whereas CO2H(-) prefers being oriented perpendicular to the bowl; ClO4(-) and BF4(-) arrange themselves with three bonds pointing to the bowl. These orientations are preferred on the basis of larger electrostatic and dispersion interactions. The preference of anions for the concave face of the bowl not only is mainly related to larger electrostatic interactions but also is because dispersion and induction are larger than in other arrangements considered. The presence of solvent modeled with a continuum model has a deep impact on the interaction energies already in solvents with low dielectric constant. All complexes remain stable, though energies in water hardly reach -7 kcal/mol. Br(-) complexes are the most stable in solvent, whereas CO2H(-) ones suffer a large penalty in solvent, becoming among the least stable complexes despite being the most stable in the gas phase.

  20. Hydrogen bonding and multiphonon structure in copper pyrazine coordination polymers.

    Science.gov (United States)

    Brown, S; Cao, J; Musfeldt, J L; Conner, M M; McConnell, A C; Southerland, H I; Manson, J L; Schlueter, J A; Phillips, M D; Turnbull, M M; Landee, C P

    2007-10-15

    We report a systematic investigation of the temperature-dependent infrared vibrational spectra of a family of chemically related coordination polymer magnets based upon bridging bifluoride (HF(2)-) and terminal fluoride (F-) ligands in copper pyrazine complexes including Cu(HF(2))(pyz)(2)BF(4), Cu(HF(2))(pyz)(2)ClO(4), and CuF(2)(H(2)O)(2)(pyz). We compare our results with several one- and two-dimensional prototype materials including Cu(pyz)(NO(3))(2) and Cu(pyz)(2)(ClO(4))(2). Unusual low-temperature hydrogen bonding, local structural transitions associated with stronger low-temperature hydrogen bonding, and striking multiphonon effects that derive from coupling of an infrared-active fundamental with strong Raman-active modes of the pyrazine building-block molecule are observed. On the basis of the spectroscopic evidence, these interactions are ubiquitous to this family of coordination polymers and may work to stabilize long-range magnetic ordering at low temperature. Similar interactions are likely to be present in other molecule-based magnets.

  1. A chiral alkyltris(pyrazolyl)borate ligand: synthesis of [(Ipc)B(pz)3Mn(CO)3] and [(Ipc)B(pz)3Ru(p-cymene)]PF6 (Ipc = Isopinocampheyl).

    Science.gov (United States)

    Bailey, Philip J; Pinho, Pedro; Parsons, Simon

    2003-12-29

    The application of the reagent (Ipc)BCl(2) (Ipc = isopinocampheyl) in the synthesis of a new tris(pyrazolyl)borate ligand having an Ipc substituent on boron is described. The sodium salt is a convenient precursor for the preparation of the complexes [(Ipc)tris(pyrazolyl)borato]tricarbonylmanganese and [[(Ipc)tris(pyrazolyl)borato](p-cymene)ruthenium](+), whose X-ray crystal structures are reported. While little distortion of the B(pz)(3)M unit is observed in these complexes, steric interaction between the Ipc group and the 3-positions of the pyrazolyl rings is noted to lead to distortion of the angles around the B-C bond.

  2. The first example of metallocene-like coordination mode of THBQ(4-): a mixed-valence heptanucler palladium complex [Pd7(THBQ)2(tben)6](PF6)4.

    Science.gov (United States)

    Asato, Eiji; Kyan, Ayano; Madanbashi, Tomokura; Tamura, Toshihide; Tadokoro, Makoto; Mizuno, Motohiro

    2010-02-28

    The title compound adopts a structure reminiscent of metallocene analogues, in which two disk-like units [Pd(II)(3)(THBQ)(tben)(3)](2+) bind to one naked Pd(0) metal in a sandwich form through each C(6)O(6)(4-) (THBQ(4-)) ring with an eta(6)-binding fashion.

  3. 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

    OpenAIRE

    Saha Sanjoy; Brahman Dhiraj; Sinha Biswajit

    2015-01-01

    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) sal...

  4. 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

    Directory of Open Access Journals (Sweden)

    Saha Sanjoy

    2015-01-01

    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.

  5. Requirements for functional models of the iron hydrogenase active site: D2/H2O exchange activity in ((mu-SMe)(mu-pdt)[Fe(CO)2(PMe3)]2+)[BF4-].

    Science.gov (United States)

    Georgakaki, Irene P; Miller, Matthew L; Darensbourg, Marcetta Y

    2003-04-21

    Hydrogen uptake in hydrogenase enzymes can be assayed by H/D exchange reactivity in H(2)/D(2)O or H(2)/D(2)/H(2)O mixtures. Diiron(I) complexes that serve as structural models for the active site of iron hydrogenase are not active in such isotope scrambling but serve as precursors to Fe(II)Fe(II) complexes that are functional models of [Fe]H(2)ase. Using the same experimental protocol as used previously for ((mu-H)(mu-pdt)[Fe(CO)(2)(PMe(3))](2)(+)), 1-H(+) (Zhao et al. J. Am. Chem. Soc. 2001, 123, 9710), we now report the results of studies of ((mu-SMe)(mu-pdt)[Fe(CO)(2)(PMe(3))](2)(+)), 1-SMe(+), toward H/D exchange. The 1-SMe(+) complex can take up H(2) and catalyze the H/D exchange reaction in D(2)/H(2)O mixtures under photolytic, CO-loss conditions. Unlike 1-H(+), it does not catalyze H(2)/D(2) scrambling under anhydrous conditions. The molecular structure of 1-SMe(+) involves an elongated Fe.Fe separation, 3.11 A, relative to 2.58 A in 1-H(+). It is proposed that the strong SMe(-) bridging ligand results in catalytic activity localized on a single Fe(II) center, a scenario that is also a prominent possibility for the enzyme active site. The single requirement is an open site on Fe(II) available for binding of D(2) (or H(2)), followed by deprotonation by the external base H(2)O (or D(2)O).

  6. Part A. Molecular Dynamics and Ionic Associations of LiAsF6 in 4-Butyrolactone Mixtures with 2-Methyl Tetrahydrofuran. Part B. Molecular Dynamics and Ionic Associations of LiBF4 in 1,2-Dimethoxymethane.

    Science.gov (United States)

    2014-09-26

    relaxations. LIAsF. solutions in pure 2MeTHF (3) show only a single Debye process, and -12- at this time we cannot determine which solvent component ...expression KFj- 4 7rL ds e- /2 e b KJ= ’ e-~ e(II) 3000 It results in a charge to charge separation in the pair d = 5.1xlO- Scm . Similarly by equating...gx1l- Scm , a value that seems too high to be reconciled with the triple ions model and definition envisaging the three Ions at contact, whereas, the value

  7. 咪唑类离子液体的微波水浴合成及性能研究%Study on microwave-assisted synthesis and performance of imidazole ionic liquids

    Institute of Scientific and Technical Information of China (English)

    李昌家; 李景印; 李娜; 郭玉凤; 刘方方

    2012-01-01

    以N-甲基咪唑、氯代正丁烷、KPF6及NaBF4等为原料,分别在微波和水浴2种加热条件下利用二步法合成出2种咪唑类离子液体[BMIM]PF6和[BMIM]BF4.比较了2种方法在中间体合成及阴离子置换中的优势和劣势,并利用IR,TGA和LSV等方法表征了所得离子液体的结构特征及电化学性能.结果表明,2种方法所合成的离子液体在物化性质上无明显差异.微波法在合成中间体时可显著缩短反应时间,产率可达90%以上;水浴加热法则更有利于阴离子置换.故采用微波法与水浴加热法相结合的方式合成离子液体可收到良好的效果.%Two kinds of imidazole ionic liquids([BM1M]PF6 and [BMIM]BF4) are synthesized from N-methyl-midazolium, chlorobutane, KPF6 and NaBF4 under microwave irradiation and water bath heating respectively by two-step method. The advantage and disadvantage in the synthesis of intermediate and anion exchange are compared, and the structure characteristics and electrochemical performance are characterized. The result shows that the ionic liquids synthesized by two different methods have no evident discrepancy. The reaction time can be cut down markedly under the microwave, and the productivity can exceed 90% , while the water bath heating is propitious to anion exchange. So combining the two methods will get a favorable result.

  8. Anion-exchange and anthracene-encapsulation within copper(II) and manganese(II)-triazole metal-organic confined space in a single crystal-to-single crystal transformation fashion.

    Science.gov (United States)

    Liu, Ju-Yan; Wang, Qian; Zhang, Li-Jun; Yuan, Bin; Xu, Yao-Yao; Zhang, Xin; Zhao, Cong-Ying; Wang, Dan; Yuan, Yue; Wang, Ying; Ding, Bin; Zhao, Xiao-Jun; Yue, Min Min

    2014-06-16

    A new multidentate ligand 1-(9-(1H-1,2,4-triazol-1-yl)anthracen-10-yl)-1H-1,2,4-triazole (tatrz) was designed and synthesized. Using tatrz as a building block, three novel coordination frameworks, namely, {[Cu(tatrz)2(NO3)2]·(CH3OH)·4H2O}n (1), {[Cu(tatrz)2(H2O)2](BF4)2}n (2), and [Mn(tatrz)2(SCN)2(CH3OH)]·2H2O (3) can be isolated. Anion-exchange experiment indicates that NO3(-) anions in the two-dimensional (2D) copper framework of 1 can be completely exchanged by ClO4(-) in an irreversible single crystal-to-single crystal (SC-SC) transformation fashion, as evidenced by the anion-exchange products of {[Cu(tatrz)2(H2O)2](ClO4)2·4CH3OH} (1a). Further, if 1a was employed as a precursor in N,N-dimethylformamide (DMF), an isomorphic solvate of {[Cu(tatrz)2(DMF)2](ClO4)2·2H2O}n (1b) can be generated during the reversible dynamic transformation process. When 1 was immersed in CH3OH, a distinct 2D layer {[Cu(tatrz)2(NO3)2]·4.4CH3OH·0.6H2O}n (1c) was isolated. Interestingly, the solvent-exchange conversion is also invertible between 1 and 1c, which exhibits spongelike dynamic behavior with retention of crystalline integrity. If the 2-fold interpenetrating three-dimensional (3D) framework 2 is selected, it can be transformed into another 2-fold interpenetrating 3D framework {[Cu(tatrz)2(H2O)2](ClO4)2·5.56H2O}n (2a) in a reversible SC-SC transformation fashion. However, when the light yellow crystals of mononuclear complex 3 were exposed to trichloromethane containing aromatic organic anthracene (atan), through our careful observation, the crystals of 3 were dissolved and reassembled into dark brown crystals of 2D crystalline coordination framework {[Mn(tatrz)2(SCN)2]·(atan)}n (3a). X-ray diffraction revealed that in 3a, atan acting as an organic template was encapsulated in the confined space of the 2D grid. Luminescent measurements illustrate that 3a is the first report of multidimensional polymers based on triazole derivatives as luminescent probes of Mg(2+).

  9. Biodiesel synthesis and conformation of lipase from Burkholderia cepacia in room temperature ionic liquids and organic solvents.

    Science.gov (United States)

    Liu, Yun; Chen, Dawei; Yan, Yunjun; Peng, Cheng; Xu, Li

    2011-11-01

    Biodiesel synthesis and conformation of Burkholderia cepacia lipase (BCL) were studied in 19 different room temperature ionic liquids (RTLLs) with a range of cation and anion structures. Overall, anion selection had a greater influence on biodiesel conversion than cation choice. RTILs containing Tf2N- and PF6- anions were suitable reaction media, while RTIL of [OmPy][BF4] was the best reaction medium with a biodiesel yield of 82.2±1.2%. RTILs with strong water miscible properties showed very low biodiesel yields. Conformational analysis by FT-IR revealed that higher biodiesel conversion in RTILs was correlated with a low tendency in α-helix content of BCL. An ultrasound-assisted biocatalysis process in RTILs was used to improve mass transfer rate, leading to 83% reduction of the reaction time for biodiesel production.

  10. Compatibility and thermal stability studies on plasticized PVC/PMMA blend polymer electrolytes complexed with different lithium salts

    Directory of Open Access Journals (Sweden)

    R. Nimma Elizabeth

    2005-03-01

    Full Text Available The lithium salt (x (X= LiAsF6, LiPF6, LiN(C2F5SO22 , LiN(CF3SO22, LiBF4 was complexed with a host of poly(vinyl chloride (PVC/ poly(methyl methacrylate (PMMA blend polymer and plasticized with a combination of ethylene carbonate (EC and propylene carbonate(PC. The polymer electrolyte films were prepared for constant PVC/PMMA blend ratio. The electrochemical stability and thermal stability of the solid polymer electrolytes were reported. The role of PMMA to the phenomena occurring at the interface between the electrolyte and the lithium metal electrode was explored.

  11. C18:1 Methyl Ester Metathesis in [bmim][X] Type Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Priya A. Thomas

    2009-11-01

    Full Text Available The efficacyof [bmim][X] ionic liquids (ILs (X = PF6–, BF4– and NTf2– as reaction media for methyl oleate metathesis was compared with that of conventional organic solvents (PhCl, PhMe, DCM and DCE using the well-defined first and second generation Grubbs precatalysts, RuCl2(PCy3(L(=CHPh (L = PCy3 or H2IMes. Best catalytic performance, with excellent selectivity (>98% at moderate reaction temperatures, was achieved in [bmim][X] ILs compared to conventional solvents. The effects of anion, reaction temperature, solvent polarity, solvent viscosity, and ligand-anion interaction on the reaction are also addressed.

  12. Ionic liquids/[bmim][N3] mixtures: promising media for the synthesis of aryl azides by SNAr.

    Science.gov (United States)

    D'Anna, Francesca; Marullo, Salvatore; Noto, Renato

    2008-08-15

    The nucleophilic aromatic substitution of some activated aryl or heteroaryl halides has been performed in ionic liquid solution, using the 1-butyl-3-methylimidazolium azide as a nucleophile. The reaction course was studied varying the structures of both substrates and ionic liquids. In particular, in the latter case, the reaction of 2-bromo-5-nitrothiophene was carried out in five different ionic liquids ([bmim][BF 4], [bmim][PF 6], [bmim][NTf 2], [bm 2im][NTf 2], and [bmpyrr][NTf 2]). Finally, for all the substrates considered, a comparison with data obtained in MeOH solution in the presence of NaN 3 was also performed. Data collected indicate that in some cases it is possible to obtain aromatic or heteroaromatic azide derivatives in satisfactory yield by means of a S NAr reaction using [bmim][N 3] as the nucleophile.

  13. 1-丁基-3-甲基咪唑类离子液体的合成及表征

    Institute of Scientific and Technical Information of China (English)

    李国强

    2014-01-01

    作为一类环境友好的绿色溶剂或催化剂,离子液体得到了化学工作者们的广泛关注。本文就几种最常见的1-丁基-3-甲基咪唑类离子液体[Bmim]C1、[Bmim]BF4、[Bmim]PF6和[Bmim][Co(CO)4]进行了合成,并通过红外光谱、核磁共振氢谱对其结构进行了表征。考察了它们在常见有机溶剂中的溶解性,为其以后的实际应用奠定了基础。

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

    Institute of Scientific and Technical Information of China (English)

    Yangyang; Jiang; Chen; Guo; Huizhou; Liu

    2007-01-01

    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.

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

    Indian Academy of Sciences (India)

    Vasishta D Bhatt; Kuldip Gohil

    2013-11-01

    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.

  16. Translational diffusion in mixtures of imidazolium ILs with polar aprotic molecular solvents.

    Science.gov (United States)

    Marekha, Bogdan A; Kalugin, Oleg N; Bria, Marc; Buchner, Richard; Idrissi, Abdenacer

    2014-05-22

    Self-diffusion coefficients of cations and solvent molecules were determined with (1)H NMR in mixtures of 1-n-butyl-3-methylimidazolium (Bmim(+)) tetrafluoroborate (BF4(-)), hexafluorophosphate (PF6(-)), trifluoromethanesulfonate (TfO(-)), and bis(trifluoromethylsulfonyl)imide (TFSI(-)) with acetonitrile (AN), γ-butyrolactone (γ-BL), and propylene carbonate (PC) over the entire composition range at 300 K. The relative diffusivities of solvent molecules to cations as a function of concentration were found to depend on the solvent but not on the anion (i.e., IL). In all cases the values exhibit a plateau at low IL content (x(IL) inversion point of relative ionic diffusivities was found around equimolar composition and does not depend on the solvent. At this point, a distinct change in the ion-diffusion mechanism appears to take place.

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

    CERN Document Server

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

    2016-01-01

    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...

  18. Imidazolium ionic liquid-supported sulfonic acids: Efficient and recyclable catalysts for esterification of benzoic acid

    Institute of Scientific and Technical Information of China (English)

    Yue Qin Cai; Guo Qiang Yu; Chuan Duo Liu; Yuan Yuan Xu; Wei Wang

    2012-01-01

    Several imidazolium ionic liquid (IL)-supported sulfonic acids with different anions,[C3SO3Hmim]HSO4,[C3SO3Hmim]BF4,[C3SO3Hmim]PF6,and [C3SO3Hmim]CF3SO3,were synthesized and applied as catalysts for esterification reaction of benzoic acid.The experimental results indicate that imidazolium IL-supported sulfonic acid containing anion of HSO4- shows the best catalytic activity.Only when less [C3SO3Hmim]HSO4 (0.3 equiv.) applied,was the product obtained with high yield of 97%.Furthermore,the produced esters could be separated by decantation,and the catalyst could be reused after the removal of water.

  19. Pyrrole-Pyridine and Pyrrole-Naphthyridine Hosts for Anion Recognition

    Directory of Open Access Journals (Sweden)

    M. Angeles García

    2015-05-01

    Full Text Available The association constants of the complexes formed by two hosts containing pyrrole, amide and azine (pyridine and 1,8-naphthyridine groups and six guests, all monoanions (Cl−, CH3CO2−, NO3−, H2PO4−, BF4−, PF6−, have been determined using NMR titrations. The X-ray crystal structure of the host N2,N5-bis(6-methylpyridin-2-yl-3,4-diphenyl-1H-pyrrole- 2,5-dicarboxamide (1 has been solved (P21/c monoclinic space group. B3LYP/6-31G(d,p and calculations were carried out in an attempt to rationalize the trends observed in the experimental association constants.

  20. Study of 6- cyclic -perimeter hydrocarbon ruthenium complexes bearing functionalized pyridyl diketones: Isolation of complexes with 2-N∩O and 4-N∩O bonding modes of ligands

    Indian Academy of Sciences (India)

    Saphidabha L Nongbri; Babulal Das; Mohan Rao Kollipara

    2012-11-01

    Chelating mono- and di-pyridyl functionalized -diketones, viz. 1-phenyl-3-(2-pyridyl) propane-1,3-dione (pppdH) and 1,3-di(2-pyridyl)propane-1,3-dione (dppdH) ligands yielded new water soluble 6-arene ruthenium(II) complexes of the formulation [(6-arene)Ru(2-N-O-pppdH)Cl]+ (arene = C6H6 1, pPrC6H4Me 2, C6Me6 3) and [(6-arene)2Ru2(4-N-O-dppd)Cl2]+ (arene = C6H6 4, -PrC6H4Me 5, C6Me6 6), as their (complexes 1-4, 6) PF6 salt or (complex 5) BF4 salt. The complexes were obtained by treatment of respective precursors, [(6-arene)Ru(-Cl)Cl]2 (arene = C6H6, -PrC6H4Me, C6Me6) in 1:2 and 1:1 molar ratio with pppdH and dppdH in the presence of NH4PF6/NH4BF4. All the complexes have been characterized on the basis of FT-IR and NMR spectroscopic data as well as by elemental analysis. Molecular structures of representative complexes 2, 5 and 6 have been confirmed by single crystal X-ray diffraction studies. The `O-C-C-C-O' fragment of the coordinated ligand (pppdH) is neutral in complexes 1-3 and that of the dppdH ligand existed as a neutral as well as concomitantly uninegative fashion in complexes 4-6 due to the delocalization of -electrons.

  1. Enzymatic hydrolysis of penicillin in mixed ionic liquids/water two-phase system.

    Science.gov (United States)

    Jiang, Yangyang; Xia, Hansong; Guo, Chen; Mahmood, Iram; Liu, Huizhou

    2007-01-01

    In this paper, an integrated process involving the mixed ionic liquids/water two-phase system (MILWS) is proposed to improve the efficiency for enzymatic hydrolysis of penicillin G. First, hydrophilic [C4mim]BF4 (1-butyl-3-methylimidazolium tetrafluoraborate) and NaH2PO4 salt form an ionic liquids aqueous two-phase system (ILATPS), which could extract penicillin from its fermentation broth efficiently. Second, a hydrophobic [C4mim]PF6 (1-butyl-3-methylimidazolium hexafluoraphosphate) is introduced into the ionic liquids-rich phase of ILATPS containing penicillin and converses it into MILWS. Penicillin is hydrolyzed by penicillin acylase in the water phase of MILWS at pH 5. The byproduct phenylacetic acid (PAA) is partitioned into the ionic liquids mixture phase, while the intended product 6-aminopenicillanic acid (6-APA) is precipitated at this pH. In comparison with a similar butyl acetate/water system (BAWS) at pH 4, MILWS exhibits two advantages. (1) The selectivity between PAA and penicillin is greatly optimized at pH 5 by varying the mole ratio of [C4mim]PF6/[C4mim]BF4 in MILWS, whereas in BAWS the unalterable nature of the organic solvent restricts the optimized pH for maximum selectivity between PAA and penicillin at pH 4. (2) The pH for 6-APA precipitation in BAWS is 4, whereas it shifts to pH 5 in MILWS due to the complexation between negatively charged 6-APA and the cationic surface of the ionic liquids micelle. As a result, the removal of the two products from the enzyme sphere at relatively high pH is permitted in MILWS, which is beneficial for enzymatic activity and stability in comparison with the acidic pH 4 environment in BAWS.

  2. An improved high-power battery with increased thermal operating range: C-LiFePO4//C-Li4Ti5O12

    Science.gov (United States)

    Zaghib, K.; Dontigny, M.; Guerfi, A.; Trottier, J.; Hamel-Paquet, J.; Gariepy, V.; Galoutov, K.; Hovington, P.; Mauger, A.; Groult, H.; Julien, C. M.

    2012-10-01

    The carbon-coated LiFePO4 and C-Li4Ti5O12 particles of 90 nm in diameter have been tested as active elements of electrodes of Li-ion batteries. The 18650-size cell using the usual electrolyte 1 mol L-1 LiPF6 in ethylene carbonate (EC) and diethylene carbonate (DEC) displays a charge capacity of 650 mAh at low C-rate and retains more than 80% of rated capacity at 60C charge rate (1 min). 2032-size coin cells have been tested with different electrolytes: 1.5 mol L-1 lithium tetrafluoroborate LiBF4 in EC+ γ-butyrolactone (GBL), and 0.5 mol L-1 lithium bis(trifluoromethanesulfonyl)imide (LiN(CF3SO2)2, LiTFSI) + 1 mol L-1 LiBF4 in EC + GBL, aiming to replace the less stable LiPF6 salt. The LiTFSI-based electrolyte can be used owing to the low operating voltage that avoids the corrosion of the aluminum of the collector. This electrolyte shows the best results as the performance is even higher at 60 °C. The infrared images show that the temperature of the cell never reaches this temperature during cycling, making this battery a high-power battery with remarkable thermal stability. The maximum temperature reached by the cell is 34 °C at 40C-rate and 40 °C at 60C. The free EC-based electrolytes even operate at 80 °C by using 1 mol L-1 lithium bis(fluorosulfonyl)imide (LiFSI) in GBL or 1 mol L-1 LiFSI in PC + GBL, thus increasing importantly the operating temperature range for the battery. The carbon coated on LTO depresses the evolution of gases during charge discharge.

  3. Independent Control of Optical and Explosive Properties: Pyrazole-Tetrazine Complexes of First Row Transition Metals.

    Science.gov (United States)

    Myers, Thomas W; Chavez, David E; Hanson, Susan K; Scharff, R Jason; Scott, Brian L; Veauthier, Jacqueline M; Wu, Ruilian

    2015-08-17

    Complexes of 3-amino-6-(3,5-dimethylpyrazole)tetrazine) (NH2TzDMP, 1) and 3-(3,3'-dinitroazetidine)-6-(3,5-dimethylpyrazole)tetrazine) (DNAZTzDMP, 2) with first row transition metal centers were synthesized. Reactions of Fe(II)(H2O)6(BF4)2 and Fe(NO3)3·9H2O with 1 and 2 both led to complexes of the form [(RTzDMP)3Fe]X2 (X = BF4, R = NH2 (3), DNAZ (4); X = NO3, R = NH2 (5), DNAZ (6)), which showed intense MLCT bands in the visible region of the spectrum. Ligands 1 and 2 also reacted with Cu(II)(NO3)2·5/2H2O to form [(RTzDMP)2Cu(NO3)][NO3] (R = NH2 (7), DNAZ (8)) in addition to reacting with Cu(I)(CH3CN)4(PF6) to form [(RTzDMP)2Cu][PF6] (R = NH2 (9), DNAZ (10)). Lastly reactions of 1 and 2 with Co(NO3)2·6H2O and Ni(NO3)2·6H2O led to [(NH2TzDMP)2Co(H2O) (NO3)][NO3] (11), [(DNAZTzDMP)2Co(H2O)2][NO3]2 (12), [(NH2TzDMP)3Ni][NO3]2 (13), and [(DNAZTzDMP)2Ni(H2O)2][NO3]2 (14). The complexes display rich electrochemical and photophysical properties that are unaffected by derivation with explosive groups.

  4. Research on Separation of H2 and N2 Mixed Gas with Ionic liquid Membrane%离子液膜法分离H2、N2混合气体研究

    Institute of Scientific and Technical Information of China (English)

    仲惟

    2015-01-01

    Two kinds of ionic liquid, 1-butyl 3-sold four fluoboric acid methyl imidazole salt ([BMIM]BF4) and 1-butyl 3-methyl imidazole six fluoride phosphate ([BMIM] PF6), were selected, and the ion exchange method was used to create two kinds of ionic liquid 1-butyl 3-methyl imidazole formate ([BMIM] HCOO) and 1-butyl 3-methyl imidazole acetate ([BMIM]CH3COO). Combined the advantages of ionic liquid and membrane separation, polyvinylidene fluoride, polysulfone and polyacrylonitrile membrane was chose to make ionic liquid supported liquid membrane by impregnation method. Compared the separation coefficient on different temperature of every kind of ionic liquid membrane for H2/N2 separation, it was found that the separation abilities of [BMIM] HCOO polysulfone membrane and polyacrylonitrile membrane were more bigger. The temperature conditions significantly affected the separation effect:at 30℃[BMIM]BF4 type poly-cvinylidene fluoride membrane, [BMIM]HCOO polysulfone membrane had the strong ability of H2/N2 separation, N2 could be separated off H2. 30℃in [BMIM]BF4 type polysulfone membrane separation N2/H2 ability was strong, H2 could be separated off N2.%选取2种市售离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)与1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6),另采用离子交换法合成出2种离子液体1-丁基-3-甲基咪唑甲酸盐([BMIM]HCOO)与1-丁基-3-甲基咪唑乙酸盐([BMIM]CH3COO)。将离子液体与膜分离法优点相结合,选取聚偏氟乙烯膜、聚砜膜和聚丙烯腈膜并用浸渍法制备离子液体支撑液膜。比较不同温度下不同类型离子液膜对H2/N2的分离系数发现,[BMIM]HCOO型聚砜膜和聚丙烯腈膜对H2/N2分离系数较大。温度条件显著影响分离效果:30℃时[BMIM]BF4型聚偏氟乙烯膜、[BMIM]HCOO型聚砜膜分离H2/N2能力较强,可分离掉N2获得H2;30℃时[BMIM]BF4型聚砜膜分离N2/H2能力较强,可分离掉H2获得N2。

  5. Distribution of 1-alkyl-3-methylimidazolium ions and their ion pairs between dichloromethane and water.

    Science.gov (United States)

    Katsuta, Shoichi; Yamaguchi, Naoko; Ogawa, Ryuji; Kudo, Yoshihiro; Takeda, Yasuyuki

    2008-10-01

    The distribution behavior of the salts of a series of 1-alkyl-3-methylimidazolium cations (RMeIm(+); R = butyl, hexyl, and octyl) with tetrafluoroborate (BF(4)(-)), hexafluorophosphate (PF(6)(-)), bis(trifluoromethanesulfonyl)amide (NTf(2)(-)), and 2,4,6-trinitrophenolate (Pic(-)) anions has been investigated in a dichloromethane-water system at 25 degrees C. The distribution constants (K(D)) of the ion pairs and the transfer activity coefficients ((o)gamma(w)) of the single ions were determined. For the ion pairs with a given anion, the log K(D) value increases linearly with the number of methylene groups (N(CH2)) in the cation, which can be explained by using the regular solution theory. A similar relationship was observed between log (o)gamma(w) and N(CH2) for the free RMeIm(+) ions, and the result was discussed by decomposing the transfer activity coefficient into the Born-type electrostatic contribution and the non-electrostatic one. For the free anions and their ion pairs with a given cation, the (o)gamma(w) and K(D) values increase with increasing molar volume of the anion: i.e., BF(4)(-) ion-pair formation in water are also discussed by comparing the present results with those of tetraalkylammonium salts previously reported.

  6. Structural Interactions within Lithium Salt Solvates: Cyclic Carbonates and Esters

    Energy Technology Data Exchange (ETDEWEB)

    Seo, D. M.; Afroz, Taliman; Allen, Joshua L.; Boyle, Paul D.; Trulove, Paul C.; De Long, Hugh C.; Henderson, Wesley A.

    2014-11-13

    Only limited information is available regarding the manner in which cyclic carbonate and ester solvents coordinate Li+ cations in electrolyte solutions for lithium batteries. One approach to gleaning significant insight into these interactions is to examine crystalline solvate structures. To this end, eight new solvate structures are reported with ethylene carbonate, γ-butyrolactone and γ-valerolactone: (EC)3:LiClO4, (EC)2:LiClO4, (EC)2:LiBF4, (GBL)4:LiPF6, (GBL)1:LiClO4, (GVL)1:LiClO4, (GBL)1:LiBF4 and (GBL)1:LiCF3SO3. The crystal structure of (EC)1:LiCF3SO3 is also re-reported for comparison. These structures enable the factors which govern the manner in which the ions are coordinated and the ion/solvent packing—in the solid-state—to be scrutinized in detail.

  7. 5 and 6 - cyclic -perimeter hydrocarbon platinum group metal complexes of 3-(2-pyridyl)pyrazole derived ligands with a pendant nitrile group: Syntheses, spectral and structural studies

    Indian Academy of Sciences (India)

    Gloria Sairem; Venkateswara Rao Anna; Peng Wang; Bbulal Das; Mohan Rao Kollipara

    2012-03-01

    Reaction of two equivalents 4-{(3-(pyridine-2-yl) 1H-pyrazole-1-yl}methyl benzonitrile (L1) and 3-{(3-(pyridine-2-yl)1H-pyrazole-1-yl}methyl benzonitrile (L2) with one equivalent of [(6-arene)Ru(- Cl)Cl]2 and [Cp∗M(-Cl)Cl]2 in methanol yielded mononuclear complexes of the formulae [(6-arene)Ru(L1/L2)Cl]BF4{arene =C6H6 (1, 6); C10H14 (2, 7); C6Me6 (3, 8)} and [Cp∗M(L1/L2)Cl]PF6/BF4 {Cp∗= 5-C5Me5, M=Rh (4, 8); Ir (5, 10)}. These complexes are characterized by IR, 1H NMR and identities of the structure are established by single crystal XRD studies of some of the representative complexes. It is confirmed from the spectral studies that the nitrile group is not taking part in complexation; instead it remains as a free pendant group only.

  8. Combined main-chain/side-chain ionic liquid crystalline polymer based on ‘jacketing’ effect: Design, synthesis, supra-molecular self-assembly and photophysical properties

    Directory of Open Access Journals (Sweden)

    L. Weng

    2015-06-01

    Full Text Available Reasonably fabricating ordered structures of ionic polymers is very important for the development of novel functional materials. By combining the ions and liquid cry stalline polymer, we successfully designed and synthesized a series of novel combined main-chain/side-chain ionic liquid crystalline polymer (MCSC-ILCPs containing imidazolium groups and different counter-anions, poly (2,5-bis{[6-(4-butoxy-4'-imidazolium biphenylhexyl]oxycarbonyl}styrene salts poly(BImBHCS-X with the following types of counter-anions (Br¯, BF4¯, PF6¯ and TFSI¯. Combined technologies confirmed the chemical structures of the monomers and polymers with imidazolium cation and different counter-anions. Differential scanning calorimetry (DSC, polarized light microscopy (PLM and one- and two-dimensional wide-angle X-ray diffraction (1D and 2D WAXD results illustrated that the LC structures and the transitions of ordered structures depended on the nature of the counter-anion employed. The polymers with Br¯ and BF4¯ counter-anions exhibited smectic A (SmA LC behavior below the isotropic temperature. The another one, poly(BImBHCS–TFSI with the large volume of the TFSI¯ anion destroyed the packing of the LC ordered structure resulting in an amorphous structure. The photophysical properties of the polymers prepared can be adjusted by tuning the ionic interaction of the polymers by switching the counter-anion.

  9. Six-Membered-Ring Malonatoborate-Based Lithium Salts as Electrolytes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Li; Zhang, Hanjun; Driscoll, Peter; Lucht, Brett; Kerr, John

    2011-09-30

    A new class of lithium salts of malonatoborate anions has been synthesized. These six-membered-ring salts provided slightly lower ionic conductivity than that of LiBOB and LiBF4. Nevertheless, compared with LiBOB and LiPF6, the lowered ring strains in the malonatoborate structures and reduced numbers of fluorine atoms in the molecules was found to enhance the thermal and water stabilities and compatibilities of these salts with ether solvents. Small amount LiDMMDFB when used as an additive, was found to stabilize LiPF6 in carbonate electrolytes at 80°C for one month. Employing LiMDFB as the electrolyte in Li/Li cells and full cells, large interfacial impedances were observed on lithium metal and the cathode. Moreover, the large impedances are at least partially attributed to the acidic hydrogen atoms in the malonate structure. This issue can be addressed by replacing the acidic atoms with methyl groups.

  10. DFT study of the energetic and noncovalent interactions between imidazolium ionic liquids and hydrofluoric acid.

    Science.gov (United States)

    Velarde, Marco V; Gallo, Marco; Alonso, P A; Miranda, A D; Dominguez, J M

    2015-04-16

    In this work, we evaluated the energetic interactions between imidazolium ionic liquids (ILs) and hydrofluoric acid, as well as the cation-anion interactions in ILs. We used DFT calculations that include dispersion corrections employing the PBE and M06 functionals. We tested 22 ILs, including [C4MIM][PF6], [C4MIM][NTf2], and [C4MIM][CH3COO], obtaining interaction energies in the range of -27 to -13 kcal/mol with the PBE functional. The NCI (noncovalent interaction) index developed by Yang and collaborators ( J. Am. Chem. Soc. 2010 , 132 , 6498 - 6506 ; J. Chem. Theory Comput. 2011 , 7 , 625 - 632 ) also was used for mapping the key noncovalent interactions (hydrogen bonds, van der Waals, and steric repulsions) between the anions and cations of ILs and also for interactions of ILs with hydrofluoric acid (HF). The results obtained show that the anions have a stronger effect with respect to cations in their capacity for interacting with hydrofluoric acid, and the strongest interaction energies occur in systems where the key noncovalent interactions are mainly hydrogen bonds. The [C4MIM][PF6], [C4MIM][NTf2], and [C4MIM][BF4] ionic liquids displayed the weakest cation-anion interactions.

  11. Transition metal complexes supported by a neutral tetraamine ligand containing N,N-dimethylaniline units.

    Science.gov (United States)

    Chu, Lei; Hardcastle, Kenneth I; MacBeth, Cora E

    2010-08-16

    First-row transition metal-halide complexes of tris(2-dimethylaminophenyl)amine, L(Me), have been synthesized and characterized. X-ray crystallographic studies on [Co(L(Me))Br]BPh(4), [Ni(L(Me))Cl]BPh(4), [Fe(L(Me))Cl]BPh(4), and [Cu(L(Me))Cl]BF(4) have been performed, and in all cases the ligand produces five-coordinate complexes with distorted trigonal bipyramidal coordination geometries. Where possible, comparisons have been made to the structures of related neutral tripodal ligands. Spectroscopic and magnetic studies of these complexes are also described. The Cu(I)-carbonyl complexes [Cu(L(Me))(CO)]PF(6) and [Cu(Me(6)tren)(CO)]PF(6) (Me(6)tren = tris(N,N-dimethylaminoethyl)amine) have also been prepared. Infrared spectroscopic investigations of these carbonyl complexes confirm that L(Me) is a less electron donating ligand than Me(6)tren and indicate that L(Me) can impart a different coordination number in the solid-state.

  12. In situ analysis of the interfacial reactions between MCMB electrode and organic electrolyte solutions

    Science.gov (United States)

    Morigaki, Ken-ichi

    The interfacial phenomena between graphite (mesocarbon-microbeads (MCMB)) electrode and organic electrolyte solution were analyzed by in situ atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. The influence of lithium salts (anion species), LiPF 6, LiBF 4, and LiClO 4, on the interfacial reaction, including lithium intercalation into graphite, was investigated in EC+DMC solutions. In situ AFM observation disclosed that morphological changes are quite different from one another depending on the kind of lithium salt (anion). A large expansion of MCMB particle was observed particularly in LiPF 6/EC+DMC. An expansion of MCMB particle started above 1.0 V versus Li/Li + and this expansion seemed to be caused by the decomposition of ternary graphite intercalation compound (GIC) ( C nLi(sol) y), because the expansion remained after de-intercalation of lithium. IRAS spectra of each electrolyte solution showed different behaviors and different reduction products of solvents. double modulation FTIR (DMFTIR) spectra on graphite electrode, which emphasize the surface species, indicated relatively small changes after cathodic polarization. Therefore, the observed morphological changes were caused mainly by the expansion of graphene layers and not by the precipitation of reduction products.

  13. Electrochemical and impedance investigation of the effect of lithium malonate on the performance of natural graphite electrodes in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL

    2010-01-01

    Lithium malonate (LM) was coated on the surface of a natural graphite (NG) electrode, which was then tested as the negative electrode in the electrolytes of 0.9 M LiPF6/EC-PC-DMC (1/1/3, by weight) and 1.0 M LiBF4/EC-PC-DMC (1/1/3, by weight) under a current density of 0.075 mA cm-2. LM was also used as an additive to the electrolyte of 1.0 M LiPF6/EC-DMC-DEC (1/1/1, by volume) and tested on a bare graphite electrode. It was found that both the surface coating and the additive approach were effective in improving first charge discharge capacity and coulomb efficiency. Electrochemical impedance spectra showed that the decreased interfacial impedance was coupled with improved coulomb efficiency of the cells using coated graphite electrodes. Cyclic voltammograms (CVs) on fresh bare and coated natural graphite electrodes confirmed that all the improvement in the half-cell performance was due to the suppression of the solvent decomposition through the surface modification with LM. The CV data also showed that the carbonate electrolyte with LM as the additive was not stable against oxidation, which resulted in lower capacity of the full cell with commercial graphite and LiCoO2 electrodes.

  14. Determination of triazine herbicides in fresh vegetables by dynamic microwave-assisted extraction coupled with homogeneous ionic liquid microextraction high performance liquid chromatography.

    Science.gov (United States)

    Wu, Lijie; Hu, Mingzhu; Li, Zhanchao; Song, Ying; Yu, Cui; Zhang, Yupu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

    2015-02-01

    A novel extraction method, dynamic microwave-assisted extraction coupled with homogeneous ionic liquid microextraction, was developed for the determination of triazine herbicides, including desmetryn, terbumeton, propazine, terbuthylazine, dimethametryn, and dipropetryn in fresh vegetable samples by high performance liquid chromatography (HPLC). In the developed method, 120 μL of 1-butyl-3-methylimidazolium tetrafluoroborate ([C4MIM][BF4]) was added to 10 mL of aqueous solution containing 0.3 g of NaCl to obtained the extraction solvent. Six triazines could be extracted completely within 4 min by the present method. Then, [NH4][PF6] was added into the extract to form a water-insoluble ionic liquid [C4MIM][PF6] via a simple metathesis reaction, and the analytes were enriched into the ionic liquid phase. After centrifugation and dilution with acetonitrile, the resulting solution was analyzed directly by HPLC. The effects of some experimental parameters, including type and volume of ionic liquid, volume of extraction solvent, amount of ion-pairing agent [NH4][PF6], salt concentration, microwave power, and flow rate of extraction solvent on the extraction efficiency were investigated and optimized. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 2.50-250.00 μg kg(-1), with the correlation coefficients ranging from 0.9989 to 0.9999. When the present method was applied to the analysis of vegetable samples, satisfactory recoveries were obtained in the range of 76.8%-106.9%, and relative standard deviations were lower than 9.8%.

  15. Preparation of highly efficient manganese catalase mimics.

    Science.gov (United States)

    Triller, Michael U; Hsieh, Wen-Yuan; Pecoraro, Vincent L; Rompel, Annette; Krebs, Bernt

    2002-10-21

    The series of compounds [Mn(bpia)(mu-OAc)](2)(ClO(4))(2) (1), [Mn(2)(bpia)(2)(muO)(mu-OAc)](ClO(4))(3).CH(3)CN (2), [Mn(bpia)(mu-O)](2)(ClO(4))(2)(PF(6)).2CH(3)CN (3), [Mn(bpia)(Cl)(2)](ClO)(4) (4), and [(Mn(bpia)(Cl))(2)(mu-O)](ClO(4))(2).2CH(3)CN (5) (bpia = bis(picolyl)(N-methylimidazol-2-yl)amine) represents a structural, spectroscopic, and functional model system for manganese catalases. Compounds 3 and 5 have been synthesized from 2 via bulk electrolysis and ligand exchange, respectively. All complexes have been structurally characterized by X-ray crystallography and by UV-vis and EPR spectroscopies. The different bridging ligands including the rare mono-mu-oxo and mono-mu-oxo-mono-mu-carboxylato motifs lead to a variation of the Mn-Mn separation across the four binuclear compounds of 1.50 A (Mn(2)(II,II) = 4.128 A, Mn(2)(III,III) = 3.5326 and 3.2533 A, Mn(2)(III,IV) = 2.624 A). Complexes 1, 2, and 3 are mimics for the Mn(2)(II,II), the Mn(2)(III,III), and the Mn(2)(III,IV) oxidation states of the native enzyme. UV-vis spectra of these compounds show similarities to those of the corresponding oxidation states of manganese catalase from Thermus thermophilus and Lactobacillus plantarum. Compound 2 exhibits a rare example of a Jahn-Teller compression. While complexes 1 and 3 are efficient catalysts for the disproportionation of hydrogen peroxide and contain an N(4)O(2) donor set, 4 and 5 show no catalase activity. These complexes have an N(4)Cl(2) and N(4)OCl donor set, respectively, and serve as mimics for halide inhibited manganese catalases. Cyclovoltammetric data show that the substitution of oxygen donor atoms with chloride causes a shift of redox potentials to more positive values. To our knowledge, complex 1 is the most efficient binuclear functional manganese catalase mimic exhibiting saturation kinetics to date.

  16. Silver(I) complexes with phthalazine and quinazoline as effective agents against pathogenic Pseudomonas aeruginosa strains.

    Science.gov (United States)

    Glišić, Biljana Đ; Senerovic, Lidija; Comba, Peter; Wadepohl, Hubert; Veselinovic, Aleksandar; Milivojevic, Dusan R; Djuran, Miloš I; Nikodinovic-Runic, Jasmina

    2016-02-01

    Five silver(I) complexes with aromatic nitrogen-containing heterocycles, phthalazine (phtz) and quinazoline (qz), were synthesized, characterized and analyzed by single-crystal X-ray diffraction analysis. Although different AgX salts reacted with phtz, only dinuclear silver(I) complexes of the general formula {[Ag(X-O)(phtz-N)]2(μ-phtz-N,N')2} were formed, X=NO3(-) (1), CF3SO3(-) (2) and ClO4(-) (3). However, reactions of qz with an equimolar amount of AgCF3SO3 and AgBF4 resulted in the formation of polynuclear complexes, {[Ag(CF3SO3-O)(qz-N)]2}n (4) and {[Ag(qz-N)][BF4]}n (5). Complexes 1-5 were evaluated by in vitro antimicrobial studies against a panel of microbial strains that lead to many skin and soft tissue, respiratory, wound and nosocomial infections. The obtained results indicate that all tested silver(I) complexes have good antibacterial activity with MIC (minimum inhibitory concentration) values in the range from 2.9 to 48.0μM against the investigated strains. Among the investigated strains, these complexes were particularly efficient against pathogenic Pseudomonas aeruginosa (MIC=2.9-29μM) and had a marked ability to disrupt clinically relevant biofilms of strains with high inherent resistance to antibiotics. On the other hand, their activity against the fungus Candida albicans was moderate. In order to determine the therapeutic potential of silver(I) complexes 1-5, their antiproliferative effect on the human lung fibroblastic cell line MRC5, has been also evaluated. The binding of complexes 1-5 to the genomic DNA of P. aeruginosa was demonstrated by gel electrophoresis techniques and well supported by molecular docking into the DNA minor groove. All investigated complexes showed an improved cytotoxicity profile in comparison to the clinically used AgNO3.

  17. Study on the Crystal Structure of a Macrocycle and Tyrosinase Activity of Its Dinuclear Copper Complexes

    Institute of Scientific and Technical Information of China (English)

    周红; 潘志权; 罗勤慧; 梅光泉; 龙德良; 陈久桐

    2005-01-01

    A ring-contracted form macrocycle, 29,30-dioxo-3,6,9,17,20,23,29,30-octaazapentacyclo[23,3,1,111,15,02,6,016,20]-triacontaneocta- 1 (28),9,11 (12), 13,15(30),23,25(29),26-ene (L) was synthesized by condensation of diethyltriamine with pyridine-1-oxide-2,6-dicarboxaldehyde. A porous three-dimensional layer structure in its crystal was formed by self-assembly through hydrogen bonds and π-π interaction. Its dinuclear copper(I) complex [Cu2L(MeOH)2]-(BF4)2*2H2O and dinuclear-copper(II) complex [Cu2L(MeOH)2](ClO4)4*2H2O were obtained and could oxidize catalytically four phenolic substrates hydroquinone, 2-methyl-hydroquinone, 2,6-di-tert-butylphenol and 2,6-dimethylphenol, in a mixture of methanol and acetonitrile (V : V, 4 : 1). The copper(I) complex reacted with dioxygen to form an oxygenated species as an initial active intermediate for oxidation of the phenols. Oxidation of the substrates by the copper(II) complex produced a copper(I) complex and the oxidation products of the substrates.

  18. Hydrogen Bonding and Multiphonon Structure in One- and Two-Dimensional Polymeric Magnets

    Science.gov (United States)

    Musfeldt, J. L.; Brown, S.; Cao, J.; Conner, M. M.; McConnell, A. C.; Southerland, H. I.; Manson, J. L.; Schlueter, J. A.; Phillips, M. D.; Turnbull, M. M.; Landee, C. P.

    2007-03-01

    We report a systematic investigation of the temperature dependent infrared vibrational spectra of a family of chemically related coordination polymeric magnets based upon two different bridging anions, fluoride (F^-) and bifluoride (HF2^-), in copper-pyrazine complexes including Cu(HF2)(pyz)2BF4, Cu(HF2)(pyz)2ClO4, and CuF2(H2O)(pyz)). We compare our results with several one- and two-dimensional prototype materials including Cu(NO3)2(pyz) and Cu(ClO4)(pyz) 2. Unusual low temperature hydrogen bonding, local structural transitions associated with stronger low-temperature hydrogen bonding, and striking multiphonon effects that derive from coupling of an infrared-active fundamental with strong Raman-active modes of the pyrazine building-block molecule are observed. Based on the spectroscopic evidence, these interactions are common to this family of coordination polymers and work to stabilize the low temperature magnetic state. Similar interactions are likely to be present in other molecule-based magnets.

  19. Synthesis and structures of ligand-dominated one-dimensional silver(I)-bis(pyridylmethyl)amine coordination chains

    Science.gov (United States)

    Lin, Hung-Jui; Liu, Yu-Chiao; Tseng, Yu-Jui; Wu, Jing-Yun

    2016-10-01

    Reactants slow diffusion of Ag(I) salts with 3,4‧-bis(pyridylmethyl)amine (3,4‧-bpma), an unsymmetric bis-pyridyl ligand equipped with a non-innocent amine backbone, afforded polymeric coordination adducts 1-5 having a general formula {[Ag(3,4‧-bpma)(solv)]X}n (solv = H2O, CH3OH, and none; X= CF3CO2-, BF4-, ClO4-, CF3SO3-, and SbF6-). Single-crystal X-ray diffraction (SCXRD) analyses reveal that colorless crystals of Ag(I) coordination polymers (CPs) 1-5 have very similar one-dimensional (1D) non-flat chain structures, which are preferentially depicted as a "zipper-like" rather than a ladder-like or a double-stranded chain topologies. The 3,4‧-bpma ligand in these Ag(I) CPs displays a μ3-bridging mode with a gauche-trans (1,4, and 5) and a trans-trans (2 and 3) conformations. Noteworthy, anions do not show strong influence on structural modulation of Ag(I) CPs in the solid state, but really affect CP conformations and packing fashions, indicative of a ligand-dominated assembly process for such a Ag(I)-3,4‧-bpma system. Thermal stabilities and solid-state photoluminescence properties of crystalline materials 1-5 were investigated.

  20. Experimental and theoretical investigation of vibrational spectra of coordination polymers based on TCE-TTF.

    Science.gov (United States)

    Olejniczak, Iwona; Lapiński, Andrzej; Swietlik, Roman; Olivier, Jean; Golhen, Stéphane; Ouahab, Lahcène

    2011-08-01

    The room-temperature infrared and Raman spectra of a series of four isostructural polymeric salts of 2,3,6,7-tetrakis(2-cyanoethylthio)-tetrathiafulvalene (TCE-TTF) with paramagnetic (Co(II), Mn(II)) and diamagnetic (Zn(II), Cd(II)) ions, together with BF(4)(-) or ClO(4)(-) anions are reported. Infrared and Raman-active modes are identified and assigned based on theoretical calculations for neutral and ionized TCE-TTF using density functional theory (DFT) methods. It is confirmed that the TCE-TTF molecules in all the materials investigated are fully ionized and interact in the crystal structure through cyanoethylthio groups. The vibrational modes related to the C=C stretching vibrations of TCE-TTF are analyzed assuming the occurrence of electron-molecular vibration coupling (EMV). The presence of the antisymmetric C=C dimeric mode provides evidence that charge transfer takes place between TCE-TTF molecules belonging to neighboring polymeric networks.

  1. A mixed Ni(II) ionic complex containing V-shaped water trimer: Synthesis, spectral, structural and thermal properties of {[Ni(2,2′-bpy)3][Ni(2-cpida)(2,2′ -bpy)]} (ClO4).3H2O

    Indian Academy of Sciences (India)

    Nallasamy Palanisami; Kabali Senthilkumar; Mohan Gopalakrishnan; Il-Shik Moon

    2015-05-01

    A mixed Ni(II) ionic complex of {[Ni(2,2′-bpy)3][Ni(2-cpida)(2,2′-bpy)]}(ClO4).3H2O (1) (2-H3cpida = N-(2-carboxyphenyl)iminodiacetic acid, 2,2′-bpy = 2,2′-bipyridyl) has been synthesized and characterized by infrared, ultraviolet and fluorescence spectroscopy, elemental and thermogravimetric analysis. The molecular structure of compound 1, as determined by single-crystal X-ray diffraction studies, showed all the three carboxylate groups are in monodendate mode. Compound 1 consists of a discrete mononuclear [Ni(2,2′-bpy)3]2+ cation, a [Ni(2-cpida)(2,2′-bpy)]− anion, a ClO$^{−}_{4}$ anion and three lattice water molecules. The H-bonding interaction between three lattice water molecule forms a V-shaped trimer (H2O)3 which gives rise to a 1-D polymeric structure in the solid state.

  2. Synthesis and Its Crystal Structure of Complex Cu(pico) (4,4'-bipy) (H2O) ClO4 ·H2O%配合物Cu(pico)(4,4′-bipy)(H2O)ClO4·H2O的合成及其晶体结构

    Institute of Scientific and Technical Information of China (English)

    黄良芳; 张元广; 任小明

    2008-01-01

    利用水热法合成了新型一维配合物Cu(pico)(4,4′-bipy)(H2O)ClO4·H2O(1,bipy=联吡啶,pico=邻吡啶甲酸根),其结构经IR,元素分析和X-射线单晶衍射表征.1属于单斜晶系,P21/n空间群,晶胞参数:a=0.853 57(8)nm,b=1.610 58(14)nm,c=1.416 85(13)nm,β=99.407(2)°,V=1.921 6(3)nm3,Z=4,Mr=477.31 g·mol-1,Dc=1.650 g·cm-3,μ=1.326mm-1,F(000)=972,R1=0.078 1,wR2=0.239 1,S=1.102.1中Cu2+与邻吡啶甲酸配体上一个N原子和一个O原子、两个4,4′-联吡啶的N原子以及一个水分子的O原子配位,形成了四方锥配位几何构型.在a+c轴方向,Cu2+与两个4,4′-联吡啶分子经桥联作用形成一维zig-zag链;链与链通过氢键形成三维结构.

  3. Vibrational and excited electronic states of six-coordinate rare earth complexes with 2,6-lutidine n-oxide: [Ln(C 7H 9NO) 6](ClO 4) 3·H 2O (Ln=Pr,Nd,Sm,Eu,Gd,Dy)

    Science.gov (United States)

    Ban-Oganowska, H.; Godlewska, P.; Macalik, L.; Hanuza, J.; Oganowski, W.; Hermanowicz, K.

    2002-09-01

    A series of six-coordinate complexes of 2,6-lutidine N-oxide (C 7H 9NO) with praseodymium, neodymium, samarium, europium, gadolinium and dysprosium has been synthesised and chemically characterised. FT-IR and FT-Raman spectra in the range 80-4000 cm -1 as well as electronic absorption and emission spectra in the range 4000-50,000 cm -1 have been measured. The Lorenzian deconvolution of the vibrational contour in the 100-300 cm -1 region has been used in the discussion of the molecular and site symmetries of the Ln 3+ ion situated in the oxygen polyhedron. The sequence of the electronic levels for all RE ions has been obtained and assigned to the respective transitions.

  4. Crystal structures, DFT calculations and Hirshfeld surface analyses of three new cobalt(III) Schiff base complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine

    Science.gov (United States)

    Masoudi, Mohaddeseh; Behzad, Mahdi; Arab, Ali; Tarahhomi, Atekeh; Rudbari, Hadi Amiri; Bruno, Giuseppe

    2016-10-01

    Three new Cobalt(III) Schiff base complexes were synthesized and characterized by spectroscopic methods and x-ray crystallography. The DFT optimized structures of the complexes agreed well with the corresponding x-ray structures. According to the calculated vibrational normal modes, the observed signals in the IR spectra of the complexes were assigned. The experimental UV-Vis spectra of the complexes were also discussed considering the calculated excited states and molecular orbitals. Hirshfeld surface analysis was carried out to study the inter-contact interactions in these complexes. These studies provided comprehensive description of such inter-contact interactions by means of an appealing graphical approach using 3D Hirshfeld surfaces and 2D fingerprint plots derived from the surfaces. It indicated the dominant role of various hydrogen intermolecular interactions such as H⋯H (above 60%), C⋯H/H⋯C (near 15%-20%), O⋯H/H⋯O (about 16% or 17% for structures with counter ion ClO4-) and H⋯F (17% for structure with counter ion PF6-) contacts into the crystal packing which are discussed in details.

  5. Study of the counter anions in the host-guest chemistry of cucurbit[8]uril and 1-ethyl-1'-benzyl-4,4'-bipyridinium.

    Science.gov (United States)

    Ji, Hailong; Liu, Fengyu; Sun, Shiguo

    2013-01-01

    A series of 1-ethyl-1'-benzyl-4,4'-bipyridinium compounds with different counter anions (BEV-X2, where the X is Cl, Br, I, PF6, ClO4) were synthesized. By using of NMR, MS, electrochemistry, Na2S2O4-induced redox chemistry, and UV-Vis, the role of the different counter anions in the host-guest chemistry of cucurbit[8]uril (CB[8]) was studied for the first time. The result demonstrated that BEV-X2 can form a 1 : 1 host-guest complex with CB[8] in water. Theoretical calculation further suggested that the viologen region was threaded through the cavity of CB[8], while the corresponding counter anions were located outside the cavity. Some difference can be observed on UV-Vis titration and Na2S2O4-induced redox chemistry, which showed that the counter anions have some effect on the host-guest chemistry. All these provide new insights into CB[8] host-guest system.

  6. Dipyridyl β-diketonate complexes and their use as metalloligands in the formation of mixed-metal coordination networks.

    Science.gov (United States)

    Burrows, Andrew D; Mahon, Mary F; Renouf, Catherine L; Richardson, Christopher; Warren, Anna J; Warren, John E

    2012-04-14

    The iron(III) and aluminium(III) complexes of 1,3-di(4-pyridyl)propane-1,3-dionato (dppd) and 1,3-di(3-pyridyl)propane-1,3-dionato (dmppd), [Fe(dppd)(3)] 1, [Fe(dmppd)(3)] 2, [Al(dppd)(3)] 3 and [Al(dmppd)(3)] 4 have been prepared. These complexes adopt molecular structures in which the metal centres contain distorted octahedral geometries. In contrast, the copper(II) and zinc(II) complexes [Cu(dppd)(2)] 5 and [Zn(dmppd)(2)] 6 both form polymeric structures in which coordination of the pyridyl groups into the axial positions of neighbouring metal centres links discrete square-planar complexes into two-dimensional networks. The europium complex [Eu(dmppd)(2)(H(2)O)(4)]Cl·2EtOH·0.5H(2)O 7 forms a structure containing discrete cations that are linked into sheets through hydrogen bonds, whereas the lanthanum complex [La(dmppd)(3)(H(2)O)]·2H(2)O 8 adopts a one-dimensional network structure, connected into sheets by hydrogen bonds. The iron complexes 1 and 2 act as metalloligands in reactions with silver(I) salts, with the nature of the product depending on the counter-ions present. Thus, the reaction between 1 and AgBF(4) gave [AgFe(dppd)(3)]BF(4)·DMSO 9, in which the silver centres link the metalloligands into discrete nanotubes, whereas reactions with AgPF(6) and AgSbF(6) gave [AgFe(dppd)(3)]PF(6)·3.28DMSO 10 and [AgFe(dppd)(3)]SbF(6)·1.25DMSO 11, in which the metalloligands are linked into sheets. In all three cases, only four of the six pyridyl groups present on the metalloligands are coordinated. The reaction between 2 and AgNO(3) gave [Ag(2)Fe(dmppd)(3)(ONO(2))]NO(3)·MeCN·CH(2)Cl(2)12. Compound 12 adopts a layer structure in which all pyridyl groups are coordinated to silver centres and, in addition, a nitrate ion bridges between two silver centres. A similar structure is adopted by [Ag(2)Fe(dmppd)(3)(O(2)CCF(3))]CF(3)CO(2)·2MeCN·0.25CH(2)Cl(2)13, with a bridging trifluoroacetate ion playing the same role as the nitrate ion in 12.

  7. Multiple functional ionic liquids based dispersive liquid-liquid microextraction combined with high performance chromatography for the determination of phenolic compounds in water samples.

    Science.gov (United States)

    Sun, Jian-Nan; Chen, Juan; Shi, Yan-Ping

    2014-07-01

    A new mode of ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) is developed. In this work, [C6MIm][PF6] was chosen as the extraction solvent, and two kinds of hydrophilic ionic liquids, [EMIm][BF4] and [BSO3HMIm][OTf], functioned as the dispersive solvent. So in the whole extraction procedure, no organic solvent was used. With the aid of SO3H group, the acidic compound was extracted from the sample solution without pH adjustment. Two phenolic compounds, namely, 2-naphthol and 4-nitrophenol were chosen as the target analytes. Important parameters affecting the extraction efficiency, such as the type of hydrophilic ionic liquids, the volume ratio of [EMIm][BF4] to [BSO3HMIm][OTf], type and volume of extraction solvent, pH value of sample solution, sonication time, extraction time and centrifugation time were investigated and optimized. Under the optimized extraction conditions, the method exhibited good sensitivity with the limits of detection (LODs) at 5.5 μg L(-1)and 10.0 μg L(-1) for 4-nitrophenol and 2-naphthol, respectively. Good linearity over the concentration ranges of 24-384 μg L(-1) for 4-nitrophenol and 28-336 μg L(-1) for 2-naphthol was obtained with correlation coefficients of 0.9998 and 0.9961, respectively. The proposed method can directly extract acidic compound from environmental sample or even more complex sample matrix without any pH adjustment procedure.

  8. Ionic Liquids Assisted Synthesis of ZnO Nanostructures: Controlled Size,Morphology and Antibacterial Properties

    Institute of Scientific and Technical Information of China (English)

    R.Rajiv Gandhi; S.Gowri; J.Suresh; M.Sundrarajan

    2013-01-01

    Systematic analysis about the exploitation of imidazolium based ionic liquids (ILs),[BMIM] BF4 [IL1],[EMIM] BF4 [IL2] and [BMIM] PF6 [IL3] as the morphological template on the basic sol-gel method adopted synthesis of nanostructured zinc oxide (ZnO) is presented.X-ray diffraction (XRD),particle size analysis (PSA) and scanning electron microscopy (SEM) have been employed for the characterization of structure and morphology of the synthesized ZnO particles.Well-defined capsule like shaped morphology with lower nanosize is observed for the ZnO nanoparticles with IL1 than those with IL2 and IL3.This confirms that IL1 served as an effective templating material due to their unique properties.Especially the effective aggregation of ZnO particles with a self-organized frame of IL1 was the essential factor to produce the lower nanosized ZnO with capsule shaped structure.The synthesized ZnO samples with IL2 and IL3 fabricated the flake like shaped and rod like shaped morphologies in the range of nanoscale.The formed ZnO nanoparticles with IL2 exhibit higher nanosize than the ZnO nanoparticles produced by IL1,owing to shorter length of alkyl group in its cation which restricts steric effect and permits the nanoparticles to grow longer.Even though IL3 produced the discrete ZnO nanorods,the hydrophobic nature of IL3 created the higher nanosize than the ZnO nanoparticles formed by other two ionic liquids.Antibacterial properties of the synthesized ZnO nanostructures were investigated against Staphylococcus aureus (gram positive) and Escherichia coli (gram negative) bacteria by Agar diffusion test method.Microbial experiments indicate that the synthesized ZnO samples show a wide spectrum of antimicrobial activities and performed better against S.aureus than E.coli with the same concentration of ZnO.

  9. Molecular dynamics simulation studies of ionic liquid electrolytes for electric double layer capacitors

    Science.gov (United States)

    Hu, Zongzhi

    Molecular Dynamics (MD) simulation has been performed on various Electric Double Layer Capacitors (EDLCs) systems with different Room Temperature Ionic Liquids (RTILs) as well as different structures and materials of electrodes using a computationally efficient, low cost, united atom (UA)/explicit atom (EA) force filed. MD simulation studies on two 1-butyl-3-methylimidazolium (BMIM) based RTILs, i.e., [BMIM][BF4] and [BMIM][PF6], have been conducted on both atomic flat and corrugated graphite as well as (001) and (011) gold electrode surfaces to understand the correlations between the Electric Double Layer (EDL) structure and their corresponding differential capacitance (DC). Our MD simulations have strong agreement with some experimental data. The structures of electrodes also have a strong effect on the capacitance of EDLCs. MD simulations have been conducted on RTILs of N-methyl-N- propylpyrrolidinium [pyr13] and bis(fluorosulfonyl)imide (FSI) as well as [BMIM][PF6] on both curvature electrodes (fullerenes, nanotube, nanowire) and atomic flat electrode surfaces. It turns out that the nanowire electrode systems have the largest capacitance, following by fullerene systems. Nanotube electrode systems have the smallest capacitance, but they are still larger than that of atomically flat electrode system. Also, RTILs with slightly different chemical structure such as [Cnmim], n = 2, 4, 6, and 8, FSI and bis(trifluoromethylsulfonyl)imide (TFSI), have been examined by MD simulation on both flat and nonflat graphite electrode surfaces to study the effect of cation and anion's chemical structures on EDL structure and DC. With prismatic (nonflat) graphite electrodes, a transition from a bell-shape to a camel-shape DC dependence on electrode potential was observed with increase of the cation alkyl tail length for FSI systems. In contrast, the [Cnmim][TFSI] ionic liquids generated only a camel-shape DC on the rough surface regardless of the length of alkyl tail.

  10. Efeito protetor do Nitrosil-RutÃnio (Cis[Ru(bpy)2SO3NO]+(PF6) em modelos experimentais de lesÃes gÃstricas em camundongos â envolvimento da via NO/GCs/KATP

    OpenAIRE

    Ana Paula MacÃdo Santana

    2013-01-01

    IntroduÃÃo: LesÃes gÃstricas relacionadas ao consumo excessivo de antiinflamatÃrios nÃo esteroidais (AINEs) e etanol possuem um importante papel na gastroenterologia clÃnica. FÃrmacos com aÃÃo anti-secretÃria gÃstrica, como os inibidores da bomba de prÃtons, representam a principal opÃÃo na terapia destas patologias. Objetivo: Avaliar o efeito do doador de NO nitrosil-rutÃnio (Rut-NO) na defesa da mucosa gÃstrica em modelos experimentais de lesÃo gÃstrica em camundongos e a participaÃÃo da gu...

  11. Adição do líquido iônico [BMIM] [BF4] em soluções aquosas de aminas: influência sobre a corrosão do aço carbono em alta pressão e capacidade de absorção de CO2

    OpenAIRE

    Bernard, Franciele Longaray

    2014-01-01

    Tecnologias de captura e armazenamento de carbono são apontadas como uma das principais tecnologias para reduzir as emissões de CO2 e mitigar o efeito das mudanças climáticas. Entre as técnicas de captura de CO2, o processo de absorção química que utilizam as soluções aquosas de aminas tem sido extensivamente estudado e utilizado por décadas. No entanto, estes processos apresentam uma série de inconvenientes. A fim de lidar com estes inconvenientes, recentemente, misturas de soluções de amina...

  12. Tunable Electrochemical and Catalytic Features of BIAN- and BIAO-Derived Ruthenium Complexes.

    Science.gov (United States)

    Hazari, Arijit Singha; Das, Ankita; Ray, Ritwika; Agarwala, Hemlata; Maji, Somnath; Mobin, Shaikh M; Lahiri, Goutam Kumar

    2015-05-18

    This article deals with a class of ruthenium-BIAN-derived complexes, [Ru(II)(tpm)(R-BIAN)Cl]ClO4 (tpm = tris(1-pyrazolyl)methane, R-BIAN = bis(arylimino)acenaphthene, R = 4-OMe ([1a]ClO4), 4-F ([1b]ClO4), 4-Cl ([1c]ClO4), 4-NO2 ([1d]ClO4)) and [Ru(II)(tpm)(OMe-BIAN)H2O](2+) ([3a](ClO4)2). The R-BIAN framework with R = H, however, leads to the selective formation of partially hydrolyzed BIAO ([N-(phenyl)imino]acenapthenone)-derived complex [Ru(II)(tpm)(BIAO)Cl]ClO4 ([2]ClO4). The redox-sensitive bond parameters involving -N═C-C═N- or -N═C-C═O of BIAN or BIAO in the crystals of representative [1a]ClO4, [3a](PF6)2, or [2]ClO4 establish its unreduced form. The chloro derivatives 1a(+)-1d(+) and 2(+) exhibit one oxidation and successive reduction processes in CH3CN within the potential limit of ±2.0 V versus SCE, and the redox potentials follow the order 1a(+) oxidation and primarily BIAN- or BIAO-based successive reduction processes. The aqua complex 3a(2+) undergoes two proton-coupled redox processes at 0.56 and 0.85 V versus SCE in phosphate buffer (pH 7) corresponding to {Ru(II)-H2O}/{Ru(III)-OH} and {Ru(III)-OH}/{Ru(IV)═O}, respectively. The chloro (1a(+)-1d(+)) and aqua (3a(2+)) derivatives are found to be equally active in functioning as efficient precatalysts toward the epoxidation of a wide variety of alkenes in the presence of PhI(OAc)2 as oxidant in CH2Cl2 at 298 K, though the analogous 2(+) remains virtually inactive. The detailed experimental analysis with the representative precatalyst 1a(+) suggests the involvement of the active {Ru(IV)═O} species in the catalytic cycle, and the reaction proceeds through the radical mechanism, as also supported by the DFT calculations.

  13. A phosphomide based PNP ligand, 2,6-{Ph2PC(O)}2(C5H3N), showing PP, PNP and PNO coordination modes.

    Science.gov (United States)

    Kumar, Pawan; Kashid, Vitthalrao S; Reddi, Yernaidu; Mague, Joel T; Sunoj, Raghavan B; Balakrishna, Maravanji S

    2015-03-07

    A new class of PNP pincer ligands, pyridine-2,6-diylbis(diphenylphosphino)methanone, 2,6-{Ph2PC(O)}2(C5H3N) (1) (hereafter referred to as "bis(phosphomide)"), was prepared by the reaction of picolinoyldichloride with diphenylphosphine in the presence of triethylamine. The bis(phosphomide) 1 shows symmetrical PNP, unsymmetrical PNO and simple bidentate PP coordination modes when treated with various transition metal precursors. The reaction between 1 and [Ru(p-cymene)Cl2]2 in a 1 : 1 molar ratio yielded a binuclear complex [Ru2Cl4(NCCH3)(p-cymene){2,6-{Ph2PC(O)}2(C5H3N)}] (2) containing an unsymmetrical PNO pincer cage around one of the ruthenium centers, whereas the second ruthenium is bonded to the other phosphorus atom along with cymene and two chloride atoms. Symmetrical pincer complexes [RuCl(NCCH3)2{2,6-{Ph2PC(O)}2(C5H3N)}](ClO4) (3), [Ru(η(5)-C5H5){2,6-{Ph2PC(O)}2(C5H3N)}](OTf) (4) and [RhCl{2,6-{Ph2PC(O)}2(C5H3N)}] (5) were obtained in the respective reactions of 1 with [RuCl(NCCH3)2(p-cymene)](ClO4), [Ru(η(5)-C5H5)Cl(PPh3)2] and [Rh(COD)Cl]2. Group 10 metal complexes [NiCl{2,6-{Ph2PC(O)}2(C5H3N)}](BF4) (6), [PdCl{2,6-{Ph2PC(O)}2(C5H3N)}]ClO4 (7) and [PtCl{2,6-{Ph2PC(O)}2(C5H3N)}]ClO4 (8) were obtained by transmetallation reactions of in situ generated Ag(I) salts of 1 with Ni(DME)Cl2 or M(COD)Cl2 (M = Ni, Pd and Pt). The reactions between 1 and CuX or [Cu(NCCH3)4](BF4) produced mononuclear complexes of the type [CuX{2,6-{Ph2PC(O)}2(C5H3N)}] (9, X = Cl; 10, X = Br; 11, X = I), [Cu(NCCH3){Ph2C(O)}2(C5H3N)}](BF4) (12) and [Cu{Ph2C(O)}2(C5H3N)}2](BF4) (13). Similarly, the silver complexes [AgX{2,6-{Ph2PC(O)}2(C5H3N)}] (14, X = ClO4; 15, X = Br) were obtained by the treatment of 1 with AgClO4 or AgBr in 1 : 1 molar ratios. Treatment of 1 with AuCl(SMe2) in 1 : 1 and 1 : 2 molar ratios produced mono- and binuclear complexes, [AuCl{2,6-{Ph2PC(O)}2(C5H3N)}] (16) and [Au2Cl2{2,6-{Ph2PC(O)}2(C5H3N)}] (17), in good yield. The structures of ligand 1

  14. Ionic liquids for improving the extraction of NSAIDs in water samples using dispersive liquid-liquid microextraction by high performance liquid chromatography-diode array-fluorescence detection.

    Science.gov (United States)

    Toledo-Neira, Carla; Álvarez-Lueje, Alejandro

    2015-03-01

    A rapid, sensitive and efficient analytical method based on the use of ionic liquids for determination of non-steroidal anti-inflammatory drugs (NSAIDs) in water samples was developed. High-performance liquid chromatography equipped with a diode array and fluorescence detector was used for quantification of ketoprofen, ibuprofen and diclofenac in tap and river water samples. This new method relies on the use of two ionic liquids with multiple functionalities: one functions as an extraction solvent (1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and the other changes the polarity in the aqueous medium (1-butyl-3-methylimidazolium tetrafluoroborate, ([BMIM][BF4]). Factors such as the type and volume of the ILs and dispersive solvent, sample volume, and centrifugation time were investigated and optimized. The optimized method exhibited good precision, with relative standard deviation values between 2% and 3%, for the three NSAIDs. Limits of detection achieved for all of the analytes were between 17 and 95 ng mL(-1), and the recoveries ranged from 89% to 103%. Furthermore, the enrichment factors ranged from 49 to 57. The proposed method was successfully applied to the analysis of NSAIDs in tap and river water samples.

  15. Improvement of the cloud point extraction of uranyl ions by the addition of ionic liquids.

    Science.gov (United States)

    Gao, Song; Sun, Taoxiang; Chen, Qingde; Shen, Xinghai

    2013-12-15

    The cloud point extraction (CPE) of uranyl ions by different kinds of extractants in Triton X-114 (TX-114) micellar solution was investigated upon the addition of ionic liquids (ILs) with various anions, i.e., bromide (Br(-)), tetrafluoroborate (BF4(-)), hexafluorophosphate (PF6(-)) and bis[(trifluoromethyl)sulfonyl]imide (NTf2(-)). A significant increase of the extraction efficiency was found on the addition of NTf2(-) based ILs when using neutral extractant tri-octylphosphine oxide (TOPO), and the extraction efficiency kept high at both nearly neutral and high acidity. However, the CPE with acidic extractants, e.g., bis(2-ethylhexyl) phosphoric acid (HDEHP) and 8-hydroxyquinoline (8-HQ) which are only effective at nearly neutral condition, was not improved by ILs. The results of zeta potential and (19)F NMR measurements indicated that the anion NTf2(-) penetrated into the TX-114 micelles and was enriched in the surfactant-rich phase during the CPE process. Meanwhile, NTf2(-) may act as a counterion in the CPE of UO2(2+) by TOPO. Furthermore, the addition of IL increased the separation factor of UO2(2+) and La(3+), which implied that in the micelle TOPO, NTf2(-) and NO3(-) established a soft template for UO2(2+). Therefore, the combination of CPE and IL provided a supramolecular recognition to concentrate UO2(2+) efficiently and selectively.

  16. Crystal Structures and Phase Sequences of Metallocenium Salts with Fluorinated Anions: Effects of Molecular Size and Symmetry on Phase Transitions to Ionic Plastic Crystals.

    Science.gov (United States)

    Mochida, Tomoyuki; Funasako, Yusuke; Ishida, Mai; Saruta, Shingo; Kosone, Takashi; Kitazawa, Takafumi

    2016-10-24

    Sandwich compounds often exhibit various phase transitions, including those to plastic phases. To elucidate the general features of the phase transitions in metallocenium salts, the thermal properties and crystal structures of [Fe(C5 Me5 )2 ]X ([1]X), [Co(C5 Me5 )2 ]X ([2]X), and [Fe(C5 Me4 H)2 ]X ([3]X) have been investigated, where the counter anions (X) are Tf2 N (=(CF3 SO2 )2 N(-) ), OTf (=CF3 SO3(-) ), PF6 , and BF4 . The Tf2 N salts commonly undergo phase transitions from an ordered phase at low temperatures to an anion-disordered phase, followed by a plastic phase and finally melt at high temperatures. All these salts exhibit a phase transition to a plastic phase, and the transition temperature generally decreases with decreasing cation size and increasing anion size. The crystal structures of these salts comprise an alternating arrangement of cations and anions. About half of these salts exhibit phase transitions at low temperatures, which are mostly correlated with the order-disorder of the anion.

  17. How to remove the influence of trace water from the absorption spectra of SWNTs dispersed in ionic liquids

    Directory of Open Access Journals (Sweden)

    Juan Yang

    2011-09-01

    Full Text Available Single-walled carbon nanotubes (SWNTs can be efficiently dispersed in the imidazolium-based ionic liquids (ILs, at relatively high concentration, with their intrinsic structure and properties retained. Due to the hygroscopicity of the ILs, water bands may be introduced in the absorption spectra of IL-dispersed SWNTs and cause problems in spectral deconvolution and further analysis. In order to remove this influence, a quantitative characterization of the trace water in [BMIM]+[PF6]− and [BMIM]+[BF4]− was carried out by means of UV–vis-NIR absorption spectroscopy. A simple yet effective method involving spectral subtraction of the water bands was utilized, and almost no difference was found between the spectra of the dry IL-dispersed SWNT samples treated under vacuum for 10 hours and the spectra of the untreated samples with subtraction of the pure water spectrum. This result makes it more convenient to characterize SWNTs with absorption spectra in the IL-dispersion system, even in the presence of trace amount of water.

  18. STUDY ON THE EXTRACTION PERFORMANCE OF NEW IONIC LIQUID FOR REMOVING BENZOTHIOPHENE AND DIBENZOTHIOPHENE%新型离子液体对苯并噻吩、二苯并噻吩的萃取性能研究

    Institute of Scientific and Technical Information of China (English)

    张进; 朴香兰; 朱慎林

    2008-01-01

    合成了5种新型离子液体[bmim]AlCl1,[bmin]DBP,[bmim]BeS,[bmim]PF6,[bmim]BF4,并将它们用于萃取模拟油品中的苯并噻吩(BT)、二笨并噻吩(DBT).比较了5种离子液体的萃取性能,结合分子间作用力的理论和价键理论阐述了离子液体萃取脱硫的机理.结果表明,离子液体的萃取性能与其阴离子结构有关,其中[bmim]DBP适宜作萃取脱硫溶剂.BT、DBT在模拟油品中的初始含量分别为1 000μg/g左右时,[bmim]DBP经4级错流萃取和5级逆流萃取,BT、DBT含量均能降至50μg/g以下.

  19. Aqueous Solutions of Ionic Liquids: Microscopic Assembly.

    Science.gov (United States)

    Vicent-Luna, Jose Manuel; Dubbeldam, David; Gómez-Álvarez, Paula; Calero, Sofia

    2016-02-01

    Aqueous solutions of ionic liquids are of special interest, due to the distinctive properties of ionic liquids, in particular, their amphiphilic character. A better understanding of the structure-property relationships of such systems is hence desirable. One of the crucial molecular-level interactions that influences the macroscopic behavior is hydrogen bonding. In this work, we conduct molecular dynamics simulations to investigate the effects of ionic liquids on the hydrogen-bond network of water in dilute aqueous solutions of ionic liquids with various combinations of cations and anions. Calculations are performed for imidazolium-based cations with alkyl chains of different lengths and for a variety of anions, namely, [Br](-), [NO3](-), [SCN](-) [BF4](-), [PF6](-), and [Tf2N](-). The structure of water and the water-ionic liquid interactions involved in the formation of a heterogeneous network are analyzed by using radial distribution functions and hydrogen-bond statistics. To this end, we employ the geometric criterion of the hydrogen-bond definition and it is shown that the structure of water is sensitive to the amount of ionic liquid and to the anion type. In particular, [SCN](-) and [Tf2N](-) were found to be the most hydrophilic and hydrophobic anions, respectively. Conversely, the cation chain length did not influence the results.

  20. Effect of the Structure of Cations and Anions of Ionic Liquids on Separation of Aromatics from Hydrocarbon Mixtures

    Institute of Scientific and Technical Information of China (English)

    Liu Yansheng; Zhang Zhongxin; Zhang Guofu; Liu Zhichang; Hu Yufeng; Shi Quan; Ji Dejun

    2006-01-01

    The effects of the structure of typical cations and anions of ionic liquids on the separation of benzene and toluene from aromatic/paraffin mixtures were studied. The results showed that the corresponding separation factors were considerably larger than those of the traditional solvents (Benzene+Hexane+sulfolane), and that the ionic liquids could be used as novel solvents for the separation of aromatics from hydrocarbon mixtures. The key parameters governing the ability of ionic liquids for separating aromatics from hydrocarbon sources were investigated. It was found that the effectiveness of the ionic liquids, based on the same anion, changed in the cation order of [BIqu]+< [BPy]+< [BMIM]+. The selectivity of the ionic liquid toward aromatics decreased apparently with the increasing length of the substituted alkyl chain of its cationic head ring. The separation factors, based on the same cation, changed in the anion order of [Tf2N]-<[PF6]-<[BF4]-<[C2H5SO4]-. The solubilities of the aromatics were greater in the ionic liquids based on the former three anions than that in the ionic liquids involving [C2H5SO4]-.

  1. Effect of Counterion on the Solvatochromic Properties of Heteroleptic Chelate Copper(II Complexes

    Directory of Open Access Journals (Sweden)

    Hamid Golchoubian

    2013-01-01

    Full Text Available A series of heteroleptic chelate copper(II complexes of the type [Cu(L(acac]X where acac = acetylacetonate; L = N,N′-1,6-bis(2-fluorophenyl-2,5-diazahexane; X=CIO4-, BPh4-, PF6-, and BF4- have been prepared and characterized by elemental analyses, IR and UV-Vis spectroscopies, and molar conductance measurements. The prepared complexes are fairly soluble in a large number of organic solvents and show positive solvatochromism. Among the complexes [Cu(L(acac]ClO4, it is demonstrated the most solvatochromism. A multiparametric equation has been utilized to explain the solvent effect on the d-d transition of the complexes using SPSS/PC software. To explore the mechanism of interaction between solvent molecules and the complexes, different solvent parameters such as DN, AN, α, ET(30, π*, and β using stepwise multiple linear regression (SMLR method were employed. The results demonstrated that the donor power of the solvent plays the most important role in the solvatochromism of the compounds.

  2. Aprotické elektrolyty pro superkondenzátory

    OpenAIRE

    2010-01-01

    Diplomová práce ověřuje vhodnost použití různých typů aprotických elektrolytů pro superkondenzátory, využívá metody impedanční spektroskopie k měření měrné iontové vodivosti a cyklické voltametrie k určení velikosti potenciálových oken. Použitá aprotická rozpouštědla - propylenkarbonát, dimethylsulfoxid, N, N dimethylformamid, ethylenkarbonát, dimethylkarbonát, diethylkarbonát a acetonitril. Do rozpouštědel byly přidány soli - LiClO4, NaClO4, KClO4, LiBF4, LiPF6, TEABF4 a TMABF4, za vzniku ro...

  3. Dynamical properties of alcohol + 1-hexyl-3-methylimidazolium ionic liquid mixtures: a computer simulation study.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; García, Manuel; Cabeza, Oscar; Gallego, Luis J; Varela, Luis M

    2011-12-29

    In this work, extensive molecular dynamics simulations of the dynamics of mixtures of ionic liquids (ILs) composed of the cation 1-hexyl-3-methylimidazolium and several anions of different hydrophobicity degrees (Cl(-), BF(4)(-), PF(6)(-)) with alcohols of different chain lengths (methanol and ethanol) are reported. We evaluated the influence of the nature of the anion, the length of the molecular chain of the alcohol, and the alcohol concentration on some dynamical properties of the mixtures, such as self-diffusion coefficients of all the species, mean square displacements (with an analysis of both ballistic and diffusive regimes), and velocity autocorrelation functions of alcohol molecules. The diffusivity of the mixtures was found to be highly dependent on the nature of the anion since the interaction between chloride and alcohols is greater than that with fluorinated anions and leads to slower dynamics. Additionally, our results show that self-diffusion coefficients increase with alcohol concentration. On the other hand, a subdiffusive regime over thousands of picoseconds was detected at intermediate times through analysis of the center-of-mass mean square displacements of alcohol molecules, a region that becomes narrower as alcohol concentration increases. Finally, the study of the role of the anion and of solvent concentration on velocity autocorrelation functions reflects an increase in mean collision times as the amount of alcohol increases until the value of pure alcohols is reached. These collision times are smaller in mixtures with halogenated ILs.

  4. Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of anthraquinones in Rheum palmatum L.

    Science.gov (United States)

    Wang, Zhibing; Hu, Jianxue; Du, Hongxia; He, Shuang; Li, Qing; Zhang, Hanqi

    2016-06-01

    The microwave-assisted ionic liquid homogeneous liquid-liquid microextraction (MA-IL-HLLME) coupled with high performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of anthraquinones, including aloe-emodin, emodin, chrysophanol and physcion in root of Rheum palmatum L. Several experimental parameters influencing the extraction efficiency, including amount of sample, type and volume of ionic liquid, volume and pH value of extraction medium, microwave power and extraction time, concentration of NH4PF6 as well as centrifugal condition were optimized. When 140μL of ionic liquid ([C8MIM][BF4]) was used as an extraction solvent, target analytes can be extracted from sample matrix in one minute with the help of microwave irradiation. The MA-IL-HLLME is simple and quick. The calibration curves exhibited good linear relationship (r>0.9984). The limits of detection and quantification were in the range of 0.015-0.026 and 0.051-0.088μgmL(-1), respectively. The spiked recovery for each analyte was in the range of 81.13-93.07% with relative standard deviations lower than 6.89%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and heat reflux extraction. The results indicated that the present method can be successfully applied to the determination of anthraquinones in medicinal plant.

  5. Solubility of β-cyclodextrin in different mixed solvents

    Institute of Scientific and Technical Information of China (English)

    Yu Yong; Li Jiguang; Sun Yan; Liang Qianqing; Peng Xiaoming; Liu Yansheng; Hu Yufeng

    2008-01-01

    The solubility of β-cyclodextrin(β-CD)in ionic liquid/N,N-dimethyl-acetamide(IL/DMAC)mixed solvent and in LiCl/DMAC mixed solvent was investigated at 323.15 K and 353.15 K.The results showed that the solubility of β-CD in IL/DMAC system increased with increasing temperature,but decreased in LiCl/DMAC system.β-CD had the highest solubility in IL/DMAC system with[Cl]- or[Br]- anions.The solubility of β-CD in LiCl/DMAC system was lower than that in IL/DMAC system with [Cl]- or[Br]- anions but higher than that in IL/DMAC system with weak-coordinated anions(e.g[BF4]- or[PF6]-).The effects of substituent groups(benzyl and butyl)of cation and the structure of cations on β-cyclodextrin solubility were also investigated.

  6. Screening of lignan patterns in Schisandra species using ultrasonic assisted temperature switch ionic liquid microextraction followed by UPLC-MS/MS analysis.

    Science.gov (United States)

    Dong, Wei; Yu, Shuijing; Deng, Yangwu; Pan, Tao

    2016-01-01

    The ultrasonic assisted temperature-switch ionic liquid microextraction (UATS-ILME) has been successfully applied in extracting of seven lignans from Schisandra. 1-Butyl-3-methylimidazolium tetrafluoroborate ([C4MIM][BF4]) aqueous solution was selected for extracting the target analytes in raw material at 80°C. The lignans were deposited into a single drop by in situ forming 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) by cooling down to 0°C and centrifuging for 10min. The extracts were analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in a robust multiple-reaction monitoring (MRM) mode in five minutes. Meanwhile, the proposed method was validated and successfully applied to the determination of seven lignans in twelve Schisandra species. The results indicated that UATS-ILME combined with UPLC-MS/MS is a powerful and practical tool, which has great potential for comprehensive quality control of herbal medicines.

  7. The Geometry and Structural Properties of the 4,8,12-Trioxa-4,8,12,12c-tetrahydrodibenzo[cd,mn]pyrene System in the Cationic State. Structures of a Planar Organic Cation with Various Monovalent- and Divalent Anions

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Laursen, Bo W.; Johannsen, Ib

    1999-01-01

    The geometry of the 4,8,12-trioxa-4,8,12,12c- tetrahydrodibenzo[cd,mn]pyrene system in the cationic state was established by X-ray structural resolution of the salts formed between the cationand various anions. The geometry was found to be planar for the 4,8,12-trioxa-4,8,12,12c- tetrahydrodibenzo...... [cd,mn]pyrenylium and 2,6,10-tri (tert-butyl)-4,8,12-trioxa-4,8,12,12c-tetrahydrodibenzo[cd,mn]pyre nylium cations with the monovalentanions I-, BF4-, PF6- AsF6-, HNO3. NO3- and CF3SO3-, and the divalent anions S2O62- and Mo6Cl142-. The salts were found to crystallize in distinct space groups...... following a characteristic pattern. Mixed cation-anion stacking resulted in space groups with high symmetry: Pbca in three cases and R (3) over bar c in one; a temperature study of the latter was made at ten different temperatures. The formation of dimers of anions and cations resulted in lower...

  8. Probing the effects of the ester functional group, alkyl side chain length and anions on the bulk nanostructure of ionic liquids: a computational study.

    Science.gov (United States)

    Fakhraee, Mostafa; Gholami, Mohammad Reza

    2016-04-14

    The effects of ester addition on nanostructural properties of biodegradable ILs composed of 1-alkoxycarbonyl-3-alkyl-imidazolium cations ([C1COOCnC1im](+), n = 1, 2, 4) combined with [Br](-), [NO3](-), [BF4](-), [PF6](-), [TfO](-), and [Tf2N](-) were explored by using the molecular dynamics (MD) simulations and quantum theory of atoms in molecules (QTAIM) analysis at 400 K. Various thermodynamic properties of these ILs were extensively computed in our earlier work (Ind. Eng. Chem. Res., 2015, 54, 11678-11700). Nano-scale segregation analysis demonstrates the formation of a small spherical island-like hydrocarbon within the continuous ionic domain for ILs with short alkyl side chain ([C1COOC1C1im]), and a sponge-like nanostructure for the compound with long alkyl side chain ([C1COOC4C1im]). Ester-functionalized ILs with ethyl side chain ([C1COOC2C1im]) are the turning point between two different morphologies. Non-polar channels were observed for [C1COOC4C1im] ILs composed of smaller anions such as [Br] and [NO3], whereas clustering organization was found for the other anions. Formation of the spherical micelle-like nanostructure was seen for lengthened cations. Finally, the incorporation of an ester group into the alkyl side chain of the cation leads to stronger segregation between charged and uncharged networks, which consequently increased the possibility of self-assembly and micelle formation.

  9. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion corrosion processes

    Science.gov (United States)

    Bermúdez, María-Dolores; Jiménez, Ana-Eva; Martínez-Nicolás, Ginés

    2007-06-01

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1- n-alkyl-3-methylimidazolium X - (X = BF 4; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF 3SO 3; n = 2 (IL4). X = (4-CH 3C 6H 4SO 3); n = 2 (IL5). X = PF 6; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of α-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  10. On the nature of ionic liquids and their effects on lipases that catalyze ester synthesis.

    Science.gov (United States)

    De Diego, Teresa; Lozano, Pedro; Abad, Miguel A; Steffensky, Katharina; Vaultier, Michel; Iborra, José L

    2009-03-25

    Free and immobilized lipases from Candida antarctica (CALA and CALB), Thermomyces lanuginosus (TLL) and Rhizomucor miehei (RML) were used as catalysts in the synthesis of butyl propionate by transesterification in reaction media consisting in nine different ionic liquids. Enzyme activities were clearly dependent on the nature of the ions, the results being improving as the alkyl chain length of the imidazolium cation increased, and as a function of the type of anion ([PF(6)], [BF(4)] or [ethylsulphate]). The best synthetic activity (655.5U/mg protein at 40 degrees C) was obtained when free CALB were assayed in the water-miscible IL cocosalkyl pentaethoxy methyl ammonium methosulfate ([CPMA][MS]), and was clearly related with the water content of the medium. The synthetic activity of free CALB in [CPMA][MS] was enhanced with the increase in temperature, while practically no effect was obtained for TLL. The ability of free CALB to synthesize aliphatic esters of different alkyl chain lengths, using different alkyl vinyl esters and 1-alkanols as substrates, was also studied in [CPMA][MS], the best results (4500U/mg protein) being obtained for the synthesis of hexyl butyrate.

  11. The Anion Effect on Li(+) Ion Coordination Structure in Ethylene Carbonate Solutions.

    Science.gov (United States)

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

    2016-09-15

    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, allowing only two EC molecules to coordinate to Li(+) directly. Our results demonstrate for the first time, to the best of our knowledge, the anion influence on the overall structure of the first solvation shell of the Li(+) ion. The formation of such a cation/solvent/anion complex provides a rational explanation for the ionic conductivity drop of lithium/carbonate electrolyte solutions at high concentrations.

  12. Adsorption Kinetics at Silica Gel/Ionic Liquid Solution Interface

    Directory of Open Access Journals (Sweden)

    Jolanta Flieger

    2015-12-01

    Full Text Available A series of imidazolium and pyridinium ionic liquids with different anions (Cl−, Br−, BF4−, PF6− has been evaluated for their adsorption activity on silica gel. Quantification of the ionic liquids has been performed by the use of RP-HPLC with organic-aqueous eluents containing an acidic buffer and a chaotropic salt. Pseudo-second order kinetic models were applied to the experimental data in order to investigate the kinetics of the adsorption process. The experimental data showed good fitting with this model, confirmed by considerably high correlation coefficients. The adsorption kinetic parameters were determined and analyzed. The relative error between the calculated and experimental amount of ionic liquid adsorbed at equilibrium was within 7%. The effect of various factors such as initial ionic liquid concentration, temperature, kind of solvent, kind of ionic liquid anion and cation on adsorption efficiency were all examined in a lab-scale study. Consequently, silica gel showed better adsorptive characteristics for imidazolium-based ionic liquids with chaotropic anions from aqueous solutions in comparison to pyridinium ionic liquids. The adsorption was found to decrease with the addition of organic solvents (methanol, acetonitrile but it was not sensitive to the change of temperature in the range of 5–40 °C.

  13. Fe(II) Spin Transition Materials Including an Amino-Ester 1,2,4-Triazole Derivative, Operating at, below, and above Room Temperature.

    Science.gov (United States)

    Dîrtu, Marinela M; Naik, Anil D; Rotaru, Aurelian; Spinu, Leonard; Poelman, Dirk; Garcia, Yann

    2016-05-02

    A new family of one-dimensional Fe(II) 1,2,4-triazole spin transition coordination polymers for which a modification of anion and crystallization solvent can tune the switching temperature over a wide range, including the room temperature region, is reported. This series of materials was prepared as powders after reaction of ethyl-4H-1,2,4-triazol-4-yl-acetate (αEtGlytrz) with an iron salt from a MeOH/H2O medium affording: [Fe(αEtGlytrz)3](ClO4)2 (1); [Fe(αEtGlytrz)3](ClO4)2·CH3OH (2); [Fe(αEtGlytrz)3](NO3)2·H2O (3); [Fe(αEtGlytrz)3](NO3)2 (4); [Fe(αEtGlytrz)3](BF4)2·0.5H2O (5); [Fe(αEtGlytrz)3](BF4)2 (6); and [Fe(αEtGlytrz)3](CF3SO3)2·2H2O (7). Their spin transition properties were investigated by (57)Fe Mossbauer spectroscopy, superconducting quantum interference device (SQUID) magnetometry, and differential scanning calorimetry (DSC). The temperature dependence of the high-spin molar fraction derived from (57)Fe Mössbauer spectroscopy in 1 reveals an abrupt single step transition between low-spin and high-spin states with a hysteresis loop of width 5 K (Tc(↑) = 296 K and Tc(↓) = 291 K). The properties drastically change with modification of anion and/or lattice solvent. The transition temperatures, deduced by SQUID magnetometry, shift to Tc(↑) = 273 K and Tc(↓) = 263 K for (2), Tc(↑) = 353 K and Tc(↓) = 333 K for (3), Tc(↑) = 338 K and Tc(↓) = 278 K for (4), T(↑) = 320 K and T(↓) = 305 K for (5), Tc(↑) = 106 K and Tc(↓) = 92 K for (6), and T(↑) = 325 K and T(↓) = 322 K for (7). Annealing experiments of 3 lead to a change of the morphology, texture, and magnetic properties of the sample. A dehydration/rehydration process associated with a spin state change was analyzed by a mean-field macroscopic master equation using a two-level Hamiltonian Ising-like model for 3. A new structural-property relationship was also identified for this series of materials [Fe(αEtGlytrz)3](anion)2·nSolvent based on Mössbauer and DSC

  14. Determination of transport properties and optimization of lithium-ion batteries

    Science.gov (United States)

    Stewart, Sarah Grace

    model. The model is compared with experimental results. The performance of this system is compared with a lithium titanate spinet/lithium iron phosphate battery. Various electrolytes are considered: 1 M LiPF6 in ethylene carbonate and dimethyl carbonate (1:2 by weight---hereafter referred to as EC:DMC), 1 M LiBF4 in gamma-butyrolactone (GBL), or 1 M LiBF4 in acetonitrile (ACN). The model is used to study the performance of these chemistries and to assist in optimization of the cells. A Ragone plot is generated for various cell designs in order to assess the ability of the chemistries to achieve the U.S. Department of Energy goals for hybrid-electric vehicles. The model is used to maximize the specific energy of the cell by optimizing the design for a fixed time of discharge. The thickness and porosity of both electrodes are varied, while holding constant a capacity ratio of one for the two electrodes, as well as the properties of the separator, and the electrolyte. The influence of the capacity ratio is discussed. The capacity ratio can be optimized for each time of discharge. A 41% increase in power density is seen when one oversizes the iron phosphate electrode in a lithium titanate spinel/iron phosphate battery because the properties of this electrode are limiting. The optimization was performed for discharge times ranging from 3 h to 30 s in order to gauge the ability of this chemistry to be used in various applications. The optimized designs derived here can be used as a starting point for battery manufacturers and to help decrease the time to commercialization. We have further improved our model in order to simulate the hybrid-pulse-power-characterization (HPPC) test described by FreedomCAR. The simulation results presented in this section improve upon traditional Ragone plots by capturing the complexity of pulse performance during HEV operation. Lithium-ion batteries are capable of satisfying Department of Energy goals for pulse power and energy densities in

  15. Macrocyclic nickel(II) complexes: Synthesis, characterization, superoxide scavenging activity and DNA-binding

    Science.gov (United States)

    Ramadan, Abd El-Motaleb M.

    2012-05-01

    A new series of nickel(II) complexes with the tetraaza macrocyclic ligand have been synthesized as possible functional models for nickel-superoxide dismutase enzyme. The reaction of 5-amino-3-methyl-1-phenylpyrazole-4-carbaldehyde (AMPC) with itself in the presence of nickel(II) ion yields, the new macrocyclic cationic complex, [NiL(NO3)2], containing a ligand composed of the self-condensed AMPC (4 mol) bound to a single nickel(II) ion. A series of metathetical reactions have led to the isolation of a number of newly complexes of the types [NiL]X2; X = ClO4 and BF4, [NiLX2], X = Cl and Br (Scheme 1). Structures and characterizations of these complexes were achieved by several physicochemical methods namely, elemental analysis, magnetic moment, conductivity, and spectral (IR and UV-Vis) measurements. The electrochemical properties and thermal behaviors of these chelates were investigated by using cyclic voltammetry and thermogravimetric analysis (TGA and DTG) techniques. A distorted octahedral stereochemistry has been proposed for the six-coordinate nitrato, and halogeno complexes. For the four-coordinate, perchlorate and fluoroborate, complex species a square-planar geometry is proposed. The measured superoxide dismutase mimetic activities of the complexes indicated that they are potent NiSOD mimics and their activities are compared with those obtained previously for nickel(II) complexes. The probable mechanistic implications of the catalytic dismutation of O2rad - by the synthesized nickel(II) complexes are discussed. The DNA-binding properties of representative complexes [NiLCl2] and [NiL](PF4)2 have been investigated by the electronic absorption and fluorescence measurements. The results obtained suggest that these complexes bind to DNA via an intercalation binding mode and the binding affinity for DNA follows the order: [NiLCl2] □ [NiL](PF4)2.

  16. 配位聚合物[Mn(4,4'-bpy)1.5(H2O)3](CIO4)·(4,4'-bpy)(L)·H2O的水热合成和晶体结构%Hydrothermal Synthesis and Crystal Structure of Coordination Polymer [Mn(4,4'-bpy)1.5(H2O)3] (ClO4)· (4,4'-bpy)(L)· H2O

    Institute of Scientific and Technical Information of China (English)

    黄妙龄

    2007-01-01

    The title compound, [Mn(4,4'-bpy)1.5(H2O)3](C1O4)·(4,4'-bpy)(L)· H2O(1), where L=2,4,6-trimethylbenzoic acid, was synthesized and its crystal structure was determined by X-ray diffraction analysis. The crystal is of triclinic, space group P(-1) with a=2.929 9(6) nm, b=1.0364(2) nm, c=8.222 0(1) nm, α=105.300(2)°, β=97.495(2)°,0.135 2. The Mn atoms are octahedrally coordinated by three N atoms of three 4,4'-bipyridine ligands and three O atoms of water. The complex shows a one-dimensional chain structure bridged by water and 4,4'-bipyridine molecules. CCDC: 615707.

  17. Phase diagrams and solvate structures of binary mixtures of glymes and Na salts.

    Science.gov (United States)

    Mandai, Toshihiko; Nozawa, Risa; Tsuzuki, Seiji; Yoshida, Kazuki; Ueno, Kazuhide; Dokko, Kaoru; Watanabe, Masayoshi

    2013-12-05

    We prepared a series of binary mixtures composed of selected Na salts and glymes (tetraglyme, G4, and pentaglyme, G5) with different salt concentrations and anionic species ([X](-): [N(SO2CF3)2](-) = [TFSA](-), [N(SO2F)2](-) = [FSA](-), ClO4(-), PF6(-)) and studied the effects of concentration, anionic structure, and glyme chain length on their phase diagrams and solvate structures. The phase diagrams clearly illustrate that all the mixtures form 1:1 complexes, [Na(G4 or G5)1][X]. The thermal stability of the equimolar mixtures was drastically improved in comparison with those of diluted systems, indicating that all the glyme molecules coordinate to Na(+) cations to form equimolar complexes. Single-crystal X-ray crystallography revealed that [Na(G5)1][X] forms characteristic solvate structures in the crystalline state irrespective of the paired anion species. A comparison of the solvate structures of the glyme-Na complexes with those of the glyme-Li complexes suggests that the ionic radii of the coordinated alkali-metal cations have substantial effects on the resulting solvate structures. The Raman bands of the complex cations were assigned by quantum chemical calculations. Concentration dependencies of cationic and anionic Raman spectra show good agreement with the corresponding phase diagrams. In addition, the Raman spectra of the 1:1 complexes strongly suggest that the glymes coordinate to Na(+) cation in the same way in both liquid and crystalline states. However, the aggregated structure in the crystalline state is broken by melting, which is accompanied by a change in the anion coordination.

  18. Synthesis and characterization of homo- and heterovalent tetra- hexa- hepta- and decanuclear manganese clusters using pyridyl functionalized beta-diketone, carboxylate and triethanolamine ligands.

    Science.gov (United States)

    Langley, Stuart K; Chilton, Nicholas F; Massi, Massimiliano; Moubaraki, Boujemaa; Berry, Kevin J; Murray, Keith S

    2010-08-21

    The syntheses and characterizations are reported for six new homo- and heterovalent manganese clusters, utilizing pyridyl functionalized beta-diketones ligands. The reaction of the trinuclear complex [Mn3O(O2CPh)6(H2O)(Py)2] with 1,3-di(pyridine-2-yl)propane-1,3-dione (dppdH) in CH2Cl2 resulted in a mixed-valence Mn3(II)Mn6(III)Mn(IV) decanuclear cluster of formula [Mn10O7(dppd)3(O2CPh)11] x 4 CH2Cl2 (1). The structure of the core of 1 is based upon a centred tricapped trigonal prism. Reacting Mn(BF4)2 x xH2O with dppdH and triethylamine (NEt3) in CH2Cl2-MeOH gave a rare, homoleptic hexanuclear cluster of formula [Mn(II)6(dppd)8][BF4]4 (2) which has a triangular based core. Reaction of Mn(Y)2 x xH2O, Y = NO3(-) or BF4(-), with dppdH or 1-phenyl-3-(2-pyridyl)propane-1,3-dione (pppdH) in the presence of triethanolamine (teaH3) and NEt3 gave a heptanuclear 'disc' like manganese core of general formula [Mn(II)7(X)6(tea)(OH)3][Y]2 x solv (3) X = pppd- or dppd- and Y = NO3(-) or BF4(-). The addition of N-(2-pyridinyl)acetoacetamide (paaH) to Mn(Y)2 x 4 H2O Y = NO3(-) or ClO4(-) in MeOH gave a second divalent heptanuclear cluster with a 'disc'-like core of general formula [Mn7(paa)6(OMe)6][X]2 x solv (4) (X = NO3(-) or ClO4(-)), whilst the addition of paaH to a mixture of Mn(NO3)2 x 4 H2O, teaH3 and NEt3 in CH2Cl2-MeOH resulted in the formation of a mixed-valence Mn2(II)Mn2(III) tetranuclear 'butterfly' complex of formula [Mn4(paa)4(teaH)2][NO3]2 x 2 MeOH x 2 CH2Cl2 (5). Compound 5 displays the rare Mn(II/III) oxidation state distribution of the body positions being Mn(II) while the wing tips are Mn(III). The in situ formation of the tetranuclear [Mn4(teaH)2(teaH2)2(O2C(CH3)3)2][O2C(CH3)3]2 'butterfly' complex followed by the addition of Mn(O2CMe)2 x 4 H2O resulted in a mixed-valence Mn4(II)Mn(III)Mn(IV) hexanuclear species of formula [Mn6O2(teaH2)4(O2CMe)4][NO3]2[O2CMe] x CH2Cl2 x MeOH x 2 H2O (6). The core of 6 displays a face sharing dicubane topology. Compounds 1 and

  19. Measurement of lithium ion transference numbers of electrolytes for lithium-ion batteries. A comparative study with five various methods.; Messung von Lithium-Ionen Ueberfuehrungszahlen an Elektrolyten fuer Lithium-Ionen Batterien. Eine vergleichende Studie mit fuenf verschiedenen Methoden

    Energy Technology Data Exchange (ETDEWEB)

    Zugmann, Sandra

    2011-03-30

    number and ideally activity coefficients. The new electrolyte lithium difluoromono(oxalato)borate LiDFOB in EC/DEC (3/7) was for example fully determined at 25 C in this work. In comparison with other salts (LiPF6 und LiBF4) it proves to be an appropriate electrolyte for lithium-ion batteries. It generates no HF by hydrolysis that avoids the use of environment friendly and cost-effective manganese spinels, and it much better soluble as lithium bis(oxalato)borate LiBOB. In addition LiDFOB protects aluminum from corrosion and is more thermal stable as the standard salt LiPF6.

  20. 离子液体/苯并15-冠-5浸渍XAD-7树脂萃取分离锂同位素%Extraction Separation of Lithium Isotopes by Using XAD-7 Resins Impregnated With Ionic Liquid and Benzo-15-Crown-5

    Institute of Scientific and Technical Information of China (English)

    顾玲; 孙晓利; 任冬红; 邱丹; 顾志国; 李在均

    2015-01-01

    Imidazolium-type ionic liquid ([C8 mim][BF4 ],[C8 mim][PF6 ]and [C8 mim] [(SO2 CF3 )2 N])and benzo-15-crown-5 were immobilized on XAD-7 resin to obtain the im-pregnated resin for lithium isotopes separation.IR and SEM characterizations of the impreg-nated resins indicate that ionic liquids and benzo-15-crown-5 are immobilized in the resins successfully and the thermal analysis indicates that the materials are thermally stable.The optimum E was obtained in the initial solution at pH=5.55.The larger extraction percenta-ges and separation factors values were obtained from LiSCN solution and CF3 COOLi solu-tion,respectively.The maximum single-stage isotopes separation factor of 6 Li/7 Li is up to 1.045±0.002.The equilibrium time of extraction is attained in 2.5-3 h.The thermodynamic parameters of the system were presented and revealed that the extraction reaction was a spontaneous process and the temperature had slight influence on the extraction separation of lithium isotopes.The mechanism of extraction system show that 6 Li enriches in the solid phase and 7 Li concentrates in the aqueous phase.The impregnated resins can be regenerated and reused for lithium isotopes separation.%以 XAD-7树脂为支撑担体制备了含有三种不同咪唑型离子液体([C8 mim][BF4]、[C8 mim][PF6]、[C8 mim][(SO2 CF3)2 N])和萃取剂(苯并15-冠-5)的浸渍树脂,并用于锂同位素的萃取分离。浸渍树脂的红外和扫描电镜表征表明,离子液体成功负载到了树脂上;热重分析表明,该浸渍树脂具有良好的热稳定性。在水相初始 pH=5.55时,浸渍树脂具有最佳萃取率。浸渍树脂在 LiSCN 溶液中具有较高的萃取率,而在CF3 COOLi 溶液中呈现较大的单级分离因子,最大单级分离因子达到1.045±0.002。浸渍树脂的萃取平衡时间为2.5~3 h。萃取热力学研究表明,该反应为自发过程,温度对体系的影响较小。6 Li 富集于固相,7 Li 富集在水相。该系列浸渍树脂易于再生,可循环使用。

  1. A Highly Aromatic and Sulfonated Ionomer for High Elastic Modulus Ionic Polymer Membrane Micro-Actuators

    Science.gov (United States)

    2012-05-01

    BMIm ][BF4]) is used as the electrolyte. The ion transport and storage at the electrodes (cross section A–A) causes a bending actuation when a voltage...imidazolium based room temperature IL, 1-methyl-3-butylimidazolium tetrafluoroborate ([ BMIm ][BF4]), which was previously used in IPMC actuators, is...utilized as the electrolyte [15]. The chemical structure of [ BMIm ][BF4] is presented in figure 2(b) and, as can be seen, BMIm − and BF+4 show a large ion

  2. Ionic liquids as an electrolyte for the electro synthesis of organic compounds.

    Science.gov (United States)

    Kathiresan, Murugavel; Velayutham, David

    2015-12-25

    The use of ionic liquids (ILs) as a solvent and an electrolyte for electro organic synthesis has been reviewed. To date several ILs exist, however the ILs based on tetraalkylammonium, pyrrolidinium, piperidinium and imidazolium cations with BF4(-), PF6(-), and TFSI anions have been widely used and explored the most. Electro organic synthesis in ionic liquid media leading to the synthesis of a wide range of organic compounds has been discussed. Anodic oxidation or cathodic reduction will generate radical cation or anion intermediates, respectively. These radicals can undergo self coupling or coupling with other molecules yielding organic compounds of interest. The cation of the IL is known to stabilize the radical anion extensively. This stabilization effect has a specific impact on the electrochemical CO2 reduction and coupling to various organics. The relative stability of the intermediates in IL leads to the formation of specific products in higher yields. Electrochemical reduction of imidazolium or thiazolium based ILs generates N-heterocyclic carbenes that have been shown to catalyze a wide range of base or nucleophile catalyzed organic reactions in IL media, an aspect that falls into the category of organocatalysis. Electrochemical fluorination or selective electrochemical fluorination is another fascinating area that delivers selectively fluorinated organic products in Et3N·nHF or Et4NF·nHF adducts (IL) via anodic oxidation. Oxidative polymerization in ILs has been explored the most; although morphological changes were observed compared to the conventional methods, polymers were obtained in good yields and in some cases ILs were used as dopants to improve the desired properties.

  3. Efficient removal of H2S at high temperature using the ionic liquid solutions of [C4mim]3PMo12O40-An organic polyoxometalate.

    Science.gov (United States)

    Ma, Yunqian; Liu, Xinpeng; Wang, Rui

    2017-02-22

    An innovative approach to H2S capture and sulfur recovery via liquid redox at high temperature has been developed using [C4mim]3PMo12O40 at temperatures ranging from 80 to 180°C, which is superior to the conventional water-based system with an upper limit of working temperature normally below 60°C. The ionic liquids used as solvents include [C4mim]Cl, [C4mim]BF4, [C4mim]PF6 and [C4mim]NTf2. Microscopic observation and turbidity measurement were used to investigate the dissolution of [C4mim]3PMo12O40 in the ionic liquids. Stabilization energy between H2S and the anion of ionic liquid as well as H2O was calculated to illustrate the interaction between H2S and the solvents. The cavity theory can be adopted to illustrate the mechanism for H2S absorption: the Cl(-) ion with small radius can be incorporated into the cavities of [C4mim]3PMo12O40, and interact with H2S strongly. The underlying mechanism for sulfur formation is the redox reaction between H2S and PMo12O40(3-). H2S can be oxidized to elemental sulfur and Mo(6+) is partly reduced during absorption, according to UV-vis and FTIR spectra. The [C4mim]3PMo12O40-[C4mim]Cl after reaction can be readily regenerated by air and thus enabling its efficient and repeatitive use. The absorbent of [C4mim]3PMo12O40-ionic liquid system provides a new approach for wet oxidation desulfurization at high temperature.

  4. Free volume in ionic liquids: a connection of experimentally accessible observables from PALS and PVT experiments with the molecular structure from XRD data.

    Science.gov (United States)

    Beichel, Witali; Yu, Yang; Dlubek, Günter; Krause-Rehberg, Reinhard; Pionteck, Jürgen; Pfefferkorn, Dirk; Bulut, Safak; Bejan, Dana; Friedrich, Christian; Krossing, Ingo

    2013-06-14

    In the current work, free volume concepts, primarily applied to glass formers in the literature, were transferred to ionic liquids (ILs). A series of 1-butyl-3-methylimidazolium ([C4MIM](+)) based ILs was investigated by Positron Annihilation Lifetime Spectroscopy (PALS). The phase transition and dynamic properties of the ILs [C4MIM][X] with [X](-) = [Cl](-), [BF4](-), [PF6](-), [OTf](-), [NTf2](-) and [B(hfip)4](-) were reported recently (Yu et al., Phys. Chem. Chem. Phys., 2012, 14, 6856-6868). In this subsequent work, attention was paid to the connection of the free volume from PALS (here the mean hole volume, ) with the molecular structure, represented by volumes derived from X-ray diffraction (XRD) data. These were the scaled molecular volume Vm,scaled and the van der Waals volume V(vdw). Linear correlations of at the "knee" temperature ((T(k))) with V(m,scaled) and V(vdw) gave good results for the [C4MIM](+) series. Further relationships between volumes from XRD data with the occupied volume Vocc determined from PALS/PVT (Pressure Volume Temperature) measurements and from Sanchez-Lacombe Equation of State (SL-EOS) fits were elaborated (V(occ)(SL-EOS) ≈ 1.63 V(vdw), R(2) = 0.981 and V(occ)(SL-EOS) ≈ 1.12 V(m,scaled), R(2) = 0.980). Finally, the usability of V(m,scaled) was justified in terms of the Cohen-Turnbull (CT) free volume theory. Empirical CT type plots of viscosity and electrical conductivity showed a systematic increase in the critical free volume with molecular size. Such correlations allow descriptions of IL properties with the easily accessible quantity V(m,scaled) within the context of the free volume.

  5. Influence of bonding mode of the linkers in the electronic communication of molecular pairs having dimolybdenum units linked by pseudohalides.

    Science.gov (United States)

    Cotton, F Albert; Murillo, Carlos A; Zhao, Qinliang

    2009-12-21

    Depending on conditions the reactions of [Mo(2)(cis-DAniF)(2)(NCCH(3))(4)](BF(4))(2) (DAniF = N,N'-di-p-anisylformamidinate) with solutions containing thiocyanate anions lead to two compounds: a quadruple-bonded dinuclear species 1, (Bu(n)(4)N)(2)[Mo(2)(cis-DAniF)(2)(NCS)(4)], and a molecular pair 3, [Mo(2)(cis-DAniF)(2)](2)(mu(1,3)-NCS)(4). The latter has a cuboidal structure having two (cis-DAniF)(2)Mo(2)(2+) units, [Mo(2)], with four thiocyanate groups bridging two [Mo(2)] units in an end-to-end fashion in which the N and S atoms serve as the bridging units. On the contrary, the structure of the cyanate isomer, [Mo(2)(cis-DAniF)(2)](2)(mu(1,1)-NCO)(4) (2), shows an end-on binding of the cyanate linkers. Various physical measurements of 2 and its oxidized species 2.PF(6) indicate that there is strong electronic communication between the two dimetal cores. For 1, two reversible oxidation processes were observed in the cyclic voltammogram corresponding to the successive oxidation to 1(+) and an uncommon 1(2+) species that has a triple-bonded Mo(2)(6+) core. DFT calculations indicate that the antibonding character between the Mo-Mo delta orbitals and thiocyanate p orbitals plays a very important role in elevating the HOMO delta orbital energy that allows formation of the dication. A selenium isomer of 3 was also studied. In both the thiocyanate and selenocyanate bridged dimers of dimers, in which the pseudohalide bridges bind the two dimetal units in an end-to-end fashion, long separations between the dimetal units are observed, and these generate very weak electronic interactions.

  6. Controlled synthesis, formation mechanism and upconversion luminescence of NaYF4: Yb, Er nano-/submicrocrystals via ionothermal approach

    NARCIS (Netherlands)

    Liu, J.; Liu, X.; Kong, X.; Zhang, H.

    2012-01-01

    In order to deepen the fundamental understanding of IL-mediated synthesis of nano-/submicrostructure, hydrophilic ILs ([Emim][BF4], [Bmim][BF4] and [Omim][BF4]), which act as solvents, templates, as well as fluorine source, have been employed to synthesize rare earth doped NaYF4 upconversion nano-/s

  7. 1,5-Diamido-9,10-anthraquinone, a Centrosymmetric Redox-Active Bridge with Two Coupled β-Ketiminato Chelate Functions: Symmetric and Asymmetric Diruthenium Complexes.

    Science.gov (United States)

    Ansari, Mohd Asif; Mandal, Abhishek; Paretzki, Alexa; Beyer, Katharina; Fiedler, Jan; Kaim, Wolfgang; Lahiri, Goutam Kumar

    2016-06-01

    The dinuclear complexes {(μ-H2L)[Ru(bpy)2]2}(ClO4)2 ([3](ClO4)2), {(μ-H2L)[Ru(pap)2]2}(ClO4)2 ([4](ClO4)2), and the asymmetric [(bpy)2Ru(μ-H2L)Ru(pap)2](ClO4)2 ([5](ClO4)2) were synthesized via the mononuclear species [Ru(H3L)(bpy)2]ClO4 ([1]ClO4) and [Ru(H3L)(pap)2]ClO4 ([2]ClO4), where H4L is the centrosymmetric 1,5-diamino-9,10-anthraquinone, bpy is 2,2'-bipyridine, and pap is 2-phenylazopyridine. Electrochemistry of the structurally characterized [1]ClO4, [2]ClO4, [3](ClO4)2, [4](ClO4)2, and [5](ClO4)2 reveals multistep oxidation and reduction processes, which were analyzed by electron paramagnetic resonance (EPR) of paramagnetic intermediates and by UV-vis-NIR spectro-electrochemistry. With support by time-dependent density functional theory (DFT) calculations the redox processes could be assigned. Significant results include the dimetal/bridging ligand mixed spin distribution in 3(3+) versus largely bridge-centered spin in 4(3+)-a result of the presence of Ru(II)-stabilizig pap coligands. In addition to the metal/ligand alternative for electron transfer and spin location, the dinuclear systems allow for the observation of ligand/ligand and metal/metal site differentiation within the multistep redox series. DFT-supported EPR and NIR absorption spectroscopy of the latter case revealed class II mixed-valence behavior of the oxidized asymmetric system 5(3+) with about equal contributions from a radical bridge formulation. In comparison to the analogues with the deprotonated 1,4-diaminoanthraquinone isomer the centrosymmetric H2L(2-) bridge shows anodically shifted redox potentials and weaker electronic coupling between the chelate sites.

  8. 不同阴离子组成的离子液体对产紫青霉生长、代谢及催化特性的影响%Effects of Ionic Liquids with Different Anion Composition on Cell Growth, Metabolism and Catalysis Characteristics of Penicillium purpurogenum Li-3

    Institute of Scientific and Technical Information of China (English)

    李扬; 曹红; 欧阳巧凤; 李春; 郑兰兰; 张馨

    2014-01-01

    研究了6种不同阴离子分别与1-丁基-3-甲基咪唑阳离子[ Bmim]+组成的6种离子液体对产紫青霉(Penicillium purpurogenum Li-3)细胞生长、代谢、细胞膜透性和催化活性的影响.结果表明,[Bmim]Ac和[ Bmim] Tf2 N对菌体细胞的生长和代谢具有明显的抑制作用;6种离子液体均改善了细胞膜透性,其中以[ Bmim] Ac最明显;全细胞催化反应实验表明,在分别含25%的疏水性离子液体[ Bmim] PF6和[ Bmim] Tf2 N的2种介质体系中,甘草酸( GL)生物转化合成单葡萄糖醛酸基甘草次酸( GAMG)的转化率分别为82.73%和89.84%, GAMG的产率分别为68.65%和76.23%,与不含离子液体的纯缓冲溶液体系相比( GL转化率和GAMG产率分别为81.82%和33.31%), GL的转化率均略有提高,而GAMG的产率则提高了2倍多,表明2种疏水性离子液体对全细胞催化反应的定向性具有明显促进作用;亲水性离子液体[ Bmim] Ac,[ Bmim] Cl和[ Bmim] NO3对细胞的催化活性具有明显的抑制作用,而[ Bmim] BF4的抑制作用则较弱.%The wild-type Penicillium purpurogenum Li-3 strain is capable of expressing highly β-glucuroni-dase, a intracellular enzyme with excellent ability to biotransform glycyrrhizin(GL) into glycyrrhetinic acid monoglucuronide ( GAMG ) possessing best biological function. To improve the production of GAMG, the effects of ionic liquids with different anion composition on Penicillium purpurogenum Li-3 cells properties of growth, metabolism, permeability of cell membrane and catalysis were studied in this paper. The results showed that [ Bmim] Ac and [ Bmim] Tf2 N had obvious inhibitory effects on cell growth and metabolism. Six kinds of ionic liquids all improved the permeability of cell membrane, and [ Bmim] Ac was the most remarka-ble. In the two catalytic medium respectively containing 25% hydrophobic [Bmim]PF6 and [Bmim]Tf2N, conversion rates of substrate GL were 82. 73% and 89. 84%, and the yields of GAMG were 68. 65

  9. Treatment of Amiodarone-Induced Thyrotoxicosis Type 2 : A Randomized Clinical Trial

    NARCIS (Netherlands)

    Eskes, Silvia A.; Endert, Erik; Fliers, Eric; Geskus, Ronald B.; Dullaart, Robin P. F.; Links, Thera P.; Wiersinga, Wilmar M.

    2012-01-01

    Context: Amiodarone-induced thyrotoxicosis (AIT) type 2 is self-limiting in nature, but most physicians are reluctant to continue amiodarone. When prednisone fails to restore euthyroidism, possibly due to mixed cases of AIT type 1 and 2, perchlorate (ClO4) might be useful because ClO4 reduces the cy

  10. Structural, spectroscopic, and electrochemical properties of tri- and tetradentate N3 and N3S copper complexes with mixed benzimidazole/thioether donors.

    Science.gov (United States)

    Castillo, Ivan; Ugalde-Saldívar, Víctor M; Rodríguez Solano, Laura A; Sánchez Eguía, Brenda N; Zeglio, Erica; Nordlander, Ebbe

    2012-08-21

    Cupric and cuprous complexes of bis(2-methylbenzimidazolyl)(2-methylthiophene)amine (L(1)), bis(2-methylbenzimidazolyl)benzylamine (L(2)), bis(2-methylbenzimidazolyl)(2,4-dimethylphenylthioethyl)amine (L(3)), bis(1-methyl-2-methylbenzimidazolyl)benzylamine (Me(2)L(2)), and bis(1-methyl-2-methylbenzimidazolyl)(2,4-dimethylphenylthioethyl)amine (Me(2)L(3)) have been spectroscopically, structurally, and electrochemically characterised. The thioether-containing ligands L(3) and Me(2)L(3) give rise to complexes with Cu-S bonds in solution and in the solid state, as evidenced by UV-vis spectroscopy and X-ray crystallography. The Cu(2+) complexes [L(1)CuCl(2)] (1), [L(2)CuCl(2)] (2) and [Me(2)L(3)CuCl]ClO(4) (3(Me,ClO4)) are monomeric in solution according to ESI mass spectrometry data, as well as in the solid state. Their Cu(+) analogues [L(1)Cu]ClO(4), [L(2)Cu]ClO(4), [L(3)Cu]ClO(4) (4-6), [BOC(2)L(1)Cu(NCCH(3))]ClO(4) (4(BOC)), [Me(2)L(2)Cu(NCCH(3))(2)]PF(6) (5(Me)) and [Me(2)L(3)Cu](2)(ClO(4))(2) (6(Me)) are also monomeric in acetonitrile solution, as confirmed crystallographically for 4(BOC) and 5(Me). In contrast, 6(Me) is dimeric in the solid state, with the thioether group of one of the ligands bound to a symmetry-related Cu(+) ion. Cyclic voltammetry studies revealed that the bis(2-methylbenzimidazolyl)amine-Cu(2+)/Cu(+) systems possess half-wave potentials in the range -0.16 to -0.08 V (referenced to the ferrocenium-ferrocene couple); these values are nearly 0.23 V less negative than those reported for related bis(picolyl)amine-derived ligands. Based on these observations, the N(3) or N(3)S donor set of the benzimidazole-derived ligands is analogous to previously reported chelating systems, but the electronic environment they provide is unique, and may have relevance to histidine and methionine-containing metalloenzymes. This is also reflected in the reactivity of [Me(2)L(2)Cu(NCCH(3))(2)](+) (5(Me)) and [Me(2)L(3)Cu](+) (6(Me)) towards dioxygen, which results

  11. Widespread presence of naturally occurring perchlorate in high plains of Texas and New Mexico.

    Science.gov (United States)

    Rajagopalan, Srinath; Anderson, Todd A; Fahlquist, Lynne; Rainwater, Ken A; Ridley, Moira; Jackson, W Andrew

    2006-05-15

    Perchlorate (CLO4-) occurrence in groundwater has previously been linked to industrial releases and the historic use of Chilean nitrate fertilizers. However, recently a number of occurrences have been identified for which there is no obvious anthropogenic source. Groundwater from an area of 155,000 km2 in 56 counties in northwest Texas and eastern New Mexico is impacted bythe presence of ClO4-. Concentrations were generally low (areas are impacted by concentrations up to 200 ppb. ClO4- distribution is not related to well type (public water system, domestic, agricultural, or water-table monitoring) or aquifer (Ogallala, Edward Trinity High Plains, Edwards Trinity Plateau, Seymour, or Cenozoic). Results from vertically nested wells strongly indicate a surface source. The source of ClO4- appears to most likely be atmospheric deposition. Evidence supporting this hypothesis primarily relates to the presence of ClO4- in tritium-free older water, the lack of relation between land use and concentration distribution, the inability of potential anthropogenic sources to account for the estimated mass of ClO4-, and the positive relationship between conserved anions (e.g., IO3-, Cl-, SO4(-2)) and ClO4-. The ClO4- distribution appears to be mainly related to evaporative concentration and unsaturated transport. This process has led to higher ClO4- and other ion concentrations in groundwater where the water table is relatively shallow, and in areas with lower saturated thickness. Irrigation may have accelerated this process in some areas by increasing the transport of accumulated salts and by increasing the number of evaporative cycles. Results from this study highlight the potential for ClO4- to impact groundwater in arid and semi-arid areas through long-term atmospheric deposition.

  12. Non-covalent interactions at bis(pyrazole)silver(i) or -gold(i) cations.

    Science.gov (United States)

    García-Pacios, Vanesa; Arroyo, Marta; Antón, Noelia; Miguel, Daniel; Villafañe, Fernando

    2009-03-28

    The reaction of AgBF(4) with two equivalents of pzH (pyrazole) or dmpzH (3,5-dimethylpyrazole) leads to [Ag(pzH)(2)]BF(4) or [Ag(dmpzH)(2)]BF(4). The reaction of [AuCl(tht)] with an equimolar amount of dmpzH in refluxing hexane leads to [Au(dmpzH)(2)][AuCl(2)]. Similar complexes [Au(dmpzH)(2)]A (A = BF(4) or NO(3)) are obtained from [AuCl(tht)], two equivalents of dmpzH, and AgBF(4) or AgNO(3). The complexes [Ag(dmpzH)(2)]BF(4) and [Au(dmpzH)(2)]A (A = [AuCl(2)], BF(4) or NO(3)) crystallize as ionic pairs where the NH groups of the pyrazoles are involved in short cation-anion interactions. The nitrate complex crystallizes as a dimer, where both molecules are supported by pi-stacking interactions between the pyrazole rings. The crystal structure of [Ag(pzH)(2)]BF(4) reveals a three dimensional array of cations and anions. In solution, [Ag(pzH)(2)]BF(4) and [Ag(dmpzH)(2)]BF(4) undergo intermolecular processes involving pyrazole decoordination, and behave as 1/1 electrolytes; whereas dimethylpyrazole gold complexes do not display any dynamic behavior, and show cation-anion association also in solution.

  13. Perchlorate in Lake Water from an Operating Diamond Mine.

    Science.gov (United States)

    Smith, Lianna J D; Ptacek, Carol J; Blowes, David W; Groza, Laura G; Moncur, Michael C

    2015-07-07

    Mining-related perchlorate [ClO4(-)] in the receiving environment was investigated at the operating open-pit and underground Diavik diamond mine, Northwest Territories, Canada. Samples were collected over four years and ClO4(-) was measured in various mine waters, the 560 km(2) ultraoligotrophic receiving lake, background lake water and snow distal from the mine. Groundwaters from the underground mine had variable ClO4(-) concentrations, up to 157 μg L(-1), and were typically an order of magnitude higher than concentrations in combined mine waters prior to treatment and discharge to the lake. Snow core samples had a mean ClO4(-) concentration of 0.021 μg L(-1) (n=16). Snow and lake water Cl(-)/ClO4(-) ratios suggest evapoconcentration was not an important process affecting lake ClO4(-) concentrations. The multiyear mean ClO4(-) concentrations in the lake were 0.30 μg L(-1) (n = 114) in open water and 0.24 μg L(-1) (n = 107) under ice, much below the Canadian drinking water guideline of 6 μg L(-1). Receiving lake concentrations of ClO4(-) generally decreased year over year and ClO4(-) was not likely [biogeo]chemically attenuated within the receiving lake. The discharge of treated mine water was shown to contribute mining-related ClO4(-) to the lake and the low concentrations after 12 years of mining were attributed to the large volume of the receiving lake.

  14. Pb(II)-promoted amide cleavage: mechanistic comparison to a Zn(II) analogue.

    Science.gov (United States)

    Elton, Eric S; Zhang, Tingting; Prabhakar, Rajeev; Arif, Atta M; Berreau, Lisa M

    2013-10-07

    Two new Pb(II) complexes of the amide-appended nitrogen/sulfur epppa (N-((2-ethylthio)ethyl)-N-((6-pivaloylamido-2-pyridyl)methyl)-N-((2-pyridyl)methyl)amine) chelate ligand, [(epppa)Pb(NO3)2] (4-NO3) and [(epppa)Pb(ClO4)2] (4-ClO4), were prepared and characterized. In the solid state, 4-NO3 exhibits κ(5)-epppa chelate ligand coordination as well as the coordination of two bidentate nitrate ions. In acetonitrile, 4-NO3 is a 1:1 electrolyte with a coordinated NO3(-), whereas 4-ClO4 is a 1:2 electrolyte. Treatment of 4-ClO4 with 1 equiv Me4NOH·5H2O in CH3CN:CH3OH (3:5) results in amide methanolysis in a reaction that is akin to that previously reported for the Zn(II) analogue [(epppa)Zn](ClO4)2 (3-ClO4). (1)H NMR kinetic studies of the amide methanolysis reactions of 4-ClO4 and 3-ClO4 as a function of temperature revealed free energies of activation of 21.3 and 24.5 kcal/mol, respectively. The amide methanolysis reactions of 4-ClO4 and 3-ClO4 differ in terms of the effect of the concentration of methanol (saturation kinetics for 4-ClO4; second-order behavior for 3-ClO4), the observation of a small solvent kinetic isotope effect (SKIE) only for the reaction of the Zn(II)-containing 3-ClO4, and the properties of an initial intermediate isolated from each reaction upon treatment with Me4NOH·5H2O. These experimental results, combined with computational studies of the amide methanolysis reaction pathways of 4-ClO4 and 3-ClO4, indicate that the Zn(II)-containing 3-ClO4 initially undergoes amide deprotonation upon treatment with Me4NOH·5H2O. Subsequent amide protonation from coordinated methanol yields a structure containing a coordinated neutral amide and methoxide anion from which amide cleavage can then proceed. The rate-determining step in this pathway is either amide protonation or protonation of the leaving group. The Pb(II)-containing 4-ClO4 instead directly forms a neutral amide-containing, epppa-ligated Pb(II)-OH/Pb(II)-OCH3 equilibrium mixture upon treatment with Me4NOH·5H2O in methanol. The rate-determining step in the amide methanolysis pathway of 4-ClO4 is nucleophilic attack of the Pb(II)-OCH3 moiety on the coordinated amide. Overall, it is the larger size of the Pb(II) center and the availability of coordination positions that enable direct formation of a Pb(II)-OH/Pb(II)-OCH3 mixture versus the initial amide deprotonation identified in the reaction of the Zn(II)-containing 3-ClO4.

  15. Temperature Effects on Electrospray Performance

    Science.gov (United States)

    2011-03-01

    thus a separate Plot script was used to output the data in graphs. 1-methyl-3-butylimidazolium tetrafluoroborate ([ BMIM ][BF4]) was chosen because...changes that occur in the surface tension, density, and electrical conductivity for BMIM BF4. These data sets are normalized with respect to the value at...calculated predictions as shown in Figure 44. This although unexpected could partly be explained by ionic emission and decomposition of the BMiM BF4

  16. Fluorescence quenching of coumarin 153 by hydroxyl-functionalized room temperature ionic liquids

    Science.gov (United States)

    Li, Shuang; Yu, Anchi; Lu, Rong

    2016-08-01

    Steady-state absorption and fluorescence as well as time-resolved fluorescence of coumarin 151 (C151) and coumarin 153 (C153) were measured in hydroxyl-functionalized ionic liquids ([HOEmim][BF4] and [HOEmim][N(CN)2]) and in nonhydroxyl-functionalized ionic liquids ([Emim][BF4] and [Emim][N(CN)2]). Both the steady-state fluorescence and time-resolved fluorescence observations reveal that hydroxyl-functionalized ionic liquid quenches the fluorescence of C153 while the nonhydroxyl-functionalized ionic liquid does not. We also measured the time-resolved fluorescence anisotropy of C151 and C153 in both [HOEmim][BF4] and [Emim][BF4]. It is found that the ratio of the rotational relaxation lifetime of C153 in [HOEmim][BF4] with respect to that in [Emim][BF4] is about 15% larger than that of C151 in [HOEmim][BF4] with respect to that in [Emim][BF4], indicating extra interaction between C153 and [HOEmim][BF4] exists except the effect of the viscosity of ionic liquid.

  17. Solution structure investigation of Ru(II) complex ion pairs: quantitative NOE measurements and determination of average interionic distances.

    Science.gov (United States)

    Zuccaccia, C; Bellachioma, G; Cardaci, G; Macchioni, A

    2001-11-07

    The structure of the Ru(II) ion pairs trans-[Ru(COMe)[(pz(2))CH(2)](CO)(PMe(3))(2)]X (X(-) = BPh(4)(-), 1a; BPh(3)Me(-), 1b; BPh(3)(n-Bu)(-), 1c; BPh(3)(n-Hex)(-), 1d; B(3, 5-(CF(3))(2)(C(6)H(3)))(4)(-), 1e; PF(6)(-), 1f; and BF(4)(-), 1g; pz = pyrazol-1-yl-ring) was investigated in solution from both a qualitative (chloroform-d, methylene chloride-d(2), nithromethane-d(3)) and quantitative (methylene chloride-d(2)) point of view by performing 1D- and 2D-NOE NMR experiments. In particular, the relative anion-cation localization (interionic structure) was qualitatively determined by (1)H-NOESY and (19)F, (1)H-HOESY (heteronuclear Overhauser effect spectroscopy) NMR experiments. The counteranion locates close to the peripheral protons of the bispyrazolyl ligand independent of its nature and that of the solvent. In complexes 1c and 1d bearing unsymmetrical counteranions, the aliphatic chain points away from the metal center as indicated by the absence of NOE between the terminal Me group and any cationic protons. An estimation of the average interionic distances in solution was obtained by the quantification of the NOE build-up versus the mixing time under the assumption that the interionic and intramolecular correlation times (tau(c)) are the same. Such an assumption was checked by the experimental measurements of tau(c) from both the dipolar contribution to the carbon-13 longitudinal relaxation time T(DD-1)and the comparison of the intramolecular and interionic cross relaxation rate constant (sigma) dependence on the temperature. Both the methodologies indicate that anion and cation have comparable tau(c) values. The determined correlation time values were compared with those obtained for the neutral trans-[Ru(COMe)[(pz(2))BH(2)](CO)(PMe(3))(2)] complex (2), isosteric with the cation of 1. They were significantly shorter (approximately 3.8 times), indicating that the main contribution to dipolar relaxation processes comes from the overall ion pair rotation. As a

  18. Photochemical oxidation of water and reduction of polyoxometalate anions at interfaces of water with ionic liquids or diethylether

    Science.gov (United States)

    Bernardini, Gianluca; Wedd, Anthony G.; Zhao, Chuan; Bond, Alan M.

    2012-01-01

    Photoreduction of [P2W18O62]6-, [S2Mo18O62]4-, and [S2W18O62]4- polyoxometalate anions (POMs) and oxidation of water occurs when water–ionic liquid and water–diethylether interfaces are irradiated with white light (275–750 nm) or sunlight. The ionic liquids (ILs) employed were aprotic ([Bmim]X; Bmim = (1-butyl-3-methylimidazolium,X = BF4,PF6) and protic (DEAS = diethanolamine hydrogen sulphate; DEAP = diethanolamine hydrogen phosphate). Photochemical formation of reduced POMs at both thermodynamically stable and unstable water–IL interfaces led to their initial diffusion into the aqueous phase and subsequent extraction into the IL phase. The mass transport was monitored visually by color change and by steady-state voltammetry at microelectrodes placed near the interface and in the bulk solution phases. However, no diffusion into the organic phase was observed when [P2W18O62]6- was photo-reduced at the water–diethylether interface. In all cases, water acted as the electron donor to give the overall process: 4POM + 2H2O + hν → 4POM- + 4H+ + O2. However, more highly reduced POM species are likely to be generated as intermediates. The rate of diffusion of photo-generated POM- was dependent on the initial concentration of oxidized POM and the viscosity of the IL (or mixed phase system produced in cases in which the interface is thermodynamically unstable). In the water-DEAS system, the evolution of dioxygen was monitored in situ in the aqueous phase by using a Clark-type oxygen sensor. Differences in the structures of bulk and interfacial water are implicated in the activation of water. An analogous series of reactions occurred upon irradiation of solid POM salts in the presence of water vapor. PMID:22753501

  19. Synthesis, structure determination, and spectroscopic/computational characterization of a series of Fe(II)-thiolate model complexes: implications for Fe-S bonding in superoxide reductases.

    Science.gov (United States)

    Fiedler, Adam T; Halfen, Heather L; Halfen, Jason A; Brunold, Thomas C

    2005-02-16

    A combined synthetic/spectroscopic/computational approach has been employed to prepare and characterize a series of Fe(II)-thiolate complexes that model the square-pyramidal [Fe(II)(N(His))(4)(S(Cys))] structure of the reduced active site of superoxide reductases (SORs), a class of enzymes that detoxify superoxide in air-sensitive organisms. The high-spin (S = 2) Fe(II) complexes [(Me(4)cyclam)Fe(SC(6)H(4)-p-OMe)]OTf (2) and [FeL]PF(6) (3) (where Me(4)cyclam = 1,4,8,11-tetramethylcyclam and L is the pentadentate monoanion of 1-thioethyl-4,8,11-trimethylcyclam) were synthesized and subjected to structural, magnetic, and electrochemical characterization. X-ray crystallographic studies confirm that 2 and 3 possess an N(4)S donor set similar to that found for the SOR active site and reveal molecular geometries intermediate between square pyramidal and trigonal bipyramidal for both complexes. Electronic absorption, magnetic circular dichroism (MCD), and variable-temperature variable-field MCD (VTVH-MCD) spectroscopies were utilized, in conjunction with density functional theory (DFT) and semiemperical INDO/S-CI calculations, to probe the ground and excited states of complexes 2 and 3, as well as the previously reported Fe(II) SOR model [(L(8)py(2))Fe(SC(6)H(4)-p-Me)]BF(4) (1) (where L(8)py(2) is a tetradentate pyridyl-appended diazacyclooctane macrocycle). These studies allow for a detailed interpretation of the S-->Fe(II) charge transfer transitions observed in the absorption and MCD spectra of complexes 1-3 and provide significant insights into the nature of Fe(II)-S bonding in complexes with axial thiolate ligation. Of the three models investigated, complex 3 exhibits an absorption spectrum that is particularly similar to the one reported for the reduced SOR enzyme (SOR(red)), suggesting that this model accurately mimics key elements of the electronic structure of the enzyme active site; namely, highly covalent Fe-S pi- and sigma-interactions. These spectral

  20. Prominent roles of impurities in ionic liquid for catalytic conversion of carbohydrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haibo; Brown, Heather M.; Holladay, Johnathan E.; Zhang, Z. Conrad

    2012-02-07

    In the last two decades, ionic liquids have emerged as new and versatile solvents, and many of them are also catalysts for a broad range of catalytic reactions. Certain ionic liquids have been found to possess the unique capability of dissolving cellulosic biomass. The potential of such ionic liquids as solvent to enable catalytic conversion of cellulosic polymers was first explored and demonstrated by Zhao et al. This field of research has since experienced a rapid growth. Most ionic liquids have negligible vapor pressure and excellent thermal stability over a wide temperature range. For example, ionic liquids composed of 1-ethyl-3-methylimidazolium (EMIM+) cation and Cl- anion was reported to be stable up to 285 C, while salts of the same cation with other anions such as BF4- and PF6- are thermally stable above 380 C under inert atmosphere. It is well known that presence of impurities in ionic liquids typically causes changes in physical properties, e.g. decreasing in melting point and viscosity. Addition of Lewis acidic metal chlorides, e.g. AlCl3 to 1-alkyl-3-methylimidazolium chloride, [AMIM]Cl, is an exothermic reaction and considerably reduces the melting point by forming [AMIM]AlCl4 or [AMIM]Al2Cl7 that are also ionic liquids but have much lower melting point than the parent [AMIM]Cl. While most early research on catalysis of ionic liquids involving metallohalide anions were typically conducted from stoichiometric ratio of such anions to organic cations, e.g. [AMIM]+, the use of pure ionic liquids only as a solvent to carry out catalysis by a catalytic amount of a metal halide as catalyst truly displayed the solvent property of such ionic liquids.4 In such reaction systems, catalytic amounts of metal halides were used to catalyze the conversion of glucose and cellulose.4,11,12 The metal chloride catalyst concentration was in the order of 10-3 M. The presence of another metal chloride in the ionic liquids, even in the order of 10-5 M concentration was found

  1. Ionic liquids for nano- and microstructures preparation. Part 2: Application in synthesis.

    Science.gov (United States)

    Łuczak, Justyna; Paszkiewicz, Marta; Krukowska, Anna; Malankowska, Anna; Zaleska-Medynska, Adriana

    2016-01-01

    Ionic liquids (ILs) are widely applied to prepare metal nanoparticles and 3D semiconductor microparticles. Generally, they serve as a structuring agent or reaction medium (solvent), however it was also demonstrated that ILs can play a role of a co-solvent, metal precursor, reducing as well as surface modifying agent. The crucial role and possible types of interactions between ILs and growing particles have been presented in the Part 1 of this review paper. Part 2 of the paper gives a comprehensive overview of recent experimental studies dealing with application of ionic liquids for preparation of metal and semiconductor based nano- and microparticles. A wide spectrum of preparation routes using ionic liquids is presented, including precipitation, sol-gel technique, hydrothermal method, nanocasting and ray-mediated methods (microwave, ultrasound, UV-radiation and γ-radiation). It was found that ionic liquids formed of a 1-butyl-3-methylimidazolium [BMIM] combined with tetrafluoroborate [BF4], hexafluorophosphate [PF6], and bis(trifluoromethanesulfonyl)imide [Tf2N] are the most often used ILs in the synthesis of nano- and microparticles, due to their low melting temperature, low viscosity and good transportation properties. Nevertheless, examples of other IL classes with intrinsic nanoparticles stabilizing abilities such as phosphonium and ammonium derivatives are also presented. Experimental data revealed that structure of ILs (both anion and cation type) affects the size and shape of formed metal particles, and in some cases may even determine possibility of particles formation. The nature of the metal precursor determines its affinity to polar or nonpolar domains of ionic liquid, and therefore, the size of the nanoparticles depends on the size of these regions. Ability of ionic liquids to form varied extended interactions with particle precursor as well as other compounds presented in the reaction media (water, organic solvents etc.) provides nano- and

  2. ANALYSIS OF HYDROPONIC FERTILIZER MATRIXES FOR PERCHLORATE: COMPARISON OF ANALYTICAL TECHNIQUES

    Science.gov (United States)

    Seven retail hydroponic nitrate fertilizer products, two liquid and five solid, were comparatively analyzed for the perchlorate anion (ClO4-) by ion chromatography (IC) with suppressed conductivity detection, complexation electrospray ionization mass spectrometry (cESI-MS), norma...

  3. Isotopic composition and origin of indigenous natural perchlorate and co-occurring nitrate in the southwestern United States.

    Science.gov (United States)

    Jackson, W Andrew; Böhlke, John Karl; Gu, Baohua; Hatzinger, Paul B; Sturchio, Neil C

    2010-07-01

    Perchlorate (ClO(4)(-)) has been detected widely in groundwater and soils of the southwestern United States. Much of this ClO(4)(-) appears to be natural, and it may have accumulated largely through wet and dry atmospheric deposition. This study evaluates the isotopic composition of natural ClO(4)(-) indigenous to the southwestern U.S. Stable isotope ratios were measured in ClO(4)(-) (delta(18)O, Delta(17)O, delta(37)Cl) and associated NO(3)(-) (delta(18)O, Delta(17)O, delta(15)N) in groundwater from the southern High Plains (SHP) of Texas and New Mexico and the Middle Rio Grande Basin (MRGB) in New Mexico, from unsaturated subsoil in the SHP, and from NO(3)(-)-rich surface caliche deposits near Death Valley, California. The data indicate natural ClO(4)(-) in the southwestern U.S. has a wide range of isotopic compositions that are distinct from those reported previously for natural ClO(4)(-) from the Atacama Desert of Chile as well as all known synthetic ClO(4)(-). ClO(4)(-) in Death Valley caliche has a range of high Delta(17)O values (+8.6 to +18.4 per thousand), overlapping and extending the Atacama range, indicating at least partial atmospheric formation via reaction with ozone (O(3)). However, the Death Valley delta(37)Cl values (-3.1 to -0.8 per thousand) and delta(18)O values (+2.9 to +26.1 per thousand) are higher than those of Atacama ClO(4)(-). In contrast, ClO(4)(-) from western Texas and New Mexico has much lower Delta(17)O (+0.3 to +1.3 per thousand), with relatively high delta(37)Cl (+3.4 to +5.1 per thousand) and delta(18)O (+0.5 to +4.8 per thousand), indicating either that this material was not primarily generated with O(3) as a reactant or that the ClO(4)(-) was affected by postdepositional O isotope exchange. High Delta(17)O values in ClO(4)(-) (Atacama and Death Valley) are associated with high Delta(17)O values in NO(3)(-), indicating that both compounds preserve characteristics of O(3)-related atmospheric production in hyper-arid settings, whereas both compounds have low Delta(17)O values in less arid settings. Although Delta(17)O variations in terrestrial NO(3)(-) can be attributed to mixing of atmospheric (high Delta(17)O) and biogenic (low Delta(17)O) NO(3)(-), variations in Delta(17)O of terrestrial ClO(4)(-) are not readily explained in the same way. This study provides important new constraints for identifying natural sources of ClO(4)(-) in different environments by multicomponent isotopic characteristics, while presenting the possibilities of divergent ClO(4)(-) formation mechanisms and(or) ClO(4)(-) isotopic exchange in biologically active environments.

  4. Isotopic composition and origin of indigenous natural perchlorate and co-occurring nitrate in the southwestern United States

    Science.gov (United States)

    Jackson, W. Andrew; Böhlke, John Karl; Gu, Baohua; Hatzinger, Paul B.; Sturchio, Neil C.

    2010-01-01

    Perchlorate (ClO4−) has been detected widely in groundwater and soils of the southwestern United States. Much of this ClO4− appears to be natural, and it may have accumulated largely through wet and dry atmospheric deposition. This study evaluates the isotopic composition of natural ClO4− indigenous to the southwestern U.S. Stable isotope ratios were measured in ClO4− (δ18O, Δ17O, δ37Cl) and associated NO3− (δ18O, Δ17O, δ15N) in groundwater from the southern High Plains (SHP) of Texas and New Mexico and the Middle Rio Grande Basin (MRGB) in New Mexico, from unsaturated subsoil in the SHP, and from NO3−-rich surface caliche deposits near Death Valley, California. The data indicate natural ClO4− in the southwestern U.S. has a wide range of isotopic compositions that are distinct from those reported previously for natural ClO4− from the Atacama Desert of Chile as well as all known synthetic ClO4−. ClO4− in Death Valley caliche has a range of high Δ17O values (+8.6 to +18.4 ‰), overlapping and extending the Atacama range, indicating at least partial atmospheric formation via reaction with ozone (O3). However, the Death Valley δ37Cl values (−3.1 to −0.8 ‰) and δ18O values (+2.9 to +26.1‰) are higher than those of Atacama ClO4−. In contrast, ClO4− from western Texas and New Mexico has much lower Δ17O (+0.3 to +1.3‰), with relatively high δ37Cl (+3.4 to +5.1 ‰) and δ18O (+0.5 to +4.8 ‰), indicating either that this material was not primarily generated with O3 as a reactant or that the ClO4− was affected by postdepositional O isotope exchange. High Δ17O values in ClO4− (Atacama and Death Valley) are associated with high Δ17O values in NO3−, indicating that both compounds preserve characteristics of O3-related atmospheric production in hyper-arid settings, whereas both compounds have low Δ17O values in less arid settings. Although Δ17O variations in terrestrial NO3− can be attributed to mixing of atmospheric (high Δ17O) and biogenic (low Δ17O) NO3−, variations in Δ17O of terrestrial ClO4− are not readily explained in the same way. This study provides important new constraints for identifying natural sources of ClO4− in different environments by multicomponent isotopic characteristics, while presenting the possibilities of divergent ClO4− formation mechanisms and(or) ClO4− isotopic exchange in biologically active environments.

  5. Counter anion dependent gradual spin transition in a 1D cobalt(ii) coordination polymer.

    Science.gov (United States)

    Roy, Subhasis; Choubey, Somnath; Bhar, Kishalay; Sikdar, Nivedita; Costa, José Sánchez; Mitra, Partha; Ghosh, Barindra Kumar

    2015-05-07

    One Co(ii) SCO coordination polymer [Co(enbzpy)(μ1,5-dca)]n(PF6)n (·PF6) has been isolated and characterised structurally and magnetostructurally. The properties of ·PF6 are compared with the reported perchlorate analogue [Co(enbzpy)(μ1,5-dca)]n(ClO4)n (·ClO4). The gradual spin transition in ·PF6 in contrast to an abrupt spin transition with a hysteresis loop in ·ClO4 has been analysed in terms of structural factors.

  6. Soil, plant, and terrain effects on natural perchlorate distribution in a desert landscape

    Science.gov (United States)

    Andraski, Brian J.; Jackson, W.A.; Welborn, Toby L.; Böhlke, John Karl; Sevanthi, Ritesh; Stonestrom, David A.

    2014-01-01

    Perchlorate (ClO4−) is a contaminant that occurs naturally throughout the world, but little is known about its distribution and interactions in terrestrial ecosystems. The objectives of this Amargosa Desert, Nevada study were to determine (i) the local-scale distribution of shallow-soil (0–30 cm) ClO4− with respect to shrub proximity (far and near) in three geomorphic settings (shoulder slope, footslope, and valley floor); (ii) the importance of soil, plant, and terrain variables on the hillslope-distribution of shallow-soil and creosote bush [Larrea tridentata (Sessé & Moc. ex DC.) Coville] ClO4−; and (iii) atmospheric (wet plus dry, including dust) deposition of ClO4− in relation to soil and plant reservoirs and cycling. Soil ClO4− ranged from 0.3 to 5.0 μg kg−1. Within settings, valley floor ClO4− was 17× less near shrubs due in part to enhanced leaching, whereas shoulder and footslope values were ∼2× greater near shrubs. Hillslope regression models (soil, R2 = 0.42; leaf, R2 = 0.74) identified topographic and soil effects on ClO4− deposition, transport, and cycling. Selective plant uptake, bioaccumulation, and soil enrichment were evidenced by leaf ClO4− concentrations and Cl−/ClO4− molar ratios that were ∼8000× greater and 40× less, respectively, than soil values. Atmospheric deposition ClO4− flux was 343 mg ha−1 yr−1, ∼10× that for published southwestern wet-deposition fluxes. Creosote bush canopy ClO4− (1310 mg ha−1) was identified as a previously unrecognized but important and active reservoir. Nitrate δ18O analyses of atmospheric deposition and soil supported the leaf-cycled–ClO4− input hypothesis. This study provides basic data on ClO4− distribution and cycling that are pertinent to the assessment of environmental impacts in desert ecosystems and broadly transferable to anthropogenically contaminated systems.

  7. Evaluation of Perchlorate Sources in the Rialto-Colton and Chino California Subbasins using Chlorine and Oxygen Isotope Ratio Analysis

    Science.gov (United States)

    2015-03-01

    chlorine-36. gt·mmdwater. forensic . Atacama. nitrate. fettilizeJ·. Chile. Rialto 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME...transport in the study area; (2) water chemistry analyses, including major ion composition, ClO4- concentrations, stable isotope ratios of...Chile. Most significantly for forensic studies in the U.S., indigenous natural ClO4- has been widely detected in the southwestern U.S., as

  8. Manganese (III) cyclam complexes with aqua, iodo, nitrito, perchlorato and acetic acid/acetato axial ligands

    DEFF Research Database (Denmark)

    Mossin, Susanne; Sørensen, Henning Osholm; Weihe, Høgni;

    2005-01-01

    The syntheses, structures and magnetic properties of five new manganese (III) cyclam complexes, trans-[Mn(cyclam)(OH2)(2)]-(CF3SO3)(3)center dot-H2O, trans-[Mn(cyclam)I-2]I, trans-[Mn(cyclam)(ONO)(2)]ClO4, trans-[Mn(cyclam)(OClO3)(2)]ClO4 and trans-[Mn(cyclam) (CH3COO)(CH3COOH)](ClO4)(2), are rep...

  9. Energetic characteristics of transition metal complexes.

    Science.gov (United States)

    Wojewódka, Andrzej; Bełzowski, Janusz; Wilk, Zenon; Staś, Justyna

    2009-11-15

    Ten transition metal nitrate and perchlorate complexes of hydrazine and ethylenediamine were synthesized, namely [Cu(EN)(2)](ClO(4))(2), [Co(EN)(3)](ClO(4))(3), [Ni(EN)(3)](ClO(4))(2), [Hg(EN)(2)](ClO(4))(2), [Cr(N(2)H(4))(3)](ClO(4))(3), [Cd(N(2)H(4))(3)](ClO(4))(2), [Ni(N(2)H(4))(3)](NO(3))(2), [Co(N(2)H(4))(3)](NO(3))(3), [Zn(N(2)H(4))(3)](NO(3))(2), and [Cd(N(2)H(4))(3)](NO(3))(2) based on the lines of the literature reported methods. All of them were tested with applying underwater detonation test and further compared to the typical blasting explosives: RDX, HMX, TNT and PETN. From the above presented complexes [Ni(N(2)H(4))(3)](NO(3))(2) (called NHN) and [Co(N(2)H(4))(3)](NO(3))(3) (called CoHN) are known as primary explosives and can be used as the standard explosives. Explosion parameters, such as shock wave overpressure, shock wave energy equivalent and bubble energy equivalent, were determined. Evaluated energetic characteristics of the tested compounds are comparable to those of the classic high explosives and are even enhanced in some cases.

  10. Widespread presence of naturally occurring perchlorate in high plains of Texas and New Mexico

    Science.gov (United States)

    Rajagopalan, S.; Anderson, T.A.; Fahlquist, L.; Rainwater, K.A.; Ridley, M.; Jackson, W.A.

    2006-01-01

    Perchlorate (ClO4-) occurrence in groundwater has previously been linked to industrial releases and the historic use of Chilean nitrate fertilizers. However, recently a number of occurrences have been identified for which there is no obvious anthropogenic source. Groundwater from an area of 155 000 km2 in 56 counties in northwest Texas and eastern New Mexico is impacted by the presence of ClO4-. Concentrations were generally low (anions (e.g., IO3-, Cl-, SO4-2) and ClO4-. The ClO4- distribution appears to be mainly related to evaporative concentration and unsaturated transport. This process has led to higher ClO4- and other ion concentrations in groundwater where the water table is relatively shallow, and in areas with lower saturated thickness. Irrigation may have accelerated this process in some areas by increasing the transport of accumulated salts and by increasing the number of evaporative cycles. Results from this study highlight the potential for ClO4- to impact groundwater in arid and semiarid areas through long-term atmospheric deposition. ?? 2006 American Chemical Society.

  11. Varying Electronic Structures of Diosmium Complexes from Noninnocently Behaving Anthraquinone-Derived Bis-chelate Ligands.

    Science.gov (United States)

    Mandal, Abhishek; Grupp, Anita; Schwederski, Brigitte; Kaim, Wolfgang; Lahiri, Goutam Kumar

    2015-08-17

    The new compounds [(bpy)2Os(II)(μ-L1(2-))Os(II)(bpy)2](ClO4)2 ([1](ClO4)2) and [(pap)2Os(II)(μ-L1(2-))Os(II)(pap)2](ClO4)2 ([2](ClO4)2) (H2L1 = 1,4-dihydroxy-9,10-anthraquinone, bpy = 2,2(/)-bipyridine, and pap = 2-phenylazopyridine) and [(bpy)2Os(II)(μ-L2(•-))Os(II)(bpy)2](ClO4)3 ([3](ClO4)3) and [(pap)2Os(II)(μ-L2(2-))Os(II)(pap)2](ClO4)2 ([4](ClO4)2) (H2L2 = 1,4-diamino-9,10-anthraquinone) have been analytically identified as the meso and rac diastereoisomers, respectively. The paramagnetic [3](ClO4)3 was also characterized by crystal structure determination. In CD3CN solution, [3](ClO4)3 displays rather narrow but widely split (13 > δ > -8 ppm) resonances in the (1)H NMR spectrum, yet no EPR signal was observed down to 120 K. Cyclic voltammetry and differential pulse voltammetry reveal several accessible redox states on oxidation and reduction, showing that the replacement of 1,4-oxido by imido donors causes cathodic shifts and that the substitution of bpy by the stronger π-accepting pap ligands leads to a strong increase of redox potentials. Accordingly, system 3(n) with the lowest (2+/3+) potential was synthetically obtained in the mono-oxidized (3+) form. The (3+) intermediates display small comproportionation constants Kc of about 10(3) and long-wavelength near-infrared absorptions; an EPR signal with appreciable g splitting (1.84, 1.96, and 2.03) was only observed for 4(3+), which exhibits the smallest spin density on the osmium centers. An oxidation state formulation [Os(III)(μ-L(•3-))Os(III)](3+) with some [Os(II)(μ-L(2-))Os(III)](3+) contribution was found to best describe the electronic structures. UV-vis-NIR absorption spectra were recorded for all accessible states by OTTLE spectroelectrochemistry and assigned on the basis of TD-DFT calculations. These results and additional EPR measurements suggest rather variegated oxidation state situations, e.g., the pap ligands competing with the bridge L for electrons, while the oxidation produces mixed spin systems with variable metal/ligand contributions.

  12. Vapor-Liquid Equilibrium for Methanol-Acetonitrile-1-Butyl-3-Methylimidazolium Tetrafluoroborate Ternary System%甲醇-乙腈-1-丁基-3-甲基咪唑四氟硼酸盐三组分物系的汽液平衡

    Institute of Scientific and Technical Information of China (English)

    李群生; 王海川; 冉晓萌; 朱炜; 付永泉; 王宝华

    2012-01-01

    在101.32 kPa下,用CE-2型Othmer汽液平衡釜测定了甲醇-乙腈-1-丁基-3-甲基咪唑四氟硼酸盐([bmim]BF4)三组分物系的等压汽液平衡数据;采用UNIFAC方程对实验数据进行了关联.实验结果表明,与未加入[bmim]BF4相比,加入[bmim]BF4后甲醇-乙腈二组分物系的汽液平衡线产生偏离,[bmim]BF4含量越高,偏离程度越大;[bmim]BF4具有明显的盐析效应,当[bmim]BF4的含量为10%(x)时,甲醇-乙腈物系的共沸点消失;UNIFAC方程可用于预测甲醇-乙腈-[bmim]BF4三组分物系的汽液平衡.%Isobaric vapor-liquid equilibrium for methanol-acetonitrile-1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) ternary system was measured at 101.32 kPa using CE-2 Othmer vapor-liquid equilibrium still. UNIFAC equations were used to correlate the experimental data. The experimental results indicated that the vapor-liquid equilibrium curves of the methanol-acetonitrile-. [bmim]BF4 system deviated from that of the [bmim]BF4-free system and the deviation increased with the increase of the [bmim]BF4 dosage. The ionic liquid [bmim]BF4 exhibited notable salt-out effect which could enhance the relative volatility. When the mole fraction of [bmim]BF4 amounted to 10%, the azeotropic point disappeared. UNIFAC equation can be used to predict the equilibrium of methanol-acetonitrile- [bmim]BF4 system.

  13. Characterization of the thermal refraction in ionic liquids induced by a train of femtosecond laser pulses

    Science.gov (United States)

    López Lago, E.; Nóvoa, J. A.; Nóvoa, D.; Michinel, H.; Cabeza, O.; Rodríguez, J. R.; Varela, L. M.

    2013-11-01

    We investigate the nonlinear refraction induced by a train of ultrashort laser pulses (repetition rate 80.75MHz) in a set of ionic liquids: [EMIM][BF4], [BMIM] [BF4], [HMIM] [BF4], [OMIM] [BF4] and [DMIM] [BF4]. Due to the high repetition rate, linear absorption processes are developed which cause a non local increase of temperature that generates an inhomogeneous and non local spatial variation of the refractive index. This effect is known as thermal refraction. The goal of this work is to characterize by z-scan the induced changes in the refractive index at λ=810nm and to determine the thermooptic coefficient of this liquids at this wavelength

  14. Raman and ab initio studies of simple and binary 1-alkyl-3-methylimidazolium ionic liquids

    DEFF Research Database (Denmark)

    Berg, R.W.; Deetlefs, M.; Seddon, K.R.;

    2005-01-01

    Raman spectra of the ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF6]), 1-hexyl-3-methylimidazolium chloride ([C(6)mim]Cl), and 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)mim][PF6]), and binary mixtures thereof, have been assigned using ab initio MP2...

  15. Effect of side-chain asymmetry on the intermolecular structure and order-disorder transition in alkyl-substituted polyfluorenes

    DEFF Research Database (Denmark)

    Knaapila, Matti; Stepanyan, R.; Torkkeli, M.;

    2016-01-01

    We study relations among the side-chain asymmetry, structure, and order-disorder transition (ODT) in hairy-rod-type poly(9,9-dihexylfluorene) (PF6) with two identical side chains and atactic poly(9-octyl-9-methyl-fluorene) (PF1-8) with two different side chains per repeat. PF6 and PF1-8 organize ...

  16. Gclust Server: 144311 [Gclust Server

    Lifescience Database Archive (English)

    Full Text Available 144311 HSA_46240864 Cluster Sequences - 2223 NP_996879.1 projection protein PF6 ; n... to cluster sequences Cluster Sequences Link to related sequences - Sequence length 2223 Representative annotation NP_996879.1 projec...tion protein PF6 ; no annotation Number of Sequences 1 H

  17. Distribution of Natural Perchlorate in a Desert Landscape-Amargosa Desert Research Site, Nevada

    Science.gov (United States)

    Andraski, B. J.; Jackson, A.; Welborn, T.; Stonestrom, D. A.; Bohlke, J. K.

    2011-12-01

    Knowledge of perchlorate (ClO4-) occurrence is important due to health concerns, evolving groundwater-protection regulations, and for forensic investigations. The distribution of natural ClO4- is being studied at the U.S. Geological Survey's Amargosa Desert Research Site to improve understanding of factors that influence its accumulation and cycling in a desert landscape. The first part of the study evaluated the effect of plants on shallow (0-30 cm) soil concentrations in three settings-shoulder slope, footslope, and valley floor; samples were collected adjacent to plants and in interspaces 2.5-5 m from plants. For the valley-floor, there was a 17-fold decrease between interspace (5.0 μg/kg) and plant-adjacent (0.3 μg/kg) ClO4- concentrations. Chloride (Cl-) concentrations also showed large differences and indicated salt accumulation beneath the interspace desert pavement, but localized leaching adjacent to plants. For the shoulder and footslope, differences between interspace and plant-adjacent ClO4- concentrations were smaller (two fold on average) and inverted (interspace 2.0 μg/kg; plant-adjacent 3.8 μg/kg), and differences between interspace and plant-adjacent Cl- were negligible. Shoulder and footslope indications of a localized increase in ClO4- adjacent to plants suggest a cyclic mechanism of plant uptake, bioaccumulation, and leaf drop. The second part of the study examined ClO4- variability across a 9-ha hillslope. Data first were analyzed by assigning each sampling point to one of three elevation bands-upper, middle, or lower. Soil and plant data both showed trends of increasing ClO4- with decreasing elevation. Concentrations were, for soil (μg/kg): upper (1.6) middle (3.9) > lower (3.6). Multiple-linear regression analyses also were used to explore the relative importance of soil, plant, and terrain variables that influenced ClO4- concentrations across the hillslope. Important explanatory variables for soil ClO4- are land-surface elevation and slope-elevation explained 37% of the variation; combined, the two variables explained 42%. Elevation and slope (both with negative coefficients) are suggestive of processes affecting deposition and transport of ClO4- by wind or water. For plant ClO4-, important variables included elevation, and soil organic and carbonate carbon-elevation explained 52% of the variation; combined, the three variables explained 68%. Organic carbon and its positive coefficient may reflect areas of increased plant cycling and ClO4- movement from shallow soil into the root zone. Carbonate carbon and its negative coefficient suggest that caliche may reduce water and ClO4- movement into the root zone. This study indicates how a combination of soil, biological, and geomorphic factors controls the accumulation and redistribution of ClO4- in a desert landscape.

  18. Reactions of hydridoirida-β-diketones with amines or with 2-aminopyridines: formation of hydridoirida-β-ketoimines, PCN terdentate ligands, and acyl decarbonylation.

    Science.gov (United States)

    Ciganda, Roberto; Garralda, María A; Ibarlucea, Lourdes; Mendicute-Fierro, Claudio; Torralba, M Carmen; Torres, M Rosario

    2012-02-01

    The hydridoirida-β-diketone [IrHCl{(PPh(2)(o-C(6)H(4)CO))(2)H}] (1) reacts with benzylamine (C(6)H(5)CH(2)NH(2)) to give the hydridoirida-β-ketoimine [IrHCl{(PPh(2)(o-C(6)H(4)CO))(PPh(2)(o-C(6)H(4)CNCH(2)C(6)H(5)))H}] (2), stabilized by an intramolecular hydrogen bond. 2 reacts with water to undergo hydrolysis and amine coordination giving hydridodiacylamino [IrH(PPh(2)(o-C(6)H(4)CO))(2)(C(6)H(5)CH(2)NH(2))] (3). Cyclohexylamine or dimethylamine lead to hydridodiacylamino [IrH(PPh(2)(o-C(6)H(4)CO))(2)L] (4-5). In chlorinated solvents hydridodiacylamino complexes undergo exchange of hydride by chloride to afford [IrCl(PPh(2)(o-C(6)H(4)CO))(2)L] (6-9). The reaction of 1 with hydrazine (H(2)NNH(2)) gives hydridoirida-β-ketoimine [IrHCl{(PPh(2)(o-C(6)H(4)CO))(PPh(2)(o-C(6)H(4)CNNH(2)))H}] (10), fluxional in solution with values for ΔH(‡) of 2.5 ± 0.3 kcal mol(-1) and for ΔS(‡) of -32.9 ± 3 eu. A hydrolysis/imination sequence can be responsible for fluxionality. 2-Aminopyridines (RHNC(5)H(3)R'N) react with 1 to afford cis-[IrCl(PPh(2)(o-C(6)H(4)CO))(PPh(2)(o-C(6)H(4)CHNRC(5)H(3)R'N))] (R = R' = H (11), R = CH(3), R' = H (12), R = H, R' = CH(3) (13)) containing new terdentate PCN ligands in a facial disposition and cis phosphorus atoms as kinetic products. The formation of 11-13 requires imination of the hydroxycarbene moiety of 1, coordination of the nitrogen atom of pyridine to iridium, and iridium to carbon hydrogen transfer. In refluxing methanol, complexes 11-13 isomerize to afford the thermodynamic products 14-16 with trans phosphorus atoms. Chloride abstraction from complexes [IrCl(PPh(2)(o-C(6)H(4)CO))(PPh(2)(o-C(6)H(4)CHNRC(5)H(4)N))] (R = H or CH(3)) leads to decarbonylation of the acylphosphine chelating group to afford cationic complexes [Ir(CO)(PPh(2)(o-C(6)H(4)))(PPh(2)(o-C(6)H(4)CHNRC(5)H(4)N))]A, 17 (R = H, A = ClO(4)) and 18 (R = CH(3), A = BF(4)) as a cis/trans = 4:1 mixture of isomers. Single crystal X-ray diffraction analysis was performed

  19. Structures and magnetic properties of an antiferromagnetically coupled polymeric copper(II) complex and ferromagnetically coupled hexanuclear nickel(II) clusters.

    Science.gov (United States)

    Tandon, Santokh S; Bunge, Scott D; Sanchiz, Joaquin; Thompson, Laurence K

    2012-03-05

    Reactions between 2,6-diformyl-4-methylphenol (DFMF) and tris(hydroxymethyl) aminomethane (THMAM = H(3)L2) in the presence of copper(II) salts, CuX(2) (X = CH(3)CO(2)(-), BF(4)(-), ClO(4)(-), Cl(-), NO(3)(-)) and Ni(CH(3)CO(2))(2) or Ni(ClO(4))(2)/NaC(6)H(5)CO(2), sodium azide (NaN(3)), and triethylamine (TEA), in one pot self-assemble giving a coordination polymer consisting of repeating pentanuclear copper(II) clusters {[Cu(2)(H(5)L(2-))(μ-N(3))](2)[Cu(N(3))(4)]·2CH(3)OH}(n) (1) and hexanuclear Ni(II) complexes [Ni(6)(H(3)L1(-))(2)(HL2(2-))(2)(μ-N(3))(4)(CH(3)CO(2))(2)]·6C(3)H(7)NO·C(2)H(5)OH (2) and [Ni(6)(H(3)L1(-))(2)(HL2(2-))(2)(μ-N(3))(4)(C(6)H(5)CO(2))(2)]·3C(3)H(7)NO·3H(2)O·CH(3)OH (3). In 1, H(5)L(2-) and in 2 and 3 H(3)L1(-) and HL2(2-) represent doubly deprotonated, singly deprotonated, and doubly deprotonated Schiff-base ligands H(7)L and H(4)L1 and a tripodal ligand H(3)L2, respectively. 1 has a novel double-stranded ladder-like structure in which [Cu(N(3))(4)](2-) anions link single chains comprised of dinuclear cationic subunits [Cu(2)(H(5)L(2-))(μ-N(3))](+), forming a 3D structure of interconnected ladders through H bonding. Nickel(II) clusters 2 and 3 have very similar neutral hexanuclear cores in which six nickel(II) ions are bonded to two H(4)L1, two H(3)L2, four μ-azido, and two μ-CH(3)CO(2)(-)/μ-C(6)H(5)CO(2)(-) ligands. In each structure two terminal dinickel (Ni(2)) units are connected to the central dinickel unit through four doubly bridging end-on (EO) μ-azido and four triply bridging μ(3)-methoxy bridges organizing into hexanuclear units. In each terminal dinuclear unit two nickel centers are bridged through one μ-phenolate oxygen from H(3)L1(-), one μ(3)-methoxy oxygen from HL2(2-), and one μ-CH(3)CO(2)(-) (2)/μ-C(6)H(5)CO(2)(-) (3) ion. Bulk magnetization measurements on 1 show moderately strong antiferromagnetic coupling within the [Cu(2)] building block (J(1) = -113.5 cm(-1)). Bulk magnetization measurements on 2

  20. A family of Fe(3+) based double-stranded helicates showing a magnetocaloric effect, and Rhodamine B dye and DNA binding activities.

    Science.gov (United States)

    Adhikary, Amit; Jena, Himanshu Sekhar; Konar, Sanjit

    2015-09-21

    Herein, the synthesis, structural characterization, magnetic properties and guest binding activities of four Fe(3+) based double-stranded helicates namely; [Fe2(L)2](ClO4)(Cl)·4(CH3OH)·2(H2O) (), [Fe2(L)2](BF4)2·2(H2O) (), [Fe2(L)2](NO3)2·3(CH3OH)·2(H2O) (), and [Fe2(L)2](Cl)2·2(CH3OH)·4(H2O) () are reported. Complexes have been synthesized using the hydrazide-based ligand H2L (H2L = N'1,N'4-bis(2-hydroxybenzylidene)succinohydrazide) and the corresponding Fe(2+) salts. Each of the independent cationic complexes [Fe2(L)2](2+) shows double-stranded helicates from the self-assembly of the ligand and metal ions in a 2 : 2 ratio, where the individual Fe(3+) centre is lying on a C2-axis and the ligand strands wrap around it. In , ligand L adopts "pseudo-C" conformations and forms a double-stranded dinuclear helicate with a small cage in between them. Moreover, in , each of the independent cationic complexes [Fe2L2](2+) is inherently chiral and possesses P for right-hand and M for left-hand helicity and as a consequence is a racemic solid. Detailed magnetic studies of all the complexes reveal that the