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Sample records for acetylacetone

  1. Effect of sodium acetylacetonate on the sublimation of scandium and lutetium acetylacetonates

    By the methods of IR spectroscopy, X-ray phase and thermal analyses, as well as by vacuum sublimation, it has been shown that interaction between sodium acetylacetonate gives rise to formation of tetrakis - acetylacetonate of NaLu(Acac)4 composition, which can be congruently sublimated in vacuum. Ib the system with scandium there is no such effect. Transition to gaseous phase of sodium acetylacetonate within the tetrakis-complex of lutetium can be considered as synergism, as sodium acetylacetonate as such is not volatile

  2. Enhancement of thermal stability of silver(I) acetylacetonate by platinum(II) acetylacetonate

    Křenek, T.; Kovářík, T.; Pola, M.; Jakubec, Ivo; Bezdička, Petr; Bastl, Zdeněk; Pokorná, Dana; Urbanová, Markéta; Galíková, Anna; Pola, Josef

    2013-01-01

    Roč. 554, FEB (2013), s. 1-7. ISSN 0040-6031 Institutional support: RVO:61388980 ; RVO:61388955 ; RVO:67985858 Keywords : thermal gravimetric analysis * differential scanning calorimetry * silver (I) acetylacetonate * platinum(II) acetylacetonate * enhancement of thermal stability Subject RIV: CA - Inorganic Chemistry; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 2.105, year: 2013

  3. Photochemical transformation of vanadium(5) acetylacetonate complexes

    Photochemical transformations of mixed vanadium (5) complex formed as a result of interaction between ethylorthovanadate and acetylacetone which includes in the first coordination sphere vanadyl oxygen, two enolate-ions and enthoxygroup are studied spectrophotometrically and using ESR method. During irradiation of ethanol solutions of the complex a successive reduction of central atom with formation of acetyl-acetonate complexes of vanadium (4) and (3) takes place. At that the solvent is oxidated. In CCl4 solution under the effect of UV irradiation ethoxygroup is replaced by chlorine ion with the formation of new mixed vanadium (5) complex, sensible to visible and UV radiation

  4. Enhancement of thermal stability of silver(I) acetylacetonate by platinum(II) acetylacetonate

    Highlights: ► Ag acetylacetonate increases thermal stability by mixing with of Pt acetylacetonate. ► Heated mixture of chelates yields a residue with Ag, Pt, O and C elements. ► Co-decomposition of metal chelates could yield novel metal structures and alloys. - Abstract: Thermal gravimetric analysis of equimolar silver(I) acetylacetonate–platinum(II) acetylacetonate mixture shows a significant increase in thermal stability of silver(I) acetylacetonate in the presence of the Pt counterpart. The heated mixture was examined by differential scanning calorimetry and complementary analyses of gaseous products, residues and sublimed fractions by Fourier transform infrared, Raman and X-ray-photoelectron spectroscopy, X-ray diffraction and scanning and high-resolution transmission electron microscopy. It is assumed that silver(I) acetylacetonate is thermally stabilized due to a week bonding with Pt chelate. An interaction between both chelates gets support from the structure of the residual powder which is composed of Ag, Pt, C and O elements and Pt oxides and contains silver nanoparticles whose decreased unit cell parameter can be due to substitution of silver by platinum

  5. MOCVD Nanoparticle Synthesis from Copper Acetylacetonate

    Moravec, Pavel; Smolík, Jiří; Klementová, Mariana; Levdansky, V.V.

    Thessaloniki : Hellenic Association for Aerosol Research, 2008, T01A058P. [European Aerosol Conference 2008. Thessaloniki (GR), 24.08.2008-29.08.2008] R&D Projects: GA ČR GA104/07/1093 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502 Keywords : generation of nanoparticles * copper acetylacetonate * hot wall reactor Subject RIV: CF - Physical ; Theoretical Chemistry

  6. Photoelectron spectra of rare earth acetylacetonates

    By the method of gaseous photoelectron spectroscopy electron structure of rare earth acetylacetonates, prepared by means of thermolysis in spectrometer of the corresponding MA3·Q adducts (Q=DMSO, HMPA), has been studied. From yttrium series compounds only for Y, Dy, Ho, Er, Lu derivatives the spectra do not contain the bands of decomposition product-acetone. Out of three studied compounds of cerium groups (M=La, Sm, Nd) only for LaA3 the attempt to record photoelectron spectrum has failed. In the first three bands of all the compounds a-e-splitting is detected, which is caused by the contribution of metal AO to molecular orbital. The greatest splitting is characteristic for n--electrons of ScA3 and LuA3. Increase in ionization energy of Π3-- and n--electrons with an increase in rare earth ordinal number is caused by lanthanide compression and constitutes 0.2-0.3 eV

  7. Acetone and the precursor ligand acetylacetone : distinctly different electron beam induced decomposition?

    Warneke, Jonas; Van Dorp, Willem F.; Rudolf, Petra; Stano, Michal; Papp, Peter; Matejcik, Stefan; Borrmann, Tobias; Swiderek, Petra

    2015-01-01

    In focused electron beam induced deposition (FEBID) acetylacetone plays a role as a ligand in metal acetylacetonate complexes. As part of a larger effort to understand the chemical processes in FEBID, the electron-induced reactions of acetylacetone were studied both in condensed layers and in the ga

  8. The Electrochemical Synthesis of Transition-Metal Acetylacetonates

    Long, S. R.; Browning, S. R.; Lagowski, J. J.

    2008-01-01

    The electrochemical synthesis of transition-metal acetylacetonates described here can form the basis of assisting in the transformation of an entry-level laboratory course into a research-like environment where all members of a class are working on the same problem, but where each member has a personal responsibility for the synthesis and…

  9. Photochemical properties of acetyl-acetonate complex of vanadium (5)

    Photochemical properties of complex [VO(OH)(OCH3)(acac)] prepared by dissolving vanadium (5) acetylacetonate (acac) complex in methanol have been studied by spectrophotometric method. It has been ascertained that in the course of irradiation of methanol solution of the above-mentioned complex by UV photochemical reduction of vanadium (5) to vanadium (4) is observed. If irradiation is discontinued, the reaction occurs in the opposite direction

  10. Performance and Characterization for Blend Membrane of PES with Manganese(III) Acetylacetonate as Metalorganic Nanoparticles

    Abdallah, H.; Shalaby, M. S.; Shaban, A. M. H.

    2015-01-01

    This study describes the preparation, characterization, and evaluation of performance of blend Polyethersulfone (PES) with manganese(III) acetylacetonate Mn(acac)3 to produce reverse osmosis blend membrane. The manganese(III) acetylacetonate nanoparticles were prepared by a simple and environmentally benign route based on hydrolysis of KMnO4 followed by reaction with acetylacetone in rapid stirring rate. The prepared nanoparticle powder was dissolved in polymer solution mixture to produce RO ...

  11. Clinical applications of indium-111-acetylacetone-labelled blood cells

    A method permitting red-cell labelling with 111In-acetylacetone was reported in 1974 for evaluating intestinal blood loss, the liver-spleen ratio and the red-cell volume. White blood cells can be tagged similarly. In white-cell labelling, simultaneous red-cell or platelet tagging is avoided. Several procedures (dextran separation and gradient centrifugations) have been combined, to develop a highly selective cell separation. In osteomyelitis it may not be as advantageous to use 67Ga-citrate, as in inflammatory soft tissue processes. The detection of inflammatory processes with labelled leukocytes could be of great importance for the scintigraphic diagnosis of osteomyelitidies. A group of 97 patients with suspected osteomyelitis have been examined using 111In-acetylacetone-labelled leukocytes (111In-AAL) immediately following positive routine skeletal scintigraphy. Images obtained 24 h post injection usually were the most satisfactory. In the followup group of 70 patients 21 true positives, 43 true negatives, 21 false negatives and 3 false positives were observed. These findings result in a specificity of 92%, sensitivity of 50% and accuracy of 70% with 111In-AAL for osteomyelitis. Preliminary investigations using 111In-acetylacetone-labelled thrombocytes (111In-AAT) were carried out to detect rejection of transplanted kidneys. The platelets were separated by means of additional special density gradient centrifugations but no dextran from 15-20 ml of autologous whole blood. Scans have been obtained 15 min, 2.5 h and 24 h post injection in an initial group of 10 patients. In acute rejection, a high transplant uptake has been detected, whereas patients without acute rejection showed no or only a minimum activity accumulation. Patients with chronic rejection have intermediate uptakes

  12. Saturated vapor pressure of lutetium tris-acetylacetonate

    By the statical method using 177Lu radioactive isotope the saturated vapor pressure of anhydrous lutetium acetylacetonate at 130 to 160 deg is determined. The calculations are carried out assuming the vapor to be monomolecular. The equation of lgP versus 1/T takes the form: lg Psub((mmHg))=(8.7+-1.6)-(4110+-690)/T. The thermodynamical characteristics of LuA3 sublimation are calculated to be ΔHsub(subl.)=79+-13 kJ/mol; ΔSsub(subl.)=111+-20 J/kxmol

  13. CuOx Nanoparticle Production from Copper Acetylacetonate

    Moravec, Pavel; Smolík, Jiří; Klementová, Mariana; Levdansky, V.V.

    Praha: Česká aerosolová společnost, 2008, s. 59-62. ISBN 978-80-86186-17-7. [konference České aerosolové společnosti /9./. Praha (CZ), 04.12.2008] R&D Projects: GA ČR GA104/07/1093 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502 Keywords : generation of nanoparticles * copper acetylacetonate * hot wall reactor Subject RIV: CF - Physical ; Theoretical Chemistry http://cas.icpf.cas.cz/download/Sbornik_VKCAS_2008. pdf

  14. Solvents and supporting electrolytes for vanadium acetylacetonate flow batteries

    Shinkle, Aaron A.; Pomaville, Timothy J.; Sleightholme, Alice E. S.; Thompson, Levi T.; Monroe, Charles W.

    2014-02-01

    Properties of supporting electrolytes and solvents were examined for use with vanadium acetylacetonate - a member of the class of metal(β-diketonate) active species - in non-aqueous redox flow batteries. Twenty supporting-electrolyte/solvent combinations were screened for ionic conductivity and supporting-electrolyte solubility. Hexane, tetrahydrofuran, and dimethylcarbonate solvents did not meet minimal conductivity and solubility criteria for any of the electrolytes used, which included tetraethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and (1-butyl, 3-methyl)imidazolium bis(trifluoromethanesulfonyl)imide. Ionic conductivities and solubilities for solutions of these electrolytes passed screening criteria in acetonitrile and dimethylformamide solvents, in which maximum supporting-electrolyte and active-species solubilities were determined. Active-species electrochemistry was found to be reversible in several solvent/support systems; for some systems the voltammetric signatures of unwanted side reactions were suppressed. Correlations between supporting-solution properties and performance metrics suggest that an optimal solvent for a vanadium acetylacetonate RFB should have a low solvent molar volume for active-species solubility, and a high Hansen polarity for conductivity.

  15. Proton transfer in acetylacetone and its α-halo derivatives.

    Dolati, Fatemeh; Tayyari, Sayyed Faramarz; Vakili, Mohammad; Wang, Yan Alexander

    2016-01-01

    A two-dimensional potential energy surface was utilized to treat the proton transfer in acetylacetone (AA) and its α-halo derivatives: α-fluoro-(FAA), α-chloro-(ClAA), and α-bromo-acetylacetone (BrAA). This potential energy function, which couples O-H stretching and in-plane bending vibrations, was acquired through ab initio calculations for a fixed skeleton geometry. The resulting potential energy surfaces were then used to calculate the proton tunneling frequencies and proton transfer barrier heights. The barrier heights (the energy difference between the saddle point and the minima) calculated at the MP2/6-31G(2d,p) level of theory for proton transfers in AA, FAA, ClAA, and BrAA are 7.2, 9.4, 6.3, and 5.9 kcal mol(-1), respectively. The theoretically predicted proton transfer barrier heights exhibit excellent linear correlations with geometrical, electronic structural, and topological parameters evaluated by the atoms-in-molecule (AIM) and natural bond orbital (NBO) analyses. PMID:26616236

  16. Reactions cyclopentadienylvanadium compounds with trifluoroacetic acid and acetylacetone

    Studied is the interaction of vanadocene (1) and vanadium cyclopentadienylcarboxylates Cp2 VOCOCF3 (2), CpV(OCOCF3)2 (3), CpV(OCOCH3)2 (4) and CpV(OCOC6H5)2 (5) with acidic reagents: trifluoroacetic acid (6) and acetylacetone (7). In interaction of (1) with (6), depending on the ratio of components, the Cp2V structure is either retained (1:1 ratio, reaction products (2) and H2) or one Cp ring is removed (ratio > 1:2) with formation of cyclopentadiene, hydrogen and (3). Interaction of (7) with (1) leads to complete rupture of V-Cp bonds and formation of V(C5H7O2)3 (8). (7) replaces Cp and acyloxy groups from all studied cyclopentadienylcarboxylate derivatives of vanadium (2, 3, 4, 5) with formation of 8, cyclopentadiene and the corresponding carboxylic acids

  17. An application of the coincidence Doppler spectroscopy for substances of chemical interest: phthalocyanine and acetylacetonate complexes

    Ito, Y

    2000-01-01

    Coincidence Doppler spectroscopy, which is particularly powerful when one is concerned with high momentum components of positron annihilation gamma-rays, has been applied to two different kinds of organo-metallic ligands: metal phthalocyanines and metal acetylacetonates. The energy (momentum) profiles of the annihilation gamma-rays were the same for metal phthalocyanines indicating that positron and/or positronium are not interacting with the metal ions. However, the profiles for the metal acetylacetonates evidently showed a dependence on the kind of metal ions. Discussion is made on the features of positron interaction which are different for phthalocyanines and acetylacetonates.

  18. Solvent extraction studies of lanthanide acetylacetonates. Part 3

    The complex formation of the heavier trivalent lanthanides (Ln) 65Tb, 67Ho, 69Tm and 71Lu with acetylacetone (HAa) has been studied at 25 ±0.1 deg. C by the liquid-liquid extraction technique in the system 0.02-3.5 M HAa in benzene/1.0 M Na(H)ClO4 using trace amounts of radioactive lanthanides. The stepwise formation constants, Kn=[LnAan][LnAan-1]-1[Aa-]-1 (n=2 to 4), the distribution constant of the neutral complex LnAa3 between the phases (P3), and the self-adduct formation of LnAa3 x HAa in the organic phase (Kadd1) have been evaluated. To obtain the necessary data for a precise evaluation of the lower formation constants, distribution values as low as 0.0001 had to be measured with high accuracy in the pH range 3-9. To make this possible the investigation was made by the recently developed AKUFVE-LISOL technique. A survey of the results on all the lanthanides studied in this series is also given. (author)

  19. Halomethyl-cobalt(bis-acetylacetonate) for the controlled synthesis of functional polymers.

    Demarteau, Jérémy; Kermagoret, Anthony; German, Ian; Cordella, Daniela; Robeyns, Koen; De Winter, Julien; Gerbaux, Pascal; Jérôme, Christine; Debuigne, Antoine; Detrembleur, Christophe

    2015-10-01

    Novel organocobalt complexes featuring weak C-CoL2 bonds (L = acetylacetonate) are prepared and used as sources of halomethyl radicals. They permit the precision synthesis of α-halide functionalized and telechelic polymers in organic media or in water. Substitution of halide by azide allows derivatization of polymers using the CuAAC click reaction. PMID:26273709

  20. Nanoparticle Formation by Thermal Decomposition and Oxidation of Manganese(II) Acetylacetonate

    Moravec, Pavel

    2012-01-01

    Over the last decade, Mn and MnOx nanoparticles has been extensively investigated due to their great importance in catalysis, electrochemistry, ion exchange materials, batteries and other areas (Si et al., 2005; Han et al., 2006). This work describes preliminary experiments producing manganese nanoparticles by metal organic chemical vapor deposition (MOCVD) using manganese(II) acetylacetonate (MnAA) as a precursor.

  1. Preparation of ferric acetylacetonate, bonzonate and caprate labelled with Fe-55 and tests of application to liquid scintillation measurements

    The methods of preparation of ferric acetylacetonate, benzoate and caprate labelled with 55Fe are described. The quenching effect, the spectral baehaviour and the count rate stability are studied by liquid scintillation measurements in toluene, INSTAGEL and HISAFE II, for two different values of the sample concentration. The ferric acetylaceton-ate is stable for all the three scintillators but shows a strong quench, while the ferric benzoate and caprate are stable only for INSTAGEL and HISAFE II showing no significant quench at the concentrat-ions of interest in habitual measurements. (Author)

  2. Preparation and Biodistribution Studies of a Radiogallium-Acetylacetonate Bis (Thiosemicarbazone) Complex in Tumor-Bearing Rodents

    Jalilian, Amir Reza; Yousefnia, Hassan; SHAFAII, KAMALEDDIN; Novinrouz, Aytak; Rajamand, Amir Abbas

    2012-01-01

    Various radiometal complexes have been developed for tumor imaging, especially Ga-68 tracer. In the present study, the development of a radiogallium bis-thiosemicarbazone complex has been reported. [67Ga] acetylacetonate bis(thiosemicarbazone) complex ([67Ga] AATS) was prepared starting [67Ga]Gallium acetate and freshly prepared acetylacetonate bis (thiosemicarbazone) (AATS) in 30 min at 90°C. The partition co-efficient and the stability of the tracer were determined in final solution (25°C) ...

  3. Extraction of carrier-free 144Ce with acetylacetone and 8-hydroxyquinoline

    The extraction of carrier-free 144Ce with 3.25 to 0.65 M solutions of acetylacetone in carbon tetrachloride and with 1.0 to 0.01 M solutions of 8-hydroxyquinoline in chloroform at a constant as well as variable pH was investigated. On the basis of the analysis of distribution curves it may be presumed that in both extraction systems the oxidation of cerium(III) to cerium(IV) microamounts takes place. The distribution curves of extraction and reextraction in the systems with 8-hydroxyquinoline show a considerable complexity. In the extraction system with acetylacetone constants were found which satisfactorily express the distribution of 144Ce in this system. (author)

  4. Mechanism of recoil implantation reactions of technetium and ruthenium in metal acetylacetonates

    Recoil implantation of Tc and Ru in metal acetylacetonates were performed using ruthenium metal as a source and MIII(acac)3 and MII(acac)2 complexes as catchers. The recoil atoms were obtained by 100Ru(γ,p)99mTc and 98Ru(γ,n)97Ru reactions. The yields of Tc(acac)3 and Ru(acac)3 were clearly dependent on the force constant of the bond between the central metal atom and oxygen in acetylacetone K(M-O). A plot of the yield vs. 1/K(M-O) showed a linear relationship. However, the yield of Tc(acac)2 implanted in M(acac)2 did not show such a dependence on the force constant. The difference of the mechanism of complex formation between Tc(acac)3 and Tc(acac)2 was discussed. (author)

  5. 1,3-Dioxolane, tetrahydrofuran, acetylacetone and dimethyl sulfoxide as solvents for non-aqueous vanadium acetylacetonate redox-flow-batteries

    Highlights: • Four solvents were employed in a non-aqueous redox flow battery system. • Coulombic efficiencies of 85.9–98.5% and energy efficiencies of 26.6–43.6% were achieved. • Discharge power density was enhanced up to 0.080 mW cm−2. • Solubility of V(acac)3 was increased to 0.8 M compared to the acetonitrile system. -- Abstract: A non-aqueous vanadium acetylacetonate redox flow battery with different organic solvents and tetrabutylammonium hexafluorophosphate has been investigated. Cyclic voltammograms show three redox couples in 1,3-dioxolane, tetrahydrofuran, acetylacetone and two redox couples in dimethyl sulfoxide. Cell potentials between 2.21 and 2.61 V are measured, depending on the solvent used. Impedance Spectroscopy has been used to determine rate limiting step in the non-aqueous redox flow battery. Experiments in a charge–discharge test cell yielded coulombic and energy efficiencies of 85.9–98.5% and 26.6–43.6%, respectively

  6. Sensing properties of tin acetylacetonate-based thin films doped with platinum

    Fitl, P.; Myslík, V.; Vrňata, M.; Náhlík, J.; Kopecký, D.; Vlček, J.; Hofmann, J.; Lančok, Ján

    2012-01-01

    Roč. 24, č. 2 (2012), s. 75-86. ISSN 0914-4935 R&D Projects: GA ČR(CZ) GAP108/11/1298 Institutional research plan: CEZ:AV0Z10100522 Keywords : gas sensing * tin acetylacetonate * pulsed laser deposition (PLD) method * selectivity tunable by temperature Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.288, year: 2012 http://122.249.91.209/myukk/Journal/Download.php?fn=SM0870.pdf

  7. Double deuterated acetylacetone in neon matrices: infrared spectroscopy, photoreactivity and the tunneling process.

    Gutiérrez-Quintanilla, Alejandro; Chevalier, Michèle; Crépin, Claudine

    2016-07-27

    The effect of deuteration of acetylacetone (C5O2H8) is explored by means of IR spectroscopy of its single and double deuterated isotopologues trapped in neon matrices. The whole vibrational spectra of chelated enols are very sensitive to the H-D exchange of the hydrogen atom involved in the internal hydrogen bond. UV excitation of double deuterated acetylacetone isolated in neon matrices induces the formation of four open enol isomers which can be divided into two groups of two conformers, depending on their formation kinetics. Within each group, one conformer is more stable than the other: slow conformer interconversion due to a tunneling process is observed in the dark at low temperature. Moreover, IR laser irradiation at the OD stretching overtone frequency is used to induce interconversion either from the most stable to the less stable conformer or the opposite, depending on the excitation wavelength. The interconversion process is of great help to assign conformers which are definitively identified by comparison between experimental and calculated IR spectra. Kinetic constants of the tunneling process at play are theoretically estimated and agree perfectly with experiments, including previous experiments with the totally hydrogenated acetylacetone [Lozada García et al., Phys. Chem. Chem. Phys., 2012, 14, 3450]. PMID:27412624

  8. Performance and Characterization for Blend Membrane of PES with Manganese(III Acetylacetonate as Metalorganic Nanoparticles

    H. Abdallah

    2015-01-01

    Full Text Available This study describes the preparation, characterization, and evaluation of performance of blend Polyethersulfone (PES with manganese(III acetylacetonate Mn(acac3 to produce reverse osmosis blend membrane. The manganese(III acetylacetonate nanoparticles were prepared by a simple and environmentally benign route based on hydrolysis of KMnO4 followed by reaction with acetylacetone in rapid stirring rate. The prepared nanoparticle powder was dissolved in polymer solution mixture to produce RO PES/Mn(acac3 blend membrane, without any treatment of Polyethersulfone membrane surface. The membrane morphology, mechanical properties, and performance were presented. The scanning electron microscopy (SEM images have displayed a typical asymmetric membrane structure with a dense top layer due to the migration of Mn(acac3 nanoparticles to membrane surface during the phase inversion process. Contact angle measurements have indicated that the hydrophilicity of the membrane was improved by adding Mn(acac3. AFM images have proved excellent pores size distribution of blend membrane and lower surface roughness compared with bare PES. The desalination test was applied to blend membrane, where the blend membrane provided good performance; particularly, permeate flux was 24.2 Kg/m2·h and salt rejection was 99.5%.

  9. Statistical modeling for Toluene Diisocyanate and Polypropylene Glycol Polymerization with Ferric Acetylacetonate as Catalyst

    Polyurethane elastomer was synthesized with propylene glycol and toluene diisocyanate with ferric acetylacetonate catalyst. This polymerization was modeled using the kinetic equations. The number and weight average degrees of polymerization (DPw and DPn), the number and weight average molecular weights (Mw and Mn) and the polydispersity index parameters were found and tested as function of time and conversion and they were finally compared with GPC laboratory and experimental results. The effect of concentration of the catalyst and the addition sequence of starting materials and catalyst on Mn, Mw, DPI and Mz/Mn are reported and discussed

  10. Effect of γ-radiation on the degradation of the M-O bond of some trivalent acetylacetonate complexes

    The effect of γ-radiation on the degradation of the M-O bond of seven trivalent acetylacetonate complexes was followed by IR spectrophotometry. The rate of degradation, K(M-O)afor K(M-O), obeyed a first order kinetics. The obtained K(M-O) and Go(M-O) for the different acetylacetonates are found to be linearly increased by the increase in the atomic radii of the chelated cations. A mechanism for the irradiation process is given. (author)

  11. A New Homogeneous Catalyst for the Dehydrogenation of Dimethylamine Borane Starting with Ruthenium(III Acetylacetonate

    Ebru Ünel Barın

    2015-06-01

    Full Text Available The catalytic activity of ruthenium(III acetylacetonate was investigated for the first time in the dehydrogenation of dimethylamine borane. During catalytic reaction, a new ruthenium(II species is formed in situ from the reduction of ruthenium(III and characterized using UV-Visible, Fourier transform infrared (FTIR, 1H NMR, and mass spectroscopy. The most likely structure suggested for the ruthenium(II species is mer-[Ru(N2Me43(acacH]. Mercury poisoning experiment indicates that the catalytic dehydrogenation of dimethylamine-borane is homogeneous catalysis. The kinetics of the catalytic dehydrogenation of dimethylamine borane starting with Ru(acac3 were studied depending on the catalyst concentration, substrate concentration and temperature. The hydrogen generation was found to be first-order with respect to catalyst concentration and zero-order regarding the substrate concentration. Evaluation of the kinetic data provides the activation parameters for the dehydrogenation reaction: the activation energy Ea = 85 ± 2 kJ·mol−1, the enthalpy of activation ∆H# = 82 ± 2 kJ·mol−1 and the entropy of activation; ∆S# = −85 ± 5 J·mol−1·K−1. The ruthenium(II catalyst formed from the reduction of ruthenium(III acetylacetonate provides 1700 turnovers over 100 hours in hydrogen generation from the dehydrogenation of dimethylamine borane before deactivation at 60 °C.

  12. Null current hysteresis for acetylacetonate electron extraction layer in perovskite solar cells

    Mohd Yusoff, Abd. Rashid Bin; Mat Teridi, Mohd Asri; Jang, Jin

    2016-03-01

    Solution processed zirconium acetylacetonate (Zr(acac)) is successfully employed as an electron extraction layer, replacing conventional titanium oxide, in planar CH3NH3PbI3 perovskite solar cells. The as-prepared Zr(acac) film possesses high transparency, high conductivity, a smooth morphology, high wettability, compatibility with PbI2 DMF solution, and an energy level matching that of CH3NH3PbI3 perovskite material. An average power conversion efficiency of about 11.93%, along with a high fill factor of 74.36%, an open circuit voltage of 1.03 V, and a short-circuit current density of 15.58 mA cm-2 is achieved. The overall performance of the devices is slight better than that of cells using ruthenium acetylacetonate (Ru(acac)). The differences between solar cells with different electron extraction layers in charge recombination, charge transport and transfer and lifetime are further explored and it is demonstrate that Zr(acac) is a more effective and promising electron extraction layer. This work provides a simple, and cost effective route for the preparation of an effective hole extraction layer.

  13. The development of radiogallium-acetylacetonate bis(thiosemicarbazone) complex for tumour imaging

    Background: Various radiometal complexes have been developed for tumour imaging, especially Ga-68 tracer. In this work, the development of a radiogallium bis(thiosemicarbazone) complex has been reported. Material and method: [67Ga]acetylacetonate bis(thio-semicarbazone) complex ([67Ga]AATS) was prepared starting with [67Ga]Gallium acetate and freshly prepared acetylacetonate bis(thiosemicarbazone) (AATS) for 30 min at 90oC. The partition co-efficient and stability of the tracer was determined in final solution (25oC) and the presence of human serum (37oC) for up to 24 hours. The biodistribution of the labelled compound in wild-type and fibrosarcoma-bearing rodents were determined for up to 72 hours. Results: The radiolabelled Ga complex was prepared to a high radiochemical purity (> 97%, HPLC) followed by initial biodistribution data with the significant tumour accumulation of the tracer at two hours, which is far higher than free Ga-67 cation, while the compound wash-out is significantly faster. Conclusion: The above-mentioned pharmacokinetic properties suggest an interesting radiogallium complex prepared by the PET Ga radioisotope, 68Ga, in accordance with the physical half life, for use in fibrosarcoma tumours and possibly in other malignancies. (authors)

  14. Structure of neodymium tris-acetylacetonate with dimethylsulfoxide [NdA3Dmso(H2O)]·Dmso

    Crystal structure of adduct of neodymium tris-acetylacetonate with dimethylsulfoxide was investigated. The adduct [NdA3Dmso(H2O)]. Dmso is crystallized in monclinic syngony. One of two Dmso molecules and water molecule enter the inner coordination sphere of the complex

  15. Ruthenium complexes with coordinated hydroxyiminoacetylacetonato or bridging nitrosyl groups formed by the reactions of nitrosylruthenium(III with acetylacetone

    Complexes formed by the reactions of nitrosylruthenium (III) with acetylacetone were investigated. The following products: [Ru(acac)2(hia)], 1; cis-[RuCl(NO)(acac)2], 2; and [(Ru(NO)(acac)2)4] 3; (acac=C5H7O2- and hia=C5H6NO3-), were isolated as crystals and were characterized. On the basis of chemical and thermal analyses, and on the basis of observations of the magnetic properties, the conductivities, the molecular weights, the infrared spectra, and the NMR spectra, it was concluded that 1 contains the hydroxyiminoacetyl acetonato ligand, which is formed by the reaction of the coordinated nitrosyl group with acetylacetone, and that 2 contains a terminal nitrosyl group, and 3, bridging nitrosyl groups. (auth.)

  16. Highly selective and sensitive monohydrogen phosphate membrane sensor based on molybdenum acetylacetonate

    Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Department of Chemisrtry, Tehran University, Tehran (Iran, Islamic Republic of)]. E-mail: Ganjali@khayam.ut.ac.ir; Norouzi, Parviz [Center of Excellence in Electrochemistry, Department of Chemisrtry, Tehran University, Tehran (Iran, Islamic Republic of); Ghomi, Mahnaz [Department of Chemistry, Azad University, North of branch, Tehran (Iran, Islamic Republic of); Salavati-Niasari, Masoud [Department of Chemistry, Kashan University, Kashan (Iran, Islamic Republic of)

    2006-05-17

    In this work, a highly selective and sensitive monohydrogen phosphate membrane sensor based on a molybdenum bis(2-hydroxyanil) acetylacetonate complex (MAA) is reported. The sensor shows a linear dynamic range between 1.0 x 10{sup -1} and 1.0 x 10{sup -7} M, with a nice Nernstian behavior (-29.5 {+-} 0.3 mV decade{sup -1}) in pH of 8.2. The detection limit of the electrode is 6.0 x 10{sup -8} M ({approx}6 ppb). The best performance was obtained with a membrane composition of 32% poly(vinyl chloride), 58% benzyl acetate, 2% hexadecyltrimethylammonium bromide and 8% MAA. The sensor possesses the advantages of short response time, low detection limit and especially, very good selectivity towards a large number of organic and inorganic anions including salicylate, citrate, tartarate, acetate, oxalate, fluoride, chloride, bromide, iodide, sulfite, sulfate, nitrate, nitrite, cyanide, thiocyanate, perchlorate, metavanadate, and bicarbonate ions. The electrode can be used for at least 10 weeks without any considerable divergence in its slope and detection limit. It was used as an indicator electrode in potentiometric titration of monohydrogenphosphate ion with barium chloride. The proposed sensor was successfully applied to direct determination of monohydrogenphosphate in two fertilizer samples (NPK)

  17. Vanadium oxide thin films and fibers obtained by acetylacetonate sol–gel method

    Berezina, O.; Kirienko, D. [Department of Physical Engineering, Petrozavodsk State University, 185910 Petrozavodsk (Russian Federation); Pergament, A., E-mail: aperg@psu.karelia.ru [Department of Physical Engineering, Petrozavodsk State University, 185910 Petrozavodsk (Russian Federation); Stefanovich, G.; Velichko, A. [Department of Physical Engineering, Petrozavodsk State University, 185910 Petrozavodsk (Russian Federation); Zlomanov, V. [Department of Chemistry, Moscow State University, 119991 Moscow (Russian Federation)

    2015-01-01

    Vanadium oxide films and fibers have been fabricated by the acetylacetonate sol–gel method followed by annealing in wet nitrogen. The samples are characterized by X-ray diffraction and electrical conductivity measurements. The effects of a sol aging, the precursor decomposition and the gas atmosphere composition on the annealing process, structure and properties of the films are discussed. The two-stage temperature regime of annealing of amorphous films in wet nitrogen for formation of the well crystallized VO{sub 2} phase is chosen: 1) 25–550 °C and 2) 550–600 °C. The obtained films demonstrate the metal–insulator transition and electrical switching. Also, the effect of the polyvinylpyrrolidone additive concentration and electrospinning parameters on qualitative (absence of defects and gel drops) and quantitative (length and diameter) characteristics of vanadium oxide fibers is studied. - Highlights: • Vanadium oxide thin films and fibers are synthesized by sol–gel method. • The effect of annealing, atmosphere, time and electrospinning parameters is studied. • Produced VO{sub 2} structures exhibit metal–insulator transition and electrical switching.

  18. Keto-Enol Tautomeric Equilibrium of Acetylacetone Solution Confined in Extended Nanospaces.

    Tsukahara, Takehiko; Nagaoka, Kyosuke; Morikawa, Kyojiro; Mawatari, Kazuma; Kitamori, Takehiko

    2015-11-19

    We aim to clarify the effects of size confinement, solvent, and deuterium substitution on keto-enol tautomerization of acetylacetone (AcAc) in solutions confined in 10-100 nm spaces (i.e., extended nanospaces) using (1)H NMR spectroscopy. The keto-enol equilibrium constants of AcAc (K(EQ) = [keto]/[enol]) in various solvents confined in extended nanospaces of 200-3000 nm were examined using the area ratios of -CH3 peaks in keto to enol forms. The results showed that the keto form of AcAc in hydrogen-bonded solvents such as water and ethanol increased drastically with decreasing space sizes below about 500 nm, but the size confinement did not induce equilibrium shifts in aprotic solvents such as DMSO. The magnitudes of K(EQ) enhancement were well correlated with solvent proton donicity. It followed from the determination of thermodynamic parameters that the stabilization of intermolecular interactions between protons in water and carbonyl oxygen (C═O) in the keto form of AcAc were promoted by size-confinement, and that the keto form could be energetically and structurally favored in extended nanospaces vis-à-vis the bulk space. Furthermore, the measurements of deuterium dependence of the K(EQ) values verified that the nanoconfinement-induced shifts of keto-enol tautomerization of AcAc are attributable to high proton mobility via a proton hopping mechanism of the confined water. PMID:26503906

  19. Synthesis and spectroscopic studies of some chromium and molybdenum derivatives of bis-(acetylacetone)ethylenediimine ligand

    Ramadan, Ramadan M.; Abdel-Rahman, Laila H.; Ismael, Mohamed; Youssef, Teraze A.; Ali, Saadia A.

    2013-10-01

    Interaction of [Cr(CO)6] with bis-(acetylacetone)ethylenediimine Schiff base, H2acacen, under reduced pressure resulted in the formation of [Cr(CO)3(H2acacen)] derivative. The Schiff base acted as a tridentate and coordinated the metal through the nitrogen of the azomethine groups and one hydroxyl group. Reaction of [Mo(CO)6] with H2acacen under sunlight irradiation in presence of air gave the oxo derivative [Mo2O6(H2acacen)2]. The ligand acted as a bidentate and coordinated the metal through the two imine groups. In presence of 2,2'-bipyridine (bpy), the reaction of [Mo(CO)6] with H2acacen gave [Mo2O6(bpy)(H2acacec)]. The structures of the reported complexes were proposed on the basis of spectroscopic studies. The proposed structures were also verified by theoretical calculations based on accurate DFT approximations. Moreover, the relative reactivity was estimated using chemical descriptors analysis.

  20. Positron decay in benzene solutions of 3d transition metal acetylacetonates and dipivaloylmethanates

    The lifetime spectra of positrons and positronium were measured in benzene solutions containing metal acetylacetonates and dipivaloylmethanates. The lifetime of orthopositronium (o-Ps) observed in pure benzene, 3.20 ns, was not significantly affected by the diamagnetic aluminum, nickel(II), and zinc complexes dissolved in benzene, whereas the lifetime was reduced by the paramagnetic manganese(III), iron(III), chromium(III), cobalt(II), and diamagnetic cobalt(III) complexes with the increase in their concentration, e.g., down to 1.60 ns in the case of 0.20 M Mn(acac)3. The intensity (I2) of o-Ps decreased rapidly with an increase in the solute concentration and became saturated at about 0.05 M. The rate constants of the o-Ps annihilation were correlated with polarographic apparent half-wave potentials of the complexes. The large reaction rate constants for Mn(acac)3 and Fe(acac)3 were attributed to the oxidation of o-Ps by the complexes, which show the potentials less negative than -0.5 V vs. mercury pool in benzene--methanol

  1. Vanadium oxide thin films and fibers obtained by acetylacetonate sol–gel method

    Vanadium oxide films and fibers have been fabricated by the acetylacetonate sol–gel method followed by annealing in wet nitrogen. The samples are characterized by X-ray diffraction and electrical conductivity measurements. The effects of a sol aging, the precursor decomposition and the gas atmosphere composition on the annealing process, structure and properties of the films are discussed. The two-stage temperature regime of annealing of amorphous films in wet nitrogen for formation of the well crystallized VO2 phase is chosen: 1) 25–550 °C and 2) 550–600 °C. The obtained films demonstrate the metal–insulator transition and electrical switching. Also, the effect of the polyvinylpyrrolidone additive concentration and electrospinning parameters on qualitative (absence of defects and gel drops) and quantitative (length and diameter) characteristics of vanadium oxide fibers is studied. - Highlights: • Vanadium oxide thin films and fibers are synthesized by sol–gel method. • The effect of annealing, atmosphere, time and electrospinning parameters is studied. • Produced VO2 structures exhibit metal–insulator transition and electrical switching

  2. L-Lactide Ring-Opening Polymerization with Tris(acetylacetonate)Titanium(IV) for Renewable Material.

    Kim, Da Hee; Yoo, Ji Yun; Ko, Young Soo

    2016-05-01

    A new Ti-type of catalyst for L-lactide polymerization was synthesized by reaction of titanium(IV) isopropoxide (TTIP) with acetylacetone (AA). Moreover, PLA was prepared by the bulk ring-opening polymerization using synthesized Ti catalyst. Polymerization behaviors were examined depending on monomer/catalyst molar ratio, polymerization temperature and time. The structure of synthesized catalysts was verified with FT-IR and 1H NMR and the properties of poly(L-lactide) (PLLA) were examined by GPC, DSC and FT-IR. There existed about 30 minutes of induction time at the monomer/catalyst molar ratio of 300. The molecular weight (MW) increased as monomer/catalyst molar ratio increased. The MW increased almost linearly as polymerization progressed. Increasing polymerization temperature increased the molecular weight of PLLA as well as monomer/catalyst molar ratio. The melting point (T(m)) of polymers was in the range of 142 to 167 degrees C. Lower T(m) was expected to be resulted from relatively lower molecular weight. PMID:27483787

  3. Photo-and radiation chemical properties of manganese (3) acetylacetonates and structurization of polymeric compositions

    Methods of electron, EPR- and IR-spectroscopy have been used to study photochemical and radiation chemical behaviour of manganese (3) acetylacetonates. Effect of manganese chelates on structurization of polymeric compositions (the first composition - on the basis of saponified copolymer of vinyl chloride with vinyl acetate and the second composition on the basis of cellulose derivatives) linked (1) or destructed (2) under γ-radiation is considered. Maximum degree of structurization for the composition 1 at the absence of the complex made up 64%, at the presence of Mn(AA)Λ3 - 88%, at the presence of Mn(AA)Λ2(OCOCFΛ3) - 94% (at equal radiation doses). Adding the complexes amplifies the process of structurization, Mn(AA)Λ2 (OCOCFΛ3) amplifying the process to a larger extent than Mn(AA)Λ3. The degree of destruction of the composition 2 at the presence of the complex is essentially lower than at its absence. The mechanism of chelate effect on polymers comprises the stage of associate formation: metal complex - free radical

  4. Spectral studies on the interaction of acetylacetone with aluminum-containing MCM-41 mesoporous materials

    Diffuse reflectance spectroscopy (DRS) was used to study the interaction of acetylacetone (acac) with the mesoporous aluminum-containing MCM-41 materials. A room temperature synthesis method was used for preparation of purely siliceous MCM-41 and for aluminum-containing MCM-41 materials. Samples with Si/Al ratios of 50, 20, 10 and 5 were synthesized. The synthesized mesoporous materials possess highly ordered structure and high surface area as evidenced from X-ray diffraction and nitrogen physisorption measurements, respectively. The treatment of the as-synthesized aluminum-containing MCM-41 samples with acac shows a distinct band at ∼290 nm. This band is assigned to six coordinated aluminum atoms in the structure which is produced by diffusion of acac molecules through surfactant micelles and their interaction with aluminum atoms. The 290-nm band disappears upon several successive washing of the sample with ethanol. The treatment of the calcined aluminum-containing MCM-41 sample with acac produces the same 290-nm band where its intensity increases with the aluminum content of the sample. The intensity of this band is reduced upon successive ethanol washing, but remains nearly constant after three times washing. This irremovable aluminum species can be assigned to framework aluminum. The measured acidity for our aluminum-containing MCM-41 samples correlates linearly with the intensity of 290-nm band for the ethanol treated samples. This supports the idea that the Bronsted acidity in aluminum-modified MCM-41 samples is a function of the amount of tetrahedral framework aluminum in the structure

  5. Copper and Copper Oxide Nanoparticle Formation by Chemical Vapor Nucleation From Copper (II) Acetylacetonate

    Crystalline nanometer-size copper and copper (I) oxide particle formation was studied by thermal decomposition of copper acetylacetonate Cu(acac)2 vapor using a vertical flow reactor at ambient nitrogen pressure. The experiments were performed in the precursor vapor pressure range of Pprec = 0.06 to 44 Pa at furnace temperatures of 431.5 deg. C, 596.0 deg. C, and 705.0 deg. C. Agglomerates of primary particles were formed at Pprec0.1 Pa at all temperatures. At 431.5 deg. C the number mean size of the primary particles increased from Dp = 3.7 nm (with geometric standard deviation σg = 1.42) to Dp = 7.2 nm (σg = 1.33) with the increasing precursor vapor particle pressure from 1.8 to 16 Pa. At 705.0 deg. C the primary particle size decreased from Dp = 24.0 nm (σg=1.57) to Dp = 7.6 nm (σg = 1.54), respectively.At furnace temperatures of 431.5 deg. C and 596.0 deg. C only crystalline copper particles were produced. At 705.0 deg. C the crystalline product of the decomposition depended on the precursor vapor pressure: copper particles were formed at Pprec>10 Pa, copper (I) oxide at Pprecleq 1 Pa, and a mixture of the metal and its oxide at intermediate vapor pressures. A kinetic restriction on copper particle growth was shown, which leads to the main role of Cu2 molecule participation in the particle formation. The formation of copper (I) oxide particles occurs due to the surface reaction of the decomposition products (mainly carbon dioxide). For the explanation of the experimental results, a model is proposed to build a semiempirical phase diagram of the precursor decomposition products

  6. Regiospecific tritium labeling of aromatic acids, amides, amines and heterocyclics using homogeneous rhodium trichloride and ruthenium acetylacetonate catalysts

    Homogeneous rhodium trichloride has been found to promote ortho-tritiation with high regioselectivity in a wide range of aromatic carboxylic acids, amides and aralkylamines. Less successful results were obtained using o-chlorobenzoic and o-anisic acids where some decomposition was seen, and in acids and amides of the phenolic type, where a degree of electrophilic exchange accompanies the ortho-exchange. The same catalyst has also been used to regiospecifically label a number of heterocyclics. In the course of investigations with other metal complexes ruthenium acetylacetonate has been identified as an excellent promoter of ortho-exchange in benzoic acids. (author)

  7. Indium Doped Zinc Oxide Thin Films Deposited by Ultrasonic Chemical Spray Technique, Starting from Zinc Acetylacetonate and Indium Chloride

    Rajesh Biswal; Arturo Maldonado; Jaime Vega-Pérez; Dwight Roberto Acosta; María De La Luz Olvera

    2014-01-01

    The physical characteristics of ultrasonically sprayed indium-doped zinc oxide (ZnO:In) thin films, with electrical resistivity as low as 3.42 × 10−3 Ω·cm and high optical transmittance, in the visible range, of 50%–70% is presented. Zinc acetylacetonate and indium chloride were used as the organometallic zinc precursor and the doping source, respectively, achieving ZnO:In thin films with growth rate in the order of 100 nm/min. The effects of both indium concentration and the substrate tempe...

  8. Solvatochromism Study on the Copper(II Complexes Containing 3–Substituted Derivatives of Acetylacetonate Ligands

    Hamid Golchoubian

    2012-01-01

    Full Text Available Solvatochromic properties of a series of bis(3–substituted derivatives of acetylacetone copper(II (X-acacH , X = Cl, H. CH3 complexes were studied. All the complexes demonstrated negative solvatochromism. Among the complexes the Cu(Cl-acac2, demonstrated the most solvatochromism. A multi-parametric equation has been utilized to explain the solvent effect on the d-d transition of the complexes using SPSS/PC software. The stepwise multiple linear regression (SMLR method demonstrated that the donor power of the solvent plays the most important role in the solvatochromism of the compounds.

  9. Solvatochromism Study on the Copper(II) Complexes Containing 3–Substituted Derivatives of Acetylacetonate Ligands

    Hamid Golchoubian; Fariba Khoshsiar

    2012-01-01

    Solvatochromic properties of a series of bis(3–substituted derivatives of acetylacetone) copper(II) (X-acacH , X = Cl, H. CH3) complexes were studied. All the complexes demonstrated negative solvatochromism. Among the complexes the Cu(Cl-acac)2, demonstrated the most solvatochromism. A multi-parametric equation has been utilized to explain the solvent effect on the d-d transition of the complexes using SPSS/PC software. The stepwise multiple linear regression (SMLR) method demonstrated th...

  10. Host--guest complexation. 15. Macrocyclic acetylacetone ligands for metal cations

    Five macrocycles containing 1,5-disubstituted acetylacetone units (AcAc) have been synthesized. Their abilities to complex metal cations in water--dioxane have been compared to those of noncyclic model compounds. The AcAc units were bound together through bridges composed of the following groups: oxa (O), ethylene (E), and 1,3-disubstituted benzene (B). Cycles O(AcAcOEOE)(EOEOE)O(7), (OEOAcAcOE)2 (8), and (OEOAcAcOE)3 (9) were prepared by hydrolysis of rings closed by the reactions of CH2[HOCH2C(SCH2)2CH2]2 (2) and appropriate polyethylene glycol ditosylates. Ligand systems O(EAcAcE)2O (12) and B(CH2AcAcCH2)2B (14) were synthesized in Ca2+ or Mg2+ templated, two-step sequences involving reactions of HAcAcH dianions with either diethylene glycol ditosylate of m-xylyl dibromide, respectively. The preparation of (CH2IsCH2O)3 (17) is also described, in which Is is the 3,5-disubstituted isoxazole unit. Also described are the preparations of O(EAcAcH)2 (11), B(CH2AcAcH)2 (13), and P(CH2AcAcH)2 (15), in which P is 2,6-disubstituted pyridine. The logarithms of the formation constants (log K/sup f//sub av/) of the salts of (OEOAcAcOE)2 with 11 divalent metal cations and of (OEOAcAcOE)3 with 3 trivalent cations were 1.8 to 6.3 units higher valued than for CH3OAcAcOCH3. The log K/sup f//sub av/values for salt formation of O(EAcAcE)2O and B(CH2AcAcCH2)2B with 10 divalent cations were compared with those of O(EAcAcH)2 and B(CH2AcAcH)2, respectively, and with HAcAcH itself. Without exception, O(EAcAcE)2O > O(EAcAcH)2 > HAcAcH in values of log k/sup f//sub av/, the maximum difference being 4.3 for Ca2+

  11. Preparation and Biodistribution Studies of a Radiogallium-Acetylacetonate Bis (Thiosemicarbazone) Complex in Tumor-Bearing Rodents

    Jalilian, Amir Reza; Yousefnia, Hassan; Shafaii, Kamaleddin; Novinrouz, Aytak; Rajamand, Amir Abbas

    2012-01-01

    Various radiometal complexes have been developed for tumor imaging, especially Ga-68 tracer. In the present study, the development of a radiogallium bis-thiosemicarbazone complex has been reported. [67Ga] acetylacetonate bis(thiosemicarbazone) complex ([67Ga] AATS) was prepared starting [67Ga]Gallium acetate and freshly prepared acetylacetonate bis (thiosemicarbazone) (AATS) in 30 min at 90°C. The partition co-efficient and the stability of the tracer were determined in final solution (25°C) and the presence of human serum (37°C) up to 24 h. The biodistribution of the labeled compound in wild-type and fibrosarcoma-bearing rodents were determined up to 72 h. The radiolabled Ga complex was prepared in high radiochemical purity (> 97%, HPLC) followed by initial biodistribution data with the significant tumor accumulation of the tracer in 2 h which is far higher than free Ga-67 cation while the compound wash-out is significantly faster. Above-mentioned pharmacokinetic properties suggest an interesting radiogallium complex while prepared by the PET Ga radioisotope, 68Ga, in accordance with the physical half life, for use in fibrosarcoma tumors, and possibly other malignancies. PMID:24250475

  12. Investigation of the weak basic butyltriethylammonium acetylacetonate and polyethylene glycol mixture as a new efficient CO2 absorption solvent

    Highlights: • The absorption of CO2 in butyltriethylammonium acetylacetonate and polyethylene glycol 200 mixtures has been reported. • The absorption enthalpy and absorption entropy were calculated. • The absorption process is efficient and reversible. • The mixtures showed low absorption enthalpy for CO2 capture. • The addition of PEG-200 can accelerate absorption process. - Abstract: Efficient and reversible absorption of CO2 was investigated by weak basic ionic liquid of butyltriethylammonium acetylacetonate ([N2224][acac]) and polyethylene glycol 200 (PEG-200) mixtures with different mass ratios. The results showed that [N2224][acac]/PEG-200 mixtures possessed a maximum absorption capacity of 0.9 mol CO2 per mole [N2224][acac] at T = 298.15 K under ambient pressure. The mixtures used could be easily regenerated by bubbling N2 through the solutions without obvious loss of absorption performance. Furthermore, the solubility data of CO2 in the mixtures at T = (303.15, 318.15, and 333.15) K under different pressures were measured. The thermodynamic parameters of absorption enthalpy and absorption entropy were calculated with resulting negative values at each condition. The mixtures showed low absorption enthalpy for CO2 capture. The addition of PEG-200 can accelerate absorption process. The CO2 capture process described using [N2224][acac]/PEG-200 mixtures is a promising method for CO2 absorption with both good reversibility and high absorption capacity

  13. Effect of magnesium acetylacetonate on the signal of organic forms of vanadium in graphite furnace atomic absorption spectrometry.

    Kowalewska, Zofia; Welz, Bernhard; Castilho, Ivan N B; Carasek, Eduardo

    2013-01-15

    The aim of this work was to investigate the influence of magnesium acetylacetonate (MgA) on the signal of organic forms of vanadium in xylene solution by graphite furnace atomic absorption spectrometry. MgA alone or mixed with palladium acetylacetonate (PdA) was considered as a chemical modifier. It has been found that MgA does not improve, but decreases significantly the integrated absorbance of V in the form of alkyl-aryl sulfonates, acetylacetonates, porphyrins and in lubricating oils, while its effect is negligible in the case of "dark products" from petroleum distillation, i.e., heavy oil fractions and residues. The decrease is also observed in the presence of Pd. The MgA (or MgA+PdA) effect on the integrated absorbance of V has been studied using the following variants: different ways of modifier application, various pyrolysis temperature, additional application of air ashing, preliminary pretreatment with iodine and methyltrioctylammonium chloride, application of various graphite furnace heating systems (longitudinal or transverse) and various optical and background correction systems (medium-resolution line source spectrometer with deuterium background correction or high-resolution continuum source spectrometer). The experiments indicate formation of more refractory compounds as a possible reason for the decrease of the integrated absorbance for some forms of V in the presence of MgA. The application of MgA as a chemical modifier in V determination is not recommended. Results of this work have general importance as, apart from the intentional use of MgA as a modifier, organic Mg compounds, present in petroleum products for other reason (e.g. as an additive), can influence the signal of V compounds and hence the accuracy in V determination. Generally, petroleum products with known amount of V are recommended as standards; however, lubricating oils can be inadequate for "dark products" from petroleum distillation. In the case of unknown samples it is

  14. Heat capacity and thermodynamic functions of ruthenium tris-acetylacetonate from 0 K up to the melting point

    Highlights: • The heat capacity for Ru(AA)3 for the entire range of solid phase existence. • Density of phonon states calculated from the low-temperature heat capacity • Thermodynamic functions in the range (0–505) K. - Abstract: In the present work, the vibrational spectrum of the ruthenium tris-acetylacetonate crystal, Ru(C5H7O2)3, was reconstructed and its heat capacity was calculated for the entire range of solid phase existence (5–505 K) based on the experimental data on heat capacity obtained by adiabatic method within the range of 6–310 K. The Cp−Cv difference was estimated at the temperatures above 310 K. Based on the heat capacity obtained from the vibrational spectrum, integral thermodynamic functions (entropy, internal energy, and Helmholtz energy) were calculated up to the melting point

  15. Heat capacity and thermodynamic functions of ruthenium tris-acetylacetonate from 0 K up to the melting point

    Kuzin, Timofei M., E-mail: kuzin@niic.nsc.ru; Bespyatov, Michael A.; Naumov, Victor N.; Musikhin, Anatoly E.; Gelfond, Nikolay V.

    2015-02-20

    Highlights: • The heat capacity for Ru(AA){sub 3} for the entire range of solid phase existence. • Density of phonon states calculated from the low-temperature heat capacity • Thermodynamic functions in the range (0–505) K. - Abstract: In the present work, the vibrational spectrum of the ruthenium tris-acetylacetonate crystal, Ru(C{sub 5}H{sub 7}O{sub 2}){sub 3}, was reconstructed and its heat capacity was calculated for the entire range of solid phase existence (5–505 K) based on the experimental data on heat capacity obtained by adiabatic method within the range of 6–310 K. The C{sub p}−C{sub v} difference was estimated at the temperatures above 310 K. Based on the heat capacity obtained from the vibrational spectrum, integral thermodynamic functions (entropy, internal energy, and Helmholtz energy) were calculated up to the melting point.

  16. Effect of chelating agent acetylacetone on corrosion protection properties of silane-zirconium sol-gel coatings

    Yu, Mei; Liang, Min; Liu, Jianhua; Li, Songmei; Xue, Bing; Zhao, Hao

    2016-02-01

    The hybrid sol-gel coatings on AA2024-T3 were prepared with a silane coupling agent 3-glycidoxypropyltrimethoxysilane (GPTMS) and a metal alkoxide tetra-n-propoxyzirconium (TPOZ) as precursors. The effect of acetylacetone (AcAc) as a chelating agent on the corrosion protection properties of sol-gel coatings were evaluated and the optimal AcAc/TPOZ molar ratio was obtained. The sol-gel coatings were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The corrosion protection properties of the coatings were evaluated by means of potentiodynamic polarization study (PDS) and electrochemical impedance spectroscopy (EIS). It is demonstrated that AcAc avoids fast hydrolysis of TPOZ and benefits to form stable sols. The coating with AcAc/TPOZ molar ratio of 3 shows the best corrosion protection performance in 0.05 M NaCl solution.

  17. Detection limits in the chromatographic element trace analysis - quantitative TLC, HPLC and GC with the example of beryllium acetylacetonate

    Chromatographic analyses of beryllium acetylacetonate are carried out in synthetic solutions within the nano- and picogram range of beryllium. For thin-layer chromatography (TLC) normal and silanized silica gel is used, for high-performance liquid chromatography (HPLC) silica gel of 7 μm particles, for gas chromatography (GC) silicone SE-30 as stationary phase. Visual evaluation and remission measurements in TLC, UV-254 nm absorption measurements in HPLC and measurements with a FID in GC are employed for the determination of the calibration curves. A calibration curve through the origin and a detection limit of 150 pg Be determinable form are received by HPLC only. For trace analyses by GC a new definition of a detection limit for the evaluation of substance peaks on a solvent tailing is suggested. (orig.)

  18. An extractive spectrophotometry method for the determination of vanadium as V(II)-8-hydroxyquinoline complex into acetylacetone-chloroform

    A simple and rapid extractive spectrophotometric method of determination of vanadium is developed by reduction of the metal ion with Zn/Hg in presence of 8-hydroxyquinoline under acidic conditions employing acetylacetone-chloroform as extractant. No interference is shown by W(VI), Cr(VI, III), U(VI), Mo(VI), Fe(II), Co(II), Ni(II), Cu(II) and several other elements of interest. The applicability of the method is tested by analysis of a large number of different samples. The method is highly reproducible with a standard deviation of 0.0065 and Sandell's sensitivity 8.6956x10-2 μg V/cm2. Stoichiometry of the complex is also studied. (author). 1 tab., 17 refs

  19. Contribution to the study of the chemical consequences of the (n, γ) reaction in solid Co(3) tris-acetylacetone

    The fragmentation and annealing of thermal neutron irradiated Co(III) tris-acetylacetone was investigated using the thin layer chromatographic technique (silica-gel 1 mm thickness). Low temperature irradiations (0 C - -72 C and -180 C) lead to 60Co retentions as low as (1,1 ± 0,2) per cent. Annealing by linear temperature programming at different heating rates has shown the existence of eight reactions. The influences of pile dose and of gases (air and helium) as well as of thermal decomposition on the annealing processes were confirmed. A temperature and dose dependent effect was found out for the retentions of the 60mCo - 60Co isomers. (author)

  20. Transport of Indium, Gallium and Thallium Metal Ions Through Chromatographic Fiber Supported Solid Membrane in Acetylacetone Containing Mixed Solvents

    Abaji Gaikwad

    2011-01-01

    The transport of metal ions of indium, gallium and thallium from source solution to receiving phase through the chromatographic fiber supported solid membrane in the acetylacetone (HAA) containing mixed solvent system has been explored. The fibers supported solid membranes were prepared with chemical synthesis from cellulose fibers and citric acid with the carboxylic acid ion exchange groups introduced. The experimental variables, such as concentration of metal ions (10^-2 to 10^-4 mol.L^-1) in the source solution, mixed solvent composition [for exampl, e, acetylacetone, (2,4-pentanedione), (HAA) 20% (by volume), 1,4-dioxane 10% to 60% and HC1 0.25 to 2 mol.L^-1] in the receiving phase and stirring speed (50-130 r.min ) of the bulk source and receiving phase, were explored. The efficiency of mixed solvents for the transport of metal ions from the source to receiving phase through the fiber supported solid membrane was evaluated. The combined ion exchange solvent extraction (CIESE) was observed effective for the selective transport of thallium, indium and gallium metal ions through fiber supported solid membrane in mixed solvents. The oxonium salt formation in the receiving phase enhances thallium, indium and gallium metal ion transport through solid membrane phase. The selective transport of thallium metal ions from source phase was observed from indium and gallium metal ions in the presence of hydrochloric acid in organic solvents in receiving phase. The separation of thallium metal ions from the binary mixtures of Be(II), Ti(IV), AI(III) Ca(II), Mg(II), K (I), La(III) and Y(III) was carried out in the mixed solvent system using cellulose fiber supported solid membrane.

  1. Calculating the thermodynamic characteristics of hydrophobic hydration of chromium(III) and cobalt(III) tris-acetylacetonates in water and regularities of their solvation in aqueous alcoholic solvents

    Vologdin, N. V.; Fabinskii, P. V.; Fedorov, V. A.

    2016-06-01

    Based on the scaled-particle theory, the Gibbs energy of the formation of cavities in the structure of water and some alcohols are calculated for the processes of dissolution of cobalt(III) and chromium(III) tris-acetylacetonates. The contribution from the hydrophobic hydration of the tris-acetylacetonate molecules in water is calculated. The location of the inversion area is clarified for a number of aqueous alcoholic solvents, and the effect the solvent's macrophysical parameters have on the patterns of tris-acetylacetonate solvation is analyzed.

  2. The chemistry and mechanism of thermal degradation reactions of lanthanum(III) and praseodymium(III) complexes of acetylacetone-bis(thiosemicarbazones)

    The reactions of acetylacetone with 4-phenyl, 4-(2-chlorophenyl), 4-(4-nitrophenyl) and 4-(2-methylphenyl) thiosemicarbazide yields acetylacetone-bis(thiosemicarbazone) ligands (H2L). Lanthanum(III) and praseodymium(III) complexes with these ligands of the type (Ln(L)Cl(H2O)) have been prepared. The thermal behaviour of these compounds in non-isothermal conditions was investigated using TG, DTG and DSC techniques. The intermediates obtained at the end of various thermal decomposition steps were identified from elemental analyses and infrared spectral studies. The graphical method of Coats and Redfern was employed to evaluate the kinetic parameters such as apparent activation energy and order of reaction. The heats of reaction for the different decomposition steps were calculated from DSC curves. (author)

  3. Formation of TiO/Al2O3/C Composite in Thermal Co-decomposition of Aluminium(III) Acetylacetonate and Titanium(IV) Oxyacetylacetonate.

    Kovářík, T.; Pokorná, Dana; Urbanová, Markéta; Bezdička, Petr; Bastl, Zdeněk; Kupčík, Jaroslav; Křenek, T.; Pola, M.; Kullová, L.; Pola, Josef

    2016-01-01

    Roč. 117, JAN 2016 (2016), s. 182-190. ISSN 0165-2370 R&D Projects: GA TA ČR TA04020860 Institutional support: RVO:67985858 ; RVO:61388980 ; RVO:61388955 Keywords : thermal co-decomposition * aluminium(III) acetylacetonate * titanium(IV) oxyacetylacetonate * titanium monoxide * alumina * Carbona Subject RIV: CF - Physical ; Theoretical Chemistry; CA - Inorganic Chemistry (UACH-T) Impact factor: 3.564, year: 2014

  4. Synthesis, structure, theoretical studies and luminescent properties of a ternary erbium(III) complex with acetylacetone and bathophenanthroline ligands

    A novel erbium(III) complex with acetylacetone (Hacac) and bathophenanthroline (4,7-diphenyl-1,10-phenanthroline, bath) ligands, formulated as [Er(acac)3(bath)], has been characterized by elemental analysis, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, absorption and emission spectroscopies. In the theoretical part of this study, semi-empirical quantum chemistry methods using AM1, PM3, PM6 and PM7 models have been employed to predict the structure of the complex, calculate the geometric and crystallographic parameters, and make comparisons with spectroscopic data using INDO/S-CI calculations. Real-time time-dependent density-functional theory (TDDFT) has also been used to calculate the optical absorption spectrum of the complex in the gas phase. - Highlights: • Synthesis and structure of a new erbium(III) β-diketonate complex. • TDDFT used for the first time to calculate the optical absorption spectrum. • Complex show strong near-infrared luminescence at 1.53 µm due to antenna effect

  5. Efficient alkene epoxidation catalyzed by molybdenyl acetylacetonate supported on aminated UiO-66 metal−organic framework

    Kardanpour, Reihaneh [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Tangestaninejad, Shahram, E-mail: stanges@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Mirkhani, Valiollah, E-mail: mirkhani@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Moghadam, Majid, E-mail: moghadamm@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Mohammadpoor-Baltork, Iraj; Zadehahmadi, Farnaz [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2015-03-15

    Metal–organic frameworks (MOFs) containing Mo Schiff base complexes were prepared by post-synthesis method and applied as efficient catalysts in the epoxidation of alkenes with tert-BuOOH. In this manner, UiO-66-NH{sub 2} (UiO=University of Oslo) MOF was reacted with salicylaldehyde and thiophene-2-carbaldehyde to produce bidentate Schiff bases. Then, the Schiff base ligands were used for immobilization of molybdenyl acetylacetonate. These new catalysts were characterized by FT-IR, UV–vis spectroscopic techniques, X-ray diffraction (XRD), BET, inductively coupled plasma atomic emission spectroscopy (ICP-AES) and field emission scanning electron microscopy (FE-SEM). These catalytic systems showed excellent activity in the epoxidation of alkenes such as cyclic and linear ones with tert-butyl hydroperoxide (TBHP) in 1,2-dichloroethane, and reused several times without any appreciable loss of their activity. - Graphical abstract: Efficient alkene epoxidation with TBHP catalyzed by heterogeneous and reusable molybdenum base catalysts is reported. - Highlights: • UiO-66-NH{sub 2} was modified with salicylaldehyde and thiophene-2-carbaldehyde. • The Schiff base groups were used for immobilization of MoO{sub 2}(acac){sub 2}. • The heterogeneous catalysts were prepared. • The prepared catalysts were used for epoxidation of alkenes. • Compared to other catalyst, our catalysts were more efficient and forceful.

  6. Efficient alkene epoxidation catalyzed by molybdenyl acetylacetonate supported on aminated UiO-66 metal−organic framework

    Metal–organic frameworks (MOFs) containing Mo Schiff base complexes were prepared by post-synthesis method and applied as efficient catalysts in the epoxidation of alkenes with tert-BuOOH. In this manner, UiO-66-NH2 (UiO=University of Oslo) MOF was reacted with salicylaldehyde and thiophene-2-carbaldehyde to produce bidentate Schiff bases. Then, the Schiff base ligands were used for immobilization of molybdenyl acetylacetonate. These new catalysts were characterized by FT-IR, UV–vis spectroscopic techniques, X-ray diffraction (XRD), BET, inductively coupled plasma atomic emission spectroscopy (ICP-AES) and field emission scanning electron microscopy (FE-SEM). These catalytic systems showed excellent activity in the epoxidation of alkenes such as cyclic and linear ones with tert-butyl hydroperoxide (TBHP) in 1,2-dichloroethane, and reused several times without any appreciable loss of their activity. - Graphical abstract: Efficient alkene epoxidation with TBHP catalyzed by heterogeneous and reusable molybdenum base catalysts is reported. - Highlights: • UiO-66-NH2 was modified with salicylaldehyde and thiophene-2-carbaldehyde. • The Schiff base groups were used for immobilization of MoO2(acac)2. • The heterogeneous catalysts were prepared. • The prepared catalysts were used for epoxidation of alkenes. • Compared to other catalyst, our catalysts were more efficient and forceful

  7. Phosphorescence quantum yield determination with time-gated fluorimeter and Tb(III)-acetylacetonate as luminescence reference

    Penzkofer, A., E-mail: alfons.penzkofer@physik.uni-regensburg.de [Fakultät für Physik, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg (Germany)

    2013-03-29

    Highlights: ► Procedure for absolute phosphorescence quantum yield measurement is described. ► Experimental setup for absolute luminescence quantum yield standard calibration. ► Tb(acac){sub 3} proposed as phosphorescence quantum yield reference standard. ► Luminescence quantum yield of Tb(acac){sub 3} in cyclohexane measured. ► Luminescence lifetime of Tb(acac){sub 3} in cyclohexane measured. - Abstract: Phosphorescence quantum yield measurements of fluorescent and phosphorescent samples require the use of time-gated fluorimeters in order to discriminate against the fluorescence contribution. As reference standard a non-fluorescent luminescent compound is needed for absolute phosphorescence quantum yield determination. For this purpose the luminescence behavior of the rare earth chelate terbium(III)-acetylacetonate (Tb(acac){sub 3}) was studied (determination of luminescence quantum yield and luminescence lifetime). The luminescence quantum yield of Tb(acac){sub 3} was determined by using an external light source and operating the fluorimeter in chemo/bioluminescence mode with a fluorescent dye (rhodamine 6G in methanol) as reference standard. A procedure is developed for absolute luminescence (phosphorescence) quantum yield determination of samples under investigation with a time-gated fluorimeter using a non-fluorescent luminescent compound of known luminescence quantum yield and luminescence lifetime.

  8. Indium Doped Zinc Oxide Thin Films Deposited by Ultrasonic Chemical Spray Technique, Starting from Zinc Acetylacetonate and Indium Chloride

    Rajesh Biswal

    2014-07-01

    Full Text Available The physical characteristics of ultrasonically sprayed indium-doped zinc oxide (ZnO:In thin films, with electrical resistivity as low as 3.42 × 10−3 Ω·cm and high optical transmittance, in the visible range, of 50%–70% is presented. Zinc acetylacetonate and indium chloride were used as the organometallic zinc precursor and the doping source, respectively, achieving ZnO:In thin films with growth rate in the order of 100 nm/min. The effects of both indium concentration and the substrate temperature on the structural, morphological, optical, and electrical characteristics were measured. All the films were polycrystalline, fitting well with hexagonal wurtzite type ZnO. A switching in preferential growth, from (002 to (101 planes for indium doped samples were observed. The surface morphology of the films showed a change from hexagonal slices to triangle shaped grains as the indium concentration increases. Potential applications as transparent conductive electrodes based on the resulting low electrical resistance and high optical transparency of the studied samples are considered.

  9. Iron-Mediated Homogeneous ICAR ATRP of Methyl Methacrylate under ppm Level Organometallic Catalyst Iron(III Acetylacetonate

    Jian Wu

    2016-01-01

    Full Text Available Atom Transfer Radical Polymerization (ATRP is an important polymerization process in polymer synthesis. However, a typical ATRP system has some drawbacks. For example, it needs a large amount of transition metal catalyst, and it is difficult or expensive to remove the metal catalyst residue in products. In order to reduce the amount of catalyst and considering good biocompatibility and low toxicity of the iron catalyst, in this work, we developed a homogeneous polymerization system of initiators for continuous activator regeneration ATRP (ICAR ATRP with just a ppm level of iron catalyst. Herein, we used oil-soluble iron (III acetylacetonate (Fe(acac3 as the organometallic catalyst, 1,1′-azobis (cyclohexanecarbonitrile (ACHN with longer half-life period as the thermal initiator, ethyl 2-bromophenylacetate (EBPA as the initiator, triphenylphosphine (PPh3 as the ligand, toluene as the solvent and methyl methacrylate (MMA as the model monomer. The factors related with the polymerization system, such as concentration of Fe(acac3 and ACHN and polymerization kinetics, were investigated in detail at 90 °C. It was found that a polymer with an acceptable molecular weight distribution (Mw/Mn = 1.43 at 45.9% of monomer conversion could be obtained even with 1 ppm of Fe(acac3, making it needless to remove the residual metal in the resultant polymers, which makes such an ICAR ATRP process much more industrially attractive. The “living” features of this polymerization system were further confirmed by chain-extension experiment.

  10. Effect of some d-transition metal complexes of salen-type ligands and acetylacetone on fluorescence of europium(III) and terbium(III)

    Fluorescence spectra of europium(III) and terbium(III) have been measured in methanolic solutions containing various amounts of [M(salen)] (M=Cu(II), Ni(II)), [Cr(salen)(H2O)2]Cl, [M(saltn)] (M=Cu(II), Ni(II)), [Cu(acacen)], [M(acac)2] (M=Cu(II), VIVO), [M(acac)3] (M=Cr(III), Co(III)), or [Ni(acac)2(H2O)2]. Our purpose was to investigate the influence of these metal complexes on the fluorescence of Eu(III) and Tb(III), where H2salen, H2saltn, H2acacen, and Hacac stand for N,N'-bis(salicylidene)ethylenediamine, N,N'-bis(salicylidene)-1,3-propanediamine, N,N'-bis(1-methyl-3-oxobutylidene)ethylenediamine, and acetylacetone, respectively. The fluorescence intensities of both Eu(III) and Tb(III) decreased with increasing the concentration of [M(salen)] (M=Cu, Ni), [Cr(salen)(H2O)2]Cl, [M(saltn)] (M=Cu, Ni), [Cu(acacen)], and [M(acac)3] (M=Cr, Co), whereas it was little affected by simple metal salts. The intensity of Tb(III) increased up to the addition of a given amount of [M(acac)2] (M=Cu, VO) or [Ni(acac)2(H2O)2] and then decreased on further addition, whereas the intensity of Eu(III) decreased gradually by the addition of these acetylacetonate complexes. These results are explained by the formation of heteronuclear complex species and by the stabilities of acetylacetonate complexes. (author)

  11. The comparison of 8-hydroxyquinoline, tropolone, and acetylaceton as mediators in the labelling of polymorphonuclear leucocytes with indium-111: A functional study

    Tropolone forms a lipophilic complex with indium-111 which is capable of mediating the labelling of polymorphonuclear leucocytes (PMNs) by this isotope; labelling efficiencies are comparable with the best achieved using 8-hydroxyquinoline and acetylacetone. However, in terms of PMN chemotaxis and phagocytosis, tropolone is significantly less toxic than either of the other ligands. 8-hydroxyquinoline was found to reduce PMN chemotaxis and phagocytosis to approximately 70% of the control values at a concentration of 20 μM. Tropolone may prove a superior labelling reagent. (orig.)

  12. Determination of Chromium(III), Chromium(VI), and Chromium(III) acetylacetonate in water by ion-exchange disk extraction/metal furnace atomic absorption spectrometry

    Kamakura, Nao, E-mail: minnie04_tb@yahoo.co.jp; Inui, Tetsuo; Kitano, Masaru; Nakamura, Toshihiro

    2014-03-01

    A new method for the separate determination of Chromium(III) (Cr(III)), Chromium(VI) (Cr(VI)), and Cr(III) acetylacetonate (Cr(acac){sub 3}) in water was developed using a cation-exchange extraction disk (CED) and an anion-exchange extraction disk (AED) combined with metal furnace atomic absorption spectrometry (MFAAS). A 100-mL water sample was adjusted to pH 5.6 and passed through the CED placed on the AED. Cr(acac){sub 3} and Cr(III) were adsorbed on the CED, and Cr(VI) was adsorbed on the AED. The adsorbed Cr(acac){sub 3} was eluted with 50 mL of carbon tetrachloride, followed by the elution of Cr(III) with 50 mL of 3 mol L{sup −1} nitric acid. Cr(VI) was eluted with 50 mL of 3 mol L{sup −1} nitric acid. The chemical species of Cr eluted from the CED with carbon tetrachloride was identified as Cr(acac){sub 3} using infrared spectroscopy. The eluate of Cr(acac){sub 3} was diluted to 100 mL with carbon tetrachloride, and those of Cr(III) and Cr(VI) were diluted to 100 mL with deionized water. All of the solutions were subsequently analyzed by MFAAS. The calibration curve for the Cr(acac){sub 3} aqueous solutions exhibited good linearity in the range of 0.1 to 1 ng. The detection limit of Cr, which corresponded to three times the standard deviation (n = 10) of the blank values, was 20 pg. The recovery test for Cr(III), Cr(VI), and Cr(acac){sub 3} exhibited desirable results (96.0%–107%) when 5 μg of each species (50 μg L{sup −1}) was added to 100 mL water samples (i.e., tap water, rainwater, and bottled drinking water). In a humic acid solution, Cr(acac){sub 3} was quantitatively recovered (103%), but Cr(III) and Cr(VI) exhibited poor recoveries (i.e., 84.8% and 78.4%, respectively). - Highlights: • A determination method of Cr(III), Cr(VI), and Cr(III) acetylacetonate in water was developed. • The combination of ion-exchange resin disks with metal furnace AAS was used. • No effect of humic acid on the recovery of Cr(III) acetylacetonate was

  13. Determination of Chromium(III), Chromium(VI), and Chromium(III) acetylacetonate in water by ion-exchange disk extraction/metal furnace atomic absorption spectrometry

    A new method for the separate determination of Chromium(III) (Cr(III)), Chromium(VI) (Cr(VI)), and Cr(III) acetylacetonate (Cr(acac)3) in water was developed using a cation-exchange extraction disk (CED) and an anion-exchange extraction disk (AED) combined with metal furnace atomic absorption spectrometry (MFAAS). A 100-mL water sample was adjusted to pH 5.6 and passed through the CED placed on the AED. Cr(acac)3 and Cr(III) were adsorbed on the CED, and Cr(VI) was adsorbed on the AED. The adsorbed Cr(acac)3 was eluted with 50 mL of carbon tetrachloride, followed by the elution of Cr(III) with 50 mL of 3 mol L−1 nitric acid. Cr(VI) was eluted with 50 mL of 3 mol L−1 nitric acid. The chemical species of Cr eluted from the CED with carbon tetrachloride was identified as Cr(acac)3 using infrared spectroscopy. The eluate of Cr(acac)3 was diluted to 100 mL with carbon tetrachloride, and those of Cr(III) and Cr(VI) were diluted to 100 mL with deionized water. All of the solutions were subsequently analyzed by MFAAS. The calibration curve for the Cr(acac)3 aqueous solutions exhibited good linearity in the range of 0.1 to 1 ng. The detection limit of Cr, which corresponded to three times the standard deviation (n = 10) of the blank values, was 20 pg. The recovery test for Cr(III), Cr(VI), and Cr(acac)3 exhibited desirable results (96.0%–107%) when 5 μg of each species (50 μg L−1) was added to 100 mL water samples (i.e., tap water, rainwater, and bottled drinking water). In a humic acid solution, Cr(acac)3 was quantitatively recovered (103%), but Cr(III) and Cr(VI) exhibited poor recoveries (i.e., 84.8% and 78.4%, respectively). - Highlights: • A determination method of Cr(III), Cr(VI), and Cr(III) acetylacetonate in water was developed. • The combination of ion-exchange resin disks with metal furnace AAS was used. • No effect of humic acid on the recovery of Cr(III) acetylacetonate was observed. • The proposed method enabled the determination of three Cr

  14. A non-empirical LCAO MO SCF and experimental investigation on the core-ionized states of acetylacetone and some of its enol tautomers

    Non-empirical LCAO MO SCF calculations have been performed on the ground and core-hole states of acetylacetone for a range of geometries. The theoretical studies have been complemented by gas-phase ESCA studies of both the O 1s and C 1s core levels. A comparison of the theoretical and experimental data shows excellent agreement for an unsymmetrical Csub(s) enol structure and a discussion is given of the low-energy shake-up satellites accompanying both C 1s and O 1s core ionization. Consideration is also given to the relative energies of the various tautomeric model systems as a function of the hole states. (orig.)

  15. Molybdenum oxide catalysts for metathesis of higher 1-alkenes via supporting MoO2(acetylacetonate)2 and MoO2(glycolate)2 on SBA-15 mesoporous molecular sieves

    Balcar, Hynek; Mishra, D.; Marceau, E.; Carrier, X.; Žilková, Naděžda; Bastl, Zdeněk

    2009-01-01

    Roč. 359, 1-2 (2009), s. 129-135. ISSN 0926-860X R&D Projects: GA MŠk MEB020723; GA AV ČR IAA400400805; GA AV ČR KAN100400701 Institutional research plan: CEZ:AV0Z40400503 Keywords : 1-alkene metathesis * Mo heterogeneous catalysts * Molybdenum dioxide bis(acetylacetonate) * Molybdenum dioxide bis(glycolate) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.564, year: 2009

  16. Thermal co-decomposition of silver acetylacetonate and tin(II) hexafluoroacetylacetonate: Formation of carbonaceous Ag/AgxSn(x = 4 and 6.7)/SnO2 composites

    Highlights: • Ag acetylacetonate increases thermal stability by mixing with Sn hexafluoroacetylacetonate. • Heated mixture of chelates yields a residue containing Ag, Sn, O and C elements. • Residues obtained at higher temperature contain Ag–Sn intermetallic compounds. - Abstract: Thermal co-decomposition of silver(I) acetylacetonate and tin(II) hexafluoroacetylacetonate has been examined by using thermal gravimetry, differential scanning calorimetry and complementary analyses of gaseous products and solid residues by Fourier transform infrared and Raman spectroscopy, X-ray diffraction and scanning electron microscopy. It is revealed that poorly stable silver(I) acetylacetonate mixed with tin(II) hexafluoroacetylacetonate does not undergo thermal decomposition at around 120 °C, but takes part in a room-temperature solid-state interaction with the Sn counterpart, which is ensued by an exothermal process at 109 °C and subsequent co-decomposition involving a pronounced stage at around 275 °C. All steps lead to carbonaceous Ag/SnO2 composites containing crystalline Ag at 200 °C, Ag and SnO2 at 400 °C, and Ag, SnO2, Ag4Sn and Ag6.7Sn at 600 °C. The intermetallic Ag6.7Sn compound is judged to arise from nanostructured environment of alloying Ag and Sn

  17. Surface chemistry of copper metal and copper oxide atomic layer deposition from copper(ii) acetylacetonate: a combined first-principles and reactive molecular dynamics study.

    Hu, Xiao; Schuster, Jörg; Schulz, Stefan E; Gessner, Thomas

    2015-10-28

    Atomistic mechanisms for the atomic layer deposition using the Cu(acac)2 (acac = acetylacetonate) precursor are studied using first-principles calculations and reactive molecular dynamics simulations. The results show that Cu(acac)2 chemisorbs on the hollow site of the Cu(110) surface and decomposes easily into a Cu atom and the acac-ligands. A sequential dissociation and reduction of the Cu precursor [Cu(acac)2 → Cu(acac) → Cu] are observed. Further decomposition of the acac-ligand is unfavorable on the Cu surface. Thus additional adsorption of the precursors may be blocked by adsorbed ligands. Molecular hydrogen is found to be nonreactive towards Cu(acac)2 on Cu(110), whereas individual H atoms easily lead to bond breaking in the Cu precursor upon impact, and thus release the surface ligands into the gas-phase. On the other hand, water reacts with Cu(acac)2 on a Cu2O substrate through a ligand-exchange reaction, which produces gaseous H(acac) and surface OH species. Combustion reactions with the main by-products CO2 and H2O are observed during the reaction between Cu(acac)2 and ozone on the CuO surface. The reactivity of different co-reactants toward Cu(acac)2 follows the order H > O3 > H2O. PMID:26399423

  18. Optimization of the Energy Level Alignment between the Photoactive Layer and the Cathode Contact Utilizing Solution-Processed Hafnium Acetylacetonate as Buffer Layer for Efficient Polymer Solar Cells.

    Yu, Lu; Li, Qiuxiang; Shi, Zhenzhen; Liu, Hao; Wang, Yaping; Wang, Fuzhi; Zhang, Bing; Dai, Songyuan; Lin, Jun; Tan, Zhan'ao

    2016-01-13

    The insertion of an appropriate interfacial buffer layer between the photoactive layer and the contact electrodes makes a great impact on the performance of polymer solar cells (PSCs). Ideal interfacial buffer layers could minimize the interfacial traps and the interfacial barriers caused by the incompatibility between the photoactive layer and the electrodes. In this work, we utilized solution-processed hafnium(IV) acetylacetonate (Hf(acac)4) as an effective cathode buffer layer (CBL) in PSCs to optimize the energy level alignment between the photoactive layer and the cathode contact, with the short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) all simultaneously improved with Hf(acac)4 CBL, leading to enhanced power conversion efficiencies (PCEs). Ultraviolet photoemission spectroscopy (UPS) and scanning Kelvin probe microscopy (SKPM) were performed to confirm that the interfacial dipoles were formed with the same orientation direction as the built-in potential between the photoactive layer and Hf(acac)4 CBL, benefiting the exciton separation and electron transport/extraction. In addition, the optical characteristics and surface morphology of the Hf(acac)4 CBL were also investigated. PMID:26684416

  19. Growth behavior and properties of atomic layer deposited tin oxide on silicon from novel tin(II)acetylacetonate precursor and ozone

    In this work, a novel liquid tin(II) precursor, tin(II)acetylacetonate [Sn(acac)2], was used to deposit tin oxide films on Si(100) substrate, using a custom-built hot wall atomic layer deposition (ALD) reactor. Three different oxidizers, water, oxygen, and ozone, were tried. Resulting growth rates were studied as a function of precursor dosage, oxidizer dosage, reactor temperature, and number of ALD cycles. The film growth rate was found to be 0.1 ± 0.01 nm/cycle within the wide ALD temperature window of 175–300 °C using ozone; no film growth was observed with water or oxygen. Characterization methods were used to study the composition, interface quality, crystallinity, microstructure, refractive index, surface morphology, and resistivity of the resulting films. X-ray photoelectron spectra showed the formation of a clean SnOx–Si interface. The resistivity of the SnOx films was calculated to be 0.3 Ω cm. Results of this work demonstrate the possibility of introducing Sn(acac)2 as tin precursor to deposit conducting ALD SnOx thin films on a silicon surface, with clean interface and no formation of undesired SiO2 or other interfacial reaction products, for transparent conducting oxide applications

  20. Synthesis, interactions, molecular structure, biological properties and molecular docking studies on Mn, Co, Zn complexes containing acetylacetone and pyridine ligands with DNA duplex.

    Thamilarasan, V; Sengottuvelan, N; Stalin, N; Srinivasan, P; Chakkaravarthi, G

    2016-07-01

    Three metal complexes (1-3) of the type [Mn(acac)2(py)·H2O] (1), [Co(acac)2(py)·H2O] (2) and [Zn(acac)2(py)·H2O] (3), [Where acac=acetylacetone, py=pyridine] were synthesized and characterized by spectral (UV-vis, FT-IR, ESI-mass) analysis. The structure of complex 2 has been determined by single crystal X-ray diffraction studies and the configuration of ligand-coordinated to metal(II) ion was well described as distorted octahedral coordination geometry. The interaction of the complexes with CT-DNA has been explored by absorption, fluorescence, circular dichromism spectroscopy, viscosity measurements and molecular docking studies. The intrinsic binding constant Kb of complexes 1-3 with CT-DNA obtained from UV-vis absorption spectral studies were 2.1×10(4), 2.1×10(5) and 1.98×10(4)M(-1), respectively, which revealed that the complexes could interact with CT-DNA through groove binding. The results indicated that the complexes (1-3) were able to bind to DNA with different binding affinity, in the order: 2>1>3. The interaction of the compounds with bovine serum albumins were also investigated using fluorescence methods and the gel electrophoresis assay demonstrates weak cleavage ability of the pBR322 plasmid DNA in the presence of the metal complexes (1-3) with various activators. Further, the in vitro cytotoxic effect of the complexes were examined on cancerous cell line, with human breast cancer cells MCF-7. PMID:27104666

  1. Determination of formaldehyde in vegetables by acetylacetone spectrophotometry%测定蔬菜中的甲醛的乙酰丙酮分光光度法

    张以春

    2012-01-01

    目的 优化测定蔬菜中甲醛含量的实验条件.方法 采用浸泡法对蔬菜样品中的甲醛进行提取,利用甲醛与乙酰丙酮及氨反应生成黄色化合物通过分光光度法检测甲醛浓度.结果 方法线性范围为0.2~3.2 mg/L,线性方程为y =0.011x+0.018,相关系数为0.999 8,对4种蔬菜样品进行6次平行测定,RSD为2.37%~ 8.22%,对豇豆测定回收率为90% ~ 96%.结论 该法快速、准确、重现性好,适用于蔬菜样品中的甲醛检测.%[ Objective ] To optimize experimental conditions for the analysis of the formaldehyde content in the vegetables. [ Methods ] Formaldehyde was extracted by soaking the vegetable samples. The yellow compound which was generated by formaldehyde and acetylacetone with ammonia was detected by spectrophotometry. [ Results] The linear range was 0. 2-3. 2 mg/L. The linear equation was y = 0. 011 x + 0. 018 , and the correlation coefficient was 0. 999 8. Four kinds of vegetable samples were determined for 6 times. The RSD was 2. 37%-78. 22% . The recovery of cowpea was 90%-96%. [Conclusion]This method is rapid, accurate, reproducible, and suitable for detection of formaldehyde in vegetable samples.

  2. Determination of Chromium(III), Chromium(VI), and Chromium(III) acetylacetonate in water by ion-exchange disk extraction/metal furnace atomic absorption spectrometry

    Kamakura, Nao; Inui, Tetsuo; Kitano, Masaru; Nakamura, Toshihiro

    A new method for the separate determination of Chromium(III) (Cr(III)), Chromium(VI) (Cr(VI)), and Cr(III) acetylacetonate (Cr(acac)3) in water was developed using a cation-exchange extraction disk (CED) and an anion-exchange extraction disk (AED) combined with metal furnace atomic absorption spectrometry (MFAAS). A 100-mL water sample was adjusted to pH 5.6 and passed through the CED placed on the AED. Cr(acac)3 and Cr(III) were adsorbed on the CED, and Cr(VI) was adsorbed on the AED. The adsorbed Cr(acac)3 was eluted with 50 mL of carbon tetrachloride, followed by the elution of Cr(III) with 50 mL of 3 mol L- 1 nitric acid. Cr(VI) was eluted with 50 mL of 3 mol L- 1 nitric acid. The chemical species of Cr eluted from the CED with carbon tetrachloride was identified as Cr(acac)3 using infrared spectroscopy. The eluate of Cr(acac)3 was diluted to 100 mL with carbon tetrachloride, and those of Cr(III) and Cr(VI) were diluted to 100 mL with deionized water. All of the solutions were subsequently analyzed by MFAAS. The calibration curve for the Cr(acac)3 aqueous solutions exhibited good linearity in the range of 0.1 to 1 ng. The detection limit of Cr, which corresponded to three times the standard deviation (n = 10) of the blank values, was 20 pg. The recovery test for Cr(III), Cr(VI), and Cr(acac)3 exhibited desirable results (96.0%-107%) when 5 μg of each species (50 μg L- 1) was added to 100 mL water samples (i.e., tap water, rainwater, and bottled drinking water). In a humic acid solution, Cr(acac)3 was quantitatively recovered (103%), but Cr(III) and Cr(VI) exhibited poor recoveries (i.e., 84.8% and 78.4%, respectively).

  3. Continuous extraction of vanadium(V) and iron(III) with acetylacetone under high-speed stirring with Teflon phase separator

    A continuous extraction system consisting of a distillation flask, an extraction flask (Morton flask) containing a high speed stirrer and a Teflon phase separator was investigated. The utility of the system was examined by the separation and concentration of V(V) and Fe(III) with acetylacetone(AA). m-Xylene was selected as the extraction solvent because distillation took place at about 140degC. Fe(III) was easily extracted into the organic solvent with AA. On the other hand, V(V) was not extracted with AA without adding pentyl alcohol. Therefore, V(V) was extracted by the synergism between AA and pentyl alcohol. The effect of stirring speed was examined on the extractions of V(V) and Fe(III). The recommended procedure for the stepwise determination of V(V) and Fe(III) was as follows: A solvent mixture of m-xylene (15cm3) and AA (1cm3) was added to the sample solution (50cm3, pH 4) containing Fe(III) and V(V) in the Morton flask (200cm3) containing a stirring rod and a Teflon phase separator. The stirring speed was kept at 1800rpm. The rate of solvent-transport by the Peristaltic pump was regulated at 1.6cm3/min. The extraction was stopped after 30min and the distillation flask containing the concentrate for Fe(III) analysis was removed. The distillation flask in the extraction-apparatus was then exchanged and 1cm3 of pentyl alcohol and 0.5cm3 of AA were added to the extraction solvent in the Morton flask. Subsequently, 1cm3 of 8 mol dm-3 HCl solution was added in order to adjust the pH to 2.5. The extraction was then performed again. After 60min, the absorbance of the concentrated extract was measured at 449nm after dilution to 10cm3 with m-xylene. Similarly, the amount of Fe(III) in the previous flask was determined at 437nm. The metal ions were quantitatively extracted by the proposed method. The extractability of V(V) by this batch method was 63%. The determination ranges of V(V) and Fe(III) were 20-100 μg and 10-80 μg, respectively. (author)

  4. Nanoparticle Synthesis from Cobalt Acetylacetonate

    Moravec, Pavel; Smolík, Jiří; Levdansky, V.V.; Bakardjieva, Snejana

    Helsinki : -, 2010, P2J35. ISBN N. [International Aerosol Conference IAC 2010. Helsinki (FI), 29.08.2010-03.09.2010] R&D Projects: GA ČR GA104/07/1093 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502 Keywords : hot wall reactor * nanoparticle generation * mocvd Subject RIV: CF - Physical ; Theoretical Chemistry www.iac2010.fi

  5. Synthesis, characterisation and electrochemical behaviour of Cu(II), Co(II), Ni(II) and Zn(II) complexes derived from acetylacetone and p-anisidine and their antimicrobial activity

    N Raman; V Muthuraj; S Ravichandran; A Kulandaisamy

    2003-06-01

    Neutral tetradentate N2O2 type complexes of Cu(II), Ni(II), Co(II) and Zn(II) have been synthesised using the Schiff base formed by the condensation of acetylacetone and p-anisidine. Microanalysis, molar conductance, magnetic susceptibility, IR, UV-Vis, 1H NMR, CV and EPR studies have been carried out to determine the structure of the complexes. From the data, it is found that all the complexes possess square-planar geometry. The EPR spectrum of the copper complex in DMSO at 300 K and 77 K was recorded and its salient features are reported. All the title complexes were screened for antimicrobial activity by the well diffusion technique using DMSO as solvent. The minimum inhibitory concentration (MIC) values were calculated at 37°C for a period of 24 h. It has been found that all the complexes are antimicrobially active and show higher activity than the free ligand.

  6. Efeito da concentração do catalisador acetilacetonato férrico na cura de poliuretano à base de polibutadieno líquido hidroxilado (PBLH) e diisocianato de isoforona (IPDI) Effect of ferric acetylacetonate catalyst concentration on the cure of polyurethane based on hydroxy terminated polybutadiene and isophorone diisocyanate

    Willian César Paterlini; Edson Cocchieri Botelho; Luís Cláudio Rezende; Vera Lucia Lourenço; Mirabel Cerqueira Rezende

    2002-01-01

    The reaction between hydroxy-terminated polybutadiene and isophorone diisocyanate constitutes the base of the curing process of the most composite solid propellant used in the propulsion of solid rocket propellant. In this work, differential scanning calorimetry and viscosity measurements were used to evaluate the effect of the ferric acetylacetonate catalyst concentration on the reaction between HTBR and IPDI. These analyses show one exotherm, which shifts to lower temperatures as the cataly...

  7. Radiation induced synthesis of In{sub 2}O{sub 3} nanoparticles - Part II: Synthesis of In{sub 2}O{sub 3} nanoparticles by thermal decomposition of un-irradiated and γ-irradiated indium acetylacetonate

    Al-Resheedi, Ajayb Saud; Alhokbany, Norah Saad [Department of Chemistry, College of Science, King Saud University, KSU, (Saudi Arabia); Mahfouz, Refaat Mohammed, E-mail: rmhfouz@science.au.edu.eg [Chemistry Department, Faculty of Science, Assiut University, AUN, (Egypt)

    2015-09-15

    Pure cubic phase, In{sub 2}O{sub 3} nanoparticles with porous structure were synthesized by solid state thermal oxidation of un-irradiated and γ-irradiated indium acetyl acetonate in presence and absence of sodium dodecyl sulphate as surfactant. The as- synthesized In{sub 2}O{sub 3} nanoparticles were characterized by X-ray diffraction (XRD), fourier transformation infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transition electron microscopy (TEM) and thermogravimetry (TG). The shapes and morphologies of as- synthesized In{sub 2}O{sub 3} nanoparticles were highly affected by γ-irradiation of indium acetyl acetonate precursor and by addition of sodium dodecyl sulphate as surfactant. Calcination of un-irradiated indium acetyl acetonate precursor to 4 hours of 600 °C leads to the formation of spherical- shaped accumulative and merged In{sub 2}O{sub 3} nanoparticles with porous structure, whereas irregular porous architectures composed of pure In{sub 2}O{sub 3} nanoparticles were obtained by using γ-irradiated indium acetylacetonate precursor. The as- prepared In{sub 2}O{sub 3} nano products exhibit photoluminescence emission (PL) property and display thermal stability in a wide range of temperature (25-800 °C) which suggest possible applications in nanoscale optoelectronic devices. (author)

  8. Efeito da concentração do catalisador acetilacetonato férrico na cura de poliuretano à base de polibutadieno líquido hidroxilado (PBLH e diisocianato de isoforona (IPDI Effect of ferric acetylacetonate catalyst concentration on the cure of polyurethane based on hydroxy terminated polybutadiene and isophorone diisocyanate

    Willian César Paterlini

    2002-05-01

    Full Text Available The reaction between hydroxy-terminated polybutadiene and isophorone diisocyanate constitutes the base of the curing process of the most composite solid propellant used in the propulsion of solid rocket propellant. In this work, differential scanning calorimetry and viscosity measurements were used to evaluate the effect of the ferric acetylacetonate catalyst concentration on the reaction between HTBR and IPDI. These analyses show one exotherm, which shifts to lower temperatures as the catalyst concentration increases. The viscosity analyses show that the increase of temperature causes, at first, a reduction in the mixture viscosity, reaching a minimum range called gelification region (increasing the crosslinking density.

  9. Nanoparticle Synthesis from Manganese(II) Acetylacetonate

    Moravec, Pavel; Smolík, Jiří; Bakardjieva, Snejana; Levdansky, V.V.

    - : -, 2012, P281. [European Aerosol Confrernce EAC 2012. Granada (ES), 02.09.2012-07.09.2012] R&D Projects: GA ČR GA104/07/1093; GA ČR(CZ) GAP503/11/2315; GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:67985858 Keywords : nanoparticle generation * metal organic CVD * hot wall tube reactor Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.eac2012.com/EAC2012Book/3.html

  10. Synthesis and characterization of tetraphenylporphyrinate of dysprosium route dysprosium acetylacetonate

    Dysprosium bis (tetraphenylporphyrinate) and bis (dysprosium) Tris (tetraphenylporphyrinate) were synthesized from dysprosium tetraphenylporphyrinate prepared in situ, and characterized by IR, UV-vis, TGA, DTA, EPR and magnetic susceptibility measurements. The double decker compound was obtained by direct oxidation of the HDy(TPP)2 intermediate. The existence of the radical anion, (TPP)- , in the double decker product was conformed by EPR spectrometry. Dysprosium monoporphyrinate was isolated and characterized by the same techniques. (Author)

  11. Metal-Acetylacetonate Synthesis Experiments: Which Is Greener?

    Ribeiro, M. Gabriela T. C.; Machado, Adlio A. S. C.

    2011-01-01

    A procedure for teaching green chemistry through laboratory experiments is presented in which students are challenged to use the 12 principles of green chemistry to review and modify synthesis protocols to improve greenness. A global metric, green star, is used in parallel with green chemistry mass metrics to evaluate the improvement in greenness.…

  12. Influence of Acetylacetone on Photocatalytic Properties of TiO2 Thin Films Deposited on PMMA Substrates%乙酰丙酮对PMMA负载锐钛矿型TiO2薄膜及其光催化性能影响

    张志清; 黄剑锋; 曹丽云; 吴建鹏

    2011-01-01

    The nanociystalline TiO2 solution was prepared using a microwave hydrotheimal process to treat precursor liquid which was obtained by control the hydrolysis of titanium-n-butoxide in the presence of excessive water and acetylacetone (AcAcH). Then nanociystalline TiO2 thin films were deposited on polymethylmethacrylate (PMMA) substrates by dip-coating process from TiO2 colloidal solution. The phase composition of TiO2 nanoparticles, morphologies and optical properties of TiO2 thin films deposited on PMMA substrates were characterized by X-ray diffraction (XRD), fourier transform infrared spectrometer (FTTR), transmission electron microscope (TEM), atomic force microscopy (AFM) and UV-vis spectroscopy. Meanwhile photocatalytic properties of TiO2 films were investigated by degradation of Rhodamine B ( RhB) under ultraviolet radiation. Trie results indicate that anatase TiO2 colloidal solution modified by AcAcH is disperse, uniform, deposit-free and the deposited TiO2 thin films are transparent, homogeneous and compact, and show high efficiency of photocatalysis. Rhodamine B has been degradated over 90% at 180 min%以钛酸丁酯作为钛源,水为溶剂,乙酰丙酮(AcAcH)为表面修饰剂,采用微波水热辅助溶胶-凝胶法制备了纳米晶二氧化钛水溶液,利用提拉镀膜法在聚合物聚甲基丙烯酸甲酯(PMMA)基板上沉积得到了透明TiO2纳米晶薄膜.通过X射线衍射(XRD)、红外光谱(FTIR)、透射电子显微镜(TEM)、原子力显微镜(AFM)和紫外-可见光吸收光谱(UV-Vis)等对TiO2纳米颗粒和薄膜的晶相组成、表面形貌及光学性能进行表征.同时通过紫外光光催化降解罗丹明B研究了TiO2薄膜的光催化性能.结果表明:通过引入乙酰丙酮,可以得到高度分散、晶相为锐钛矿型的TiO2水溶胶,在PMMA基板上沉积得到的薄膜表面平整、致密,具有良好的透光率,经过180 min紫外光照射,对罗丹明B的降解率达到90%以上.

  13. NiOx Nanoparticle Synthesis by Chemical Vapor Deposition from Nickel Acetylacetonate

    Moravec, Pavel; Smolík, Jiří; Keskinen, H.; Mäkelä, J.M.; Bakardjieva, Snejana; Levdansky, V.V.

    2011-01-01

    Roč. 2, č. 4 (2011), s. 258-264. ISSN 2153-117X R&D Projects: GA ČR GA104/07/1093 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502 Keywords : electron diffraction * nickel nanostructures * hot wall tube reactor Subject RIV: CF - Physical ; Theoretical Chemistry http://www.scirp.org/journal/msa/

  14. Nanoparticle Formation by Thermal Decomposition and Oxidation of Manganese(II) Acetylacetonate

    Moravec, Pavel; Smolík, Jiří; Bakardjieva, Snejana; Levdansky, V.V.

    Praha : Česká aerosolová společnost, 2012 - (Vodička, P.; Zíková, N.), s. 39-42 ISBN 978-80-86186-40-5. [Výroční konference České aerosolové společnosti /13./. Třeboň (CZ), 25.10.2012-26.10.2012] R&D Projects: GA ČR GA104/07/1093; GA ČR(CZ) GAP503/11/2315; GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:67985858 ; RVO:61388980 Keywords : nanoparticle generation * metal organic cvd * hot wall tube reactor Subject RIV: CF - Physical ; Theoretical Chemistry; DN - Health Impact of the Environment Quality (UACH-T)

  15. Studies in technetium chemistry, Project 1: Evaluation of technetium acetylacetonates as potential cerebral blood flow agents, Project 2

    Although the emphasis in our original submission was on N2S2 and N3S coordinating ligands in technetium(V), we have now broadened the chemistry studies into areas that encompass new systems that allow the generation of neutral complexes. This change was based upon developments that have taken place in our basic chemistry studies that could bear on one of the original aims of this work, i.e., the design of complexes designed to penetrate cellular membranes and to remain trapped in target tissues. Among these topics are oxotechnetium(V) complexes containing amine and alcoholate ligands, coordination compounds containing the alternative technetium(V) nitrido core and the synthesis at macroscopic levels of a tetradentate ''umbrella'' ligand that successfully binds the metal. Basic studies with the original bisamide-bisthiol ligand system have continued with the identification of the products formed when aqueous solutions of the complex [TcO(ema)]- are acidified. This material is isolatable as yellow/brown crystals when HCl is added to the tetraphenylarsonium salt of the complex synthesized according to published procedures. Elemental analysis, FAB(+) mass spectrometry and 1H NMR results were consistent with the formulation TcO(ema)H. Infrared spectra showed a dramatic shift in the Tc = O stretch to 966 cm-1, as distinct from 945 cm-1 in the original complex

  16. Effect of polyethylene glycol and crown ether additives on the decomposition of cyclohexenyl hydroperoxide in the presence of vanadyl acetylacetonate

    This paper investigates the kinetic characteristics of the VO (AcAc)2catalyzed liquid-phase decomposition of cyclohexenyl hydroperoxide in the presence of additives (A), such as polyethylene glycol (PEG) and a crown ether. The reaction occurs via the formation of a complex of the type (A...VO(AcAc)2). The rate constants for complex formation, as well as for hydroperoxide decomposition in the presence of this complex, have been determined. The differences in the calculated values of these constants have been attributed to contributions of the energy of nonequilibrium conformations of the PEG polymer chain to the rates of catalysis

  17. Corrigendum to "Electronic structure and photoelectron spectra of nickel (II) acetylacetonate and its thio- and amino-substituted analogues" [J. Mol. Struct. 1099 (2015) 579-587

    Vovna, Vitaliy I.; Korochentsev, Vladimir V.; Komissarov, Alexander A.; L'vov, Igor B.; Myshakina, Nataliya S.

    2016-01-01

    The authors regret to inform that it was given erroneous spelling of Vitaliy I. Vovna author name in the published version of the article. It was written "Vitaliy V. Vovna" instead of "Vitaliy I. Vovna".

  18. The Triruthenium Complex [{(acac)(2)Ru-II}(3)(L)] Containing a Conjugated Diquinoxaline[2,3-a : 2 '',3 ''-c]phenazine (L) Bridge and Acetylacetonate (acac) as Ancillary Ligands. Synthesis, Spectroelectrochemical and EPR Investigation

    Patra, S.; Sarkar, B.; Ghumaan, S.; Fiedler, Jan; Kaim, W.; Lahiri, G. K.

    -, č. 5 (2004), s. 754-758. ISSN 1477-9226 R&D Projects: GA MŠk OC D14.20; GA MŠk OC D15.10 Institutional research plan: CEZ:AV0Z4040901 Keywords : nonlinear-optical properties * electrochemical properties * spectroelectrochemistry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.926, year: 2004

  19. Thermal Co-Decomposition of Silver Acetylacetonate and Tin (II) Hexafluoroacetylacetonate: Formation of Carbonaceous Ag/AgxSn(x=4 and 6.7)/SnO2 Composites

    Křenek, T.; Duchek, P.; Urbanová, Markéta; Pokorná, Dana; Bezdička, Petr; Jakubec, Ivo; Pola, M.; Čerstvý, R.; Kovářík, T.; Galíková, Anna; Pola, Josef

    2013-01-01

    Roč. 566, AUG 20 (2013), s. 92-99. ISSN 0040-6031 Grant ostatní: GA MŠK(CZ) CZ1.05/2.1.00/03.0088 Institutional support: RVO:67985858 ; RVO:61388980 Keywords : co-decomposition * thermal gravimetric analysis * Ag-Sn intermetallic compounds Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.105, year: 2013

  20. Preparation and characterization of technetium complexes with Schiff base and phosphine coordination. 1. complexes of technetium-99g and -99m with substituted acac2en and trialkyl phosphines (where acac2en N,N'-ethylenebis[acetylacetone iminato])

    A series of 23 technetium(III) complexes of the type [TcL(PR3)2]+, where L represents a tetradentate Schiff base ligand in the equatorial plane and PR3 represents the axial phosphine ligands, are reported. Full ligand syntheses and characterizations are included. The technetium complexes were prepared with 99mTc to study the organ distribution in guinea pigs at 5 and 60 min postinjection. Four prototypical complexes of the series were also prepared with either 99gTc or 99gTc/99mTc (designated as carrier-added) to allow macroscopic characterization. Equivalence of the 99gTc and 99mTc complexes was demonstrated by dual detection high performance liquid chromatography (HPLC) techniques. The development of a one-step preparation from the standard two-step method is discussed for some complexes. Biodistribution data are related to structure and lipophilicity. None of the complexes in the series exhibited a tendency for in vivo reduction. Myocardial uptake was favorable for a number of complexes. The optimal agent from this series for further imaging development was chosen based on myocardial uptake, rapid blood and liver clearance, and ability to be formulated as a one-step kit

  1. Narrow bandgap host material for high quantum efficiency yellow phosphorescent organic light-emitting diodes doped with iridium(III) bis(4-phenylthieno[3,2-c]pyridine)acetylacetonate

    Yook, Kyoung Soo; Lee, Jun Yeob, E-mail: leej17@skku.edu

    2015-05-15

    A narrow bandgap host material, 4,5-di(9H-carbazol-9-yl)phthalonitrile (2CzPN), was used as a bipolar host material to improve the device performances of yellow phosphorescent organic light-emitting diodes(PHOLEDs). The device performances of the yellow PHOLEDs were optimized at a low doping concentration of 1%. A low turn-on voltage of 3.0 V and high quantum efficiency of 19.3% were achieved using the 2CzPN host material and no efficiency roll-off of the device was observed up to 1000 cd/m{sup 2} compared with 25% of reference device. - Highlights: • High quantum efficiency in yellow phosphorescent organic light-emitting diodes. • Narrow bandgap host material with donor–acceptor structure for low driving voltage. • Low optimum doping concentration of 1% for high quantum efficiency and power efficiency.

  2. An investigation of tautomeric equilibria by means of mass spectrometry

    Zamir, Lolita; Jensen, Bror Skytte; Larsen, Elfinn

    1969-01-01

    Changes in the mass spectra with inlet temperature were used in this work to demonstrate the dependence of keto-enol tautomerism of acetylacetone, 3-methyl acetylacetone and 3-allyl acetylacetone on temperature. The largest dependence of temperature were shown by the ion [M 42]+. arising from a M...

  3. Ultrasound-assisted dealumination of zeolite Y

    M Hosseini; M A Zanjanchi; B Ghalami-Choobar; H Golmojdeh

    2015-01-01

    We demonstrate a new procedure for dealumination of zeolite Y. The method employs a 28 KHz ultrasound bath and an ethanolic acetylacetone solution. Acetylacetone was used as chelating agent and ultrasound irradiation was used as extraction intensifier. Four types of samples, as-synthesized, ammoniumexchanged, acidic and neutralized zeolite were used for dealumination. Parts of the framework aluminumatoms are removed from their sites in the structure of zeolite Y upon the use of either acetylacetone on its own or simultaneous use of acetylacetone and ultrasound waves. Higher dealumination was observed for those samples subjected to both ultrasound irradiation and acetylacetone extraction.

  4. Structure of alumina supported vanadia catalysts for oxidative dehydrogenation of propane prepared by flame spray pyrolysis

    Høj, Martin; Jensen, Anker Degn; Grunwaldt, Jan-Dierk

    2013-01-01

    A series of five vanadia on alumina catalysts for oxidative dehydrogenation of propane to propene were synthesized by flame spray pyrolysis (FSP) using vanadium(III)acetylacetonate and aluminium(III)acetylacetonate dissolved in toluene as precursors. The vanadium loading was 2, 3, 5, 7.5 and 10wt...

  5. Asymmetric Synthesis of ( - ) -(2R, 3R, 6S ) -Irnigaine

    MA, Nan; MA, Da-Wei

    2003-01-01

    Asymmetric synthesis of irnigaine was achieved starting from an enantiopure β-amino ester 5 using the condensation of amino alcohol 2 with acetylacetone and the subsequent intramolecular cyclization as the key steps.

  6. Characterization of tetraketone ligands for active materials of all-uranium redox flow battery

    For active materials of the all-uranium redox flow battery for power storage, two tetraketone ligands, which possess two monomer acetylacetone moieties, were investigated in terms of the complexation with uranium. Detailed NMR measurements were conducted to reveal the keto-enol tautomerism of the tetraketones in CDCl3 and titration measurements were carried out in water-dioxane (1:1 (v/v)) solutions to evaluate formation constants with metal ions at III-VI valences. Although the first acid dissociation constants for tetraketones are close to that for the acetylacetone, the formation constants of tetraketones at large coordination numbers are larger than those of acetylacetone. On the basis of these formation constants, the thermodynamic distributions of tetraketone complexes are evaluated in the solution to demonstrate that the change in the coordination number is not expected during the redox reactions contrary to the case of the acetylacetone

  7. Synchrotron X-Ray Absorption Spectroscopy Study of Self-Assembled Nanoparticles Synthesized from Fe(acac)3 and Pt(acac)2

    Chokprasombat, K.; Sirisathitkul, C; Harding, P.; S. Chandarak; R. Yimnirun

    2012-01-01

    The synchrotron X-ray absorption technique was used to complement electron microscopy in the investigation of nanoparticles synthesized from the coreduction of iron acetylacetonate, Fe(acac)3 and platinum acetylacetonate, Pt(acac)2. A much higher Pt composition than Fe leads to an extended X-ray absorption fine structure (EXAFS) spectrum for the sample that differs from that of fcc FePt nanoparticles. Most importantly, X-ray absorption near-edge structure (XANES) spectra clearly indicate the ...

  8. Селективное определение оксида свинца(II) во фториде свинца(II)

    Гайдук, О. В.

    2014-01-01

    The possibility of use of acetylacetone to selective separation the lead(II) oxide from lead(II) fluoride was investigated. Were рroposed to use mixture of acetone, acetylacetone and Triton X-100 for dissolving PbO. Were chosen the optimum concentration of the reactants and selective dissolution conditions allowing quantitatively retrieve lead(II) oxide at minimum solubility of lead(II) fluoride. A complexonometric techniques for determining 0.3-3% PbO in the mixture ...

  9. Hydrothermal Synthesis of Indium Tin Oxide Nanoparticles without Chlorine Contamination

    Indium tin oxide (In2Sn1-xO5-y) nanoparticles were synthesized by hydrothermal method from stable indium tin acetylacetone complexes and post annealing at 600 .deg. C. The absence of chlorine ions shortened the synthesis process, decreased the particle agglomeration and improved the particle purity. The introduced complexing ligand acetylacetone decreased the obtained nanoparticle size. The improved powder properties accelerated the sintering of the In2Sn1-xO5-y nanoparticles and reached a relative density of 96.4% when pressureless sintered at 1400 .deg. C

  10. Laboratory animals pulmonary clearance study with chromium 51 labelled polystyrene spherical particles: investigations for clinical application

    Polystyrene spherical particles labelled with chromium 51, retaining a small amount of chromium acetylacetonate, were administered through different ways to laboratory animals, mice, rats, dogs and monkeys, in order to work out a suitable technique for clinical investigations. The following results were obtained: radioactive labelling may be considered as stable because in vivo chromium elution from the particles does not exceed 0.1% daily. No short-term toxicity has been found for any of the ways of administration due to acetylacetonate or the particles themselves. Long-term pulmonary clearance of inhaled polystyrene particles is close to that of metallic oxides, and no detectable nuisance was observed

  11. Coordination Complexes as Catalysts: The Oxidation of Anthracene by Hydrogen Peroxide in the Presence of VO(acac)[subscript 2

    Charleton, Kimberly D. M.; Prokopchuk, Ernest M.

    2011-01-01

    A laboratory experiment aimed at students who are studying coordination chemistry of transition-metal complexes is described. A simple vanadyl acetylacetonate complex can be used as a catalyst in the hydrogen peroxide oxidation of anthracene to produce anthraquinone. The reaction can be performed under a variety of reaction conditions, ideally by…

  12. Ni/NiO Nanoparticle Synthesis by MOCVD

    Moravec, Pavel; Smolík, Jiří; Keskinen, H.; Mäkelä, J.M.; Levdansky, V.V.

    - : -, 2007. T09A029. [European Aerosol Conference. 09.09.2007-14.09.2007, Salzburg] R&D Projects: GA ČR(CZ) GA104/07/1093 Institutional research plan: CEZ:AV0Z40720504 Keywords : CVD * generation of nanoparticles * nickel acetylacetonate Subject RIV: CF - Physical ; Theoretical Chemistry

  13. Quenching of the triplet state of benzophenone by lanthanide 1,3-diketonate chelates in solutions

    The phosphorescence of benzophenone in benzene and acetonitrile was quenched by several lanthanide (Sm, Eu, Gd, Tb and Dy) acetylacetonate chelates. The results of Stern-Volmer analysis including the quenching of benzophenone triplet and sensitization of lanthanide emission indicate that the quenching process occurs by the energy transfer mechanism via the excited triplet state of the ligand. (Author)

  14. A facile route to inverted polymer solar cells using a precursor based zinc oxide electron transport layer

    Bruyn, P. de; Moet, D.J.D.; Blom, P.W.M.

    2010-01-01

    Inverted polymer:fullerene solar cells with ZnO and MoO3 transport layers are demonstrated. ZnO films are prepared through spin casting of a zinc acetylacetonate hydrate solution, followed by low temperature annealing under ambient conditions. The performance of solar cells with an inverted structur

  15. Preparation of ZnO-Al2O3 Particles in a Premixed Flame

    Jensen, Joakim Reimer; Johannessen, Tue; Wedel, Stig;

    2000-01-01

    Zinc oxide (ZnO) and alumina (Al2O3) particles are synthesized by the combustion of their volatilized acetylacetonate precursors in a premixed air-methane flame reactor. The particles are characterized by XRD, transmission electron microscopy, scanning mobility particle sizing and by measurement of...

  16. Influence of metal β-diketonates on processes of radiation-chemical cross-linking of polymeric compositions

    The effect of copper (2) and manganese (3) acetylacetonates on the cross-linking and destruction of polymer compositions on the basis of sapon ficated copolymer of vinyl chloride and vinyl acetate, cellulose nitrate and acetobutyrate under the effect of γ-radiation, is studied using the EPR method

  17. A facile route to inverted polymer solar cells using a precursor based zinc oxide electron transport layer

    de Bruyn, P.; Moet, D. J. D.; Blom, P. W. M.

    2010-01-01

    Inverted polymer: fullerene solar cells with ZnO and MoO(3) transport layers are demonstrated. ZnO films are prepared through spin casting of a zinc acetylacetonate hydrate solution, followed by low temperature annealing under ambient conditions. The performance of solar cells with an inverted struc

  18. Substituent effects of iridium (III) complexes with 2,4-diphenylquinoline for efficient red organic light-emitting diodes

    We demonstrate efficient red electrophosphorescence using bis[2-(5-methoxyphenyl)-4-phenylquinolinato-N,C2] iridium(III)(acetylacetonate) [Ir(dpq-5OCH3)2(acac)], bis[2-(5-methylphenyl)-4-phenylquinolinato-N,C2] iridium(III)(acetylacetonate)[Ir(dpq-5CH3)2(acac)] and bis[2-(5-fluorophenyl)-4-phenylquinolinato-N,C2] iridium(III) (acetylacetonate) [Ir(dpq-5F)2(acac)] in compared with bis[2,4-diphenylquinolinato-N,C2] iridium(III)(acetylacetonate) [Ir(dpq)2(acac)]. The -CH3, -OCH3 and -F group substituted on the 5'-position of phenyl ring strongly affected the energy level of molecule. The organic light-emitting diodes (OLEDs) with Ir(dpq-5OCH3)2(acac), Ir(dpq-5CH3)2(acac), Ir(dpq-5F)2(acac) and Ir(dpq)2(acac) have a maximum luminous efficiency of 8.20 cd/A, 10.20 cd/A, 15.80 cd/A and 11.60 cd/A, respectively. Also, their electroluminescent emission appeared at 605, 617, 610 and 617 nm, respectively

  19. Revisiting curcumin chemistry part I: A new strategy for the synthesis of curcuminoids

    E Venkata Rao

    2011-01-01

    Full Text Available A new strategy for the synthesis of curcuminoids is described involving the reaction of acetylacetone difluroboronite with an aromatic aldehyde in the presence of n-butylamine as catalyst. The new intermediate products, curcuminoid difluroboronites, of symmetrically substituted curcuminoids like curcumin and bisdemethoxycurcumin are stable, can be isolated and hydrolysed with aq. methanol at pH 5.8 to get the curcuminoids of high purity. The method is applicable for unsymmetrical curcuminoids like demethoxycurcumin also with some modification involving column chromatography. The intermediate curcuminoid difluroboronites, as also the natural β-diketone pongamol difluroboronite, prepared for the first time were characterized on the basis of physical and chemical properties and spectroscopic data. The advantage of using borontrifluoride to protect the enol group in acetylacetone over the generally used boric oxide is brought out. The importance of conducting biological activity studies using pure curcuminoids is explained.

  20. Preparation and characterization of nanometer-scale powders ceria by electrochemical deposition method

    Ceria (CeO2) nanoparticles of 10-30 nm in average particle size have been synthesized via electrochemical deposition method in cerium(III) chloride solution with an undivided cell as electrochemical cell and ethanol-acetylacetone as additives. X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformation infrared spectroscopy (FT-IR) and thermal analysis (TG-DTA) are introduced to characterize the samples. The results indicate that the as-prepared powders after being treated at 650 deg. C are nanocrystalline with the cubic fluorite structure and the sphericity in shape. It is revealed that the size of ceria nanoparticles can be decreased effectively by adding the ethanol-acetylacetone solution. In addition, the possible formed mechanism of CeO2 nanometer-scale powder. The role of additive is also investigated in this paper

  1. One-pot synthesis of amphiphilic superparamagnetic FePt nanoparticles and magnetic resonance imaging in vitro

    Yang Hong; Zhang Jingjing; Tian Qiwei; Hu He [Department of Chemistry, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China); Fang Yong [No.3 People' s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (China); Wu Huixia [Department of Chemistry, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China); Yang Shiping, E-mail: shipingy@shnu.edu.c [Department of Chemistry, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China)

    2010-04-15

    Monodispersed amphiphilic FePt nanoparticles with the diameter of about 4 nm were synthesized by high temperature pyrolysis of iron(III) acetylacetonate and platinum(II) acetylacetonate. Their amphiphilicity is contributed to the tetraethylene glycol (TEG) and oleic acid (OA) on the surface, which is confirmed by FTIR and XPS spectra. They provide a superparamagnetic property with the saturation magnetization (Ms) of about 25 emu/g and the transverse relaxivity (r{sub 2}) of about 122.6 mM{sup -1} s{sup -1} in aqueous solutions. Furthermore, FePt nanoparticles show low cytotoxicity in living cells. They can be uptaken by HeLa cells effectively and result in the obvious decrease of T{sub 2} relaxation time after internalization.

  2. Synthesis of Pt{sub 3}Sn alloy nanoparticles and their catalysis for electro-oxidation of CO and methanol.

    Liu, Y.; Li, D.; Stamenkovic, V. R.; Soled, S.; Henao, J. D.; Sun, S. (Materials Science Division); (Brown Univ.); (Exxon Mobil Res. Eng. Co.)

    2011-11-04

    Monodisperse Pt{sub 3}Sn alloy nanoparticles (NPs) were synthesized by a controlled coreduction of Pt(II) acetylacetonate and Sn(II) acetylacetonate at 180-280 C in 1-octadecene. In the synthesis, oleylamine was used as a reducing agent, and oleylamine/oleic acid served as surfactants. The sizes of the Pt{sub 3}Sn NPs were tuned from 4 to 7 nm by controlling the metal salt injection temperatures from 180 to 240 C. These monodisperse Pt3Sn NPs were highly active for CO and methanol oxidation in 0.1 M HClO{sub 4} solutions, and their activity and stability could be further improved by a postsynthesis thermal treatment at 400 C in Ar + 5% H{sub 2} for 1 h. They are promising as a practical catalyst for CO and methanol oxidation reactions in polymer electrolyte membrane fuel cell conditions.

  3. Effects of chromium and cobalt compounds on burning rate of ammonium nitrate/hydroxyl-terminated polybutadiene composite propellants. Shosan ammonium/HTPB kei composite suishin'yaku no nensho sokudo ni oyobosu chromium to cobalt kagobutsu no eikyo

    Hagihara, Y.; Ichikawa, T.; Shinpo, H.; Suzuki, M. (The National Defense Academy, Yokosuka (Japan))

    1991-12-31

    Study was made on the effects of chromium and cobalt compounds on burning rate of AN/HTPB composite propellants by using 14 types of chromium and cobalt compounds as catalysts and it was clear that burning rate of composite propellants increases with all catalysts and increase in burning rate by ammonium dichromate and chromium (III) acetylacetone is significantly large. Pressure exponent for cobalt(II) oxide and cobalt(II) benzoate has decreased but it has increased with other catalysts. Pressure exponent has significantly increased in the case of cobalt 2-ethylhexanoate and cobalt(II) acetylacetone. Effect of compounds on slurry viscosity also has shown the decrease in the viscosity except chromium(III) oxide and cobalt(II,III) oxide, and in the case of cobalt 2-ethylhexanoate the viscosity is significantly low. Drophammer sensitivity of AN is not affected with the added compounds. 4 refs., 3 figs., 4 tabs.

  4. Chemical modification of chitosan in the absence of solvent for diclofenac sodium removal: pH and kinetics studies

    Pereira, Kerlaine Alexandre Araujo; Osorio, Luizangela Reis; Silva, Marcos Pereira; Silva Filho, Edson Cavalcanti da, E-mail: edsonfilho@ufpi.edu.br [Universidade Federal do Piaui (UFPI/CCN), Teresina, PI (Brazil). Centro de Ciencias da Natureza. Lab. Interdisciplinar de Materiais Avancados; Sousa, Kaline Soares [Universidade Federal da Paraiba (UFPB/CCEN), Joao Pessoa, PB (Brazil). Centro de Ciencias Exatas e da Natureza. Dept. de Quimica

    2014-08-15

    Chitosan was modified with acetylacetone and ethylenediamine in the absence of solvent. The new biopolymer obtained from the modification was characterized by elemental analysis and NMR 13C and applied in the removal of diclofenac sodium aqueous solution varying the pH and time. Through elemental analysis was possible to verify a decreasing in C/N relation after reaction with acetylacetone and an increasing after modification with ethylenediamine. From NMR analysis was verified the appearance of peaks around 160-210 ppm in both materials due to free carbonyl groups in the first step of the modification, besides the formation of imine bonds. The adsorption tests showed that the highest value occurred at pH 4 and from the results of the kinetic study was found that maximum adsorption occurred within 45 minutes and experimental data adjusted better to linear adjustment, following pseudo second-order model. The results show a material efficient in the removal of emerging pollutants. (author)

  5. Bis(acetylacetonato-κ2O,O′(pyridine-κN(thiocyanato-κNmanganese(III: a redetermination using data from a single crystal

    Christian Näther

    2013-12-01

    Full Text Available In the crystal structure of the title compound, [Mn(C5H7O22(NCS(C5H5N], the Mn3+ cation is coordinated by two acetylacetonate anions, one terminal thiocyanate anion and one pyridine ligand within a slightly distorted octahedron. The asymmetric unit consists of half a complex molecule with the Mn3+ cation, the thiocyanate anion and the pyridine ligand located on a mirror plane. The acetylacetonate anion is in a general position. The title compound was previously described [Stults et al. (1975. Inorg. Chem. 14, 722–730] but could only be obtained as a powder. Suitable crystals have now been obtained for a high-precision single-crystal structure determination.

  6. Copper(II) complex of 3-cinnamalideneacetylacetone: Synthesis and characterisation

    A Veeraraj; P Sami; N Raman

    2000-10-01

    A bidentate ligand derived from cinnamaldehyde and acetylacetone and its copper(II) complex have been synthesized and characterized by elemental analysis, UV-Vis, IR, ESR and magnetic susceptibility measurements. Magnetic susceptibility measurements, ESR and electronic spectral data indicate the presence of six coordinated Cu(II) ion. The ligand and complex are tested for antibacterial activity against Pseudomonas aeroginosa. They are found to show the antibacterial activity

  7. Reaction of cycloheptatriene derivatives with 1,3-diketones in the presence of Mn(OAc)3

    SÜDEMEN, Mahir Burak; ZENGİN, Mustafa; and, Hayriye GENÇ

    2011-01-01

    The reactions of some 1,3-dicarbonyl compounds with cycloheptatriene derivatives in the presence of Mn(OAc)3 were examined. Cycloheptatriene forms mainly [2+3] and [6+3] dihydrofuran addition products derived from cycloheptatriene. However, the reaction of acetylacetone with cycloheptatriene substituted with an electron withdrawing group exclusively gave products derived from the norcaradiene structure. The formation mechanism of the products as well as the role of the substituent a...

  8. Structural study of Ni- or Mg-based complexes incorporated within UiO-66-NH2 framework and their impact on hydrogen sorption properties

    Nickel and magnesium acetylacetonate molecular complexes were post-synthetically incorporated into microporous zirconium-based MOF (UiO-66-NH2) in order to introduce active open-metal sites for hydrogen sorption. Elemental analysis, nitrogen physisorption and DFT calculations revealed that 5 molecules of Ni(acac)2 or 2 molecules of Mg(acac)2 were incorporated into one unit cell of UiO-66-NH2. 1H–13C CPMAS and 1H MAS NMR spectroscopy showed that, although embedded within the pores, both Ni- and Mg-complexes interacted with the UiO-66-NH2 framework only through weak van der Waals bonds. Inclusion of metal complexes led to the decrease of hydrogen sorption capacities in Ni-modified as well as in Mg-modified samples in comparison with the parent UiO-66-NH2. The isosteric hydrogen adsorption enthalpy slightly increased in the case of Ni-modified material, but not in the case of Mg-modified analogue. - Graphical abstract: A post-synthesis impregnation of Mg- and Ni-acetylacetonate complexes performed on zirconium-based MOF UiO-66-NH2 does influence the hydrogen sorption performance with respect to the parent matrix. The structural study revealed that Mg- and Ni-acetylacetonate molecules interact with zirconium-terephthalate framework only by weak interactions and they are not covalently bonded to aminoterephthalate ligand. Still, they remain confined into the pores even after hydrogen sorption experiments. - Highlights: • Mg- and Ni-acetylacetonate molecules embedded in the pores of UiO-66-NH2 by PSM. • Molecules of complexes interact with framework only by van der Waals interactions. • Type/structure of deposited metal-complex impact hydrogen enthalpy of adsorption

  9. Synthese und Charakterisierung neuer Phthalocyanine für eine mögliche industrielle Anwendung

    Moustafa, Tamer Ezzat Youssef

    2004-01-01

    Zusammenfassung: Das Ziel dieser Arbeit war die Synthese und die Charakterisierung sowie das Studium der nichtlinear optischen Eigenschaften der löslichen monomeren und binuclear phthalocyanine 10 und 11 und der trinuclear Verbindung 13 und 20. Eingeschlossen, ist auch die strukturelle Modifikationen der Pc-Systeme mit (2-ethylhexyloxy) als peripheren Substituenten und Indium-acetylacetonate (Inacac) als axialen Liganden Weiterhin werden asymmetrisches Pc-Systeme mit stickstoff Heterocyclisch...

  10. VO(acac)2 catalyzed condensation of o-phenylenediamine with aromatic carboxylic acids/aldehydes under microwave radiation affording benzimidazoles

    Madhudeepa Dey; Krishnajyoti Deb; Siddhartha Sankar Dhar

    2011-01-01

    Vanadyl acetylacetonate, VO(acac)2, has been found to be very effective catalyst for synthesis of a variety of benzimidazoles under solvent-free condition. The methodology involves the exposure of a mixture of o-phenylenediamine and a selected aromatic carboxylic acid/aldehyde to microwave radiation without the use of any solvent or supporting agents. The benzimidazoles were obtained in quick time with high yields.

  11. Synthesis and Characterization of Biodegradable Polyurethane for Hypopharyngeal Tissue Engineering

    Shen, Zhisen; Lu, Dakai; Li, Qun; Zhang, Zongyong; Zhu, Yabin

    2015-01-01

    Biodegradable crosslinked polyurethane (cPU) was synthesized using polyethylene glycol (PEG), L-lactide (L-LA), and hexamethylene diisocyanate (HDI), with iron acetylacetonate (Fe(acac)3) as the catalyst and PEG as the extender. Chemical components of the obtained polymers were characterized by FTIR spectroscopy, 1H NMR spectra, and Gel Permeation Chromatography (GPC). The thermodynamic properties, mechanical behaviors, surface hydrophilicity, degradability, and cytotoxicity were tested via d...

  12. Mesoporous TiO2 Yolk-Shell Microspheres for Dye-sensitized Solar Cells with a High Efficiency Exceeding 11%

    Li, Zhao-Qian; Chen, Wang-Chao; Guo, Fu-Ling; Mo, Li-E.; Hu, Lin-Hua; Dai, Song-Yuan

    2015-09-01

    Yolk-shell TiO2 microspheres were synthesized via a one-pot template-free solvothermal method building on the aldol condensation reaction of acetylacetone. This unique structure shows superior light scattering ability resulting in power conversion efficiency as high as 11%. This work provided a new synthesis system for TiO2 microspheres from solid to hollow and a novel material platform for high performance solar cells.

  13. Synthesis of Polyfunctionalized 4H-Pyrans

    Manisha Bihani

    2013-01-01

    Full Text Available Amberlyst A21 catalyzed one-pot three-component coupling of aldehyde and malononitrile with active methylene compounds such as acetylacetone and ethyl acetoacetate for the synthesis of pharmaceutically important polyfunctionalized 4H-pyrans has been reported. Simple experimental procedure, no chromatographic purification, no hazardous organic solvents, easy recovery and reusability of the catalyst, and room temperature reaction conditions are some of the highlights of this protocol for the synthesis of pharmaceutically relevant focused libraries.

  14. Designer synthesis of monodisperse heterodimer and ferrite nanoparticles

    Nakhjavan, Bahar

    2011-01-01

    The work presented in this doctoral thesis is a facile procedure, thermal decomposition, forrnthe synthesis of different types of monodisperse heterodimer M@iron oxide (M= Cu, Co, Nirnand Pt) and single ferrites, MFe2O4 (M= Cu and Co), nanoparticles. In the following chapter,rnwe study the synthesis of these monodiperse nanoparticles with the similar iron precursorrn(iron pentacarbonyl) and different transition metal precursors such as metalrnacetate/acetylacetonate/formate precursors in the ...

  15. Fuel cell electrodes from organometallic Pt precursors: an easy atmospheric plasma approach

    Merche, Delphine; Dufour, Thierry; Baneton, Joffrey; Caldarella, Giuseppe; Debaille, Vinciane; Job, Nathalie; Reniers, François

    2016-01-01

    An organometallic powder (platinum (II) acetylacetonate) is decomposed in the post-discharge of an atmospheric RF plasma torch to deposit Pt nanoparticles on carbon black supports. The resulting nanohybrid materials are characterized by FEG-SEM and XPS techniques to highlight their high content in Pt, their oxidation degree, and the dispersion of the Pt nanoparticles on the substrate. ICP-MS and electrochemical characterizations in a single fuel cell (cyclic voltammetry, dynamic polarization ...

  16. Fabrication of Size-Tunable Metallic Nanoparticles Using Plasmid DNA as a Biomolecular Reactor

    Charles Michael Drain; Raihan Saleh; Amit Aggarwal; Andrea Parpas; Patrick Nahirney; Alex Yampolski; Jacopo Samson; Irene Piscopo

    2011-01-01

    Plasmid DNA can be used as a template to yield gold, palladium, silver, and chromium nanoparticles of different sizes based on variations in incubation time at 70 °C with gold phosphine complexes, with the acetates of silver or palladium, or chromium acetylacetonate. The employment of mild synthetic conditions, minimal procedural steps, and aqueous solvents makes this method environmentally greener and ensures general feasibility. The use of plasmids exploits the capabilities of the biotechno...

  17. Structural study of Ni- or Mg-based complexes incorporated within UiO-66-NH{sub 2} framework and their impact on hydrogen sorption properties

    Žunkovič, E.; Mazaj, M. [Laboratory for Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); Mali, G. [Laboratory for Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); EN-FIST Centre of Excellence, Dunajska 156, 1000 Ljubljana (Slovenia); Rangus, M. [Laboratory for Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); Devic, T.; Serre, C. [Institut Lavoisier, UMR CNRS 8180, Université de Versailles Saint-Quentin-en-Yvelines, 78035 Versailles (France); Logar, N. Zabukovec, E-mail: natasa.zabukovec@ki.si [Laboratory for Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); CO-NOT Centre of Excellence, Hajdrihova 19, 1000 Ljubljana (Slovenia); University of Nova Gorica, Vipavska 13, 5000 Nova Gorica (Slovenia)

    2015-05-15

    Nickel and magnesium acetylacetonate molecular complexes were post-synthetically incorporated into microporous zirconium-based MOF (UiO-66-NH{sub 2}) in order to introduce active open-metal sites for hydrogen sorption. Elemental analysis, nitrogen physisorption and DFT calculations revealed that 5 molecules of Ni(acac){sub 2} or 2 molecules of Mg(acac){sub 2} were incorporated into one unit cell of UiO-66-NH{sub 2}. {sup 1}H–{sup 13}C CPMAS and {sup 1}H MAS NMR spectroscopy showed that, although embedded within the pores, both Ni- and Mg-complexes interacted with the UiO-66-NH{sub 2} framework only through weak van der Waals bonds. Inclusion of metal complexes led to the decrease of hydrogen sorption capacities in Ni-modified as well as in Mg-modified samples in comparison with the parent UiO-66-NH{sub 2}. The isosteric hydrogen adsorption enthalpy slightly increased in the case of Ni-modified material, but not in the case of Mg-modified analogue. - Graphical abstract: A post-synthesis impregnation of Mg- and Ni-acetylacetonate complexes performed on zirconium-based MOF UiO-66-NH{sub 2} does influence the hydrogen sorption performance with respect to the parent matrix. The structural study revealed that Mg- and Ni-acetylacetonate molecules interact with zirconium-terephthalate framework only by weak interactions and they are not covalently bonded to aminoterephthalate ligand. Still, they remain confined into the pores even after hydrogen sorption experiments. - Highlights: • Mg- and Ni-acetylacetonate molecules embedded in the pores of UiO-66-NH{sub 2} by PSM. • Molecules of complexes interact with framework only by van der Waals interactions. • Type/structure of deposited metal-complex impact hydrogen enthalpy of adsorption.

  18. Laser-induced chemical liquid deposition of discontinuous and continuous copper films

    Ouchi, A.; Bastl, Zdeněk; Boháček, Jaroslav; Šubrt, Jan; Pola, Josef

    2007-01-01

    Roč. 201, č. 8 (2007), s. 4728-4733. ISSN 0257-8972 R&D Projects: GA AV ČR 1ET400400413 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40320502; CEZ:AV0Z40720504 Keywords : copper films * laser photolysis * Cu(II) acetylacetonate * chemical liquid deposition Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.678, year: 2007

  19. UV Laser Photolytic Solution Deposition of α-Fe/Polyoxocarbosilane/Carbon Nanocomposite and Evolution to α-Fe2O3/Polyoxocarbosilane/Carbon Nanocomposite

    Pola, Josef; Maryško, Miroslav; Vorlíček, Vladimír; Bakardjieva, Snejana; Šubrt, Jan; Bastl, Zdeněk; Ouchi, A.

    2008-01-01

    Roč. 199, 2-3 (2008), s. 156-164. ISSN 1010-6030 R&D Projects: GA AV ČR IAA400720619 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z10100521; CEZ:AV0Z40320502; CEZ:AV0Z40400503 Keywords : Fe(II) acetylacetonate * Fe composite * laser solution deposition Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.362, year: 2008

  20. Combustion deposition of MoO3 films: from fundamentals to OPV applications

    MARCHAL, Wouter; De Dobbelaere, Christopher; KESTERS, Jurgen; Bonneux, Gilles; Vandenbergh, Joke; DAMM, Hanne; Junkers, Thomas; Maes, Wouter; D'Haen, Jan; Van Bael, Marlies K; Hardy, An

    2015-01-01

    A systematic study of a combustion precursor's thermal decomposition pathway is undertaken, in both powders and thin films, to obtain insights in the various parameters influencing the combustion process. The study focuses on MoO3 as a hole transporting layer (HTL) for applications in organic photovoltaics (OPV). Via evolved gas analysis, it was found that fuel volatility occurs prior to the actual combustion reaction of the acetylacetonate based precursor, affecting the optimal oxidizer to f...

  1. Oxidative coupling polymerization of p-alkoxyphenols with Mn(acac)2-ethylenediamine catalysts

    Hideyuki Higashimura; Shigeki Habaue; Osamu Haba; Soichiro Murakami; Yuuta Akutsu

    2010-01-01

    The oxidative coupling polymerization of p alkoxyphenols with Mn(acac)2ethylenediamine catalysts was carried out. The polymerization of pmethoxyphenol with the manganese(II) acetylacetonate [Mn(acac)2]N,N’diethylethylene diamine catalyst in CH2Cl2 at room temperature under an O2 atmosphere afforded a polymer, which mainly consists of the mphenylene unit, whereas the polymer obtained with Mn(acac)2 was rich in the oxyphenylene structure. The polymer yield and regioselectivity were significantl...

  2. Synthesis, characterization, and reactivity of pentamethylcyclopentadienyl complexes of divalent cobalt and nickel

    Smith, M.E.

    1993-10-01

    The thesis is divided into the following 4 chapters: synthesis, characterization, and reactivity of trinuclear pentamethylcyclopentadienyl cobalt and nickel clusters with triply-bridging methylidyne groups; chemical and physical properties of pentamethylcyclopentadienyl acetylacetonate complexes of Co(II) and Ni(II); synthesis, characterization, and reactivity of pentamethylcyclopentadienyl halide complexes of Co and Ni; and crystallographic studies of distortions in metallocenes with C{sub 5}-symmetrical cyclopentadienyl rings.

  3. sup(1)H, sup(13)C and sup(17)O NMR studies of cumene hydroperoxide coordination to Cr(AA)sub(3)

    The mechanism of the catalytic decomposition of hydroperoxides by tris-chelates of transition metals was studied by means of NMR. It was established that the outer sphere coordination of cumene hydroperoxide to tris-acetylacetonate of Cr(III) (Cr(AA)sub(3)) is due to both the formation of hydrogen bonds between hydroxyl proton and chelate oxygen atoms and the π-π-interactions between the aromatic ring and chelate π-system. (author)

  4. Epoxidación de aceite de soja refinado mediante oxígeno molecular. Influencia de las variables. Estudio cinético

    Martínez de la Cuesta, P. J.; Rus Martínez, E.; Román Cortés, V.

    1991-01-01

    The influences of temperature, concentration of catalyst and initial concentration of unsaturation on epoxide formation and esters from oleic and linoleic acids disappearance in liquid phase epoxidation reaction by molecular oxygen of soy-bean oil using molibdenyl-acetylacetonate as catalyst, has been studied. From experimental data obtained by a complex factorial design, an equation for epoxide formation reaction rate as a function of temperature, catalyst concentration and unsaturation...

  5. Synthesis and Properties of MPEG-Coated Superparamagnetic Magnetite Nanoparticles

    Xueli Cao; Baolin Zhang; Fangyuan Zhao; Lingyun Feng

    2012-01-01

    The magnetite nanoparticles were synthesized by the thermal decomposition of iron(III) acetylacetonate in methoxy polyethylene glycol, which was used as solvent, reducing agent, and modifying agent in the reaction. The morphologies and phase compositions of the nanoparticles were determined by transmission electron microscopy and X-ray diffraction, respectively. The surface coating of the nanoparticles was recognized using Fourier transform infrared spectroscopy. Magnetic properties were meas...

  6. Synthesis, structural characterization, and antimicrobial efficiency of sulfadiazine azo-azomethine dyes and their bi-homonuclear uranyl complexes for chemotherapeutic use

    Khedr, Abdalla M.; SAAD, FAWAZ A.

    2015-01-01

    Two sulfadiazine azo-azomethine dyes containing two active coordination centers and their bi-homonuclear UO_2(II)-complexes were synthesized for potential chemotherapeutic use. The ligands were prepared, starting from the coupling of sulfadiazine dizonium salt with acetylacetone, followed by condensation with ethylenediamine and 1,6-hexanediamine (HL^I and HL^{II}) using a modified literature procedure. The structures of the ligands and their UO_2(II)-complexes were elucidated by conve...

  7. Diastereoselective metal-catalyzed synthesis of C-aryl and C-vinyl glycosides.

    Nicolas, Lionel; Angibaud, Patrick; Stansfield, Ian; Bonnet, Pascal; Meerpoel, Lieven; Reymond, Sébastien; Cossy, Janine

    2012-10-29

    Cobalt, the catalyst of choice: The diastereoselective cobalt-catalyzed cross-coupling of 1-bromo glycosides and aryl or vinyl Grignard reagents is described. A convenient and inexpensive catalyst, [Co(acac)(3)]/tmeda (acac = acetylacetonate, tmeda = N,N'-tetramethylethylenediamine), gives full α selectivity in the mannose and galactose series, and an α selectivity in the glucose series with α/β ratios of 1.3:1-3:1. PMID:23023954

  8. Studies of solution deposited cerium oxide thin films on textured Ni-alloy substrates for YBCO superconductor

    Cerium oxide (CeO2) buffer layers play an important role for the development of YBa2Cu3O7-x (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO2 films on textured Ni-3 at.% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H2 gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 deg. C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO2 films. Highly textured CeO2 layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a J c of 1.5 MA/cm2 were obtained on cerium acetylacetonate-based CeO2 films with sputtered YSZ and CeO2 cap layers

  9. Comparative evaluation of red cell-labelling parameters of three lipid-soluble 111-In-chelates: Effect of lipid solubility on membrane incorporation and stability constant on transchelation

    A rabbit red cell model was used to determined the cell labeling properties of three lipid-soluble 111In-complexes: 111In-oxine, 111In-acetylacetone, and 111In-tropolone. Partition coefficients (olive oil/buffer) were measured to determine the lipid solubility and were 3.54, 7.93, and 18.18 for 111In-oxine, 111In-acetylacetone, and 111In-tropolone respectively. The effect of the concentration of these three chelating agents on labeling efficiencies was studied. The factors influencing the labeling efficiencies of these complexes such as cell density, time of incubation, influence of temperature, pH, effect of plasma proteins, and citrate ion concentration in the cell-labeling medium were studied. Labeling yields as high as 95.15 +- 4.15% were achieved with 111In-tropolone after a 10-min incubation at 370C. The optimum pH for cell labeling was 6.5 Excess critrate ion (> 3.02 mg/ml) and small amounts of plasma proteins (> 10 μl/ml) decreased the labeling efficiencies in all three cases. Distribution of these 111In-complexes in membrane, membrane frgments, and hemoglobin was studied after hemolysis. In spite of the higher lipid solubility of 111In-tropolone, the transchelation capacity appears to be similar to that of 111In-oxine. 111In-acetylacetone had the highest transchelation capacity. (orig.)

  10. Synthesis of oxide and spinel nanocrystals for use in solid state lighting

    Foley, Megan Elizabeth

    In this dissertation, microwave chemistry is employed to synthesize a variety of different crystalline nanoparticles (NPs). This introduction will describe the structures, properties and applications of the NPs studied within the dissertation, with a main focus being on ligand sensitization for the goal of enhanced luminescence. The use of metal acetylacetonate complexes to make Europium (III) doped Ytrrium (Y2O3) NPs is explored, where the acetylacetonate acts both as a source of oxygen for the synthesis of Y2O3, as well as an organic chromophore acting as an "antenna" for the absorption of light and subsequent excitation transfer to the incorporated Europium (III) (Chapter 2). Other host materials are investigated by method of metal acetylacetonate decomposition to synthesize a variety of different nanospinels, having the general formula AB2X4, with sulfide variants made by decomposition of diethyldithiocarbamate, (Chapter 3). The antenna ligand thenoyltrifluoroacetone (tta), which is known to undergo a Dexter energy transfer (DET) mechanism to efficiently sensitize Europium (III) emission, is used to determine the distance of energy transfer in Europium (III) doped nanospinels by passivating the surface of the nanospinel with a tta (Chapter 4). A variety of ligands are explored in order to optimize the sensitization efficiency in relation to the difference in energy between the singlet and triplet levels of the ligands versus the 5D0 and 5D4 energy levels of Europium (III) and Terbium (III) respectively (Chapter 5).

  11. Electrochemical decontamination in easily processed electrolytes

    Metallic surfaces can be reduced to very low levels of residual activity by electrochemical decontamination, thus reducing decommissioning and disposal costs. Two electrolyte systems have been developed which minimize the volume for disposal of secondary waste containing the bulk of the activity. Kraftanlagen, Heidelberg has developed a system for use in an immersion tank based on a KBr solution of acetylacetone. This leads to a continuous precipitation of the insoluble acetylacetonates of ferrous substrates together with such active species as 60Co. The bath performance can be maintained by continuous acetylacetone addition. From pilot scale trials, a solids waste volume of 1.1 dm3/m2 of surface decontaminated has been determined. Harwell has developed both immersion and in-situ processes based on nitric acid, as the spent electrolyte is compatible with existing UK waste treatment philosophy - potentially yielding an immobilized product volume of 0.6 dm3/m2 area treated. Nitric acid has the additional advantage of suppressing any hydrogen production. Both processes have been developed from laboratory to microprocessor controlled pilot scale units which have been demonstrated successfully for the treatment of genuine waste. The immersion tank process uses electroetching at low current densities for the treatment of extended areas, while the in-situ technique uses electropolishing in 6M HNO3 in an engineered head connected to a service trolley by an umbilical. This has also shown potential for incorporation in an integrated monitoring/decontamination system under robotic control. (abstract)

  12. ET-AAS determination of aluminium in dialysis concentrates after continuous flow solvent extraction.

    Komárek, J; Cervenka, R; Růzicka, T; Kubán, V

    2007-11-01

    Conditions of a continuous flow extraction (CFE) of aluminium acetylacetonate in acetylacetone and aluminium 8-hydroxyquinolinate into methylisobutylketone (lengths of reaction and extraction coils, flow rates of aqueous and organic phases and their flow rate ratio, pH of aqueous phase, lengths of coils for transport of aqueous and organic phases and effect of salts) were studied. The analytical signal of the aluminium chelates present in the organic phase was measured at 309.3 nm using atomic absorption spectrometry with electrothermal atomization (ET-AAS) at the flow rate ratio F aq/F org=3 for aqueous and organic phases. The five points calibration curves were linear (R2 0.9973 and 0.9987) up to 21 microgl(-1) Al with the limits of detection of 0.3 microgl(-1) and the recovery 100+/-2% and precision of 3% at 2-10-fold dilution of the dialysis concentrates. The acetylacetonate method was applied to the determination of aluminium in real dialysis concentrates. Aluminium in concentrations 5-6 microgl(-1) (R.S.D.s 5-10% in real samples) were found and the results were in the very good agreement with those obtained by an ET-AAS using preconcentration of Al(III) on a Spheron-Salicyl chelating sorbent (absolute and relative differences were under 0.4 microgl(-1) and 8.2%, respectively). PMID:17897803

  13. Characterization of microstructure and catalytic of cerium oxide obtained by colloidal solution

    This study investigated to obtain particles of cerium oxide, for use as catalysts for the combustion of methane using the technique of through polymeric colloidal solution. Obtaining the colloidal system is based on hydrolysis of salts such as cerium acetylacetonate, cerium nitrate in the presence of additives such as polyvinylbutyral (PVB), polyvinylpyrrolidone (PVP) and polyvinyl acetate (PVA), at concentrations of 5, 10 and 15% in aqueous or alcoholic medium. These solutions containing ions of interest were subjected to a heat treatment at 650° C for 30 minutes, with heating rate of 2 ° C/ min. After heat treatment, the fibers were characterized according to their morphology, surface area, crystallinity, weight loss and catalytic activity. Samples obtained from cerium acetylacetonate were more reactive than the cerium nitrate to the combustion of methane, as showed greater conversions and higher temperatures reached during the process, which is of utmost importance since the combustion catalytic methane is used for generating thermal energy. After the reaction with methane, the samples underwent significant change in surface area, probably due to the intensity of combustion reactions of the nitrate and the generation of heat involved in this reaction, which gave rise to coarse particles. During the combustion process using the obtained from particles of cerium acetylacetonate, there was the release of large quantities of nitrogen compared to the results of assays with the particles obtained with cerium nitrate. (author)

  14. Characterization of microstructure and catalytic of cerium oxide obtained by colloidal solution; Caracterizacao da microestrutura e da atividade catalitica de oxido de cerio obtido por solucao coloidal

    Senisse, C.A.L.; Bergmann, C.P.; Alves, A.K., E-mail: carolinasenisse@hotmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alege, RS (Brazil). Lab. de Materiais Ceramicos

    2012-07-01

    This study investigated to obtain particles of cerium oxide, for use as catalysts for the combustion of methane using the technique of through polymeric colloidal solution. Obtaining the colloidal system is based on hydrolysis of salts such as cerium acetylacetonate, cerium nitrate in the presence of additives such as polyvinylbutyral (PVB), polyvinylpyrrolidone (PVP) and polyvinyl acetate (PVA), at concentrations of 5, 10 and 15% in aqueous or alcoholic medium. These solutions containing ions of interest were subjected to a heat treatment at 650° C for 30 minutes, with heating rate of 2 ° C/ min. After heat treatment, the fibers were characterized according to their morphology, surface area, crystallinity, weight loss and catalytic activity. Samples obtained from cerium acetylacetonate were more reactive than the cerium nitrate to the combustion of methane, as showed greater conversions and higher temperatures reached during the process, which is of utmost importance since the combustion catalytic methane is used for generating thermal energy. After the reaction with methane, the samples underwent significant change in surface area, probably due to the intensity of combustion reactions of the nitrate and the generation of heat involved in this reaction, which gave rise to coarse particles. During the combustion process using the obtained from particles of cerium acetylacetonate, there was the release of large quantities of nitrogen compared to the results of assays with the particles obtained with cerium nitrate. (author)

  15. Angularly and spectrally resolved light scattering from lead zirconate titanate thin films

    The results of light-scattering measurements for a series of Pb(Zr,Ti)O3 thin films prepared by a sol-gel method are presented and analyzed. The films differed due to the addition of different concentrations of acetylacetone to the precursor solution immediately prior to film fabrication. Visual inspection of the films indicated improvements in optical quality with the addition of acetylacetone. To quantify these improvements, two types of light-scattering measurements were performed: angularly resolved light scattering and spectrally resolved light scattering. Surprisingly, only slight differences between the films were observed using angularly resolved light scattering at 633 nm. In contrast, the spectrally resolved scattering revealed large differences between the films, with the films prepared using the largest concentrations of acetylacetone exhibiting the lowest scattering. The apparent contradiction between these findings is resolved using a theoretical model for light scattering due to fluctuations in the dielectric constant occurring within the volume of the thin film and by noting that slight thickness differences exist between the films in the series. Analysis of the light scattering from the best sample yields estimates for the amplitude (ξ0 = 0.08) and the characteristic size (τ0 = 110 nm) of the dielectric constant fluctuations. These estimates are consistent with the variations of the dielectric constant expected due to the birefringent, polycrystalline nature of these films

  16. Preparation of molybdenum oxide thin films by MOCVD

    In this study, molybdenum oxide films were prepared in a horizontal hot-wall MOCVD apparatus using molybdenum dioxide acetylacetonate as precursor. The molybdenum precursor was synthesized from acetylacetone and molybdenum oxide powder. Thermal gravimetric (TG) and differential thermal analyses (DTA) of the precursor suggested the formation of molybdenum oxides around 430 oC (703 K). Thus, a range of deposition temperatures varying from 350 to 630 oC (623-903 K) was explored to investigate the effects on the nature of the molybdenum oxide films. X-ray diffraction (XRD) results showed that the films consisted of α-MoO3 phase at deposition temperatures ranging from 400 to 560 oC (673-833 K). Crystalline α-MoO3 films can be obtained from molybdenum dioxide acetylacetonate precursor, without need of a post-annealing treatment. The best crystalline quality was found in films having needle-like crystallites grown at deposition temperature of about 560 oC (833 K), which exhibit a strong (0 1 0) preferred orientation and a transparent visual appearance

  17. Study of the Gelling Process for the Preparation of Tin Oxide Materials Based on Tin Tetrabutoxide%Sn(OBun)4为前驱体制备SnO2材料中的溶胶-凝胶过程

    黄瑞安; 侯立松; 赵启涛; 任叔华

    2005-01-01

    The gelling process in the preparation of tin oxide materials based on tin tetrabutoxide is studied. Sn(OBun)4 modified by two moles of acetylacetone (AcAc) has a stable six-member ring structure and is less susceptive to water. In a system with a lower molar ratio of acetylacetone to Sn(OBun)4 ([AcAc]/[Sn(OBun)4]<2.0) or a larger portion of water ([H2O]/[Sn(OBun)4]>2.5), colloidal suspension or white precipitation will take place. A system with molar ratios of both acetylacetone to Sn(OBun)4 and water to Sn(OBun)4 at 2.0 is transparent and olivaceous sol. As catalysts, hydrofluoric,hydrochloric, hydrobromic and acetic acids, and ammonia all accelerate the hydrolysis and condensation of Sn(OBun)4 during the sol-gel process. Light scattering measurement indicates that cluster size distribution in the sol system undergoes gradual broadening during the sol-gel transition.

  18. Ruthenium based redox flow battery for solar energy storage

    Research highlights: → Undivided redox flow battery employing porous graphite felt electrodes was used. → Ruthenium acetylacetonate dissolved in acetonitrile was the electrolyte. → Charge/discharge conditions were determined for both 0.02 M and 0.1 M electrolytes. → Optimum power output of 0.180 W was also determined for 0.1 M electrolyte. → 55% voltage efficiency was obtained when battery was full of electrolytes. -- Abstract: The technical performance for the operation of a stand alone redox flow battery system for solar energy storage is presented. An undivided reactor configuration has been employed along with porous graphite felt electrodes and ruthenium acetylacetonate as electrolyte in acetonitrile solvent. Limiting current densities are determined for concentrations of 0.02 M and 0.1 M ruthenium acetylacetonate. Based on these, operating conditions for 0.02 M ruthenium acetylacetonate are determined as charging current density of 7 mA/cm2, charge electrolyte superficial velocity of 0.0072 cm/s (through the porous electrodes), discharge current density of 2 mA/cm2 and discharge electrolyte superficial velocity of 0.0045 cm/s. An optimum power output of 35 mW is also obtained upon discharge at 2.1 mA/cm2. With an increase in the concentration of ruthenium species from 0.02 M to 0.1 M, the current densities and power output are higher by a factor of five approximately (at same superficial velocities) due to higher mass transport phenomenon. Moreover at 0.02 M concentration the voltage efficiency is better for battery full of electrolytes prior to charging (52.1%) in comparison to an empty battery (40.5%) due to better mass transport phenomenon. Voltage efficiencies are higher as expected at concentrations of 0.1 M ruthenium acetylacetonate (55% when battery is full of electrolytes and 48% when empty) showing that the all-ruthenium redox flow battery has some promise for future applications in solar energy storage. Some improvements for the system are

  19. Study on Progress in Synthesis of Natural Product Curcumin%天然产物姜黄素合成工艺研究

    邹春阳; 王凤秋; 田家明

    2011-01-01

    Curcumin was prepared by a modified method in this paper. Meanwhile, the optimum condition was also established. The mixture of acetylacetone and boric anhydride in ethyl acetate was stirred under reflux temperature for 30 minutes and gived a boron complex of acetylacetone. N - Butylamine was added dropwise to a solution of vanillin, tributyl borate and boron complex of acetylacetone in DMF (N, N -dimethylformamide) at 80X1. After stirred for 3 hours, crude curcumin was obtained by use 5% acetic acid to destroy the boron complex of curcumin. It was furtherly purified by re-crystallization from chloroform methanol. The overyield reaches 70% under the condition of inventory rating reaching one hundred grams - level. This method provides a reference for the large scale preparation of curcumin.%采用了一种改良的合成方法制备姜黄素,并确定了最优工艺条件.即:先将乙酰丙酮与硼酸酐于乙酸乙酯内回流反应30min,制得乙酰丙酮的硼络合物;然后在DMF(N,N-二甲基甲酰胺)中,将香兰素、三丁基硼酸酯及新制的乙酰丙酮的硼络合物于80℃,以正丁胺为催化剂反应3h;最后向其中加入5%的醋酸破坏络合物得到姜黄素粗品,以氯仿-甲醇重结晶得到姜黄素纯品.在投料量为百克级情况下,总收率达到了70%.这也为大量制备提供参考.

  20. A dual chelating sol–gel synthesis of BaTiO{sub 3} nanoparticles with effective photocatalytic activity for removing humic acid from water

    Wang, Peigong [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Fan, Caimei, E-mail: fancm@163.com [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Yawen; Ding, Guangyue; Yuan, Peihong [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2013-02-15

    Graphical abstract: The cubic phase BaTiO{sub 3} nanoparticles can be obtained at 600 °C and changed into tetragonal phase at 900 °C by a dual chelating sol–gel method, and the photocatalytic activities of the photocatalysts calcined at different temperatures were investigated by the removal of humic acid (HA) from water under UV light irradiation. Highlights: ► The humic acid in water was firstly degradated by BaTiO{sub 3} photocatalyst. ► The cubic BaTiO{sub 3} was obtained and changed into tetragonal phase at lower temperature. ► The chelating agents had an important influence on the phase formation of BaTiO{sub 3}. ► The tetragonal phase BaTiO{sub 3} calcined at 900 °C exhibited higher photocatalytic activity under UV irradiation. -- Abstract: In this paper, a dual chelating sol–gel method was used to synthesize BaTiO{sub 3} nanoparticles by using acetylacetone and citric acid as chelating agents. The samples calcined at different temperatures were analyzed by thermogravimetric and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscope (SEM) and UV–vis diffuse reflectance spectra (UV–vis). The results indicated that cubic phase BaTiO{sub 3} nanoparticles about 19.6 nm can be obtained at 600 °C and changed into tetragonal phase at 900 °C about 97.1 nm. All the BaTiO{sub 3} nanoparticles showed effective photocatalytic activities on the removal of humic acid (HA) under UV light irradiation. A comparison of single (acetylacetone or citric acid) and dual chelating (acetylacetone and citric acid) synthetic processes was also studied and the results demonstrated that the dual chelating agents indeed reduced phase transformation temperature from cubic to tetragonal BaTiO{sub 3}.

  1. Synthesis and characterization of potential iron–platinum drugs and supplements by laser liquid photolysis

    Forbes A

    2012-06-01

    Full Text Available Steven S Nkosi,1,2 Bonex W Mwakikunga,4 Elias Sideras-Haddad,2 Andrew Forbes1,31CSIR National Laser Centre, Pretoria, South Africa; 2DST/NRF Centre for Excellence in Strong Materials and School of Physics, University of the Witwatersrand, Johannesburg, 3School of Physics, University of KwaZulu-Natal, Durban, South Africa; 4DST/CSIR National Centre for Nano-Structured Materials, Pretoria, South AfricaAbstract: Highly crystalline nanospherical iron–platinum systems were produced by 248 nm laser irradiation of a liquid precursor at different laser fluences, ranging from 100–375 mJ/cm2. The influence of laser intensity on particle size, iron composition, and structure was systematically investigated. Different nanostructures of iron–platinum alloy and chemically disordered iron–platinum L10 phase were obtained without annealing. The prepared precursor solution underwent deep photolysis to polycrystalline iron–platinum nanoalloys through Fe(III acetylacetonate and Pt(II acetylacetonate. Fe(II and Pt(I acetylacetone decomposed into Fe0 and Pt0 nanoparticles. We found that the (001 diffraction peak shifted linearly to a lower angle, with the last peak shifting in opposition to the others. This caused the face-centered cubic L10 structure to change its composition according to laser fluence. The nanostructures were shown to contain iron and platinum only by energy-dispersive spectroscopy at several spots. The response of these iron–platinum nanoparticles to infrared depends on their stoichiometric composition, which is controlled by laser fluence.Keywords: nanostructures, iron, platinum, nanoparticles, laser liquid photolysis, composition

  2. Microspheres with an ultra high holmium content for brachytherapy of malignancies

    Lira, Raphael A.; Myamoto, Douglas M.; Souza, Jaime R.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia; Osso Junior, Joao A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia; Martinelli, Jose R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencias e Tecnologia de Materiais

    2011-07-01

    The overall objective of this work is to develop biodegradable microspheres intended for internal radiation therapy which provides an improved treatment for hepatic carcinomas. The most studied brachytherapy system employing microspheres made of holmium-biopolymer system is composed by poly(L-lactic acid) (PLLA) and holmium acetylacetonate (HoAcAc). The importance of the holmium high content in the microspheres can be interpreted as follow from a therapeutic standpoint, to achieve an effective use of microspheres loaded with HoAcAc, a high content of holmium is required to yield enough radioactivity with a relatively low amount of microspheres.The usual amounts of holmium that are incorporated in the microspheres composed by poly(L-lactic acid) and HoAcAc are 17.0 {+-} 0.5% (w/w) of holmium, which corresponds to a loading of about 50% of HoAcAc. Different approaches have been investigated to increase that value. One updated approach towards this direction is the production of microspheres with ultrahigh holmium as matrix using HoAcAc crystals as the sole starting material without the use of biopolymer. Likewise, in the search of microspheres with increased holmium content , it has been demonstrated that by changing the HoAcAc crystal structure by its recrystallization from crystal phase to the amorphous there is lost of acetylacetonate and water molecules causing the increasing of the holmium content. Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized by using light and scanning electron microscopy, infrared and Raman spectroscopy, differential scanning calorimetry, X-rays diffraction, and confocal laser scanning microscopy. (author)

  3. Sol-gel synthesis of Pt-Ru-Os-Ir based anode electro-catalysts for direct methanol fuel cells

    Research highlights: → Complex sol-gel synthesis (CSG) of high specific surface area Pt-Ru-Os-Ir catalysts. → Catalysts exhibit specific surface area of ∼95 m2/g. → Electrocatalytic activity is 35-40% higher than CSG derived Pt0.5Ru0.5 and commercially obtained JM catalyst. - Abstract: A high specific surface area (∼95 m2/g) Pt44Ru41Os10Ir5 based anode electro-catalysts for direct methanol fuel cell, synthesized by a novel complexed sol-gel (CSG) process, shows better catalytic activity in comparison to pure equi-atomic compositions of Pt-50 at.% Ru anode catalysts synthesized by similar sol-gel processes. A homogeneous amorphous gel was successfully synthesized by complexing platinum(II) acetylacetonate, ruthenium(III) acetylacetonate, iridium(III) acetylacetonate and osmium(III) chloride with tetramethylammonium hydroxide (TMAH) used as a complexing agent. Phase-pure Pt(Ru,Os,Ir) and Pt(Ru) solid solutions possessing high specific surface area (SSA) (∼90-120 m2/g) were successfully synthesized by thermal decomposition of the amorphous gel followed by controlled removal of carbonaceous species present in the thermally treated powders. The controlled removal of carbon, present in the thermally treated Pt-Ru-Os-Ir powder, has been successfully achieved by conducting precise thermal treatments of the thermally treated powders using controlled oxidizing atmospheres. Results indicate that the nano-crystalline pure Pt(Ru,Os,Ir) solid solution of nominal composition Pt-41 at.%Ru-10 at.%Os-5 at.% Ir possessing good chemical homogeneity exhibit excellent catalytic activity, demonstrating the potential of the novel complexed sol-gel process for synthesizing high-performance Pt-Ru-Os-Ir based catalysts for direct methanol fuel cells.

  4. Sol-gel synthesis of Pt-Ru-Os-Ir based anode electro-catalysts for direct methanol fuel cells

    Alyousef, Yousef M. [Energy Research Institute, King Abdulaziz City for Science and Technology, Riyadh 11442 (Saudi Arabia); Datta, Moni Kanchan [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kadakia, Karan [Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Yao, S.C. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.ed [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2010-09-17

    Research highlights: {yields} Complex sol-gel synthesis (CSG) of high specific surface area Pt-Ru-Os-Ir catalysts. {yields} Catalysts exhibit specific surface area of {approx}95 m{sup 2}/g. {yields} Electrocatalytic activity is 35-40% higher than CSG derived Pt{sub 0.5}Ru{sub 0.5} and commercially obtained JM catalyst. - Abstract: A high specific surface area ({approx}95 m{sup 2}/g) Pt{sub 44}Ru{sub 41}Os{sub 10}Ir{sub 5} based anode electro-catalysts for direct methanol fuel cell, synthesized by a novel complexed sol-gel (CSG) process, shows better catalytic activity in comparison to pure equi-atomic compositions of Pt-50 at.% Ru anode catalysts synthesized by similar sol-gel processes. A homogeneous amorphous gel was successfully synthesized by complexing platinum(II) acetylacetonate, ruthenium(III) acetylacetonate, iridium(III) acetylacetonate and osmium(III) chloride with tetramethylammonium hydroxide (TMAH) used as a complexing agent. Phase-pure Pt(Ru,Os,Ir) and Pt(Ru) solid solutions possessing high specific surface area (SSA) ({approx}90-120 m{sup 2}/g) were successfully synthesized by thermal decomposition of the amorphous gel followed by controlled removal of carbonaceous species present in the thermally treated powders. The controlled removal of carbon, present in the thermally treated Pt-Ru-Os-Ir powder, has been successfully achieved by conducting precise thermal treatments of the thermally treated powders using controlled oxidizing atmospheres. Results indicate that the nano-crystalline pure Pt(Ru,Os,Ir) solid solution of nominal composition Pt-41 at.%Ru-10 at.%Os-5 at.% Ir possessing good chemical homogeneity exhibit excellent catalytic activity, demonstrating the potential of the novel complexed sol-gel process for synthesizing high-performance Pt-Ru-Os-Ir based catalysts for direct methanol fuel cells.

  5. Multiferroic PbFe12O19 Ceramics

    Tan, Guo-Long; Wang, Min

    2011-01-01

    PbFe12O19 (PFO) powders in hexagonal structure have been synthesized by sol-gel process using lead acetate, glycerin and ferric acetylacetonate as the precursor. PbFe12O19 ceramics were obtained by sintering the PbFe12O19 powders at 1000\\degree C for 1 hour. Distorted flaky hexahedron grains are frequently observed in the SEM images of sintered PbFe12O19 ceramics. Large spontaneous polarization was observed in PbFe12O19 ceramic at room temperature, exhibiting a clear ferroelectric hysteresis ...

  6. Metalorganic chemical vapor deposition of highly oriented thin film composites of V2O5 and V6O13: Suppression of the metal–semiconductor transition in V6O13

    Sahana, MB; Shivashankar, SA

    2004-01-01

    Thin films of vanadium oxides were grown on fused quartz by metalorganic chemical vapor deposition using vanadyl acetylacetonate as the precursor. Growth at temperatures \\geq560 °C results in composites of strongly (00l)-oriented $V_{2}O_{5}$ and $V_{6}O_{13}$. The dominant phase of the film changes from $V_{2}O_{5}$ to $V_{6}O_{13}$, and back to $V_{2}O_{5}$, as the growth temperature is raised from 560 to 570 °C, then to 580 °C, as evidenced by x-ray diffraction and Rutherford backscatterin...

  7. Syntheses, magnetic and spectral studies on polystyrene supported coordination compounds of bidentate and tetradentate Schiff bases

    D Kumar; P K Gupta; A Syamal

    2005-05-01

    The reaction of aminomethylated polystyrene (PSCH2-NH2) and 2-hydroxyacetanilide in DMF results in the formation of polystyrene-anchored monobasic bidentate Schiff base, PSCH2-LH (I). On the other hand, the reaction of chloromethylated polystyrene (PSCH2-Cl), 3-formylsalicylic acid, ethylenediamine and acetylacetone in DMF in presence of ethyl acetate (EA) and triethylamine (TEA) produces another polystyrene-anchored dibasic tetradentate Schiff base, PSCH2-L'H2 (II). Both I and II react with a number of di-, tri- and hexavalent metal ions like Co, Ni, Cu, Zn and Cd to form polystyreneanchored coordination compounds, and these have been characterized and discussed.

  8. Preparation and Characterization of TiO2/CdS Layers as Potential Photoelectrocatalytic Materials

    Teofil-Danut Silipas; Ioan Bratu; Simina-Virginia Dreve; Ramona-Crina Suciu; Marcela-Corina Rosu; Emil Indrea

    2011-01-01

    The TiO2/CdS semiconductor composites were prepared on
    indium tin oxide (ITO) substrates in di®erent mass proportions via wet-chemical techniques using bi-distilled water, acetyl-acetone, poly-propylene-glycol and Triton X-100 as additives. The composite layers were annealed in normal conditions at the temperature of 450±C, 120 min. with a rate of temperature increasing of 5±C/min. The structural and optical properties of all the TiO2/CdS ayers were ch...

  9. Facile synthesis of deuterated and [14C]labeled analogues of vanillin and curcumin for use as mechanistic and analytical tools

    Gordon, Odaine N.; Graham, Leigh A.; Schneider, Claus

    2013-01-01

    Curcumin is a dietary diphenol with antioxidant, antinflammatory and antitumor activity. We describe facile procedures for the synthesis of [14C2]curcumin (4 mCi/mmol), [d6]curcumin, [d3]curcumin, [13C5]curcumin, and [d6]bicyclopentadione, the major oxidative metabolite of curcumin. We also describe synthesis of the labeled building blocks [14C]vanillin, [d3]vanillin, and [13C5]acetylacetone. The overall molar yields of the labeled products were 52% ([14C]) and 47% ([d3]) for vanillin and 25%...

  10. An Sn-Fe/carbon nanocomposite as an alternative anode material for rechargeable lithium batteries

    Sn-Fe/carbon nanocomposites were synthesized by the mechanochemical treatment of Sn with various amounts of an Fe/C composite through the pyrolysis of Fe(III) acetylacetonate. The composites were then evaluated as alternative anode materials for rechargeable lithium batteries. Based on the obtained ex situ X-ray diffraction (XRD) data, X-ray absorption spectroscopy (XAS) results, and differential capacity plots (DCPs), a reaction mechanism was suggested. It was found that increasing the amounts of the SnFe phase and pyrolyzed carbon in the composite improved its electrochemical characteristics in terms of its capacity retention

  11. Ferrocene and cobaltocene derivatives for non-aqueous redox flow batteries.

    Hwang, Byunghyun; Park, Min-Sik; Kim, Ketack

    2015-01-01

    Ferrocene and cobaltocene and their derivatives are studied as new redox materials for redox flow cells. Their high reaction rates and moderate solubility are attractive properties for their use as active materials. The cyclability experiments are carried out in a static cell; the results showed that these materials exhibit stable capacity retention and predictable discharge potentials, which agree with the potential values from the cyclic voltammograms. The diffusion coefficients of these materials are 2 to 7 times higher than those of other non-aqueous materials such as vanadium acetylacetonate, iron tris(2,2'-bipyridine) complexes, and an organic benzene derivative. PMID:25428116

  12. Fabrication of supported Ca-doped lanthanum niobate electrolyte layer and NiO containing anode functional layer by electrophoretic deposition

    Bozza, Francesco; Bonanos, Nikolaos

    2012-01-01

    The technique of electrophoretic deposition (EPD) has been applied for the preparation of a dense calcium-doped lanthanum niobate electrolyte film. La0.995Ca0.005NbO4 (LCN) powder was suspended in a solution of acetylacetone, iodine and water. The effects of suspension composition and deposition...... conditions were analyzed in order to identify a suitable set of EPD process parameters. The powders were deposited on a composite substrate of LCN, NiO, binder and graphite. A dense 8 μm film of lanthanum niobate supported on a porous substrate was obtained after sintering at 1200 °C. The technique was found...

  13. I- V characteristics of vanadium-flavonoid complexes based Schottky diodes

    Karimov, Khasan S.; Mahroof-Tahir, Mohammad; Saleem, Muhammad; Ahmad, Zubair

    2011-08-01

    In this study, we have investigated the current-voltage characteristics of the Schottky diodes of two vanadium complexes, VO 2(3-fl) ( 1) (3-fl=3-hydroxyflavone) and VO(acac) 2 ( 2), (acac=acetylacetonate), and their composites with TiO 2. Thin films of vanadium complexes and their composites were deposited by the centrifugation method. Current-voltage characteristics of the samples were processed by the modified Shockley equation, Cheung functions and space-charge limited currents (SCLC) approaches. Different junction parameters, such as series resistances, reverse saturation currents, ideality factors and barrier height of the samples, were determined.

  14. AVALIAÇÃO DE DIFERENTES REAGENTES COLORIMÉTRICOS PARA A DETERMINAÇÃO DE FORMALDEÍDO EM AMOSTRAS DE AR EM AMBIENTES INTERNOS

    Darllene Silveira

    2015-07-01

    Full Text Available Different colorimetric reagents, the Nash reagent (acetylacetone/ammonia solution, Purpald (4-amino- 3-hydrazino-5-mercapto-1,2,4-triazole/sodium hydroxide solution and 3-methyl-2-benzothiazolinone hydrazone (MBTH, were evaluated for the determination of formaldehyde in indoor air samples. Analytical parameters such as color stability of the product formed, sampling efficiency and reaction conditions were compared for the methodologies. Several method validation parameters were determined for the three colorimetric methods. The MBTH method showed better results and was used for the determination of formaldehydes in indoor environments.

  15. Structural and Luminescence Properties of Lu2O3:Eu3+ F127 Tri-Block Copolymer Modified Thin Films Prepared by Sol-Gel Method

    María Luz Carrera Jota; Dulce Yolotzin Medina Velazquez; Joel Moreno Palmerin; Antonieta García Murillo; Felipe de Jesús Carrillo Romo; Margarita García Hernández; Angel de Jesus Morales Ramírez

    2013-01-01

    Lu2O3:Eu3+ transparent, high density, and optical quality thin films were prepared using the sol-gel dip-coating technique, starting with lutetium and europium nitrates as precursors and followed by hydrolysis in an ethanol-ethylene glycol solution. Acetic acid and acetylacetonate were incorporated in order to adjust pH and as a sol stabilizer. In order to increment the thickness of the films and orient the structure, F127 Pluronic acid was incorporated during the sol formation. Structural, m...

  16. Binary heterocyclic systems containing the ethylideneamino linkage: synthesis of some new heterocyclic compounds bearing the naphtho-[2,1-b]furan moiety

    A. H. BEDAIR

    2006-05-01

    Full Text Available Ethylidene hydrazine (4a,b and thiazolidin-4-one (5 derivatives were synthesized by the reaction of ethylidenethiosemicarbazide derivative (3a with a-haloketone/ethyl bromoacetate, respectively. Hetrocyclization of ethylideneacetohydrazide derivative (7 with o-phenolic aldehydes gave the corresponding coumarin derivatives (8,9. The interaction of 7 with acetylacetone afforded the corresponding pyridine derivative (10. Treatment of the arylidene derivative 11b with malononitrile afforded the corresponding pyran derivative (12. The new products 3-12 were subjected to IR, 1H NMR and mass spectra studies.

  17. Influence of liquid-phase synthesis parameters on particle sizes and structural properties of nanocrystalline ZnO powders

    Chory, Christine; Mueller, Gerd [Lehrstuhl fuer Silicatchemie, Julius-Maximilians-Universitaet Wuerzburg, Roentgenring 11, 97070 Wuerzburg (Germany); Neder, Reinhard B.; Korsunskiy, Vladimir I. [Institut fuer Mineralogie, Julius-Maximilians-Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Niederdraenk, Franziska; Kumpf, Christian; Umbach, Eberhard [Lehrstuhl fuer Experimentelle Physik II, Physikalisches Institut, Julius-Maximilians-Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Schumm, Marcel; Lentze, Michael; Geurts, Jean; Astakhov, Georgy; Ossau, Wolfgang [Lehrstuhl fuer Experimentelle Physik III, Physikalisches Institut, Julius-Maximilians-Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany)

    2007-07-01

    In order to obtain well-controlled size and optimized structural properties, ZnO nanoparticles were grown from ethanolic solutions using acetate, acetylacetonate and dimethylpropylendiamine as stabilizer molecules. The low-temperature syntheses yield considerably large amounts of pure, nanocrystalline powder. Structural properties like particle size, crystal structure and quality were investigated by x-ray diffractometry, photoluminescence, and Raman spectroscopy. Particle sizes down to 4 nm and a size dependent anisotropic shape are observed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Bis(acetylacetonato-κ2O,O′(2-amino-1-methyl-1H-benzimidazole-κN3oxidovanadium(IV

    Zukhra Ch. Kadirova

    2009-07-01

    Full Text Available The title mixed-ligand oxidovanadium(IV compound, [VO(C5H7O22(C8H9N3], contains a VIV atom in a distorted octahedral coordination, which is typical for such complexes. The vanadyl group and the N-heterocyclic ligand are cis to each other. The coordination bond is located at the endocyclic N atom of the benzimidazole ligand. Intramolecular hydrogen bonds between the exo-NH2 group H atoms and acetylacetonate O atoms stabilize the crystal structure.

  19. 1. Mono([8]annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

    A reproducible, high-yield synthesis of mono([8]annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono([8]annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 is reported

  20. Effect of O2 flow rate on the thermochromic performance of VO2 coatings grown by atmospheric pressure CVD

    This paper reports the atmospheric pressure chemical vapor deposition of vanadium oxide coatings using vanadyl (IV) acetylacetonate at 500 oC. The as-grown samples for 0.8 L min-1 O2 flow rate showed an (022)-oriented single vanadium dioxide monoclinic phase of low crystallinity. The narrowest hysteresis width is observed for the particular flow rate indicating a dependency on the shape of the grown crystallites. Regarding the difference in transmittance is determined by the enhanced presence of short- and long-range bond ordering of the samples. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Perspectives of applications of alkoxide sol-gel process in heterogeneous catalysis

    Basic principles, specific features, advantages and drawbacks of alkoxide technology application for the preparation of oxide heterogeneous catalysts and carriers (RuO, V2O5, ZrO2, B2O3) have been considered. Application of acetylacetonates E(acac)n is considered alongside with mixed alkoxyacetylacetonates E(OR)x(acac)n-1. The lack of extensive commercial production of Al and Zr alkoxides in Russia rather than their high cost, is a real obstacle for alkoxide technology introduction. 293 refs., 2 figs., 2 tabs

  2. Complexometric titration of zirconium and yttrium in the same solution for its application in zirconia-yttria ceramics

    A simple stepwise complexometric method with EDTA has been developed for the determination of zirconium and yttrium in a single aliquot solution involving direct titration of zirconium at 1N HNO3 and 90 degC and of yttrium at pH 5.3 using methyl thymol blue as indicator. Interferences due to Fe, Ti, Al and Cu have been eliminated by masking with acetylacetone. The method has been standardised against synthetic solutions and applied to various zirconia-yttria ceramics and other yttria bearing materials. (author). 7 refs., 4 tabs

  3. Investigation into kinetics of redox interaction in the system Ce(4) β-diketonate-additional ligand

    The rate of reduction of β-diketonate complexes of Ce(4) to Ce(3) β-diketonates in benzene solution in the presence and in the absence of additional ligands is studied using spectrophotometry. The rate of reduction of Ce(4) β-diketonates increases in the series Ce(TTFA)44444 (TTFA - thenoyltrifluoroacetone, DPM- --dipivaloylmethane, DBM - dibenzoylemethane, BA benzoylacetone, AA - acetylaceton). The studied phosphorus-containing additional ligands as to their effect on the rate of Ce (4) reduction can be arranged in the following order: trioctylphosphine oxide>triphenylphosphine oxide>tributyl phosphate

  4. Near-Monodisperse Ni-Cu Bimetallic Nanocrystals of Variable Composition: Controlled Synthesis and Catalytic Activity for H2 Generation

    Zhang, Yawen; Huang, Wenyu; Habas, Susan E.; Kuhn, John N.; Grass, Michael E.; Yamada, Yusuke; Yang, Peidong; Somorjai, Gabor A.

    2008-07-22

    Near-monodisperse Ni{sub 1-x}Cu{sub x} (x = 0.2-0.8) bimetallic nanocrystals were synthesized by a one-pot thermolysis approach in oleylamine/1-octadecene, using metal acetylacetonates as precursors. The nanocrystals form large-area 2D superlattices, and display a catalytic synergistic effect in the hydrolysis of NaBH{sub 4} to generate H{sub 2} at x = 0.5 in a strongly basic medium. The Ni{sub 0.5}Cu{sub 0.5} nanocrystals show the lowest activation energy, and also exhibit the highest H{sub 2} generation rate at 298 K.

  5. Enhancement of Nitrite Reduction Kinetics on Electrospun Pd-Carbon Nanomaterial Catalysts for Water Purification.

    Ye, Tao; Durkin, David P; Hu, Maocong; Wang, Xianqin; Banek, Nathan A; Wagner, Michael J; Shuai, Danmeng

    2016-07-20

    We report a facile synthesis method for carbon nanofiber (CNF) supported Pd catalysts via one-pot electrospinning and their application for nitrite hydrogenation. A mixture of Pd acetylacetonate (Pd(acac)2), polyacrylonitrile (PAN), and nonfunctionalized multiwalled carbon nanotubes (MWCNTs) was electrospun and thermally treated to produce Pd/CNF-MWCNT catalysts. The addition of MWCNTs with a mass loading of 1.0-2.5 wt % (to PAN) significantly improved nitrite reduction activity compared to the catalyst without MWCNT addition. The results of CO chemisorption confirmed that the addition of MWCNTs increased Pd exposure on CNFs and hence improved catalytic activity. PMID:27387354

  6. Epoxidation of Alkenes with Molecular Oxygen Catalyzed by Immobilized Co(acac)2 and Co(bpy)2Cl2 Complexes within Nanoreactors of Al-MCM-41

    Farzaneh, F; Jalalian, M; Tayebi, L.

    2012-01-01

    Cobalt complexes with different ligands such as bipyridine, and acetylacetonate were immobilized within nanoreactors of Al-MCM-41, designated as Co(acac)2/Al-MCM-41 and Co(bipy)22+/Al-MCM41. The immobilized complexes were characterized by XRD, N2-adsorption desorption, FT-IR and UV-Vis techniques. It was found that Co(bipy)22+/Al-MCM41 and Co(acac)2/Al-MCM-41 successfully catalyze the oxidation of norbornene, styrene, cis-stilbene, trans-stilbene, and cyclohexene with 68% to 100% conversion a...

  7. Fluorine doped vanadium dioxide thin films for smart windows

    Kiri, Pragna [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Warwick, Michael E.A. [UCL Energy Institute, Central House, 14 Upper Woburn Place, London, WC1H 0HY (United Kingdom); Ridley, Ian [Bartlett School of Graduate Studies, University College London, Wates House, 22 Gordon Street, WC1H 0QB, London (United Kingdom); Binions, Russell, E-mail: r.binions@ucl.ac.uk [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London, WC1H 0AJ (United Kingdom)

    2011-12-01

    Thermochromic fluorine doped thin films of vanadium dioxide were deposited from the aerosol assisted chemical vapour deposition reaction of vanadyl acetylacetonate, ethanol and trifluoroacetic acid on glass substrates. The films were characterised with scanning electron microscopy, variable temperature Raman spectroscopy and variable temperature UV/Vis spectroscopy. The incorporation of fluorine in the films led to an increase in the visible transmittance of the films whilst retaining the thermochromic properties. This approach shows promise for improving the aesthetic properties of vanadium dioxide thin films.

  8. Effect of O{sub 2} flow rate on the thermochromic performance of VO{sub 2} coatings grown by atmospheric pressure CVD

    Louloudakis, Dimitris [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Department of Physics, University of Crete, 711 00 Heraklion, Crete (Greece); Vernardou, Dimitra; Dokianakis, Spyros [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Spanakis, Emmanouel [Department of Materials Science and Technology, University of Crete, 711 00 Heraklion, Crete (Greece); Panagopoulou, Marianthi; Raptis, Giannis [School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografou Campus, 157 80 Athens (Greece); Aperathitis, Elias [Department of Physics, University of Crete, 711 00 Heraklion, Crete (Greece); Kiriakidis, George [Department of Physics, University of Crete, 711 00 Heraklion, Crete (Greece); Institute of Electronic Structure and Laser, Foundation for Research and Technology- Hellas, P.O. Box 1527, 711 10 Heraklion, Crete (Greece); Katsarakis, Nikolaos [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Department of Electrical Engineering, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Institute of Electronic Structure and Laser, Foundation for Research and Technology- Hellas, P.O. Box 1527, 711 10 Heraklion, Crete (Greece); Koudoumas, Emmanouel [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Department of Electrical Engineering, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece)

    2015-07-15

    This paper reports the atmospheric pressure chemical vapor deposition of vanadium oxide coatings using vanadyl (IV) acetylacetonate at 500 {sup o}C. The as-grown samples for 0.8 L min{sup -1} O{sub 2} flow rate showed an (022)-oriented single vanadium dioxide monoclinic phase of low crystallinity. The narrowest hysteresis width is observed for the particular flow rate indicating a dependency on the shape of the grown crystallites. Regarding the difference in transmittance is determined by the enhanced presence of short- and long-range bond ordering of the samples. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. The role of detergent in labeling of Erysipelothrix rhusiopathiae bacteria

    The chelating agents oxine, acetylacetone, tropolone, and 2-mercaptopyridine 1-oxide were analysed for their suitability in labelling the bacterium Erysipelothrix rhusiopathiae (E.r.), strain B10, with 111In and 67Ga. The labelling conditions were improved. The bactericidal activity of the labeling process was investigated. The different chelates did not result in a significant difference in labelling yield. The addition of 0.01% detergent to the labelling buffer doubled the labelling yield up to 45%. Labelled bacteria were injected intravenously into rats. The percentage organ distribution was determined and compared with a control group. (author)

  10. The isolation of beryllium and mercury from lithium chloride solution by means of gas extraction

    The possibility and optimal conditions of beryllium and mercury extraction using acetylacetone (HAA) from lithium chloride solution by argon blowing through the solution are determined. Dependences of extraction degrees and distribution coefficients on different parameters of liquid phase: initial pH value, lithium chloride concentration and initial content of HAA, are presented. The degree of beryllium extraction reaches the maximum at liquid phase pH of 4.4-5.25 and concentration of lithium chloride of 8.5 mol/l. Distribution coefficient changes in inverse proportion to the extraction degree

  11. Fabrication of Size-Tunable Metallic Nanoparticles Using Plasmid DNA as a Biomolecular Reactor

    Charles Michael Drain

    2011-10-01

    Full Text Available Plasmid DNA can be used as a template to yield gold, palladium, silver, and chromium nanoparticles of different sizes based on variations in incubation time at 70 °C with gold phosphine complexes, with the acetates of silver or palladium, or chromium acetylacetonate. The employment of mild synthetic conditions, minimal procedural steps, and aqueous solvents makes this method environmentally greener and ensures general feasibility. The use of plasmids exploits the capabilities of the biotechnology industry as a source of nanoreactor materials.

  12. Complete removal of uranyl nitrate from tissue matrix using supercritical fluid extraction

    The removal of uranyl nitrate from tissue matrix has been studied with supercritical carbon dioxide modified with methanol alone as well as complexing reagents dissolved in methanol. A systematic study of various complexing agents led to the development of an extraction procedure for the quantitative recovery of uranium from tissue matrix with supercritical carbon dioxide modified with methanol containing small quantities of acetylacetone. The drying time and temperature employed in loading of uranyl nitrate onto tissue paper were found to influence the extraction efficiency significantly

  13. Determination of the Hydrogenation Degree of Telechelic Polybutadiene by {sup 1}H NMR

    Lira, C.H.; Nicolini, L.F.; Dolinsky, M.C.B. [Petroflex Industria e Comercio S.A., Duque de Caxias, RJ (Brazil)]. E-mail: clira@petroflex.com.br; Oliveira, C.M.F.; Gomes, A.S. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas Professora Eloisa Mano

    2006-07-01

    The liquid hydroxyl terminated polybutadiene (HTPB) was hydrogenated to improve its thermal and oxidative resistance. Hydrogenation was carried out using cyclohexane as solvent and a soluble catalyst system consisting of diisobutyl aluminum hydride (DIBAL-H) and Co{sup III} acetylacetonate, at a molar ratio of 6:1. Hydrogenation was only possible after esterification of hydroxyl groups due to interactions with the catalyst system. {sup 1}H NMR technique was used to confirm the esterification and hydrogenation of the polymeric material. This method can be also used to determine the degree of hydrogenation in different reaction times. (author)

  14. 1. Mono([8]annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

    Boussie, T.R.

    1991-10-01

    A reproducible, high-yield synthesis of mono([8]annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono([8]annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 is reported.

  15. 1. Mono((8)annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

    Boussie, T.R.

    1991-10-01

    A reproducible, high-yield synthesis of mono((8)annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono((8)annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 is reported.

  16. NOVEL SYNTHESIS OF POLYARYLENESULFONIUM CATIONS THROUGH A MULTI-ELECTRON TRANSFER PROCESS

    1998-01-01

    The oxidative polymerization of aryl sulfoxides provides a novel polysulfonium compound, poly(methylsulfonio-1,4-phenylenethio-1,4-phenylene cation) in quantitative yield. The polymerization proceeds efficiently in an acidic solution under atmospheric conditions. Oxygen, chemical and electrochemical oxidations are available. Vanadyl acetylacetonate and cerium ammonium nitrate act as an effective catalyst for the oxygen oxidative polymerization. The polymerization mechanism involves multielectron oxidation of the sulfides followed by successive electrophilic substitution. The resulting polyarylenesulfonium cations are useful as a soluble precursor for the synthesis of high molecular weight (Mw>105) poly(thio arylne)s.

  17. Avaliação da "microverdura" de sínteses com a estrela verde

    Rita C. C. Duarte

    2014-07-01

    Full Text Available This article reports a study to increase the overall greenness of chemical syntheses for first-year university laboratories. The separate evaluation of the micro-greenness of the three stages of synthesis (reaction, isolation and purification using the Green Star (GS was implemented and their respective contribution to overall greenness was investigated for two examples: syntheses of cobalt (III tris(acetylacetonate and potassium nitrilosulfonate. Results showed that the post-reaction (work-up steps are the most problematic for overall greenness. Greenness optimization can be achieved by combining the greenest procedures for each step obtained from different protocols available in the literature.

  18. Density Functional Theory Study of Atomic Layer Deposition of Zinc Oxide on Graphene

    Ali, Amgad Ahmed; Hashim, Abdul Manaf

    2015-07-01

    The dissociation of zinc ions (Zn2+) from vapor-phase zinc acetylacetonate, Zn(C5H7O2)2, or Zn(acac)2 and its adsorption onto graphene oxide via atomic layer deposition (ALD) were studied using a quantum mechanics approach. Density functional theory (DFT) was used to obtain an approximate solution to the Schrödinger equation. The graphene oxide cluster model was used to represent the surface of the graphene film after pre-oxidation. In this study, the geometries of reactants, transition states, and products were optimized using the B3LYB/6-31G** level of theory or higher. Furthermore, the relative energies of the various intermediates and products in the gas-phase radical mechanism were calculated at the B3LYP/6-311++G** and MP2/6-311 + G(2df,2p) levels of theory. Additionally, a molecular orbital (MO) analysis was performed for the products of the decomposition of the Zn(acac)2 complex to investigate the dissociation of Zn2+ and the subsequent adsorption of H atoms on the C5H7O2 cluster to form acetylacetonate enol. The reaction energies were calculated, and the reaction mechanism was accordingly proposed. A simulation of infrared (IR) properties was performed using the same approach to support the proposed mechanism via a complete explanation of bond forming and breaking during each reaction step.

  19. 黄铁矿和黄铜矿中铁铜钴镍的纸层析及定量测定

    中国科学院贵阳地球化学研究所中心分析室

    1973-01-01

    The method of paper chromatography for the separation and quantitative determination of iron, copper, cobalt and nickel in pyrite and chalcopyrite is described.The three systems of ehromtograpbie solvents for the separation of iron, copper, cobalt and nickel on the 8×25 or 15×26 cm Whatman No. 3, involving acetone-hydrochloric acid-water, butanone-hydrochloric acid-water and acetone-acetylacetone-hydrochloric acid-water have been tested. As a developing system for the separation of this four elements in samples, the mixture of aoetone-acetylacetone-hydroehlorio acid-water is considered to be the best. After developing in a 30×40 cm glass dryer, the paper is dried in air and rendered the zone visible by treatment with 0.1% (W/V) rubeanic acid solution. The R1 values, colour reactions with this spray reagent and the eolour are given. A good paper chromatography of elements has been obtained. The elements are determined by colorimetrie method, with 1-nitroso-2-naphthol for cobalt,1-(2-pyridylozo)-2-naphthol for nickel, oxalic acid bis-cyelohexylidene hydrozide for copper, and sulfosalicylic acid for iron. In addition, iron and copper can also be determined by titration with potassium dichromate solution and iodimetry respectively.

  20. Graphene oxide/manganese ferrite nanohybrids for magnetic resonance imaging, photothermal therapy and drug delivery.

    Yang, Yan; Shi, Haili; Wang, Yapei; Shi, Benzhao; Guo, Linlin; Wu, Dongmei; Yang, Shiping; Wu, Huixia

    2016-01-01

    Superparamagnetic manganese ferrite (MnFe2O4) nanoparticles have been deposited on graphene oxide (GO) by the thermal decomposition of manganese (II) acetylacetonate and iron (III) acetylacetonate precursors in triethylene glycol. The resulting GO/MnFe2O4 nanohybrids show very low cytotoxicity, negligible hemolytic activity, and imperceptible in vivo toxicity. In vitro and in vivo magnetic resonance imaging experiments demonstrate that GO/MnFe2O4 nanohybrids could be used as an effective T2 contrast agent. The strong optical absorbance in the near-infrared (NIR) region and good photothermal stability of GO/MnFe2O4 nanohybrids result in the highly efficient photothermal ablation of cancer cells. GO/MnFe2O4 nanohybrids can be further loaded with doxorubicin (DOX) by π-π conjugate effect for chemotherapy. DOX release from GO/MnFe2O4 is significantly influenced by pH and can be triggered by NIR laser. The enhanced cancer cell killing by GO/MnFe2O4/DOX composites has been achieved when irradiated with near-infrared light, suggesting that the nanohybrids could deliver both DOX chemotherapy and photothermal therapy with a synergistic effect. PMID:26296777

  1. Simple one-pot synthesis of platinum-palladium nanoflowers with enhanced catalytic activity and methanol-tolerance for oxygen reduction in acid media

    Graphical abstract: PtPd nanoflowers were fabricated by one-pot solvothermal co-reduction method in oleylamine system, which exhibited the improved electrocatalytic activity and higher methanol tolerance for oxygen reduction, compared with commercial Pt and Pd black catalysts. - Highlights: • Bimetallic alloyed PtPd nanoflowers are prepared by a simple one-pot solvothermal co-reduction method. • PtPd nanoflowers display high catalytic performance for ORR dominated by a four-electron pathway. • PtPd nanoflowers show good methanol tolerance for ORR. - Abstract: In this work, bimetallic alloyed platinum-palladium (PtPd) nanoflowers are fabricated by one-pot solvothermal co-reduction of Pt (II) acetylacetonate and Pd (II) acetylacetonate in oleylamine system. The as-prepared nanostructures show the enhanced electrocatalytic activity for oxygen reduction reaction (ORR), dominated by a four-electron pathway based on the Koutecky-Levich plots, mainly owing to the inhibition of the formation of Pt–OHad via the downshift of d-band center for Pt. Meanwhile, PtPd nanoflowers display good methanol tolerance and improved stability for ORR. The chronoamperometry test reveals that the current of PtPd nanoflowers remains 45.9% of its original value within 6000 s, much higher than those of commercial Pt (36.7%) and Pd (32.2%) black catalysts. Therefore, PtPd nanoflowers with unique interconnected structures can be used as a promising cathode catalyst in direct methanol fuel cells

  2. Nano-sized, quaternary titanium(IV) metal-organic frameworks with multidentate ligands

    Baranwal, Balram Prasad; Singh, Alok Kumar

    2010-12-01

    Some mononuclear nano-sized, quaternary titanium(IV) complexes having the general formula [Ti(acac)(OOCR) 2(SB)] (where Hacac = acetylacetone, R = C 15H 31 or C 17H 35, HSB = Schiff bases) have been synthesized using different multidentate ligands. These were characterized by elemental analyses, molecular weight determinations and spectral (FTIR, 1H NMR and powder XRD) studies. Conductance measurement indicated their non-conducting nature which may behave like insulators. Structural parameters like the values of limiting indices h, k, l, cell constants a, b, c, angles α, β, γ and particle size are calculated from powder XRD data for complex 1 which indicated nano-sized triclinic system in them. Bidentate chelating nature of acetylacetone, carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Molecular weight determinations confirmed mononuclear nature of the complexes. On the basis of physico-chemical studies, coordination number 8 was assigned for titanium(IV) in the complexes. Transmission electron microscopy (TEM) and the selected area electron diffraction (SAED) studies indicated spherical particles with poor crystallinity.

  3. Optimization of process conditions for the production of TiO2–N film by sol–gel process using response surface methodology

    Rui Liu; Ching-Shieh Hsieh; Wein-Duo Yang; Hui-Yi Tsai

    2014-10-01

    TiO2–N film has been synthesized successfully through the sol–gel method. It is found that the anatase phase is formed at 400 °C and converted to rutile phase at 600 °C. The response surface methodology (RSM) and Box–Behnken design were employed to optimize the process conditions of sol–gel process. Based on the results in preliminary experiments, we selected molar ratio of surfactant to Ti, molar ratio of acetylacetone to Ti, molar ratio of water to Ti and calcination temperature as the key process factors affecting the roughness of TiO2–N film. The adjusted determination coefficient ($R^{2}_{\\text{Adj}}$) of the regression model was 0.9651, which indicated that the regression model is significant. By analysing the contour plots of response surface as well as solving the regression model, the optimized conditions were obtained as: 0.19 for molar ratio of surfactant to Ti, 2.01 for molar ratio of acetylacetone to Ti, 1.38 for molar ratio of water to Ti and 500 °C for calcination temperature. The predicted roughness of TiO2–N film for the optimized condition was calculated to be 41 nm. Confirmation experiments using the optimized conditions were performed, and a value about 43 nm was obtained. The experimental results are in good agreement with the predicted results.

  4. Long-chain amine-templated synthesis of gallium sulfide and gallium selenide nanotubes

    Seral-Ascaso, A.; Metel, S.; Pokle, A.; Backes, C.; Zhang, C. J.; Nerl, H. C.; Rode, K.; Berner, N. C.; Downing, C.; McEvoy, N.; Muñoz, E.; Harvey, A.; Gholamvand, Z.; Duesberg, G. S.; Coleman, J. N.; Nicolosi, V.

    2016-06-01

    We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization.We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01663d

  5. Mesoporous Titania Powders: The Role of Precursors, Ligand Addition and Calcination Rate on Their Morphology, Crystalline Structure and Photocatalytic Activity

    Elisabetta Masolo

    2014-07-01

    Full Text Available We evaluate the influence of the use of different titania precursors, calcination rate, and ligand addition on the morphology, texture and phase content of synthesized mesoporous titania samples, parameters which, in turn, can play a key role in titania photocatalytic performances. The powders, obtained through the evaporation-induced self-assembly method, are characterized by means of ex situ X-Ray Powder Diffraction (XRPD measurements, N2 physisorption isotherms and transmission electron microscopy. The precursors are selected basing on two different approaches: the acid-base pair, using TiCl4 and Ti(OBu4, and a more classic route with Ti(OiPr4 and HCl. For both precursors, different specimens were prepared by resorting to different calcination rates and with and without the addition of acetylacetone, that creates coordinated species with lower hydrolysis rates, and with different calcination rates. Each sample was employed as photoanode and tested in the water splitting reaction by recording I-V curves and comparing the results with commercial P25 powders. The complex data framework suggests that a narrow pore size distribution, due to the use of acetylacetone, plays a major role in the photoactivity, leading to a current density value higher than that of P25.

  6. Ion-molecule interactions of biological importance. A vibrational spectroscopic study of magnesium complexes with hydroxylated quinones

    Luteoskyrin and rugulosin are two naturally occurring yellow pigments with hydroxylated bis-anthraquinonic structures. They cause serious liver disorders in man due to the formation of complexes of the type pigment-Mg2+-DNA. In order to elucidate the structure of these complexes we have studied the vibrational spectra of some model systems, namely 1-hydroxy- and 1,4-dihydroxyanthraquinone, their magnesium chelate complexes, and a series of simpler complexes as the acetylacetonates of some divalent metals. Complete vibrational assignment are proposed for anthraquinone-9,10, the two hydroxylated and deureroxylated derivatives and their magnesium complexes. The substitution of 26Mg in place of 24Mg in these complexes enabled us to assign the Mg-O vibrations; their number corresponds to a hexa-coordinated metal in the acetylacetonate case and to a tetra-coordinated structure in the anthraquinone-olates complexes. The position of the ν C=0 and ν C-0 vibrations bands in the complexes shows that the bonds in the chelated ring of Mg(1-O-AQ)2 retains their single and double bond characteristic whereas in the CMg(1,4-O2,-AQ)n a resonating structure appears in the ring. The study of the IR and R spectra of the complexes enabled a tetrahedral structure to be proposed for the oxygens around the magnesium. Finally it was noted that the Mg-O bonds possessed a high degree of covalent character. (author)

  7. Synthesis and spectroscopic characterization of some lanthanide(III nitrate complexes of ethyl 2-[2-(1-acetyl-2-oxopropylazo]-4,5-dimethyl-3-thiophenecarboxyate

    CHEMPAKAM JANARDHANAN ATHIRA

    2011-02-01

    Full Text Available Ethyl 2-[2-(1-acetyl-2-oxopropylazo]-4,5-dimethyl-3-thiophenecarboxyate was synthesized by coupling diazotized ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate with acetylacetone. Based on various spectral studies and elemental analysis, an intramolecularly hydrogen-bonded azo-enol structural form was assigned for the ligand. This ligand is versatile in forming a series of lanthanide(III complexes, viz., lanthanum(III, cerium(III, praseodymium(III, neodymium(III, samarium(III and gadolinium(III, which were characterized through various spectral studies, elemental analysis, magnetic susceptibility measurements, molar conductance and thermal analysis. The spectral data revealed that the ligand acted as a neutral tridentate, coordinating to the metal ion through one of the azo nitrogen atoms, the ester carbonyl and the enolic oxygen of the acetylacetone moiety, without deprotonation. Molar conductance values adequately supported their non-electrolytic nature. The ligand and lanthanum(III complex were subjected to X-ray diffraction studies. In addition, the lanthanum(III complex underwent a facile transesterification reaction on refluxing with methanol for a long period. The thermal behaviour of the lanthanum(III complex was also examined

  8. Frequency-dependent conductivity in tris(acetylacetonato)manganese(III) thin films on Si(1 0 0) substrates

    Thin tris(acetylacetonate)manganese(III) films of amorphous structure were prepared by vacuum deposition on glass and Si (1 0 0) substrates. The as-deposited and annealed-in-vacuum films were characterised by X-ray fluorescence, X-ray diffraction and optical absorption spectroscopy. The prepared title-complex amorphous films were investigated as insulators for Al/insulator/Si(P) metal-insulator-semiconductor (MIS) structures, which were characterised by the measurement of their capacitance and AC-conductance as a function of gate voltage. From those measurements, State density D it at insulator/semiconductor interface and the density of the fixed charges in the complex insulator were determined. It was found that D it was in order of 1011 eV-1 cm-2 and the surface charge density in the insulator film was in order of 1011-1012 cm-2.The frequency dependence of the electrical conductivity and dielectric properties of MIS structures were studied at room temperature. The results follow the correlated barrier-hopping (CBH) model, from which the fundamental absorption bandgap, the minimum hopping distance and other parameters of the model were determined. This study shows that the tris(acetylacetonate)manganese(III) films grown on Si(1 0 0) is a promising candidate for high-ε dielectric applications. It displays sufficiently high-ε value in the range 30-40

  9. Fabrication and performance of silver coated copper powder

    Cao, Xiao Guo; Zhang, Hai Yan

    2012-08-01

    Electroless silver coating on copper powder and its effects on oxidation resistance were investigated by varying the fabrication parameters. Using acetylacetone (C5H8O2) as chelating reagent, silver-coated copper powder was fabricated by displacement reaction method. In the process, acetylacetone forms chelating compound with Cu 2+, which prevent the formation of [Cu (NH3)4]2+. Therefore, Ag + can be reduced continully and deposited on the surface of copper particles. As-coated copper particles were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDS). The oxidation resistance of silver coated copper powder was investigated by gravimetric method. It was found that a fairly continuous silver layer was formed on the surface of copper powder by the electroless type of substitution plating. When the silver content reached 10 wt. %, silver was homogeneously distributed around the copper particles and few free silver particles were detected. The results showed that the silver coated copper powder with the best oxidation resistance was prepared at 40°C and the C5H8O2/AgNO3 molar ratio was 1:1.

  10. Influences of alcoholic solvents on spray pyrolysis deposition of TiO2 blocking layer films for solid-state dye-sensitized solar cells

    Influences of alcoholic solvents for titanium diisopropoxide bis(acetylacetonate) (TPA) precursor solutions on the spray pyrolysis deposited TiO2 films and the photovoltaic performance of the solid-state dye-sensitized solar cells (SDSCs) using these TiO2 films as the blocking layers were investigated. Smooth TiO2 films were obtained by spray pyrolysis deposition of a TPA solution in isopropanol (IPA) at a relatively low temperature of 260 °C. On the other hand, when ethanol was used as solvent, the TiO2 films fabricated at the same temperature showed much rougher surfaces with many pinholes. Our results showed that ethanol reacts with TPA to form titanium diethoxide bis(acetylacetonate) (TEA), which requires a higher thermal decomposition temperature than that of TPA. SDSCs with TiO2 blocking layer films fabricated using a TPA solution in IPA showed higher power conversion efficiencies with smaller variations. - Graphical abstract: Alcoholic solvents used for the TiO2 precursor play a critical role in determining the surface morphology of blocking layers and thus the photovoltaic performance of the SDSCs. Highlights: ► Solvent influences morphology of spray pyrolysis deposited TiO2 blocking layer. ► Ethanol reacts with TPA, resulting poor quality of blocking layer. ► Isopropanol is better than ethanol for obtaining smooth blocking layer. ► SDSC with blocking layer made with isopropanol showed better performance.

  11. Effects of the addition of H2O and NH4OH in the optical and structural properties of the thin films of Y2O3 deposited by pyrolytic spray

    In this work we studied the optical and structural properties of yttrium oxide thin films deposited by spray pyrolysis. Yttrium acetylacetonate was used as raw material and N, N-DMF was used as solvent. The films were deposited on Si (100) and Si (111) substrates at temperatures of 400, 450, 500 and 550 C. The optical and structural characteristics of the films were dramatically improved when a mist of H2O and/or NH40H was simultaneously added during deposition of the films. A refraction index up to 1.88, and deposition rates lower than 10 A/sec were obtained in the films. Infrared spectroscopy measurements indicate that the films resulted free from -OH bonds. X-ray diffraction patterns reveal that the films were polycrystalline. In addition, the relative chemical composition of the films was determined by Energy Dispersive Spectroscopy and the surface morphology was analyzed in the Atomic Force Microscope. (Author)

  12. Electronic structure of planar-quasicycled organic molecules with intramolecular hydrogen bond

    ALEXEI N. PANKRATOV

    2007-03-01

    Full Text Available By means of the HF/6-311G(d,p method, the electronic structure of the series of organic molecules, among which are malonaldehyde, acetylacetone, thiomalonaldehyde,’the derivatives of aniline 2-XC6H4NH2, phenol 2-XC6H4OH, benzenethiol 2-XC6H4SH (X = CHO, COOH, COO-, NO, NO2, OH, OCH3, SH, SCH3, F, Cl, Br, 8-hydroxyquinoline, 8-mercaptoquinoline, tropolone, has been studied. The intramolecular hydrogen bond (IHB has been established to lead to a local electron redistribution in quasicycle, and primarily to the electron density transfer between the direct IHB participants – from the hydrogen atom toward the proton-aceptor atom. On forming the IHB of the S–H···O type, the electron density in general decreases on the sulphohydryl hydrogen atom and increases on the sulphur atom.

  13. Thermodynamic study of CVD-ZrO{sub 2} phase diagrams

    Torres-Huerta, A.M., E-mail: atorresh@ipn.m [Research Center for Applied Science and Advanced Technology, Altamira-IPN, Altamira C.P.89600 Tamaulipas (Mexico); Vargas-Garcia, J.R. [Dept of Metallurgical Eng., ESIQIE-IPN, Mexico 07300 D.F. (Mexico); Dominguez-Crespo, M.A. [Research Center for Applied Science and Advanced Technology, Altamira-IPN, Altamira C.P.89600 Tamaulipas (Mexico); Romero-Serrano, J.A. [Dept of Metallurgical Eng., ESIQIE-IPN, Mexico 07300 D.F. (Mexico)

    2009-08-26

    Chemical vapor deposition (CVD) of zirconium oxide (ZrO{sub 2}) from zirconium acetylacetonate Zr(acac){sub 4} has been thermodynamically investigated using the Gibbs' free energy minimization method and the FACTSAGE program. Thermodynamic data Cp{sup o}, DELTAH{sup o} and S{sup o} for Zr(acac){sub 4} have been estimated using the Meghreblian-Crawford-Parr and Benson methods because they are not available in the literature. The effect of deposition parameters, such as temperature and pressure, on the extension of the region where pure ZrO{sub 2} can be deposited was analyzed. The results are presented as calculated CVD stability diagrams. The phase diagrams showed two zones, one of them corresponds to pure monoclinic phase of ZrO{sub 2} and the other one corresponds to a mix of monoclinic phase of ZrO{sub 2} and graphite carbon.

  14. Thermodynamic study of CVD-ZrO2 phase diagrams

    Chemical vapor deposition (CVD) of zirconium oxide (ZrO2) from zirconium acetylacetonate Zr(acac)4 has been thermodynamically investigated using the Gibbs' free energy minimization method and the FACTSAGE program. Thermodynamic data Cpo, ΔHo and So for Zr(acac)4 have been estimated using the Meghreblian-Crawford-Parr and Benson methods because they are not available in the literature. The effect of deposition parameters, such as temperature and pressure, on the extension of the region where pure ZrO2 can be deposited was analyzed. The results are presented as calculated CVD stability diagrams. The phase diagrams showed two zones, one of them corresponds to pure monoclinic phase of ZrO2 and the other one corresponds to a mix of monoclinic phase of ZrO2 and graphite carbon.

  15. Conformational features of meso-tetrathienylporphyrins and photosensitising properties of their β-1-acetyl-2-oxopropyl derivatives

    Prasath, Rangaraj; Bhavana, Purushothaman

    2015-08-01

    The difference in the site of electrophilic nitration of meso-tetra-thien-2-yl- and thien-3-yl-porphyrins is explained based on the difference in extended conjugation between porphyrin core and meso-thienyl rings. The significance of resonance in dictating the site of substitution is also explained based on the behavior of tetrakis(5-bromothien-2-yl)porphyrin toward electrophilic nitration. Three new β-1-acetyl-2-oxopropyl-substituted porphyrins are synthesized by Michael addition of acetylacetone group on pyrrole β-nitroporphyrins. The photosensitizing properties of these porphyrins is investigated using porphyrin-TiO2 composites in the degradation of 4-nitrophenol. The results showed the importance of the effect of the position of sulfur on the thienyl ring and the orientation of meso-thienyl groups with the central macrocyclic ring of porphyrins in deciding its efficiency as photosensitiser.

  16. Phosphorescent Platinum(II) Complexes with Mesoionic 1H-1,2,3-Triazolylidene Ligands.

    Soellner, Johannes; Tenne, Mario; Wagenblast, Gerhard; Strassner, Thomas

    2016-07-11

    The synthesis and characterization of eight unprecedented phosphorescent C^C* cyclometalated mesoionic aryl-1,2,3-triazolylidene platinum(II) complexes with different β-diketonate ligands are reported. All compounds proved to be strongly emissive at room temperature in poly(methyl methacrylate) films with an emitter concentration of 2 wt %. The observed photoluminescence properties were strongly dependent on the substitution on the aryl system and the β-diketonate ligand. Compared to acetylacetonate, the β-diketonates with aromatic substituents (mesityl and duryl) were found to significantly enhance the quantum yield while simultaneously reducing the emission lifetimes. Characterization was carried out by standard techniques, as well as solid-state structure determination, which confirmed the binding mode of the carbene ligand. DFT calculations, carried out to predict the emission wavelength with maximum intensity, were in excellent agreement with the (later) obtained experimental data. PMID:27294887

  17. Novel magnetite-silica nanocomposite (Fe3O4-SBA-15) particles for DNA binding and gene delivery aided by a magnet array.

    Yiu, Humphrey H P; McBain, Stuart C; Lethbridge, Zoe A D; Lees, Martin R; Palona, Iryna; Olariu, Cristina I; Dobson, Jon

    2011-04-01

    Novel magnetite-silica nanocomposite particles were prepared using SBA-15 nanoporous silica as template. Magnetite nanoparticles were impregnated into the nanopore array of the silica template through thermal decomposition of iron(III) acetylacetonate, Fe(AcAc)3 at 200 degrees C. These composite particles were characterized using TEM, XRD and SQUID magnetometry. The TEM images showed that the size of composite particles was around 500 nm and the particles retained the nanoporous array of SBA-15. The formation of magnetite nanoparticles was confirmed by the powder XRD study. These composite particles also exhibited ferrimagnetic properties. By coating with short chain polyethyleneimine (PEI), these particles are capable of binding DNA molecules for gene delivery and transfection. With an external magnetic field, the transfection efficiency was shown to have an increase of around 15%. The results indicated that these composite nanoparticles may be further developed as a new tool for nanomagnetic gene transfection. PMID:21776740

  18. Solution processed nickel oxide anodes for organic photovoltaic devices

    Mustafa, Bestoon; Griffin, Jonathan; Alsulami, Abdullah S.; Lidzey, David G.; Buckley, Alastair R., E-mail: alastair.buckley@sheffield.ac.uk [Department of Physics and Astronomy, Hicks Building, Hounsfield Road, University of Sheffield, Sheffield S3 7RH (United Kingdom)

    2014-02-10

    Nickel oxide thin films have been prepared from a nickel acetylacetonate (Ni(acac)) precursor for use in bulk heterojunction organic photovoltaic devices. The conversion of Ni(acac) to NiO{sub x} has been investigated. Oxygen plasma treatment of the NiO layer after annealing at 400 °C affords solar cell efficiencies of 5.2%. Photoelectron spectroscopy shows that high temperature annealing converts the Ni(acac) to a reduced form of nickel oxide. Additional oxygen plasma treatment further oxidizes the surface layers and deepens the NiO work function from 4.7 eV for the annealed film, to 5.0 eV allowing for efficient hole extraction at the organic interface.

  19. Deposition of indium tin oxide by atmospheric pressure chemical vapour deposition

    We report the deposition of indium tin oxide (ITO) by atmospheric pressure chemical vapour deposition (APCVD). This process is potentially scalable for high throughput, large area production. We utilised a previously unreported precursor combination; dimethylindium acetylacetonate, [Me2In(acac)] and monobutyltintrichloride, MBTC. [Me2In(acac)] is a volatile solid. It is more stable and easier to handle than traditional indium oxide precursors such as pyrophoric trialkylindium compounds. Monobutyltintrichloride (MBTC) is also easily handled and can be readily vaporised. It is compatible with the process conditions required for using [Me2In(acac)]. Cubic ITO was deposited at a substrate temperature of 550 °C with growth rates exceeding 15 nm/s and growth efficiencies of between 20 and 30%. Resistivity was 3.5 × 10−4 Ω cm and transmission for a 200 nm film was > 85% with less than 2% haze.

  20. Deposition of fluorine doped indium oxide by atmospheric pressure chemical vapour deposition

    We report the deposition of fluorine doped indium oxide by atmospheric pressure chemical vapour deposition (APCVD) using a previously unreported precursor combination; dimethylindium acetylacetonate, [Me2In(acac)] and trifluoroacetic acid (TFA). This process is potentially scalable for high throughput, large area production. [Me2In(acac)] is a volatile solid. It is more stable and easier to handle than traditional indium oxide precursors such as pyrophoric trialkylindium compounds. Cubic fluorine doped indium oxide (F.In2O3) was deposited at a substrate temperature of 550 °C with growth rates exceeding 8 nm/s. Resistivity was 8 × 10−4 Ω cm and transmission for a 200 nm film was > 80% with less than 1% haze.

  1. Effects of gamma radiation on the photoluminescence properties of polycarbonate matrices doped with terbium complex

    Luminescent films containing terbium complex [Tb(acac)3(H2O)3] (acac=acetylacetonate) doped into a polycarbonate (PC) matrix were prepared and irradiated at low-dose gamma radiation with ratio of 5 and 10 kGy. The PC polymer was doped with 5% (w/w) of the Tb3+ complex. The thermal behavior was investigated by utilization of differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). Changes in thermal stability due to the addition of doping agent into the polycarbonate matrix. Based on the emission spectra of PC:5% Tb(acac)3 film were observed the characteristic bands arising from the 5D4→7FJ transitions of Tb3+ ion (J=0-6), indicating the ability to obtain the luminescent films. Doped samples irradiated at low dose of gamma irradiation showed a decrease in luminescence intensity with increasing of the dose.

  2. Synthesis and characterization of spherical calcia stabilized zirconia nano-powders obtained by spray pyrolysis

    Fine, spherical Ca0.15Zr0.85O1.85 nano-powders were prepared by spray pyrolysis, starting from a mixed aqueous and ethylic solution of zirconium acetylacetonate and calcium acetate. The influence of solution concentration, furnace temperature, mass flow of carrier gas and voltage of precipitator on microstructure, average particles size and recovery percentage were evaluated. The powders were synthesized without sintering, and for adequate preparation conditions, were mostly spherical, solid and narrowly size distributed. Average particle size ranges between 40 and 350 nm. Transmission electron micrographs showed that crystalline calcia stabilized zirconia particles were constituted by small crystallites, their size varying between 2 and 40 nm. X-ray diffraction analysis shows that powders obtained at low temperature were amorphous; for higher temperatures (∼800 deg. C), it is found the presence of the tetragonal and cubic phases

  3. Abordagem teórico-experimental da teoria do campo cristalino na disciplina de síntese inorgânica

    Bárbara C Leal

    2011-01-01

    Full Text Available We describe herein the synthesis and characterization of the complexes KNiF3, [Ni(en3]I2, [Ni(en3]Cl2, [Ni(acac2(H2O2], [Ni(en2(H2O2]Cl2 and [Ni(NH36](BF42 (en = ethylenediamine, acac- = acetylacetonate performed in the inorganic synthesis major course at the Chemistry Institute of UFRGS (Universidade Federal do Rio Grande do Sul. The compounds were characterized by infrared and electronic spectroscopy and the electrolytic conductivity was measured. The parameters 10Dq and B were obtained from the electronic spectra and the nefelauxetic and spectrochemical series were determined. The obtained spectrochemical series was F- < acac- < NH3 < en and the nefeulaxetic series was en < NH3 < acac- < F-.

  4. The investigation of structure and energetics of beta-diketonates. Communication X. The structure of Sc(aa)3 studied by gas electron diffraction

    Synchronous electronographic and mass-spectrometric study of saturated vapor of scandium tris-acetylacetonate was carried out. It was ascertained that at 155(5) deg C only monomer molecules Sc(aa)3 are present in vapor, for which ra-, rg- and rα-structural parameters were determined. The values of internuclear distances in chelate ring made up: rα (Sc-O)=2.076 (4) A, rα (O-C) = 1.271 (3) A, rα (C-Cr) = 1.386 (4) A. Coordination polyhedron of ScO6 has a structure with D3 symmetry similar to antiprism. Angle of the O-O-O triangular faces turning in reference to position in a regular prism makes up 26.8 (1.1) deg

  5. Structural Variety of Cobalt(II), Nickel(II), Zinc(II), and Cadmium(II) Complexes with 4,4'-Azopyridine: Synthesis, Structure and Luminescence Properties.

    Pladzyk, Agnieszka; Ponikiewski, Łukasz; Dołęga, Anna; Słowy, Klaudia; Sokołowska, Agata; Dziubińska, Katarzyna; Hnatejko, Zbigniew

    2015-11-01

    Self-assembled bi- and polymetallic complexes of Co(II), Ni(II), Zn(II), and Cd(II) were obtained by the reaction of 4,4'-azopyridine (azpy) with metal tri-tert-butoxysilanethiolates (Co, 1; Cd, 2), acetylacetonates (Ni, 3; Zn, 4), and acetates (Cd, 5). All compounds were characterized by single-crystal X-ray structure analysis, elemental analysis, FTIR spectroscopy, and thermogravimetry. Complexes 1, 2 and 4, 5 exhibit diverse structural conformations: 1 is bimetallic, 2 and 4 are 1D coordination polymers, and 5 is a 2D coordination framework formed from bimetallic units. The obtained complexes contain metal atoms bridged by a molecule of azpy. The luminescent properties of 1-5 were investigated in the solid state. PMID:26178314

  6. Characterization of La0.995Ca0.005NbO4/Ni anode functional layer by electrophoretic deposition in a La0.995Ca0.005NbO4 electrolyte based PCFC

    Bozza, Francesco; Schafbauer, W.; Meulenberg, W.A.;

    2012-01-01

    and water. Selectivity in the composition of the deposited layer was analyzed as a function of the suspension compositions and deposition conditions. A quasi-symmetrical cell was produced by depositing La0.995Ca0.005NbO4 electrolyte layer on the anode layer by EPD, and by applying a porous La0.995Ca0......The Electrophoretic Deposition (EPD) technique has been applied to the preparation of a porous La0.995Ca0.005NbO4/Ni composite anode layer, deposited on a porous pre-sintered La0.995Ca0.005NbO4/Ni support. Powders of La0.995Ca0.005NbO4 and NiO were suspended in a solution of acetylacetone, iodine...

  7. A new approach to suppress nonlinearity-transparency trade-off through coordination chemistry: syntheses and spectroscopic study on second-order nonlinear optical properties of a series of square-pyramidal zinc(II) complexes

    Ren, Peng; Liu, Tao; Qin, Jingui; Chen, Chuangtian

    2003-03-01

    Five new square-pyramidal coordination compounds L · Zn(acac) 2 ( 1- 5) (acac=acetylacetonate; L is a variety of thiosemicarbazones: p-dimethylaminobenzaldehyde thiosemicarbazone ( 1), p-hydroxy- o-methoxybenzaldehyde thiosemicarbazone ( 2), p-methoxybenzaldehyde thiosemicarbazone ( 3), p-hydroxybenzaldehyde thiosemicarbazone ( 4), o-hydroxybenzaldehyde thiosemicarbazone ( 5)) have been synthesized and characterized by 1H NMR, IR, and elemental analysis. All of these compounds exhibit pretty wide transparent ranges in the visible region. Their electronic absorption spectra have been studied experimentally, and theoretically by ZINDO/S calculation. The latter has also been utilized to estimate the extent of intramolecular charge transfer. The MOPAC software package has been used to evaluate their first-order molecular hyperpolarizabilities ( β). All β values of the five coordination compounds are larger than those of the corresponding thiosemicarbazones. And complex 1 shows the largest β0 (39.1×10 -30 esu) in the series.

  8. Lifetime enhanced phosphorescent organic light emitting diode using an electron scavenger layer

    Hong, Seokhwan; Kim, Ji Whan; Lee, Sangyeob, E-mail: sy96.lee@samsung.com [Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, Gyeonggi 443-803 (Korea, Republic of)

    2015-07-27

    We demonstrate a method to improve lifetime of a phosphorescent organic light emitting diode (OLED) using an electron scavenger layer (ESL) in a hole transporting layer (HTL) of the device. We use a bis(1-(phenyl)isoquinoline)iridium(III)acetylacetonate [Ir(piq){sub 2}(acac)] doped HTL to stimulate radiative decay, preventing thermal degradation in HTL. The ESL effectively prevented non-radiative decay of leakage electron in HTL by converting non-radiative decay to radiative decay via a phosphorescent red emitter, Ir(piq){sub 2}(acac). The lifetime of device (t{sub 95}: time after 5% decrease of luminance) has been increased from 75 h to 120 h by using the ESL in a phosphorescent green-emitting OLED.

  9. Azo coupling of 4-nitrophenyldiazonium chloride with aliphatic nucleophiles: an integrated organic synthesis and X-ray crystallography experiment; Acoplamento de cloreto de 4-nitrofenildiazonio com nucleofilos alifaticos: experimento integrado de sintese organica e cristalografia de raios X

    Cunha, Silvio; Marques, Monique F.; Rocha, Valeria, E-mail: silviodc@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Instituto de Quimica; Lariucci, Carlito; Vencato, Ivo [Universidade Federal de Goiania (UFG), GO (Brazil). Instituto de Fisica

    2013-11-01

    This article describes an undergraduate experiment for the synthesis of p-nitrophenyldiazonium chloride and its coupling with acetylacetone and two enaminones, 4-phenylamino-pent-3-en-2-one and 4-amino-pent-3-en-2-one, in an adaptation of a previously reported synthetic protocol. The azo dyes 4-(E)-phenylamino-3-[(E)-2-(4-nitrophenylazo)]-3-penten-2-one and 4-(E)-amino-3-[(E)-2-(4-nitrophenylazo)]-3-penten-2-one were obtained, and the solid state structure of this latter azo compound was characterized by single crystal X-ray diffraction studies. This two-week integrated laboratory approach involves simple synthetic experiments and microwave chemistry in the organic laboratory plus crystallography analysis, suitable for novice students on undergraduate experimental chemistry courses. (author)

  10. Heteroleptic protonated bis(phthalocyaninato) rare earth compounds containing 1,4,8,11,15,18,22,25-octa(butyloxy)-phthalocyanine ligand

    Condensation between M(Pc)(acac) (M = Sm, Eu, Gd; Pc = phthalocyaninate; acac = acetylacetonate) and metal-free 1,4,8,11,15,18,22,25-octa(butyloxy)phthalocyanine in n-octanol afforded heteroleptic double-deckers H{M(Pc)[Pc(α-OC4H9)8]} [Pc(α-OC4H9)8 1,4,8,11,15,18,22,25-octa(butyloxy)phthalocyaninate]. The series of double-decker complexes were characterized by elemental analysis, mass spectra, electronic absorption spectra, and IR spectra. The molecular structure of the compound of Gd was determined by single-crystal X-ray diffraction analysis. It was found that it exists as a pair of enantiomers in the unit cell of the crystals. Furthermore, the complex of Sm reacted with NaOH producing a supramolecule in which two Na+ ions connect two double-deckers together

  11. High mass-resolution electron-ion-ion coincidence measurements on core-excited organic molecules

    Tokushima, T; Senba, Y; Yoshida, H; Hiraya, A

    2001-01-01

    Total electron-ion-ion coincidence measurements on core excited organic molecules have been carried out with high mass resolution by using multimode (reflectron/linear) time-of-flight mass analyzer. From the ion correlation spectra of core excited CH sub 3 OH and CD sub 3 OH, the reaction pathway to form H sub 3 sup + (D sub 3 sup +) is identified as the elimination of three H (D) atoms from the methyl group, not as the inter-group (-CH sub 3 and -OH) interactions. In a PEPIPICO spectrum of acetylacetone (CH sub 3 COCH sub 2 COCH sub 3) measured by using a reflectron TOF, correlations between ions up to mass number 70 with one-mass resolution was recorded.

  12. (Acetylacetonato-κ2O,O′(phthalocyaninato-κ4N(phenanthroline-κ2N,N′erbium(III

    Hong-Feng Li

    2012-03-01

    Full Text Available The title complex, [Er(C32H16N8(C5H7O2(C12H8N2], possesses a mirror plane and the asymmetric unit is half of the molecule. The ErIII cation, lying on the mirror plane, is eight-coordinated by two O atoms from acetylacetone, two N (Nphen atoms from 1,10-phenanthroline and four isoindole N (Niso atoms from the phthalocyanine ligand in an antiprismatic geometry. The Er—N distances are in the range 2.376 (5–2.529 (4 Å and the Er—O distance is 2.272 (3 Å. Notably, the Er—Niso bonds are shorter than the Er—Nphen bonds, but longer than the Er—O bonds.

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

    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.

  14. Quantum molecular dynamics and molecular interactions studied by NMR and INS Nuclear magnetic resonance; Proton tunnelling; Hydrogen bond

    Jones, N

    2002-01-01

    The wavefunction of a particle extends into the classically forbidden barrier region of the potential energy surface. The consequence of this partial delocalisation is the phenomenon of quantum tunnelling, an effect which enables a particle to penetrate a potential barrier of magnitude greater than the energy of the particle. The tunnelling probability is an exponential function of the particle mass. The effect is therefore an important contribution to the behaviour of light atoms, in particular the proton. The hydrogen bond has long been appreciated to be an essential component of many biological and chemical systems, and the proton transfer reaction in the hydrogen bond is fundamental to many of these processes. The proton behaviour in the hydrogen bonds of benzoic acid, acetylacetone and calix-4-arene has been studied. A variety of techniques, both experimental and computational, were adopted for the study of the three hydrogen bonded systems. The complementary spectroscopic techniques of inelastic neutron...

  15. Convenient preparation of ITO nanoparticles inks for transparent conductive thin films

    Tin-doped indium oxide (ITO) nanoparticles are useful precursors to transparent electrodes in a variety of technologically important applications. We synthesized ITO nanoparticles from indium and tin acetylacetonates in oleyl alcohol using a novel temperature ramp profile. The monodispersed ITO nanoparticles have an average diameter of 8.6 nm and form dense, flat films by simple spin coating. The thickness of the film can be controlled by varying the number of additional depositions. The resulting ITO film is transparent and has a resistivity of 7 × 10−3 Ω cm after sintering at 300 °C. Using a suitable solvent, it is possible to coat high-aspect-ratio structures with ITO nanoparticles. This approach to ITO coatings is greener and offers a number of advantages for transparent electrodes because it is highly versatile, easily scalable, and supports low-cost manufacturing.

  16. Solvothermal synthesis and characterization of acicular -Fe2O3 nanoparticles

    S Basavaraja; D S Balaji; Mahesh D Bedre; D Raghunandan; P M Prithviraj Swamy; A Venkataraman

    2011-12-01

    Nanometer-sized -Fe2O3 particles have been prepared by a simple solvothermal method using ferric acetylacetonate as a precursor. The products were characterized by X-ray diffraction (XRD), energy dispersive X-ray microanalysis (EDAX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transition electron microscopy (TEM), infrared spectroscopy (IR) and thermal analysis (TG–DTA). XRD indicates that the product is single-phase -Fe2O3 with rhombohedral structure. Bundles of acicular shaped nanoparticles are seen in TEM images with an aspect ratio ∼ 12; typically 8–12 nm wide and over 150 nm long. The -Fe2O3 nanoparticles posses a high thermal stability, as observed on thermal analysis traces.

  17. Continuous tubular nanofibers of vanadium pentoxide by electrospinning for energy storage devices

    Tubular nanofibers (TNFs) of vanadium pentoxide (V2O5) were synthesized by electrospinning technique using a single spinneret for the first time by controlling the properties of the precursor solution. A partially miscible polymeric solution of vanadium oxytrihydroxide [VO(OH)3] was produced by hydrolysis of vanadyl acetylacetonate in Poly(vinylpyrrolidone) (PVP). The phase-separated polymer solution formed the core of the electrospun fibers whereas the VO(OH)3 formed the shell; the core PVP has been removed by controlled heat treatment. The TNFs had an inner diameter ∼60 nm and wall thickness ∼±100 nm. The capacitive behavior of the V2O5 TNFs was studied using cyclic voltammetry and galvanostatic cycling techniques. The studies showed ideal stable supercapacitive characteristics in the electrospun V2O5 TNFs.

  18. Continuous tubular nanofibers of vanadium pentoxide by electrospinning for energy storage devices

    Lala, Neeta L., E-mail: neeta@ump.edu.my; Jose, Rajan, E-mail: rjose@ump.edu.my; Yusoff, Mashitah M. [Universiti Malaysia Pahang, Faculty of Industrial Sciences and Technology (FIST) (Malaysia); Ramakrishna, Seeram [NUS Center for Nanofibers and Nanotechnology (Singapore)

    2012-11-15

    Tubular nanofibers (TNFs) of vanadium pentoxide (V{sub 2}O{sub 5}) were synthesized by electrospinning technique using a single spinneret for the first time by controlling the properties of the precursor solution. A partially miscible polymeric solution of vanadium oxytrihydroxide [VO(OH){sub 3}] was produced by hydrolysis of vanadyl acetylacetonate in Poly(vinylpyrrolidone) (PVP). The phase-separated polymer solution formed the core of the electrospun fibers whereas the VO(OH){sub 3} formed the shell; the core PVP has been removed by controlled heat treatment. The TNFs had an inner diameter {approx}60 nm and wall thickness {approx}{+-}100 nm. The capacitive behavior of the V{sub 2}O{sub 5} TNFs was studied using cyclic voltammetry and galvanostatic cycling techniques. The studies showed ideal stable supercapacitive characteristics in the electrospun V{sub 2}O{sub 5} TNFs.

  19. Synthesis of thiophene-linked pyrimidopyrimidines as pharmaceutical leads

    M B Siddesh; Basavaraj Padmashali; K S Thriveni; C Sandeep

    2014-05-01

    Thiophene-substituted chalcones were cyclised with guanidine in the presence of potassium hydroxide to get 4-substituted-6-thiophenopyrimidines 2a-e which were then refluxed with acetylacetone to obtain pyrimidopyrimidines 3a-e. Compounds 2a-e were also refluxed with ethylacetoacetate to afford pyirmidopyirimidines 4a-e which on refluxing with POCl3 in presence of DMF produced compounds 5a-e. Nucleophilic substitution reactions on 5a-e were carried out with aniline to obtain 6a-e. The structures of the newly synthesised compounds have been confirmed by elemental analysis and spectral studies. Some selected compounds have been screened for antibacterial and analgesic activities.

  20. Lifetime enhanced phosphorescent organic light emitting diode using an electron scavenger layer

    We demonstrate a method to improve lifetime of a phosphorescent organic light emitting diode (OLED) using an electron scavenger layer (ESL) in a hole transporting layer (HTL) of the device. We use a bis(1-(phenyl)isoquinoline)iridium(III)acetylacetonate [Ir(piq)2(acac)] doped HTL to stimulate radiative decay, preventing thermal degradation in HTL. The ESL effectively prevented non-radiative decay of leakage electron in HTL by converting non-radiative decay to radiative decay via a phosphorescent red emitter, Ir(piq)2(acac). The lifetime of device (t95: time after 5% decrease of luminance) has been increased from 75 h to 120 h by using the ESL in a phosphorescent green-emitting OLED

  1. Blistering during the atomic layer deposition of iridium

    The authors report on the formation of blisters during the atomic layer deposition of iridium using iridium acetylacetonate and oxygen precursors. Films deposited on fused silica substrates led to sparsely distributed large blisters while in the case of silicon with native oxide additional small blisters with a high density was observed. It is found that the formation of blisters is favored by a higher deposition temperature and a larger layer thickness. Postdeposition annealing did not have a significant effect on the formation of blisters. Finally, changing purge duration during the film growth allowed us to avoid blistering and evidenced that impurities released from the film in gas phase were responsible for the formation of blisters

  2. Preparation of Sr1-xCaxRuO3 thin films

    The series Sr1-xCaxRuO3 displays a continuous evolution from itinerant electron magnetism with (Tc=160 K,x=0) towards a paramagnetic metallic state at x=1. Previous studies on polycrystalline bulk samples raise the question whether the series shows a quantum critical point or phase separation near x=0.7. Here, we report first results on thin films which have been grown epitaxially on SrTiO3 substrates by the metalorganic aerosol deposition technique. This technique is based on the use of a solution containing acetylacetonates of Sr2+, Ca2+ and Ru3+. Growth conditions have been optimized by the variation of the (Sr1-xCax) to Ru ratio, deposition rate, molarity of the solution and deposition temperature. X-ray diffraction as well as STM, electrical resistivity and magnetization measurements are reported

  3. Efficient solution route to transparent ZnO semiconductor films using colloidal nanocrystals

    Satoshi Suehiro

    2016-09-01

    Full Text Available ZnO nanocrystals (NCs were synthesized by heating Zn (II acetylacetonate in oleic acid/oleylamine in the presence of 1,2-hexadecanediol at 220 °C. Transmission electron microscopy (TEM and dynamic light scattering (DLS measurements revealed the formation of monodispersed ZnO NCs of ca. 7 nm. ZnO NC assembled films were fabricated on a glass substrate by deposition with the colloidal ZnO NCs dispersed in toluene. The film composed of the NCs showed good optical transparency in the visible to near-infrared region. A device coupling the ZnO NC film with a p-type Cu2ZnSnS4 (CZTS NC film exhibited an obvious diode-like current–voltage behavior. The results suggest that the transparent ZnO film has a potentiality to be used for an n-type window layer in some optoelectronic applications.

  4. Preparation and characterization of electroluminescent devices based on complexes of β-diketonates of Tb3+, Eu3+, Gd3+ ions with macrocyclic ligands and UO22+ films

    Complexes containing Rare Earth ions are of great interest in the manufacture of electro luminescent devices as organic light emitting devices (OLED). These devices, using rare earth trivalent ions (TR3+) as emitting centers, show high luminescence with extremely fine spectral bands due to the structure of their energy levels, long life time and high quantum efficiency. This work reports the preparation of Rare Earth β-diketonate complexes (Tb3+, Eu3+ and Gd3+) and (tta - thenoyltrifluoroacetonate and acac - acetylacetonate) containing a ligand macrocyclic crown ether (DB18C6 - dibenzo18coroa6) and polymer films of UO22+. The materials were characterized by complexometric titration with EDTA, CH elemental analysis, near infrared absorption spectroscopy, thermal analysis, X-ray diffraction (powder method) and luminescence spectroscopy. For manufacturing the OLED it was used the technique of deposition of thin films by physical vapor (PVD, Physical Vapor Deposition). (author)

  5. Some regularities of Ce(3) and Ce(4) stabilization in their compounds with β-diketones

    Adduct formation of cerium (3) and cerium (4) β-diketonates (acetylacetonate, benzoylacetonate, dibenzoylmethanate and thenoyltrifluoroacetonate) with oxygen- and nitrogen-donor ligands (Q-α, α'-dipyridyl, o-phenanthroline, trioctylphosphine oxide and triphenylphosphine oxide) is studied. The compounds obtained as a results of the reactions are studied by means of IR-spectroscopic, derivatographic and X-ray phase methods. It is concluded that composition and thermodynamic stability of adducts of Ce(3) tris-β-diketonates are determined by correlation of donor properties of the basis and additional ligand and stability of adducts to oxidation - as well as by their solubility. Introduction of the additional ligand to the system Ce(4)-β-diketones even in the presence of air oxygen stabilizes Ce(3) and destabilizes Ce(4)

  6. Luminescent properties of compounds of europium(III) with quinaldic acid and β-diketones

    Kalinovskaya, I. V.; Mirochnik, A. G.

    2015-12-01

    We have obtained luminescent complex compounds of europium(III) with quinaldic acid and β- diketones of composition Eu(Quin)2β-dic • H;2O, where Quin is the anion of quinaldic acid, and β-dic is the anion of acetylacetone (acac), benzoylacetone (bzac), or dibenzoylmethane (dbm). The spectral properties of the obtained compounds have been examined. The joint presence of quinaldic acid and β-diketone in the coordination sphere of europium(III) leads to a broadening of the absorption spectral range of the investigated complex compounds. We have found that the "anomalous" Stark structure of luminescence spectra and the luminescence quenching of complexes at 300 K are determined by the occurrence of a high-lying ligand-europium(III) charge-transfer state.

  7. Temperature and Exciton Concentration Induced Excimer Emission of 4,4'-Bis(4''-Triphenylsilyl) Phenyl-1,1'-Binaphthalene and Application for Sunlight-Like White Organic Light-Emitting Diodes.

    Xu, Tao; Li, Weiling; Gao, Xicun; Sun, Chang; Chen, Guo; Zhang, Xiaowen; Li, Chunya; Zhu, Wenqing; Wei, Bin

    2016-12-01

    This paper demonstrates the influence of temperature, exciton concentration, and electron transportation layers on the excimer emission of a novel deep-blue material: 4,4'-bis(4''-triphenylsilyl) phenyl-1,1'-binaphthalene (SiBN), by studying the photoluminescence and electroluminescence spectra of SiBN-based film. We have further developed sunlight-like and warm-light white organic light-emitting diodes (WOLEDs) with high efficiency and wide-range spectra, using SiBN and bis(2-phenylbenzothiozolato-N,C2')iridium(acetylacetonate) (bt2Ir(acac)) as the blue excimer and yellow materials, respectively. The resulting device exhibited an excellent spectra overlap ratio of 82.9 % with sunlight, while the device peak current efficiency, external quantum efficiency, and power efficiency were 18.5 cd/A, 6.34 %, and 11.68 lm/W, respectively, for sunlight-like WOLEDs. PMID:27562015

  8. Speciation of titanium in solvent refined coal using SESC - INAA

    The preasphaltenes (Pa) separated from solvent refined coal (SRC-I) were fractionated by sequential elution solvent chromatography (SESC) on silica column into 10 fractions. Titanium was determined by instrumental neutron activation analysis (INAA), and was found to be concentrated in fractions 7-10. The preasphaltenes form stable complexes with bis (cyclopentadienyl) titanium(IV) dichloride (BTD), cyclopentadienyl titanium(IV) trichloride (CTT) and titanium(IV) oxide bis (acetylacetone) (TOBA). Preasphaltene titanium complexes (Pa-BTD, Pa-CTT, and Pa-TOBA) were fractionated using the SESC scheme, and the concentration of titanium in each fraction was determined. The mechanism for the reaction between titanium complexes (BTD, CTT or TOBA) and Pa was studied, and the existence of titanium phenoxide type complexes in SRC-I was proposed

  9. Synthesis and functionalization of biocompatible Tb:CePO{sub 4} nanophosphors with spindle-like shape

    Rodriguez-Liviano, Sonia; Aparicio, Francisco J.; Becerro, Ana I. [Instituto de Ciencia de Materiales de Sevilla (CSIC-US) (Spain); Garcia-Sevillano, Jorge; Cantelar, Eugenio [C-04. Universidad Autonoma de Madrid, Dpto. Fisica de Materiales (Spain); Rivera, Sara; Hernandez, Yulan; Fuente, Jesus M. de la [Universidad de Zaragoza, Instituto de Nanociencia de Aragon (Spain); Ocana, Manuel, E-mail: mjurado@icmse.csic.es [Instituto de Ciencia de Materiales de Sevilla (CSIC-US) (Spain)

    2013-02-15

    Monoclinic Tb:CePO{sub 4} nanophosphors with a spindle-like morphology and tailored size (in the nanometer and micrometer range) have been prepared through a very simple procedure, which consists of aging, at low temperature (120 Degree-Sign C), ethylene glycol solutions containing only cerium and terbium acetylacetonates and phosphoric acid, not requiring the addition of surfactants or capping agents. The influence of the heating mode (conventional convection oven or microwave oven) and the Tb doping level on the luminescent, structural and morphological features of the precipitated nanoparticles have also been analyzed. This study showed that microwave-assisted heating resulted in an important beneficial effect on the luminescent properties of these nanophosphors. Finally, a procedure for the functionalization of the Tb:CePO{sub 4} nanoparticles with aspartic-dextran is also reported. The functionalized nanospindles presented negligible toxicity for Verocells, which along with theirs excellent luminescent properties, make them suitable for biomedical applications.

  10. Catalytic performance for CO{sub 2} conversion to methanol of gallium-promoted copper-based catalysts. Influence of metallic precursors

    Toyir, Jamil; Ramirez de la Piscina, Pilar; Homs, Narcis [Departament de Quimica Inorganica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Fierro, Jose Luis G. [Instituto de Catalisis y Petroleoquimica, C.S.I.C., Cantoblanco, 28049 Madrid (Spain)

    2001-11-28

    This study reports new gallium-promoted copper-based catalysts prepared by co-impregnation of methoxide-acetylacetonate (acac) precursors from methanolic solutions onto silica and zinc oxide supports. Catalyst performance in the CO{sub 2} hydrogenation to methanol was investigated at 2MPa and temperatures between 523 and 543K. A high activity and selectivity for ZnO-supported catalysts was found, which also showed a high stability in terms of both activity and selectivity. The maximum value for the activity was 378gMeOH/kgcath at 543K, with a selectivity of 88% towards methanol production. The high performance of these materials in the CO{sub 2} hydrogenation is related to the presence of Ga{sub 2}O{sub 3} promoter and highly dispersed Cu{sup +} species on the surface, determined by XPS and Auger on used catalysts.

  11. Controlled Synthesis and Characterization of Monodisperse Fe3O4 Nanoparticles

    SHI,Rongrong; GAO,Guanhua; YI,Ran; ZHOU,Kechao; QIU,Guanzhou; LIU,Xiaohe

    2009-01-01

    Monodisperse Fe3O4 nanoparticles were successfully synthesized through the thermal decomposition of iron acetylacetonate in octadecene solvent in the presence of oleic acid and oleylamine.The influences of experimental parameters,such as reacting temperature,amounts and kinds of surfactants,solvents,oleic acid and oleylamine,on the size and shape of monodisperse Fe3O4 nanoparticles were discussed.The phase structures,morphology,and size of the as-prepared products were investigated in detail by X-ray diffraction (XRD),transmission electron microscopy (TEM),selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM).Magnetic property was measured using a vibrating sample magnetometer (VSM) at room temperature,which revealed that Fe3O4 nanoparticles were of ferromagnetism with a saturation magnetization (Ms) of 74.0 emu/g and coercivity (Hc) of 72.6 Oe.

  12. Shape control of the magnetic iron oxide nanoparticles under different chain length of reducing agents

    Ngoi, Kuan Hoon; Chia, Chin-Hua, E-mail: chia@ukm.edu.my; Zakaria, Sarani [School of Applied Physics, Faculty Science and Technology, University Kebangsaan Malaysia 43600 UKM Bangi, Selangor (Malaysia); Chiu, Wee Siong [Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur (Malaysia)

    2015-09-25

    We report on the effect of using reducing agents with different chain-length on the synthesis of iron oxide nanoparticles by thermal decomposition of iron (III) acetylacetonate in 1-octadecene. This modification allows us to control the shape of nanoparticles into spherical and cubic iron oxide nanoparticles. The highly monodisperse 14 nm spherical nanoparticles are obtained under 1,2-dodecanediol and average 14 nm edge-length cubic iron oxide nanoparticles are obtained under 1,2-tetradecanediol. The structural characterization such as transmission electron microscope (TEM) and X-ray diffraction (XRD) shows similar properties between two particles with different shapes. The vibrating sample magnetometer (VSM) shows no significant difference between spherical and cubic nanoparticles, which are 36 emu/g and 37 emu/g respectively and superparamagnetic in nature.

  13. Total synthesis and absolute configuration assignment of MRSA active garcinol and isogarcinol.

    Socolsky, Cecilia; Plietker, Bernd

    2015-02-01

    A short total synthesis of (±)-garcinol and (±)-isogarcinol, two endo-type B PPAPs with reported activity against methiciline resistant Staphylococcus aureus (MRSA), is presented. The separation of framework-constructing from framework-decorating steps and the application of two highly regio- and stereoselective Pd-catalysed allylations, that is, the Pd-catalysed decarboxylative Tsuji-Trost allylation and the diastereoselective Pd-catalysed allyl-allyl cross-coupling, are key elements that allowed the total synthesis to be accomplished within 13 steps starting from acetylacetone. After separation of the enantiomers the absolute configurations of the four natural products (i.e., (-)-garcinol, (+)-guttiferone E (i.e., ent-garcinol), (-)-isogarcinol, and (+)-isoxanthochymol (i.e., ent-isogarcinol)) were assigned based on ECD spectroscopy. PMID:25537962

  14. Prospects for Thermal Atomic Layer Etching Using Sequential, Self-Limiting Fluorination and Ligand-Exchange Reactions.

    George, Steven M; Lee, Younghee

    2016-05-24

    Thermal atomic layer etching (ALE) of Al2O3 and HfO2 using sequential, self-limiting fluorination and ligand-exchange reactions was recently demonstrated using HF and tin acetylacetonate (Sn(acac)2) as the reactants. This new thermal pathway for ALE represents the reverse of atomic layer deposition (ALD) and should lead to isotropic etching. Atomic layer deposition and ALE can together define the atomic layer growth and removal steps required for advanced semiconductor fabrication. The thermal ALE of many materials should be possible using fluorination and ligand-exchange reactions. The chemical details of ligand-exchange can lead to selective ALE between various materials. Thermal ALE could produce conformal etching in high-aspect-ratio structures. Thermal ALE could also yield ultrasmooth thin films based on deposit/etch-back methods. Enhancement of ALE rates and possible anisotropic ALE could be achieved using radicals or ions together with thermal ALE. PMID:27216115

  15. Electrochemical investigation of tetravalent uranium β-diketones for active materials of all-uranium redox flow battery

    For active materials of the all-uranium redox flow battery for the power storage, tetravalent uranium β-diketones were investigated. The electrode reactions of U(ba)4 and U(btfa)4 were examined in comparison with that of U(acac)4, where ba denotes benzoylacetone, btfa benzoyltrifluoroacetone and acac acetylacetone. The cyclic voltammograms of U(ba)4 and U(btfa)4 solutions indicate that there are two series of redox reactions corresponding to the complexes with different coordination numbers of four and three. The electrode kinetics of the U(IV)/U(III) redox reactions for btfa complexes is examined. The obtained result supports that the uranium β-diketone complexes examined in the present study will serve as excellent active materials for negative electrolyte in the redox flow battery. (author)

  16. PVP-Stabilized Palladium Nanoparticles in Silica as Effective Catalysts for Hydrogenation Reactions

    Caroline Pires Ruas

    2013-01-01

    Full Text Available Palladium nanoparticles stabilized by poly (N-vinyl-2-pyrrolidone (PVP can be synthesized by corresponding Pd(acac2 (acac = acetylacetonate as precursor in methanol at 80°C for 2 h followed by reduction with NaBH4 and immobilized onto SiO2 prepared by sol-gel process under acidic conditions (HF or HCl. The PVP/Pd molar ratio is set to 6. The effect of the sol-gel catalyst on the silica morphology and texture and on Pd(0 content was investigated. The catalysts prepared (ca. 2% Pd(0/SiO2/HF and ca. 0,3% Pd(0/SiO2/HCl were characterized by TEM, FAAS, and SEM-EDS. Palladium nanoparticles supported in silica with a size 6.6 ± 1.4 nm were obtained. The catalytic activity was tested in hydrogenation of alkenes.

  17. Dual catalysis with magnetic chitosan: direct synthesis of cyclic carbonates from olefins with carbon dioxide using isobutyraldehyde as the sacrificial reductant.

    Kumar, Subodh; Singhal, Nikita; Singh, Raj K; Gupta, Piyush; Singh, Raghuvir; Jain, Suman L

    2015-07-14

    Chitosan coated magnetic nanoparticles were synthesized and used as a support for the immobilization of the cobalt(II) acetylacetonate complex [Co(acac)2] and quaternary triphenylphosphonium bromide [P(+)Ph3Br(-)] targeting -NH2 and -OH moieties located on the surface of chitosan. The synthesized material was used as a catalyst for one pot direct synthesis of cyclic carbonates from olefins via an oxidative carboxylation approach with carbon dioxide using isobutyraldehyde as the sacrificial reductant and molecular oxygen as the oxidant. After the reaction, the catalyst was recovered by applying an external magnet and reused for several runs without significant loss in catalytic activity and no leaching was observed during this course. PMID:26055991

  18. Blistering during the atomic layer deposition of iridium

    Genevée, Pascal, E-mail: pascal-genevee@chimie-paristech.fr, E-mail: a.szeghalmi@uni-jena.de; Ahiavi, Ernest; Janunts, Norik; Pertsch, Thomas; Kley, Ernst-Bernhard; Szeghalmi, Adriana, E-mail: pascal-genevee@chimie-paristech.fr, E-mail: a.szeghalmi@uni-jena.de [Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Oliva, Maria [Fraunhofer IOF, Albert-Einstein-Strasse 7, 07743 Jena (Germany)

    2016-01-15

    The authors report on the formation of blisters during the atomic layer deposition of iridium using iridium acetylacetonate and oxygen precursors. Films deposited on fused silica substrates led to sparsely distributed large blisters while in the case of silicon with native oxide additional small blisters with a high density was observed. It is found that the formation of blisters is favored by a higher deposition temperature and a larger layer thickness. Postdeposition annealing did not have a significant effect on the formation of blisters. Finally, changing purge duration during the film growth allowed us to avoid blistering and evidenced that impurities released from the film in gas phase were responsible for the formation of blisters.

  19. Filmes de titânio-silício preparados por "spin" e "dip-coating"

    Nassar Eduardo J.

    2003-01-01

    Full Text Available The conditions for the preparation of luminescent materials, consisting of Eu3+ ions entrapped in a titanium matrix, in the forma of a thin film, using the sol-gel process, are described. The films were obtained from sols prepared with TEOS and TEOT, in the presence of acetylacetone as the hidrolysis-retarding agent, using the dip-coating and spin-coating techniques. The influence of these techniques on the films based on titanium and silicon are presented. The Eu3+ was used as a luminescent probe. The films have been characterized by luminescence, reflection and transmittance. The thickness of the films could be related to the preparation procedure. Transparent thin films have been prepared by dip-coating technique.

  20. N-[3-(2,6-Dimethylanilino-1-methylbut-2-enylidene]-2,6-dimethylanilinium chlorideThis paper is dedicated to Professor Dr Dr mult. h.c. Herbert W. Roesky.

    Víctor M. Jiménez-Pérez

    2009-07-01

    Full Text Available The title salt, C21H27N2+·Cl− resulted from the condensation between 2,6-dimethylaniline and acetylacetone in acidified ethanol. The bulky cation is stabilized in a β-iminoenamine tautomeric form, and presents a W-shaped conformation. The benzene rings are arranged almost parallel, with a dihedral angle of 6.58 (4° between the mean planes. Both N—H groups in the cation form strong hydrogen bonds with two symmetry-related chloride anions. The resulting supramolecular structure is a one dimensional polymer running along [001], alternating cations and anions. The π–π interaction observed in the molecule, characterized by a centroid–centroid separation of 4.298 (4 Å, is thus extended to the chains, with separations of 5.222 (4 Å between benzene rings of neighbouring cations in the crystal.

  1. One-Pot Synthesis of Disperse Dyes Under Microwave Irradiation: Dyebath Reuse in Dyeing of Polyester Fabrics

    Huda M. Mahmoud

    2012-04-01

    Full Text Available A series of 4-hydroxyphenylazopyrazolopyrimidine disperse dyes were prepared via one-pot reactions of p-hydroxyphenylhydrazone, hydrazine hydrate, and acetylacetone or enaminones using microwave irradiation as an energy source. Structural assignments of the dyes were confirmed by X-ray crystallographic structure determination. Instead of discharging the dyebath after each dyeing cycle, the residual dyebath was spectrophotometrically analyzed and then pH readjusted for a repeat dyeing with longer time. Fastness of the dyed samples was measured after each recycle. Most of the dyed fabrics tested displayed good light fastness and excellent fastness to washing and perspiration. Finally, the biological activity of the synthesized dyes against Gram positive bacteria, Gram negative bacteria and yeast were evaluated.

  2. Synthesis, properties and colour assessment of some new 5-(3- and 4-substituted phenylazo-4,6-dimethyl-3-cyano-2-pyridones

    DUSAN MIJIN

    2006-05-01

    Full Text Available A series of 5-(3- and 4-substituted phenylazo-4,6-dimethyl-3-cyano-2-pyridones were synthesized, starting from acetylacetone and arenediazonium salt, followed by condensation with cyanoacetamide using a modified literature procedure. The experimental investigation included modification of the synthetic procedure in terms of solvent, temperature, isolation techniques as well as purification and identification of the products. The azo dyes were characterized by melting point, IR, UV/Vis, 1H NMR and MS data. HPLC analyses were also performed. The 2-hydroxypyridine/ 2-pyridone tautomeric equilibration was found to depend on the polarity of the applied solvents. A colour assessment of the solid dyes and dyed polyester fabrics was also performed and the correlation between the colour and the structure of the dyes is discussed.

  3. MnO-carbon hybrid nanofiber composites as superior anode materials for lithium-ion batteries

    MnO-carbon hybrid nanofiber composites are fabricated by electrospinning polyimide/manganese acetylacetonate precursor and a subsequent carbonization process. The composition, phase structure and morphology of the composites are characterized by scanning and transmission electron microscopy, X-ray diffraction and thermogravimetric analysis. The results indicate that the composites exhibit good nanofibrous morphology with MnO nanoparticles uniformly encapsulated by carbon nanofibers. The hybrid nanofiber composites are used directly as freestanding anodes for lithium-ion batteries to evaluate their electrochemical properties. It is found that the optimized MnO-carbon nanofiber composite can deliver a high reversible capacity of 663 mAh g−1, along with excellent cycling stability and good rate capability. The superior performance enables the composites to be promising candidates as an anode alternative for high-performance lithium-ion batteries

  4. Dating soil layers by 10Be

    The main problem in dating soil layers by the cosmogenic nuclide 10Be is the isolation of beryllium from big quantities of sample materials. The authors apply the following chemical process: leaching the sample material with HCl, extraction of Be as acetylacetonate, and ion exchange on diallyl phosphate. It is thus possible to isolate Be(OH)2 in a chemically pure form containing no other radionuclides. This procedure was tested by the determination of 7Be accumulated in soil. The measured 7Be activity corresponds well with the mean activity of 7Be in rain water. Besides humic acids in soils metal hydroxides are able to concentrate Be to a large extent. Thus 10Be was found in iron ore deposits containing limonite. A calculation of the 10Be production rate is given and the possibility of radioactive dating with 10Be using the chemical process mentioned above is discussed. (author)

  5. Preparation and characterization of electroluminescent devices based on complexes of {beta}-diketonates of Tb{sup 3+}, Eu{sup 3+}, Gd{sup 3+} ions with macrocyclic ligands and UO{sub 2}{sup 2+} films; Preparacao e caracterizacao de dispositivos eletroluminescentes de complexos de {beta}-dicetonados de ions Tb{sup 3+}, Eu{sup 3+}, Gd{sup 3+} com ligantes macrociclicos e filmes de UO{sub 2}{sup 2+}

    Gibelli, Edison Bessa

    2010-07-01

    Complexes containing Rare Earth ions are of great interest in the manufacture of electro luminescent devices as organic light emitting devices (OLED). These devices, using rare earth trivalent ions (TR{sup 3+}) as emitting centers, show high luminescence with extremely fine spectral bands due to the structure of their energy levels, long life time and high quantum efficiency. This work reports the preparation of Rare Earth {beta}-diketonate complexes (Tb{sup 3+}, Eu{sup 3+} and Gd{sup 3+}) and (tta - thenoyltrifluoroacetonate and acac - acetylacetonate) containing a ligand macrocyclic crown ether (DB18C6 - dibenzo18coroa6) and polymer films of UO{sub 2}{sup 2+}. The materials were characterized by complexometric titration with EDTA, CH elemental analysis, near infrared absorption spectroscopy, thermal analysis, X-ray diffraction (powder method) and luminescence spectroscopy. For manufacturing the OLED it was used the technique of deposition of thin films by physical vapor (PVD, Physical Vapor Deposition). (author)

  6. Effect of stabilizer on optical and structural properties of MgO thin films prepared by sol–gel method

    Z Bazhan; F E Ghodsi; J Mazloom

    2013-10-01

    The effects of monoethanolamine (MEA) and acetylacetone (ACAC) addition as stabilizer on the crystallization behaviour, morphology and optical properties of magnesium oxide were investigated using thermogravimetry (TG/DTG), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Visible, photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopy. Stabilizer addition reduces transparency of the films. MgO films prepared at 500 °C showed weak orientation of (200). However, the films prepared by addition of stabilizer are amorphous. MgO powders were prepared for exhibiting the structural properties. The patterns of MgO powders showed a preferred orientation of (200). The addition of stabilizer causes a reduction in grain size. SEM micrographs show that a homogenous and crack-free film can be prepared at 500 °C and addition of stabilizer causes an increase in packing density.

  7. Parent type chemical species formed by recoil implantation reaction in tris(β-diketonato)metal(III)

    Chemical reactions induced by recoil implantation were studied focussing on parent type species in tris(β-diketonato)metal(III) complexes. The yield of the substitution reaction *M + M(acac)3 → *M(acac)3 + M was dependent on the force constant ratio K(*M-O)/K(M-O), showing that competition occurred between *M and M in the cage of the acetylacetonate complex. In the case of *Cr implantation in Co(acac)3, an exceptionally large yield could be explained by formation of Co(acac)2, whose central metal easily exchanges with *Cr, and by pickup of acac. When different β-diketonate complexes were examined in the reaction *Cr + M(β-dik)3 → *Cr(β-dik)3 + M the yield was dependent on the stability of the M(β-dik)3 complexes. A reaction model to explain these results reasonably was presented. (orig.)

  8. Shape control of the magnetic iron oxide nanoparticles under different chain length of reducing agents

    We report on the effect of using reducing agents with different chain-length on the synthesis of iron oxide nanoparticles by thermal decomposition of iron (III) acetylacetonate in 1-octadecene. This modification allows us to control the shape of nanoparticles into spherical and cubic iron oxide nanoparticles. The highly monodisperse 14 nm spherical nanoparticles are obtained under 1,2-dodecanediol and average 14 nm edge-length cubic iron oxide nanoparticles are obtained under 1,2-tetradecanediol. The structural characterization such as transmission electron microscope (TEM) and X-ray diffraction (XRD) shows similar properties between two particles with different shapes. The vibrating sample magnetometer (VSM) shows no significant difference between spherical and cubic nanoparticles, which are 36 emu/g and 37 emu/g respectively and superparamagnetic in nature

  9. Polyesters from 1,4 cyclohexanediol: kinetics aspects in protic and non protic catalysis

    Continuing with the kinetic studies in polycondensation, it has been choosen the 1,4 cyclohexane diol as a monomer to polyesterify with acid and succinic anhydride, using p.toluen sulphonic acid as protic external catalyst and cooper (II) acetylacetonate as non protic catalyst. The reactions were carried out in bulk and the acid number followed for kinetical approaches. The structure of the polyester was characterized by means of IR, NMR and the thermal properties were studied by TGA and DSC. The molecular weight were measured by GPC and end group analysis. The kinetics is accomplish and the properties of the resulting material is compared to those of the polymer prepared from 1,4 cyclohexane dimethanol, in order to explore its probable liquid crystal behaviour

  10. Coordination Chemistry of [Co(acac)2 ] with N-Doped Graphene: Implications for Oxygen Reduction Reaction Reactivity of Organometallic Co-O4 -N Species.

    Han, Jongwoo; Sa, Young Jin; Shim, Yeonjun; Choi, Min; Park, Noejung; Joo, Sang Hoon; Park, Sungjin

    2015-10-19

    Hybridization of organometallic complexes with graphene-based materials can give rise to enhanced catalytic performance. Understanding the chemical structures within hybrid materials is of primary importance. In this work, archetypical hybrid materials are synthesized by the reaction of an organometallic complex, [Co(II) (acac)2 ] (acac=acetylacetonate), with N-doped graphene-based materials at room temperature. Experimental characterization of the hybrid materials and theoretical calculations reveal that the organometallic cobalt-containing species is coordinated to heterocyclic groups in N-doped graphene as well as to its parental acac ligands. The hybrid material shows high electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media, and superior durability and methanol tolerance to a Pt/C catalyst. Based on the chemical structures and ORR experiments, the catalytically active species is identified as a Co-O4 -N structure. PMID:26331625

  11. Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

    Sudipta Pathak

    2013-11-01

    Full Text Available A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the starting materials, and the excellent yields of products.

  12. Platinum-Iridium Alloy Films Prepared by MOCVD

    WEI Yan; CHEN Li; CAI Hongzhong; ZHENG Xu; YANG Xiya; HU Changyi

    2012-01-01

    Platinum-Iridium alloy films were prepared by MOCVD on Mo substrate using metal-acetylacetonate precursors.Effects of deposition conditions on composition,microstructure and mechanical properties were determined.In these experimental conditions,the purities of films are high and more than 99.0%.The films are homogeneous and monophase solid solution of Pt and Ir.Weight percentage of platinum are much higher than iridium in the alloy.Lattice constant of the alloy changes with the platinum composition.Iridium composition showing an up-down-up trend at the precursor temperature of 190~230℃ and the deposition temperature at 400~550℃.The hardness of Pt-Ir alloys prepared by MOCVD is three times more than the alloys prepared by casting.

  13. Development of multicomponent hybrid density functional theory with polarizable continuum model for the analysis of nuclear quantum effect and solvent effect on NMR chemical shift

    We have developed the multicomponent hybrid density functional theory [MC-(HF+DFT)] method with polarizable continuum model (PCM) for the analysis of molecular properties including both nuclear quantum effect and solvent effect. The chemical shifts and H/D isotope shifts of the picolinic acid N-oxide (PANO) molecule in chloroform and acetonitrile solvents are applied by B3LYP electron exchange-correlation functional for our MC-(HF+DFT) method with PCM (MC-B3LYP/PCM). Our MC-B3LYP/PCM results for PANO are in reasonable agreement with the corresponding experimental chemical shifts and isotope shifts. We further investigated the applicability of our method for acetylacetone in several solvents

  14. Epoxidation of soybean oil with [MoO{sub 2}(acac){sub 2}]/TBHP Catalytic system in [bmim][PF{sub 6}]; Epoxidacao do oleo de soja com o sistema catalitico [MoO{sub 2}(acac){sub 2}]/TBHP em [bmim][PF{sub 6}

    Farias, Maritana [Instituto Federal de Educacao, Ciencia e Tecnologia Sul-rio-grandense, Pelotas, RS (Brazil); Martinelli, Marcia, E-mail: maritana@pelotas.ifsul.edu.br [Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil). Inst. de Quimica. Dept. de Quimica Inorganica

    2012-07-01

    Epoxidation of soybean oil was investigated using 1-n-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF{sub 6}] 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 deg C 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 {sup 1}H NMR data. (author)

  15. A selective nanocatalyst for an efficient Ugi reaction: Magnetically recoverable Cu(acac)2/NH2-T/SiO2@Fe3O4 nanoparticles

    Monireh Ghavami; Maryam Koohi; Mohammad Zaman Kassaee

    2013-11-01

    A novel, magnetically recoverable nanocatalyst is fabricated through simple immobilization of copper(II) acetylacetonate on the surface of amine-terminated silica-coated Fe3O4 nanoparticles: Cu(acac)2/NH2-T/SiO2@Fe3O4NPs. Unambiguous bonding of Cu to the terminal amine is indicated by Xray photoelectron spectroscopy (XPS). Further characterizations are carried out by different techniques. Selectivity of this catalyst is demonstrated through one-pot synthesis of fourteen α-aminoacyl amides using Ugi four-component reaction of cyclohexyl isocyanide, acetic acid, amines and various aldehydes. Interestingly, all aromatic aldehydes react with short reaction times and high yields, but heteroaromatic aldehydes do not yield any product. Catalyst efficiency remains unaltered through three consecutive experiments.

  16. Schiff bases of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and its silatranes: Synthesis and characterization

    Gurjaspreet Singh; Amandeep Saroa; Sadhika Khullar; Sanjay K Mandal

    2015-04-01

    This paper aims at the introduction of azomethine group by the condensation reaction of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane with different compounds containing carbonyl group such as 2’-hydroxyacetophenone, salicylaldehyde, pyrrole-2-carboxaldehyde, acetylacetone and ethyl acetoacetate. Further, transesterification reaction of these Schiff base modified silanes with triethanolamine as a tripodal ligand leads to the synthesis of corresponding silatranes 1–5 bearing Schiff base functionalized long chain in the axial position. All the synthesized compounds are characterized by spectroscopic methods, elemental analysis and mass spectrometry. The authentication of Schiff base modified silatranes is scrutinized by single X-ray crystal structure of silatrane 1. The thermal stability of the five silatranes is studied by thermo-gravimetric analysis (TGA).

  17. Issues Affecting the Synthetic Scalability of Ternary Metal Ferrite Nanoparticles

    Lauren Morrow

    2015-01-01

    Full Text Available Ternary Mn-Zn ferrite (MnxZn1-xFe2O4 nanoparticles (NPs have been prepared by the thermal decomposition of an oleate complex, sodium dodecylbenzenesulfonate (SDBS mediated hydrazine decomposition of the chloride salts, and triethylene glycol (TREG mediated thermal decomposition of the metal acetylacetonates. Only the first method was found to facilitate the synthesis of uniform, isolable NPs with the correct Mn : Zn ratio (0.7 : 0.3 as characterized by small angle X-ray scattering (SAXS, transmission electron microscopy (TEM, and inductively coupled plasma-optical emission spectroscopy (ICP-OES. Scaling allowed for retention of the composition and size; however, attempts to prepare Zn-rich ferrites did not result in NP formation. Thermogravimetric analysis (TGA indicated that the incomplete decomposition of the metal-oleate complexes prior to NP nucleation for Zn-rich compositions is the cause.

  18. Atomic layer deposition of cobalt carbide films and their magnetic properties using propanol as a reducing agent

    Sarr, Mouhamadou; Bahlawane, Naoufal; Arl, Didier; Dossot, Manuel; McRae, Edward; Lenoble, Damien

    2016-08-01

    The investigation of highly conformal thin films using Atomic Layer Deposition (ALD) is driven by a variety of applications in modern technologies. In particular, the emergence of 3D memory device architectures requires conformal materials with tuneable magnetic properties. Here, nanocomposites of carbon, cobalt and cobalt carbide are deposited by ALD using cobalt acetylacetonate with propanol as a reducing agent. Films were grown by varying the ALD deposition parameters including deposition temperature and propanol exposure time. The morphology, the chemical composition and the crystalline structure of the cobalt carbide film were investigated. Vibrating Sample Magnetometer (VSM) measurements revealed magnetic hysteresis loops with a coercivity reaching 500 Oe and a maximal saturation magnetization of 0.9 T with a grain size less than 15 nm. Magnetic properties are shown to be tuneable by adjusting the deposition parameters that significantly affect the microstructure and the composition of the deposited films.

  19. Aloe vera plant-extracted solution hydrothermal synthesis and magnetic properties of magnetite (Fe3O4) nanoparticles

    Phumying, Santi; Labuayai, Sarawuth; Thomas, Chunpen; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan; Maensiri, Santi

    2013-06-01

    Magnetite (Fe3O4) nanoparticles have been successfully synthesized by a novel hydrothermal method using ferric acetylacetonate (Fe(C5H8O2)3) and aloe vera plant-extracted solution. The influences of different reaction temperatures and times on the structure and magnetic properties of the synthesized Fe3O4 nanoparticles were investigated. The synthesized nanoparticles are crystalline and have particle sizes of ˜6-30 nm, as revealed by transmission electron microscopy (TEM). The results of X-ray diffraction (XRD), High resolution TEM (HRTEM) and selected area electron diffraction (SAED) indicate that the synthesized Fe3O4 nanoparticles have the inverse cubic spinel structure without the presence of any other phase impurities. The hysteresis loops of the Fe3O4 nanoparticles at room temperature show superparamagnetic behavior and the saturation magnetization of the Fe3O4 samples increases with increasing reaction temperature and time.

  20. Structural and morphological evolution of cerium oxide thin film on silicon prepared by metal-organic decomposition route

    Thin film of cerium oxide (CeO2) were prepared on silicon (Si) substrate by metal organic decomposition route. 0.25 M of cerium (III) acetylacetonate (acac) was used as starting materials with the addition of methanol and acetic acid as solvents. Oxide conversion of the film by thermal treatment was conducted at temperature ranging from 400 degree Celsius to 1000 degree Celsius for 15 min in argon ambient. X-ray diffraction (XRD) analysis utilizing Cukα radiation (Model Brukker DiffracPlus), Filmetrics system measurement, field emission scanning electron microscope (FESEM) (Model Zeiss Supra 35 VP FESEM) and atomic force microscopy (AFM) (Model SII Nanonavi) were employed to characterize the phase formed and morphologies of the film produced. (author)

  1. Reversible-Deactivation Radical Polymerization of Methyl Methacrylate Induced by Photochemical Reduction of Various Copper Catalysts

    Jaroslav Mosnáček

    2014-11-01

    Full Text Available Photochemically mediated reversible-deactivation radical polymerization of methyl methacrylate was successfully performed using 50–400 ppm of various copper compounds such as CuSO4·5H2O, copper acetate, copper triflate and copper acetylacetonate as catalysts. The copper catalysts were reduced in situ by irradiation at wavelengths of 366–546 nm, without using any additional reducing agent. Bromopropionitrile was used as an initiator. The effects of various solvents and the concentration and structure of ligands were investigated. Well-defined polymers were obtained when at least 100 or 200 ppm of any catalyst complexed with excess tris(2-pyridylmethylamine as a ligand was used in dimethyl sulfoxide as a solvent.

  2. Rapid radiochemical separation of short-lived radionuclides in neutron-activated samples

    Radiochemical separation procedures based on the removal of metal ions by columns of C18-bonded silica gel after selective complexation are examined and the simplicity of the method demonstrated by its application to determination of Mn, Cu and Zn in neutron-activated biological material from the following solutions (pH 0-10, sulphate concentration 0,18M and 1,44M SO4): 8-hydroxyquinoline (oxine), ammonium pyrrolidinedithiocarbamate (APDC), cupferron (CUP), 1-(2-pyridylazo)-2-naphthol (PAN), 1-(2'-thiazolylazo)-2-naphthol (TAN), 4-(2-pyridylazo) resorcinol (PAR), diethylammonium diethyldithiocarbamate (DDC), potassium ethyl xanthate (PEX), acetylacetone (AcAc) or thenoyltrifluoracetone (TTA). The method is rapid and reliable and readily adaptable in all radiochemical laboratories

  3. Azo coupling of 4-nitrophenyldiazonium chloride with aliphatic nucleophiles: an integrated organic synthesis and X-ray crystallography experiment

    This article describes an undergraduate experiment for the synthesis of p-nitrophenyldiazonium chloride and its coupling with acetylacetone and two enaminones, 4-phenylamino-pent-3-en-2-one and 4-amino-pent-3-en-2-one, in an adaptation of a previously reported synthetic protocol. The azo dyes 4-(E)-phenylamino-3-[(E)-2-(4-nitrophenylazo)]-3-penten-2-one and 4-(E)-amino-3-[(E)-2-(4-nitrophenylazo)]-3-penten-2-one were obtained, and the solid state structure of this latter azo compound was characterized by single crystal X-ray diffraction studies. This two-week integrated laboratory approach involves simple synthetic experiments and microwave chemistry in the organic laboratory plus crystallography analysis, suitable for novice students on undergraduate experimental chemistry courses. (author)

  4. Luminescent complexes of terbium ion for molecular recognition of ibuprofen.

    Selivanova, Natalia; Vasilieva, Kristina; Galyametdinov, Yury

    2014-05-01

    The complexation behavior and luminescent properties of terbium (Tb(3+) ) complexes containing bi-dental ligands were studied: nitrogen - 1,10-phenanthroline, and oxygen - trifluoroacetylacetone as well as acetylacetone ligands with ibuprofen (Ibu; a non-steroidal anti-inflammatory drug). Aqueous and aqueous alcohol microheterogeneous solutions were used as media. The effects of solubilization by various micellar solutions, pH and ligand type on luminescent properties of Tb(3+) complexes were investigated. Sensitized luminescence of mixed ligand complex Tb(1,10-phenanthroline)-Ibu and dynamic quenching effect in complex Tb(trifluoroacetylacetone)3 -Ibu allow Ibu determination with the limit of detection 5.3 × 10(-8)  mol/L and 1.26 × 10(-6)  mol/L, respectively. PMID:23713065

  5. Preparation and biodistribution of copper-67 complexes with tetradentate Schiff-base ligands

    We report here the synthesis and biodistribution of the copper-67 complexes of a series of tetradentate Schiff-base ligands. The ligands were synthesized by condensation of ethylenediamine (en), 1,2-propanediamine (pn), 1,3-propanediamine (tn), or 2,2-dimethyl-1,3-propanediamine (2,2-Me2tn) with either salicylaldehyde (sal), 4-methoxysalicylaldehyde(4-MeOsal), 2-hydroxyacetophenone (2-HO-aceptoph), or acetylacetone (acac). The fourteen [Cu-67]-Schiff-base complexes studied were readily obtained by reaction of the acetate-buffered divalent Cu-67 ion with an excess of the tetradentate ligand dissolved in ethanol. In all cases the radiochemical purity of the product exceeded 95% as assessed by thin layer chromatography on silica gel plates eluted with ethyl acetate. The biodistribution of each of these [Cu-67]-Schiff-base complexes was determined in rats following injection into the femoral vein. (author)

  6. Dioxouranium(VI) complexes with potential ter-and tetra-dentate Schiff base ligands

    A series of dioxouranium(VI) complexes were synthesised with the tetradentate Schiff base ligands (N202 donor set) obtained by the condensation of ethylenediamine with salicyladehyde(H2salen), acetylacetone (H2aaen) or benzoyl acetone (H2baen) and ter-dentate Schiff base ligands derived by condensation of salicylaldehyde with glycine(glysal), o-aminophenol(APhSal) or 2-amino 4-methyl pyridine (AMPy Sal) as well as glycine with acetylacetone (glyaa). The terdentate ligands have the N02 or N20 donor set. The tetradentate ligands formed complexes of the type [U02LX2], where L =H2salen, H2aaen, H2baen and X = Cl, I, N03, NCS, 0.5 S04; and the complexes contain 6-coordinated U022+ group with the anions inside the coordination sphere. The IR evidence shows that the thiocyanate group is actually N-bonded iso-thiocyanato, the nitrato group is involved in unidentate covalent bonding and the sulphato group is bonded covalently in a bidentate manner. The far IR spectra was studied to find the ν(U-Cl) at 234 cm-1 and the delta(0U0) at ca. 225 cm-1. U02(Cl04)2 reacted with H2salen to form U02(salen). The terdentate ligands H2glysal and H2glyaa formed complexes of the type U02(glysal)H20 and U02(glyaa)2H20, which is confirmed on the basis of IR and DTG, TGA data. The U022+ group is 4- and 5-coordinated respectively, in these complexes. The potential ter-dentate ligands H2APhSal and HAMPySal behaved essentially as bidentate ligands and formed 4-coordinate, neutral complexes, U02L2(L= H-APhSal or AMPySal). author)

  7. Pure magnetic hard fct FePt nanoparticles: Chemical synthesis, structural and magnetic properties correlations

    Suber, L., E-mail: lorenza.suber@ism.cnr.it [ISM-CNR, Area della Ricerca di Roma 1, Via Salaria km 29.300, 00015 Monterotondo Scalo, RM (Italy); Marchegiani, G. [ISM-CNR, Area della Ricerca di Roma 1, Via Salaria km 29.300, 00015 Monterotondo Scalo, RM (Italy); Olivetti, E.S.; Celegato, F.; Coïsson, M.; Tiberto, P. [INRIM, Electromagnetism Division, Strada delle Cacce 91, 10135 Torino (Italy); Allia, P. [DISAT Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Barrera, G. [Dipartimento di Chimica, Università di Torino, Via Pietro Giuria 7, 10125 Torino (Italy); Pilloni, L. [UTTMAT-CHI, Via Anguillarese 10, 00123 S. Maria di Galeria, Roma (Italy); Barba, L. [IC-CNR, Area Science Park, SS 14 Km 163.5 Basovizza, 34149 Trieste (Italy); Padella, F. [UTTMAT-CHI, Via Anguillarese 10, 00123 S. Maria di Galeria, Roma (Italy); Cossari, P. [IGAG-CNR, Area della Ricerca di Roma 1, Via Salaria km 29.300, 00015 Monterotondo Scalo, RM (Italy); Chiolerio, A. [Istituto Italiano di Tecnologia, Center for Space Human Robotics, Corso Trento 21, 10129 Torino (Italy)

    2014-03-01

    FePt nanoparticles, containing a near-equal atomic percentage of Fe and Pt, with a face centered tetragonal structure (fct), are challenging for potential applications in high performance permanent magnets and high density data storage. In this study, we report on the chemical synthesis, carried out both solvothermally and hydrothermally in autoclave reacting iron (III) acetylacetonate and platinum (II) acetylacetonate with tri- or tetra-ethylene glycol, these employed as solvents, reducers and particle surface protecting agents as well. In both methods, a subsequent thermal treatment at high temperatures is necessary to transform the magnetic soft face centered cubic (fcc) phase to the hard fct one. Organic low-weight molecules, generally used to protect the nanoparticle surface and avoid particle aggregation, are decomposed by the thermal treatment resulting in particle aggregation and coalescence phenomena; on the contrary, in this case, a polymer matrix is formed as particle protecting agent and, by thermally treating the hydrothermally prepared nanoparticles up to 750 °C for 1 h, the pure magnetic hard fct phase is obtained while preserving the nanostructure. A detailed study is carried out on FePt nanoparticle structure (fcc and fct phases) and correlated to the magnetic properties of the system. - Highlights: • fct FePt nanoparticles for hard magnetic nanotechnology applications. • Influence of synthesis parameters on the precursor fcc FePt nanoparticle structure. • Easy hydrothermal method for preparing pure fct FePt nanoparticles. • Monitoring the role of temperature and time on the FePt fcc–fct phase transformation. • Correlation between FePt nanoparticle structural and magnetic properties.

  8. Action of chelators on solid iron in phosphate-containing aqueous solutions

    To study the effect of strong iron-ligands on steel corrosion, mild steel electrodes were immersed in solutions containing 20 mM phosphate buffer (pH=7.2) and between 0.01 mM and 1 M of either the iron(II)-chelators 2,2'-bipyridine or FerroZine, or the iron(III)-chelators citrate or acetylacetonate. Resulting surface reactions were investigated by quantifying the electrochemical potential (E), the electrochemical polarization resistance (Rp), the corrosion current (Icorr) and the release of iron into solution. The surface was further analyzed by scanning electron microscopy (SEM/SEM-EDAX) and atomic force microscopy. Concentrations of 0.1 mM of any of the chelators led to slight, temporary changes in E, Icorr and Rp. Concentrations of 10 mM resulted in characteristic changes of E, which were the same for all chelators and in the precipitation of FePO4 in the case of citrate and acetylacetonate, or vivianite [Fe3(PO4)2 · 8H2O] in the case of bipyridine and FerroZine. Concentrations of 1 mM of both iron(III)-chelators led to a temporary drop of E similar to that found with 0.1 mM chelator. With iron(II)-chelators, E dropped to about -500 mV before oscillating for several days. The amplitudes of the oscillations were up to 200 mV with periods of 30 and 20-25 min for bipyridine and FerroZine, respectively

  9. Simple solvothermal synthesis of hydrophobic magnetic monodispersed Fe3O4 nanoparticles

    Graphical abstract: A facile method to produce monodispersed magnetite nanoparticles is based on the solvothermal reaction of iron acetylacetonate (Fe(acac)3) decomposition. The sizes ranged from 7 to 12 nm, which could be controlled by adjusting the volume ratio of oleylamine to n-hexane. Display Omitted Highlights: ► The solvethermal reaction of Fe(acac)3 decomposition was carried out at mild temperature in the presence of oleylamine and n-hexane. ► The size of nanocrystals is controlled by adjusting the volume ratio of oleylamine to n-hexane. ► The low-boiling-point solvent n-hexane offered autogenous pressure parameter after gasified in the reaction temperature. ► The as prepared hydrophobic monodisperse Fe3O4 NPs can be used to prepare the magnetic micelles for future biomedical applications. -- Abstract: A new solvothermal method is proposed for the preparation of Fe3O4 nanoparticles (NPs) from iron acetylacetonate in the presence of oleylamine and n-hexane. The products are characterized by X-ray powder diffraction, infrared (IR) spectroscopy, transmission electron microscopy, thermogravimetry/differential thermogravimetry (TG/DTG) analysis, and vibrating sample magnetometery. The new procedure yields superparamagnetic monodispersed Fe3O4 particles with sizes ranging from 7 nm to 12 nm. The nanocrystal sizes are controlled by adjusting the volume ratio of oleylamine to n-hexane. IR and TG/DTG analyses indicate that the oleylamine molecules, as stabilizers, are adsorbed on the surface of Fe3O4 NPs as bilayer adsorption models. The surface adsorption quantities of oleylamine on 7.5 and 10.4 nm-diameter Fe3O4 NPs are 18% and 11%, respectively. The hydrophobic surface of the obtained nanocrystals is passivated by adsorbed organic solvent molecules. These molecules provide stability against agglomeration, enable solubility in nonpolar solvents, and allow the formation of magnetic polymer micelles.

  10. Studies on the porphine labeled with 99mTc-pertechnetate

    The aim of this research is to use acetylacetonate as a 99mTc chelating agent label with porphyrin and evaluate its radiochemical and biological characteristics. Stannous chloride was used as a reductant to determine the chemical and biological characterization of 99mTc-complexes from labeling porphine (4',4'',4'''-(2lH,23H-Porphine-5,10,15,20-terayl)tetrakis-(benzoic acid), TPPB) with 99mTc-pertechnetate. Instant thin layer chromatography (ITLC), size exclusion chromatography (SEC), paper electrophoresis, and UV/Vis spectrophotometry were used to evaluate chemical characterization. Finally, biodistribution and liver function tests were applied to evaluate biological characteristics. The results of this study show that the labeling efficiency of 99mTc(acac)-TPPB was nearly 100% when using acetylacetone (acac) as a conjugator. Three major 99mTc(acac)-TPPB complexes were separated by SEC, and all of them were hydrophilic. The UV-Vis spectra of 99mTc(acac)-TPPB complexes closely resembled those of the TPPB, but the wave lengths of their peaks changed 430, 521, 556, 591 and 647 nm after complexation. The biodistribution study selected the liver as the target organ. The 99mTc(acac)-TPPB complex may cause short-term liver injury. However, this injury can be repaired, and the reagent is quickly metabolized. Hence, the toxicity of the 99mTc(acac)-TPPB complex is within an acceptable range, and making it a promising liver imaging agent. (author)

  11. Increasing the energy density of the non-aqueous vanadium redox flow battery with new electrolytes

    Redox flow battery (RFB) is a promising energy storage technology which is similar to a polymer electrolyte membrane fuel cell. Currently, this electrochemical energy conversion device is used as a storage system for renewable energies or as uninterruptable power source. All-Vanadium-RFB (VRFB) and Zinc-Bromine-RFB are most well-known types of the aqueous RFB for these applications. But also the non-aqueous RFB is becoming more and more famous, because non-aqueous electrolytes offer wider operating temperature ranges, wider stable potential windows and a potentially higher energy density. However, current research studies show that the solubility of the most used redox active species is not sufficient. Therefore, present study aims to show concepts in order to solve this problem. Vanadium(III)acetylacetonate (V(acac)3) is used as active species, supported by tetrabutylammonium hexafluorophosphate. In acetonitrile it shows two quasi-reversible redox couples and a cell potential ∝2.2 V. The maximum solubility is ∝0.6 M. In this work other solvents and solvent mixtures were examined with the objective of increasing the solubility of V(acac)3. In 1,3-dioxolane the solubility was e.g. 0.8 M, dimethyl sulfoxide showed good battery performance with the highest energy efficiency ∝44 %. Acetylacetone is able to regenerate V(acac)3 from the side product that is formed by reaction with water. The new electrolyte solution consisting of acetonitrile, 1,3-dioxolane and dimethyl sulfoxide nearly doubled the solubility of V(acac)3. In galvanostatic charge-discharge tests, single cell V(acac)3 RFB exhibited energy efficiency between 25-50 % depending an test conditions. Also, the influence of water and oxygen addition an electrolyte was investigated. Finally, experiments with different ambient temperatures show that V(acac)3 RFB is able to operate at temperatures such as 0 C and -25 C.

  12. Chemical modification of titanium isopropoxide for producing stable dispersion of titania nano-particles

    Stable colloidal TiO2 nano-particles are synthesized through the controlled hydrolysis of chemically modified titanium (Ti) isopropoxide with acetylacetone and acetic acid whereas ammonium salts of poly(acrylic acid) is used as a dispersing agent. Acetylacetone and acetic acid used as chelating ligand to retard the hydrolysis and condensation rates. The process is found promising for producing homogeneous aqueous phase colloidal dispersion of TiO2 particles. Fourier transformed infrared and nuclear magnetic resonance spectra reveal the formation of monodentate bridging of ligands with Ti-isopropoxide. UV–Vis spectroscopy confirms the effective adsorption of poly(acrylic acid) within the modified Ti precursor. Zeta potential of modified titanium isopropoxide precursor is measured to understand its stability in different pH. The thermal stability of the precursors modified with different chelating ligands and dispersing agent has been studied using thermo-gravimetric in conjunction to differential thermal analysis (TG-DTA). Phase formation behavior and the morphological features of the synthesized particles are studied using X-ray diffraction and electron microscopy techniques. The sizes of the anatase phase particles are found in the range of 12–20 nm. - Highlights: • Nanosized colloidal TiO2 is prepared by controlled hydrolysis of Ti-isopropoxide. • Effect of chelating and dispersing agent on stability of colloidal TiO2 is studied. • Phase, morphology and stability of colloidal TiO2 are investigated. • The sizes of synthesized TiO2 particles are found in the range of 12–20 nm. • Suitable chelating and dispersing agent can improve particle loading in sol

  13. Increasing the energy density of the non-aqueous vanadium redox flow battery with new electrolytes; Neue Elektrolyte zur Steigerung der Energiedichte einer nicht-waessrigen Vanadium-Acetylacetonat-Redox-Flow-Batterie

    Herr, Tatjana

    2015-07-01

    Redox flow battery (RFB) is a promising energy storage technology which is similar to a polymer electrolyte membrane fuel cell. Currently, this electrochemical energy conversion device is used as a storage system for renewable energies or as uninterruptable power source. All-Vanadium-RFB (VRFB) and Zinc-Bromine-RFB are most well-known types of the aqueous RFB for these applications. But also the non-aqueous RFB is becoming more and more famous, because non-aqueous electrolytes offer wider operating temperature ranges, wider stable potential windows and a potentially higher energy density. However, current research studies show that the solubility of the most used redox active species is not sufficient. Therefore, present study aims to show concepts in order to solve this problem. Vanadium(III)acetylacetonate (V(acac){sub 3}) is used as active species, supported by tetrabutylammonium hexafluorophosphate. In acetonitrile it shows two quasi-reversible redox couples and a cell potential ∝2.2 V. The maximum solubility is ∝0.6 M. In this work other solvents and solvent mixtures were examined with the objective of increasing the solubility of V(acac){sub 3}. In 1,3-dioxolane the solubility was e.g. 0.8 M, dimethyl sulfoxide showed good battery performance with the highest energy efficiency ∝44 %. Acetylacetone is able to regenerate V(acac){sub 3} from the side product that is formed by reaction with water. The new electrolyte solution consisting of acetonitrile, 1,3-dioxolane and dimethyl sulfoxide nearly doubled the solubility of V(acac){sub 3}. In galvanostatic charge-discharge tests, single cell V(acac){sub 3} RFB exhibited energy efficiency between 25-50 % depending an test conditions. Also, the influence of water and oxygen addition an electrolyte was investigated. Finally, experiments with different ambient temperatures show that V(acac){sub 3} RFB is able to operate at temperatures such as 0 C and -25 C.

  14. Sol-gel chemistry applied to the synthesis of polymetallic oxides including actinides reactivity and structure from solution to solid state; Synthese par voie douce d'oxydes polymetalliques incluant des actinides: reactivite et structure de la solution au solide

    Lemonnier, St

    2006-02-15

    Minor actinides transmutation is studied at present in order to reduce the radiotoxicity of nuclear waste and the assessment of its technical feasibility requires specific designed materials. When considering americium, yttria stabilized zirconia (Am{sup III} YII Zriv)Or{sub x} is among the ceramic phases that one which presents the required physico-chemical properties. An innovative synthesis of this mixed oxide by sol-gel process is reported in this manuscript. The main aim of this work is to adjust the reactivity of the different metallic cations in aqueous media using complexing agent, in order to initiate a favourable interaction for a homogeneous elements repartition in the forming solid phase. The originality of the settled synthesis lies on an in-situ formation of a stable and monodisperse nano-particles dispersion in the presence of acetylacetone. The main reaction mechanisms have been identified: the sol stabilisation results from an original interaction between the three compounds (Zrly, trivalent cations and acetylacetone). The sol corresponds to a structured system at the nanometer scale for which zirconium and trivalent cations are homogeneously dispersed, preliminary to the sol-gel transition. Furthermore, preliminary studies were carried out with a view to developing materials. They have demonstrated that numerous innovative and potential applications can be developed by taking advantage of the direct and controlled formation of the sol and by adapting the sol-gel transition. The most illustrating result is the preparation of a sintered pellet with the composition Am0,13Zro,73Yo,0901,89 using this approach. (author)

  15. Sol-gel chemistry applied to the synthesis of polymetallic oxides including actinides reactivity and structure from solution to solid state

    Minor actinides transmutation is studied at present in order to reduce the radiotoxicity of nuclear waste and the assessment of its technical feasibility requires specific designed materials. When considering americium, yttria stabilized zirconia (AmIII YII Zriv)Orx is among the ceramic phases that one which presents the required physico-chemical properties. An innovative synthesis of this mixed oxide by sol-gel process is reported in this manuscript. The main aim of this work is to adjust the reactivity of the different metallic cations in aqueous media using complexing agent, in order to initiate a favourable interaction for a homogeneous elements repartition in the forming solid phase. The originality of the settled synthesis lies on an in-situ formation of a stable and monodisperse nano-particles dispersion in the presence of acetylacetone. The main reaction mechanisms have been identified: the sol stabilisation results from an original interaction between the three compounds (Zrly, trivalent cations and acetylacetone). The sol corresponds to a structured system at the nanometer scale for which zirconium and trivalent cations are homogeneously dispersed, preliminary to the sol-gel transition. Furthermore, preliminary studies were carried out with a view to developing materials. They have demonstrated that numerous innovative and potential applications can be developed by taking advantage of the direct and controlled formation of the sol and by adapting the sol-gel transition. The most illustrating result is the preparation of a sintered pellet with the composition Am0,13Zro,73Yo,0901,89 using this approach. (author)

  16. Sol-Gel chemistry applied to the synthesis of Am-bearing cubic stabilised zirconia: reactivity and structure from solution to solid state

    Full text of publication follows. In the frame of the transmutation of minor actinides, recent concepts of nuclear targets imply the elaboration of inert host phases. Wet chemical routes are under investigations for their synthesis as alternative ways to the powder metallurgy. The main advantages of these methods are a minimization of the dissemination of contaminating dusts when elaborating nuclear materials and a better accessibility to very homogenous compounds and interesting nano-structures. Among these routes, an innovative synthesis by sol-gel process is reported here to synthesize yttria-stabilised zirconia, an inert ceramic phase candidate for the transmutation of americium: (AmIII,YIII,ZrIV)O2-x. Starting from an initial solution containing Zr(IV), Y(III) and Am(III) [or Nd(III)], the main aim of this work is to adjust the reactivity of different metallic cations in aqueous media using a complexing agent, in order to initiate a favourable interaction for the repartition of homogeneous elements in the forming solid phase. Investigations on several complexing agents to control the reactivity of these cations with a view to making them react simultaneously have been performed. Among them, the use of acetylacetone led to the formation of a stable and monodisperse nano-particle dispersion under controlled conditions. The main reaction mechanisms implied in the sol formation were identified using different techniques: IR and UV-visible spectroscopies, quasi-elastic light scattering, electrokinetic measurements and potentiometric studies. The sol stabilisation may result from an original interaction between the three compounds (ZrIV, trivalent cations and acetylacetone): hydrous zirconia nano particles (homogenous in size and around 5 nm) are formed and stabilised by surface complexation with acac and trivalent cations. This sol corresponds to a structured system at the nanometer scale for which zirconium and trivalent cations are homogeneously dispersed, before

  17. High energy sodium based room temperature flow batteries

    Shamie, Jack

    As novel energy sources such as solar, wind and tidal energies are explored it becomes necessary to build energy storage facilities to load level the intermittent nature of these energy sources. Energy storage is achieved by converting electrical energy into another form of energy. Batteries have many properties that are attractive for energy storage including high energy and power. Among many different types of batteries, redox flow batteries (RFBs) offer many advantages. Unlike conventional batteries, RFBs store energy in a liquid medium rather than solid active materials. This method of storage allows for the separation of energy and power unlike conventional batteries. Additionally flow batteries may have long lifetimes because there is no expansion or contraction of electrodes. A major disadvantage of RFB's is its lower energy density when compared to traditional batteries. In this Thesis, a novel hybrid Na-based redox flow battery (HNFB) is explored, which utilizes a room temperature molten sodium based anode, a sodium ion conducting solid electrolyte and liquid catholytes. The sodium electrode leads to high voltages and energy and allows for the possibility of multi-electron transfer per molecule. Vanadium acetylacetonate (acac) and TEMPO have been investigated for their use as catholytes. In the vanadium system, 2 electrons transfers per vanadium atom were found leading to a doubling of capacity. In addition, degradation of the charged state was found to be reversible within the voltage range of the cell. Contamination by water leads to the formation of vanadyl acetylacetonate. Although it is believed that vanadyl complex need to be taken to low voltages to be reduced back to vanadium acac, a new mechanism is shown that begins at higher voltages (2.1V). Vanadyl complexes react with excess ligand and protons to reform the vanadium complex. During this reaction, water is reformed leading to the continuous cycle in which vanadyl is formed and then reduced back

  18. Quantum molecular dynamics and molecular interactions studied by NMR and INS

    The wavefunction of a particle extends into the classically forbidden barrier region of the potential energy surface. The consequence of this partial delocalisation is the phenomenon of quantum tunnelling, an effect which enables a particle to penetrate a potential barrier of magnitude greater than the energy of the particle. The tunnelling probability is an exponential function of the particle mass. The effect is therefore an important contribution to the behaviour of light atoms, in particular the proton. The hydrogen bond has long been appreciated to be an essential component of many biological and chemical systems, and the proton transfer reaction in the hydrogen bond is fundamental to many of these processes. The proton behaviour in the hydrogen bonds of benzoic acid, acetylacetone and calix-4-arene has been studied. A variety of techniques, both experimental and computational, were adopted for the study of the three hydrogen bonded systems. The complementary spectroscopic techniques of inelastic neutron scattering (INS) and rapid field cycling nuclear magnetic resonance (NMR) were used, both of which are sensitive to the motion of protons and hence contain information on the proton dynamics within their recorded spectra. An optimised force field model was determined using structural data for benzoic acid under pressure. This was then used, with limited success, to calculate the energy asymmetry as a function of applied pressure. NMR studies of partially deuterated benzoic acid samples were conducted and the dynamical motion for the different components determined and modelled. The dynamical behaviour of the methyl groups of acetylacetone was investigated by neutron scattering at ambient and high pressure for a variety of isotopic compounds. Evidence of coupling between the hydrogen bond proton and the methyl groups was observed. That the energy asymmetry of the potential energy surface describing the hydrogen bond is small and could be reduced by the

  19. Colloidal chemical synthesis and formation kinetics of uniformly sized nanocrystals of metals, oxides, and chalcogenides.

    Kwon, Soon Gu; Hyeon, Taeghwan

    2008-12-01

    nanoparticles of copper and nickel using metal(II) acetylacetonates. Ni/Pd core/shell nanoparticles were synthesized by simply heating the reaction mixture composed of acetylacetonates of nickel and palladium. Using alternative chalcogen reagents, we synthesized uniform nanocrystals of various metal chalcogenides. Uniform nanocrystals of PbS, ZnS, CdS, and MnS were obtained by heating reaction mixtures composed of metal chlorides and sulfur dissolved in oleylamine. In the future, a detailed understanding of nanocrystal formation kinetics and synthetic chemistry will lead to the synthesis of uniform nanocrystals with controlled size, shape, and composition. In particular, the synthesis of uniform nanocrystals of doped materials, core/shell materials, and multicomponent materials is still a challenge. We expect that these uniformly sized nanocrystals will find important applications in areas including information technology, biomedicine, and energy/environmental technology. PMID:18681462

  20. Pt-doped In{sub 2}O{sub 3} nanoparticles prepared by flame spray pyrolysis for NO{sub 2} sensing

    Inyawilert, K. [Chiang Mai University, Department of Physics and Materials Science, Faculty of Science (Thailand); Channei, D. [Naresuan University, Department of Chemistry, Faculty of Science (Thailand); Tamaekong, N. [Maejo University, Program in Materials Science, Faculty of Science (Thailand); Liewhiran, C. [Chiang Mai University, Department of Physics and Materials Science, Faculty of Science (Thailand); Wisitsoraat, A.; Tuantranont, A. [National Electronics and Computer Technology Center (NECTEC), Nanoelectronics and MEMS Laboratory (Thailand); Phanichphant, S., E-mail: sphanichphant@gmail.com [Chiang Mai University, Faculty of Science, Materials Science Research Center (Thailand)

    2016-02-15

    Undoped In{sub 2}O{sub 3} and 0.25–1.00 wt% M (M=Pt, Nb, and Ru)-doped/loaded In{sub 2}O{sub 3} nanoparticles were successfully synthesized in a single-step flame spray pyrolysis technique using indium nitrate, platinum (II) acetylacetonate, niobium ethoxide, and ruthenium (III) acetylacetonate precursors. The undoped In{sub 2}O{sub 3} and M-doped In{sub 2}O{sub 3} nanoparticles were characterized by Brunauer–Emmett–Teller (BET) analysis, X-ray diffraction (XRD), and scanning and transmission electron microscopy (SEM & TEM). The BET average diameter of spherical nanoparticles was found to be in the range of 10.2–15.2 nm under 5/5 (precursor/oxygen) flame conditions. All XRD peaks were confirmed to correspond to the cubic structure of In{sub 2}O{sub 3}. TEM images showed that there is no Pt nanoparticle loaded on In{sub 2}O{sub 3} surface, suggesting that Pt should form solid solution with the In{sub 2}O{sub 3} lattice. Gas sensing studies showed that 0.5 wt% Pt doping in In{sub 2}O{sub 3} nanoparticles gave a significant enhancement of NO{sub 2} sensing performances in terms of sensor response and selectivity. 0.5 wt% Pt/In{sub 2}O{sub 3} exhibited a high NO{sub 2} response of ∼1904 to 5 ppm NO{sub 2} at 250 °C and good NO{sub 2} selectivity against NO, H{sub 2}S, H{sub 2}, and C{sub 2}H{sub 5}OH. In contrast, Nb and Ru loading resulted in deteriorated NO{sub 2} response. Therefore, Pt is demonstrated to be an effective additive to enhance NO{sub 2} sensing performances of In{sub 2}O{sub 3}-based sensors.

  1. Synthesis of magnetic cobalt ferrite nanoparticles with controlled morphology, monodispersity and composition: the influence of solvent, surfactant, reductant and synthetic conditions

    Lu, Le T.; Dung, Ngo T.; Tung, Le D.; Thanh, Cao T.; Quy, Ong K.; Chuc, Nguyen V.; Maenosono, Shinya; Thanh, Nguyen T. K.

    2015-11-01

    In our present work, magnetic cobalt ferrite (CoFe2O4) nanoparticles have been successfully synthesised by thermal decomposition of Fe(iii) and Co(ii) acetylacetonate compounds in organic solvents in the presence of oleic acid (OA)/ oleylamine (OLA) as surfactants and 1,2-hexadecanediol (HDD) or octadecanol (OCD-ol) as an accelerating agent. As a result, CoFe2O4 nanoparticles of different shapes were tightly controlled in size (range of 4-30 nm) and monodispersity (standard deviation only at ca. 5%). Experimental parameters, such as reaction time, temperature, surfactant concentration, solvent, precursor ratio, and accelerating agent, in particular, the role of HDD, OCD-ol, and OA/OLA have been intensively investigated in detail to discover the best conditions for the synthesis of the above magnetic nanoparticles. The obtained nanoparticles have been successfully applied for producing oriented carbon nanotubes (CNTs), and they have potential to be used in biomedical applications.In our present work, magnetic cobalt ferrite (CoFe2O4) nanoparticles have been successfully synthesised by thermal decomposition of Fe(iii) and Co(ii) acetylacetonate compounds in organic solvents in the presence of oleic acid (OA)/ oleylamine (OLA) as surfactants and 1,2-hexadecanediol (HDD) or octadecanol (OCD-ol) as an accelerating agent. As a result, CoFe2O4 nanoparticles of different shapes were tightly controlled in size (range of 4-30 nm) and monodispersity (standard deviation only at ca. 5%). Experimental parameters, such as reaction time, temperature, surfactant concentration, solvent, precursor ratio, and accelerating agent, in particular, the role of HDD, OCD-ol, and OA/OLA have been intensively investigated in detail to discover the best conditions for the synthesis of the above magnetic nanoparticles. The obtained nanoparticles have been successfully applied for producing oriented carbon nanotubes (CNTs), and they have potential to be used in biomedical applications. Electronic

  2. Separation through liquid-liquid extraction and spectrophotometric determination of U(VI) with the ortho-aminophenol reagent

    The extractive properties of the ortho-aminophenol reagent upon U(VI) were investigated in two solvents: 4-chlor-acetophenone and acetylacetone, in a water-organic solvent system. The method here proposed is based on the complexation reaction of the uranyl ion, UO22+, with ortho-aminophenol dissolved in 4-chlor-acetophenone, at room temperature, over a pH interval 4-6, followed by spectro-photometry of the organic phase, involving measuring of absorbancy at 569.6 nm. The Beer law is valid over the 1-12, μg U(VI)/mL concentration interval, with molar absorptivity εmax 4.3 x 105 mol-1 cm2 and Sandell sensitivity = 0.0526 μg cm-2. The structure, stability and solubility of the formed complex was studied by UV-VIS and IR spectrometry, diffractometry and scanning electron microscopy. The mixed complex formed between the uranyl ion and the ortho-aminophenol dissolved in 4-chlor-acetophenone, [UO2.(L)2.(S)4], is characterized by the following parameters: metal/ligand combination ratio: M/L = 1/2, stability constant β = 2.06 x 106, distribution coefficient D = 66.56 (Vorg = Vaq), percentage extraction E% = 98.52, and recovery factor, R%, ranging between 99.48 and 99.85%. (author)

  3. A novel route to size and shape controlled synthesis of DMSO capped ruthenium dioxide nanoparticles

    Ruthenium dioxide nanoparticles (RuO2) with an average particle size of 54-95 nm are readily synthesized from RuCl3.xH2O via the formation of ruthenium acetylacetone. The particle size of RuO2 nanoparticle increases with increase in calcination time at 800 deg C. The ruthenium dioxide nanoparticles have also been capped with DMSO to make them soluble in common organic solvents. These synthesized nanocrystallites have been characterized by FTIR, UV-vis, SEM-EDX, 1H NMR, magnetic measurements and XRD techniques. The XRD pattern demonstrates the crystalline nature of these nanoparticles. The downfield shift of vs=o frequency (Δv=74 cm-1 ) in FTIR, as well as SEM-EDX and 1H NMR spectra of the capped RuO2 nanoparticle confirm the capping with DMSO. UV-vis analysis shows that the absorption peak is blue-shifted with decrease of particle size. Magnetic measurements show that these nano oxides have nearly zero magnetic remanence, a linear response of magnetization and finally reach saturation magnetization at low external field in the range 2625-2650 Oe. (author)

  4. Dependence of precursor composition on patterning and morphology of sol–gel soft lithography based zinc zirconium oxide thin films

    Bera, Susanta; Pal, Moumita; Sarkar, Saswati [Sol–Gel Division, CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032 (India); Jana, Sunirmal, E-mail: sjana@cgcri.res.in [Sol–Gel Division, CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032 (India)

    2013-05-15

    Array-like surface patterned zinc zirconium oxide thin films (135–163 nm thickness) on soda lime silica glass substrate were prepared by sol–gel soft lithography from the precursor solutions (8 wt% equivalent metal oxides) having zinc acetate dihydrate (ZA) and zirconium oxychloride octahydrate (ZOO = 0–100 mol% w.r.t. ZA) in ethanol-2-butanol medium with acetylacetone. The ZOO concentration in solutions strongly influenced the pattern formation, crystallinity, morphology and optical property of the films. The films were crystalline in nature and enriched with only h-ZnO or a mixture of h-ZnO and c-ZrO{sub 2} below 55 mol% of ZOO content. On increasing ZOO concentration, a systematic change in morphology of h-ZnO nano/micro crystals from spherical to rod-shaped to sunflower-like particles was evident from electron microscopes (FESEM and TEM). Below 30 and above 65 mol% of ZOO, light surface patterns formed. However, the films from 30 to 65 mol% ZOO containing solutions evident distinct surface patterns with average periodicity, 1.5 μm and peak height, 20–70 nm by AFM measurements. The films were also characterized by UV–vis and FTIR spectral studies. Water and chloride contents from ZOO in the precursor solutions found to play a key role for generation of the film characteristics.

  5. Solvothermal synthesis and characterization of sandwich-like graphene/ZnO nanocomposites

    Graphene-based nanocomposites are emerging as a new class of materials that hold promise for many applications. In this paper, we present a general approach for the preparation of sandwich-like graphene/ZnO nanocomposites in ethylene glycol (EG) medium using graphene oxide as a precursor of graphene and zinc acetylacetonate as a single-source precursor of zinc oxide. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and thermogravimetry analysis. It was shown that the as-formed ZnO nanoparticles with a diameter of about 5 nm were densely and uniformly deposited on both surfaces of the graphene sheets to form a sandwich-like composite structure and as a result, the restacking of the as-reduced graphene sheets was effectively prevented. The ZnO-coated graphene nanocomposites can be expected to effectively improve the photocatalysis and sensing properties of ZnO and would be promising for practical applications in future nanotechnology.

  6. Direct dry-grinding synthesis of monodisperse lipophilic CuS nanoparticles

    Li, Yajuan; Scott, Julie; Chen, Yi-Tzai; Guo, Liangran; Zhao, Mingyang; Wang, Xiaodong [Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, The University of Rhode Island, Kingston, RI 02881 (United States); Lu, Wei, E-mail: weilu@uri.edu [Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, The University of Rhode Island, Kingston, RI 02881 (United States); School of Pharmacy, Fudan University, Shanghai 201203 (China)

    2015-07-15

    Copper sulfide nanoparticles, effective absorbers of near-infrared light, are recently attracting broad interest as a photothermal coupling agent for cancer therapy. Lipophilic copper sulfide nanoparticles are preferred for high performance biomedical applications due to high tissue affinity. Synthesis of lipophilic copper sulfide nanoparticles requires complicated multi-step processes under severe conditions. Here, we describe a new synthetic process, developed by direct dry-grinding of copper(II) acetylacetonate with sulfur under ambient environment at low temperature. The formed CuS nanoparticles are of uniform size, ∼10 nm in diameter, and are monodispersed in chloroform. Each covellite CuS nanocrystal surface is modified with oleylamine through hydrogen bonding between sulfur atoms and amine groups of oleylamine. The nanoparticles demonstrate near-infrared light absorption for photothermal applications. The synthetic methodology described here is more convenient and less extreme than previous methods, and should thus greatly facilitate the preparation of photothermal lipophilic copper sulfide nanomaterials for cancer therapy. - Highlights: • We make lipophilic CuS nanoparticles by mechanical grinding method in large scale. • The reaction condition is studied to obtain high yield and uniform size. • The synthesis does not need nitrogen protection or high temperature. • Lipophilic CuS nanoparticles show significant near-infrared absorbance.

  7. Ruthenium nanoparticles decorated curl-like porous carbons for high performance supercapacitors

    Lou, Bih-Show; Veerakumar, Pitchaimani; Chen, Shen-Ming; Veeramani, Vediyappan; Madhu, Rajesh; Liu, Shang-Bin

    2016-01-01

    The synthesis of highly dispersed and stable ruthenium nanoparticles (RuNPs; ca. 2–3 nm) on porous activated carbons derived from Moringa Oleifera fruit shells (MOC) is reported and were exploited for supercapacitor applications. The Ru/MOC composites so fabricated using the biowaste carbon source and ruthenium acetylacetonate as the co-feeding metal precursors were activated at elevated temperatures (600–900 oC) in the presence of ZnCl2 as the pore generating and chemical activating agent. The as-prepared MOC carbonized at 900 oC was found to possess a high specific surface area (2522 m2 g−1) and co-existing micro- and mesoporosities. Upon incorporating RuNPs, the Ru/MOC nanocomposites loaded with modest amount of metallic Ru (1.0–1.5 wt%) exhibit remarkable electrochemical and capacitive properties, achiving a maximum capacitance of 291 F g−1 at a current density of 1 A g−1 in 1.0 M H2SO4 electrolyte. These highly stable and durable Ru/MOC electrodes, which can be facily fabricated by the eco-friendly and cost-effective route, should have great potentials for practical applications in energy storage, biosensing, and catalysis. PMID:26818461

  8. Generation of hydrophilic, bamboo-shaped multiwalled carbon nanotubes by solid-state pyrolysis and its electrochemical studies.

    Shanmugam, Sangaraju; Gedanken, Aharon

    2006-02-01

    A simple, efficient, and novel method was developed for the direct preparation of hydrophilic, bamboo-shaped carbon nanotubes by the pyrolysis of ruthenium(III) acetylacetonate in a Swagelock cell is reported. The obtained product exhibits mostly bamboo-shaped, straight, periodic twisted, multiwalled carbon nanotubes possessing diameters of 50-80 nm and lengths of around 10 microm. The pyrolyzed product was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), micro-Raman, and cyclic voltammetric techniques. HRTEM studies showed that the walls of bamboo-shaped carbon nanotubes consisted of oblique grapheme planes with respect to the tube axis. The interlayer spacing between two graphitic layers was found to be 0.342 nm. XPS measurements have suggested that as-prepared carbon nanotubes consist the surface functional groups on the surface of carbon nanotubes. The electrochemical properties of synthesized carbon nanotubes have been evaluated. Thermogravimetric analysis (TGA), IR, and cyclic voltammetric studies showed the presence of oxygen functionalities. Raman studies revealed the presence of disorder in the graphitic carbon and the presence of exposed edge plane defects in the generated carbon nanotubes for influencing the surface behavior and electrochemical properties. The electrochemical behavior of electrodes made of bamboo-shaped carbon nanotubes served for an oxygen reduction reaction. PMID:16471780

  9. A novel blue-emitting Ir(III) complex with short excited state lifetime: Synthesis, structure, photophysical property, and electrophosphorescence performance

    In this paper, we synthesize a triphenylamine-derived cyclometalating ligand of (4-benzothiazol-2-yl-phenyl)-diphenyl-amine (referred as BPDA) and its corresponding Ir(III) complex of (BPDA)2Ir(acac) (acac=acetylacetone). The photophysical property, molecular structure, thermal property and electroluminescence performance of (BPDA)2Ir(acac) are investigated in detail. It is found that (BPDA)2Ir(acac) is an efficient emitter with high thermal stability and short excited state lifetime. The emission of (BPDA)2Ir(acac) changes from deep blue (417 nm) to bluish green (500 nm) upon addition of different solvents. We also investigate its electrophosphorescence performance. A maximum electroluminance of 8820 cd/m2 peaking at 494 nm is achieved, with the highest device efficiency of 1.72 cd/A. - Highlights: ► A blue-emitting Ir complex is synthesized and characterized. ► The photophysical property and molecular structure are investigated. ► The blue emission changes from deep blue to bluish green upon addition of various solvents. ► A maximum electroluminance of 8820 cd/m2 peaking at 494 nm is achieved.

  10. Direct dry-grinding synthesis of monodisperse lipophilic CuS nanoparticles

    Copper sulfide nanoparticles, effective absorbers of near-infrared light, are recently attracting broad interest as a photothermal coupling agent for cancer therapy. Lipophilic copper sulfide nanoparticles are preferred for high performance biomedical applications due to high tissue affinity. Synthesis of lipophilic copper sulfide nanoparticles requires complicated multi-step processes under severe conditions. Here, we describe a new synthetic process, developed by direct dry-grinding of copper(II) acetylacetonate with sulfur under ambient environment at low temperature. The formed CuS nanoparticles are of uniform size, ∼10 nm in diameter, and are monodispersed in chloroform. Each covellite CuS nanocrystal surface is modified with oleylamine through hydrogen bonding between sulfur atoms and amine groups of oleylamine. The nanoparticles demonstrate near-infrared light absorption for photothermal applications. The synthetic methodology described here is more convenient and less extreme than previous methods, and should thus greatly facilitate the preparation of photothermal lipophilic copper sulfide nanomaterials for cancer therapy. - Highlights: • We make lipophilic CuS nanoparticles by mechanical grinding method in large scale. • The reaction condition is studied to obtain high yield and uniform size. • The synthesis does not need nitrogen protection or high temperature. • Lipophilic CuS nanoparticles show significant near-infrared absorbance

  11. Solvothermal synthesis and characterization of sandwich-like graphene/ZnO nanocomposites

    Wu, Jili; Shen, Xiaoping; Jiang, Lei; Wang, Kun; Chen, Kangmin

    2010-02-01

    Graphene-based nanocomposites are emerging as a new class of materials that hold promise for many applications. In this paper, we present a general approach for the preparation of sandwich-like graphene/ZnO nanocomposites in ethylene glycol (EG) medium using graphene oxide as a precursor of graphene and zinc acetylacetonate as a single-source precursor of zinc oxide. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and thermogravimetry analysis. It was shown that the as-formed ZnO nanoparticles with a diameter of about 5 nm were densely and uniformly deposited on both surfaces of the graphene sheets to form a sandwich-like composite structure and as a result, the restacking of the as-reduced graphene sheets was effectively prevented. The ZnO-coated graphene nanocomposites can be expected to effectively improve the photocatalysis and sensing properties of ZnO and would be promising for practical applications in future nanotechnology.

  12. Mesoporous activated carbons with metal-oxide particles prepared from Morwell coal; Morwell tan wo genryo to shita kinzoku sankabutsu tanji kasseitan no saiko kozo

    Yoshizawa, N.; Yamada, Y.; Shiraishi, M. [National Institute for Resources and Environment, Tsukuba (Japan); Kojima, S.; Tamai, H.; Yasuda, H. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

    1996-10-28

    The metal dependence of mesoporous activated carbons with various metal acetylacetonate (acac) particles prepared from Morwell coal was studied. In experiment, the mixture of Morwell coal and acac metal complexes were dissipated into tetrahydrofuran, and after agitation in Ar atmosphere, the solvent was removed by vacuum distillation. Coal specimens with Fe(acac)3, Ni(acac)2 and Co(acac)2 as acac complexes were activated by exchanging flow gas with water vapor after heat treatment in N2 gas flow at 900{degree}C. The pore sizes of the specimens were obtained from N2 adsorption isotherms by BET method and BJH method. Conditions of pores and metals in the specimens were examined by XRD measurement and TEM observation. The relation between the above conditions and pore characteristics obtained from adsorption experiment was also examined. As a result, the difference in mesopore ratio between the specimens and blank specimens was larger in the order of Fe, Co and Ni, and the effect of added metal complexes was also larger in this order. 3 refs., 3 figs., 3 tabs.

  13. Effect of the substrate on the properties of ZnO-MgO thin films grown by atmospheric pressure metal-organic chemical vapor deposition

    Torres-Huerta, A.M., E-mail: atohuer@hotmail.com [Instituto Politecnico Nacional, Grupo de Ingenieria en Procesamiento de Materiales CICATA-IPN, Unidad Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, Grupo de Ingenieria en Procesamiento de Materiales CICATA-IPN, Unidad Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Brachetti-Sibaja, S.B. [Alumna del postgrado en Tecnologia Avanzada del CICATA-IPN, Unidad Altamira IPN, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Arenas-Alatorre, J. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000, D.F. (Mexico); Rodriguez-Pulido, A. [Unidad Profesional Adolfo Lopez Mateos, Luis Enrique Erro s/n, 07738, D. F. (Mexico)

    2011-07-01

    The ZnO-MgO alloys possess attractive properties for possible applications in optoelectronic and display devices; however, the optical properties are strongly dependent on the deposition parameters. In this work, the effect of the glassy and metallic substrates on the structural, morphological and optical properties of ZnO-MgO thin films using atmospheric pressure metal-organic chemical vapor deposition was investigated at relatively low deposition temperature, 500 deg. C. Magnesium and zinc acetylacetonates were used as the metal-organic source. X-ray diffraction experiments provided evidence that the kind of substrates cause a deviation of c-axis lattice constant due to the constitution of a oxide mixture (ZnO and MgO) in combination with different intermetallic compounds(Mg{sub 2}Zn{sub 11} and Mg{sub 4}Zn{sub 7}) in the growth films. The substitutional and interstitial sites of Mg{sup 2+} instead of Zn{sup 2+} ions in the lattice are the most probable mechanism to form intermetallic compounds. The optical parameters as well as thickness of the films were calculated by Spectroscopic Ellipsometry using the classical dispersion model based on the sum of the single and double Lorentz and Drude oscillators in combination with Kato-Adachi equations, as well as X-ray reflectivity.

  14. MOCVD of zirconium oxide thin films: Synthesis and characterization

    The synthesis of thin films of zirconia often produces tetragonal or cubic phases, which are stable at high temperatures, but that can be transformed into the monoclinic form by cooling. In the present study, we report the deposition of thin zirconium dioxide films by metalorganic chemical vapor deposition using zirconium (IV)-acetylacetonate as precursor. Colorless, porous, homogeneous and well adherent ZrO2 thin films in the cubic phase were obtained within the temperature range going from 873 to 973 K. The deposits presented a preferential orientation towards the (1 1 1) and (2 2 0) planes as the substrate temperature was increased, and a crystal size ranging between 20 and 25 nm. The kinetics is believed to result from film growth involving the deposition and aggregation of nanosized primary particles produced during the CVD process. A mismatch between the experimental results obtained here and the thermodynamic prediction was found, which can be associated with the intrinsic nature of the nanostructured materials, which present a high density of interfaces.

  15. Preparation and characterization of IrO{sub 2}-YSZ nanocomposite electrodes by MOCVD

    Torres-Huerta, A.M. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales, A.P. 75-874, 07300 Mexico (Mexico); Universidad Nacional Autonoma de Mexico, Instituto de Investigacion en Materiales, Circuito Exterior s/n, Ciudad Universitaria, A.P. 70-360, Del. Coyoacan, C.P. 04510 Mexico (Mexico); Vargas-Garcia, J.R. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales, A.P. 75-874, 07300 Mexico (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, Grupo de Ingenieria en Procesamiento de Materiales CICATA-IPN, Unidad Altamira. Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600. Altamira, Tamps. (Mexico)

    2007-12-15

    The electrochemical performance of IrO{sub 2}/yttria stabilized zirconia (YSZ) cermet cathodes for solid oxide fuel cells was experimentally evaluated in relation to their microstructure. Noble metal films were prepared by MOCVD using metal-acetylacetonate precursors which were mixed and evaporated together (493 K) to achieve codeposition. The effects of experimental conditions on deposition rates, composition and microstructure were studied, and the optimum conditions were determined. The growth of the films was columnar and layered in structure, with porous morphology. TEM observations revealed that the IrO{sub 2}-YSZ composites are constituted by single-phase particles, between 4 and 10 nm in size, with an excellent composite distribution. The cathode-related polarization resistance, Rp, was measured by impedance spectroscopy and found to be in the range of 21-968 {omega} cm{sup 2} under the experimental conditions (573-873 K). IrO{sub 2}-YSZ electrodes undergo structural and/or morphological changes caused by cathodic polarization and high temperature (873 K). However, this behavior could contribute to the improvement of the electrochemical performance of the electrode. IrO{sub 2}-YSZ films displayed superior electrochemical properties as electrodes to zirconia electrolytes than that exhibited for the Pt-C and conventional Pt paste electrodes. (author)

  16. MOCVD of zirconium oxide thin films: Synthesis and characterization

    Torres-Huerta, A.M., E-mail: atohuer@hotmail.com [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira, Instituto Politecnico Nacional, Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Dominguez-Crespo, M.A.; Ramirez-Meneses, E. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira, Instituto Politecnico Nacional, Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Vargas-Garcia, J.R. [ESIQIE, Departamento de Metalurgia y Materiales, Instituto Politecnico Nacional. A.P. 75-876, 07300 Mexico, D.F. (Mexico)

    2009-02-15

    The synthesis of thin films of zirconia often produces tetragonal or cubic phases, which are stable at high temperatures, but that can be transformed into the monoclinic form by cooling. In the present study, we report the deposition of thin zirconium dioxide films by metalorganic chemical vapor deposition using zirconium (IV)-acetylacetonate as precursor. Colorless, porous, homogeneous and well adherent ZrO{sub 2} thin films in the cubic phase were obtained within the temperature range going from 873 to 973 K. The deposits presented a preferential orientation towards the (1 1 1) and (2 2 0) planes as the substrate temperature was increased, and a crystal size ranging between 20 and 25 nm. The kinetics is believed to result from film growth involving the deposition and aggregation of nanosized primary particles produced during the CVD process. A mismatch between the experimental results obtained here and the thermodynamic prediction was found, which can be associated with the intrinsic nature of the nanostructured materials, which present a high density of interfaces.

  17. Effect of the substrate on the properties of ZnO-MgO thin films grown by atmospheric pressure metal-organic chemical vapor deposition

    The ZnO-MgO alloys possess attractive properties for possible applications in optoelectronic and display devices; however, the optical properties are strongly dependent on the deposition parameters. In this work, the effect of the glassy and metallic substrates on the structural, morphological and optical properties of ZnO-MgO thin films using atmospheric pressure metal-organic chemical vapor deposition was investigated at relatively low deposition temperature, 500 deg. C. Magnesium and zinc acetylacetonates were used as the metal-organic source. X-ray diffraction experiments provided evidence that the kind of substrates cause a deviation of c-axis lattice constant due to the constitution of a oxide mixture (ZnO and MgO) in combination with different intermetallic compounds(Mg2Zn11 and Mg4Zn7) in the growth films. The substitutional and interstitial sites of Mg2+ instead of Zn2+ ions in the lattice are the most probable mechanism to form intermetallic compounds. The optical parameters as well as thickness of the films were calculated by Spectroscopic Ellipsometry using the classical dispersion model based on the sum of the single and double Lorentz and Drude oscillators in combination with Kato-Adachi equations, as well as X-ray reflectivity.

  18. Phase controlled colour tuning of samarium and europium complexes and excellent photostability of their PVA encapsulated materials. Structural elucidation, photophysical parameters and the energy transfer mechanism in the Eu(3+) complex by Sparkle/PM3 calculations.

    Dar, Wakeel Ahmed; Iftikhar, K

    2016-06-01

    Luminescent [Sm(acac)3(pyz)2] (1) and [Eu(acac)3(pyz)2] (2) complexes (acac is the anion of acetylacetone and pyz is pyrazine) have been synthesized and thoroughly characterized by microanalyses, TGA, DTA, IR, ESI-MS(+) and NMR spectroscopy. The photophysical properties of these complexes have been investigated. The Sparkle/PM3 model was utilized for predicting the ground-state geometry of (2). The Judd-Ofelt intensity parameters, radiative parameters, intramolecular energy transfer rates and quantum efficiency are calculated and discussed. The intramolecular energy transfer rates predict that the major energy transfer (96%) is from the ligand triplet state to the levels (5)D1 (74.53%) and (5)D0 (21.87%) of the Eu(3+) ion, in the complex. Complexes (1) and (2) were analysed for colour tuning properties and these show varying colours upon changing phases. This property would possibly allow the use of these complexes as 'colour indicators'. The photoluminescence and photostability of the thin hybrid films of both complexes (1) and (2) in polyvinyl alcohol (PVA) are investigated and discussed. The hybrid films of (1) and (2) are quite robust due to their higher photostability. An important feature of complex (2) is that the excitation window extends close to the visible range (393 nm). The lasing property of the Eu(3+) complex in various phases is also presented. PMID:27157414

  19. Electric field assisted aerosol assisted chemical vapour deposition of nanostructured metal oxide thin films

    Nanostructured thin films of tungsten, vanadium and titanium oxides were deposited on gas sensor substrates from the electric field assisted chemical vapour deposition reaction of tungsten hexaphenoxide, vanadyl acetylacetonate and titanium tetraisopropoxide respectively. The electric fields were generated by applying a potential difference between the inter-digitated electrodes of the gas sensor substrates during the deposition. The deposited films were characterised using scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The application of an electric field, encouraged the formation of interesting and unusual nanostructured morphologies, with a change in scale length and island packing. It was also noted that crystallographic orientation of the films could be controlled as a function of electric field type and strength. The gas sensor properties of the films were also examined; it was found that a two to three fold enhancement in the gas response could be observed from sensors with enhanced morphologies compared to control sensors grown without application of an electric field. - Highlights: • Electric field assisted chemical vapour deposition method • Ability to create high surface area film architectures • Can produce enhanced sensor response • Good control over film properties

  20. Direct synthesis and easy axis alignment of L10-FePt nanoparticles

    Partially ordered Fe53Pt47 nanoparticles with size around 8 nm were prepared by the simultaneous decomposition of iron pentacarbonyl and platinum acetylacetonate. The high boiling point chemical, hexadecylamine, was used as a solvent, and 1-adamantanecarboxylic acid was used as a stabilizer. The reflux temperature of the solution could exceed 360 deg. C, where disordered FePt particles could be partially transformed into the ordered L10 phase. A nonmagnetic mechanical stirrer was used in order to avoid agglomeration of the fct-FePt particles during synthesis. The particles were dispersed in toluene and films of the particles were cast onto silicon wafers from the solution. X-ray diffraction patterns of as-made samples showed weak superlattice peaks, indicating partial chemical ordering of the Fe53Pt47 particles. The room-temperature hysteresis loop of the as-made sample reveals a small coercivity (∼600 Oe) because of thermal fluctuations; however, the loop is wide open and hard to saturate. The remanence coercivity from the dcd curve is about 2.5 kOe, which is four times larger than the hysteresis coercivity. The large remanent to hysteresis coercivity ratio and the shapes of the hysteresis loop and dcd curve suggest a broad distribution of anisotropies in the partially ordered particles. By coating the ordered nanoparticles with a polymer binder, the easy axis of the particles could be aligned under an external field

  1. APCVD Transition Metal Oxides – Functional Layers in ''Smart windows''

    Transition metal oxides (TMO) exhibit electrochromic effect. Under a small voltage they change their optical transmittance from transparent to collored (absorbing) state. The individual material can manifest its electrochromic properties only when it is part of electrochromic (EC) multilayer system. Smart window is controlling the energy of solar flux entering the building or car and makes the interiors comfortable and energy utilization more effective. Recently the efforts of material researchers in this field are directed to price decreasing. APCVD technology is considered as promissing as this process permits flowthrough large-scale production process. The paper presents results on device optimization based on WO3-MoO3 working electrode. Extensive research reveals that WO3-MoO3 structure combines positive features of single oxides: excellent electrochromic performance of WO3 and better kinetic properties of MoO3 deposition. The achieved color efficiency of APCVD WO3-MoO3 films is 200cm2/C and optical modulation of 65-70% are practically favorable electrochromic characteristics. To respond to low cost requirement, the expensive hexacarbonyl can be replaced with acetylacetonate. We have started with this precursor to fabricate mixed WxV1-xO3 films. The films possess excellent surface coverage and high growth-rate. CVD deposition of VO2, a promissing thermochromic thin film material is also presented

  2. Understanding and predicting the orientation of heteroleptic phosphors in organic light-emitting materials

    Jurow, Matthew J.; Mayr, Christian; Schmidt, Tobias D.; Lampe, Thomas; Djurovich, Peter I.; Brütting, Wolfgang; Thompson, Mark E.

    2016-01-01

    Controlling the alignment of the emitting molecules used as dopants in organic light-emitting diodes is an effective strategy to improve the outcoupling efficiency of these devices. To explore the mechanism behind the orientation of dopants in films of organic host materials, we synthesized a coumarin-based ligand that was cyclometalated onto an iridium core to form three phosphorescent heteroleptic molecules, (bppo)2Ir(acac), (bppo)2Ir(ppy) and (ppy)2Ir(bppo) (bppo represents benzopyranopyridinone, ppy represents 2-phenylpyridinate, and acac represents acetylacetonate). Each emitter was doped into a 4,4'-bis(N-carbazolyl)-1,1'-biphenyl host layer, and the resultant orientation of their transition dipole moment vectors was measured by angle-dependent p-polarized photoluminescent emission spectroscopy. In solid films, (bppo)2Ir(acac) is found to have a largely horizontal transition dipole vector orientation relative to the substrate, whereas (ppy)2Ir(bppo) and (bppo)2Ir(ppy) are isotropic. We propose that the inherent asymmetry at the surface of the growing film promotes dopant alignment in these otherwise amorphous films. Modelling the net orientation of the transition dipole moments of these materials yields general design rules for further improving horizontal orientation.

  3. Metal oxide films on glass and steel substrates

    Sohi, A M

    1987-01-01

    in the pH8 electrolyte supports the view that the rate limiting reduction reaction is possibly oxygen (or water) reduction although some contribution from an organic 'impurity' cannot be ruled out. Coatings of Fe sub 3 O sub 4 on mild steel have been prepared by CVD using pneumatic spraying techniques and the corrosion behaviour of coated electrodes in organic-phosphate electrolyte (pH8) has been examined. A variety of thin (10-1000nm) metal oxide films have been deposited on flat glass substrates by the pyrolysis of an aerosol of metal acetylacetonates in a suitable carrier. The optical characteristics and thickness of the films have been measured and particular interest has centered on the use of a novel pin on disc apparatus to measure the physical durability of such thin films. Characteristic friction/penetration force traces have been established for 1st Series transition metal oxide films and some ranking in terms of 'hardness' established. The use of SnO sub 2 - coated glass for electrodes in a light m...

  4. Chemical vapor deposition and analysis of thermally insulating ZrO2 layers on injection molds

    High quality injection molding requires a precise control of cooling rates. Thermal barrier coating (TBC) of zirconia with a thickness of 20-40 μm on polished stainless steel molds could provide the necessary insulating effect. This paper presents results of zirconia deposition on stainless steel substrates using chemical vapor deposition (CVD) aiming to provide the process parameters for the deposition of uniform zirconia films with such a thickness. The deposition was performed with zirconium (IV) acetylacetonate (Zr(C5H7O2)4) as precursor and synthetic air as co-reactant, which allows deposition at temperatures below 600 C. The experiments were carried out in a hot-wall reactor at pressures between 7.5 mbar and 500 mbar and in a temperature range from 450 C to 600 C. Important growth parameters were characterized and growth rates between 1 and 2.5 μm/h were achieved. Thick and well adhering zirconia layers of 38 μm could be produced on steel within 40 h. The transient heat transfer rate upon contact with a hot surface was also evaluated experimentally with the thickest coatings. These exhibit a good TBC performance. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Complexes of N-hydroxyethyl-N-benzimidazolylmethylethylenediaminediacetic acid with group 12 metals and vanadium-Synthesis, structure and bioactivity of the vanadium complex.

    Habala, Ladislav; Bartel, Caroline; Giester, Gerald; Jakupec, Michael A; Keppler, Bernhard K; Rompel, Annette

    2015-06-01

    Four new complexes of group 12 metals [Zn(II), Cd(II) and Hg(II)], along with vanadyl bound to the ligand N-hydroxyethyl-N-benzimidazolylmethylethylenediaminediacetic acid, have been synthesized and characterized. The structure of the complexes with Zn(II), Hg(II) and V(IV) was determined by X-ray structural analysis. In all observed cases, the symmetry of these complexes was found to be distorted octahedral. The inhibition of protein tyrosine phosphatase 1B by the vanadium(IV) complex was demonstrated. The cytotoxicity of the vanadium(IV) complex was tested in vitro against three cancer cell lines, with a comparison of the activity of the free ligand and of vanadyl acetylacetonate and sodium orthovanadate. The IC50 values of the complex were in the range of 9 to 21μM. Remarkably, cytotoxic potency in the multidrug-resistant non-small cell lung cancer cell line A549 was at least as high as in the broadly chemosensitive ovarian teratocarcinoma cell line CH1(PA-1). PMID:25920686

  6. Sol-gel derived titania hybrid thin films with high refractive index

    Incorporation of metal alkoxides into polymers through sol-gel process is of significant interest for tuning the refractive index of optical materials. In this paper, the organic-inorganic hybrid material with high refractive index (RI) and transparency was studied. Tetrabutoxytitanate (TBOT) and alkoxysilanes including diphenyldimethoxysilane (DPS) and γ-glycidoxypropyl trimethoxysilane (GPTS) were employed as sources of the titania sol and the silica sol, respectively. Two series of titania-based inorganic-organic hybrid materials with and without acetylacetone (AcAc) were prepared using the sol-gel method. Subsequently, crack-free films were fabricated by spin coating. The hybrid films with different Ti content were characterized by various techniques including IR, UV-vis, TG/DSC, SEM and auto-laser ellipsometer. The results indicated that the hybrid films displayed homogeneous morphology and titania was crosslinked with alkoxysilanes. Films without AcAc showed higher optical transparency in the visible region than those containing AcAc. The RI of films without AcAc increased from 1.54 to 1.64 at 633 nm with Ti molar fraction varying from 10 to 70%. Whereas, in the films with AcAc, the refractive indices were higher and unorderly. The study has demonstrated great potential to obtain titania hybrid films with high RI and transparency.

  7. Experimental investigation of some coordination complexes using the sup(151)Eu Moessbauer resonance

    Several Schiff base complexes containing Eu151 metal ions have been synthesized and their Moessbauer spectra are recorded using the constant acceleration velocity spectrometer. The least-square analysis method for the evaluation of the hyperfine field coupling constants is adopted using the computer dec system-10. From the systematic analysis of the quadrupole coupling constants (q.c.c.) and isomer shifts it has been established that the coordination number of the metal ion of Bis(acetylacetone) benzidine and thiourea complexes is five, that of bis-vanillin benzidine and bis-salicylaldehyde-o-dianisidine is six, and that of bis-vanillin-o-phenylene diamine is seven. It is also found that the q.c.c. being negative in all these complexes decreases monotonically as the coordination number increases. One unusual aspect of this experimental data is that most of the coordination complexes have very low f-factors whereas the Schiff base complexes studied here have a fairly high recoilless fractions. Attempts are in progress to synthesize and study the Fe Schiff base complexes in place of Eu. (auth.)

  8. Red phosphorescent organic light-emitting diodes (PhOLEDs) based on a heteroleptic cyclometalated Iridium (III) complex

    Lepeltier, Marc [Institut Lavoisier de Versailles, UMR 8180 CNRS, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France); Dumur, Frédéric, E-mail: frederic.dumur@univ-amu.fr [Aix-Marseille Université, CNRS, ICR, UMR 7273, F-13397 Marseille (France); Wantz, Guillaume, E-mail: guillaume.wantz@ims-bordeaux.fr [University of Bordeaux, IMS, UMR 5218, F-33400 Talence (France); CNRS, IMS, UMR 5218, F-33400 Talence (France); Vila, Neus; Mbomekallé, Israel [Institut Lavoisier de Versailles, UMR 8180 CNRS, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France); Bertin, Denis; Gigmes, Didier [Aix-Marseille Université, CNRS, ICR, UMR 7273, F-13397 Marseille (France); Mayer, Cédric R., E-mail: cmayer@lisv.uvsq.fr [Laboratoire d’Ingénierie des Systèmes de Versailles LISV – EA 4048, Université de Versailles Saint Quentin en Yvelines, 10/12 avenue de l’Europe, 78140 Vélizy (France)

    2013-11-15

    Highly efficient red-emitting Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) based on a neutral vacuum-sublimatable heteroleptic iridium (III) complex have been designed and studied. Heteroleptic complex Ir(piq){sub 2}(acac) was prepared in one step with acetylacetone (acac) as the ancillary ligand. Electronic and spectroscopic properties of Ir(piq){sub 2}(acac) were investigated by UV–visible absorption, fluorescence spectroscopy and cyclic voltammetry. Electrophosphorescent devices comprising Ir(piq){sub 2}(acac) as dopant of TCTA exhibited outstanding electroluminescence performance with a current efficiency of 10.0 cd A{sup −1}, a maximum power efficiency of 7.2 lm W{sup −1} and a maximal brightness of 3540 cd m{sup −2} was reached at 8.0 V. CIE coordinates close to the standard red of the national television system committee were obtained (0.67, 0.33). -- Highlights: • A saturated red OLED has been prepared. • High power efficiency and brightness were obtained. • Thickness of the device was determined as a parameter determining the overall performance. • CIE coordinates close to the standard red of the national television system committee were obtained.

  9. Increasing the energy density of the non-aqueous vanadium redox flow battery with the acetonitrile-1,3-dioxolane-dimethyl sulfoxide solvent mixture

    Herr, T.; Fischer, P.; Tübke, J.; Pinkwart, K.; Elsner, P.

    2014-11-01

    Different solvent mixtures were investigated for non-aqueous vanadium acetylacetonate (V(acac)3) redox flow batteries with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. The aim of this study was to increase the energy density of the non-aqueous redox flow battery. A mixture of acetonitrile, dimethyl sulfoxide and 1-3-dioxolane nearly doubles the solubility of the active species. The proposed electrolyte system was characterized by Raman and FT-IR spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge set-up. Spectroscopic methods were applied to understand the interactions between the solvents used and their impact on the solubility. The potential difference between oxidation and reduction of V(acac)3 measured by cyclic voltammetry was about 2.2 V. Impedance spectroscopy showed an electrolyte resistance of about 2400 Ω cm2. Experiments in a charge-discharge test cell achieved coulombic and energy efficiencies of ∼95% and ∼27% respectively. The highest discharge power density was 0.25 mW cm-2.

  10. Electric field assisted aerosol assisted chemical vapour deposition of nanostructured metal oxide thin films

    Naik, Anupriya J.T.; Bowman, Christopher; Panjwani, Naitik [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H OAJ (United Kingdom); Warwick, Michael E.A. [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H OAJ (United Kingdom); UCL Energy Institute, Central House, 14 Upper Woburn Place, London WC1H 0HY (United Kingdom); Binions, Russell, E-mail: r.binions@qmul.ac.uk [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H OAJ (United Kingdom); School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2013-10-01

    Nanostructured thin films of tungsten, vanadium and titanium oxides were deposited on gas sensor substrates from the electric field assisted chemical vapour deposition reaction of tungsten hexaphenoxide, vanadyl acetylacetonate and titanium tetraisopropoxide respectively. The electric fields were generated by applying a potential difference between the inter-digitated electrodes of the gas sensor substrates during the deposition. The deposited films were characterised using scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The application of an electric field, encouraged the formation of interesting and unusual nanostructured morphologies, with a change in scale length and island packing. It was also noted that crystallographic orientation of the films could be controlled as a function of electric field type and strength. The gas sensor properties of the films were also examined; it was found that a two to three fold enhancement in the gas response could be observed from sensors with enhanced morphologies compared to control sensors grown without application of an electric field. - Highlights: • Electric field assisted chemical vapour deposition method • Ability to create high surface area film architectures • Can produce enhanced sensor response • Good control over film properties.

  11. Characterization of nano porous TiO2 films prepared by sol-gel method

    Nano-porous TiO2 films as a key component in dye sensitized and extremely thin absorber (ETA) solar cells were prepared by the sol-gel method using spin-coating and spray pyrolysis deposition techniques. The precursor sol contained titanium (IV) iso-prop-oxide, acetylacetone and polyethylene glycol (PEG) in ethanol. Glass and n-type Si (100) were used as substrates. SEM, XRD and FT-IR were used to study the effect of the PEG concentration in the precursor solution as well as different annealing routes on the film composition and structural properties. Crystalline films with anatase structure could be grown by the spray technique at 500 C. Post-annealing at 500 C increases the crystallite size (from 5 to 9 nm) and results in an average pore size around 40 nm. A film thickness of about 2.3 μm is attained using 50 spray pulses. In spin coated films the formation of Ti-O-Ti anatase bonds is observed after annealing at 450 C. Crystalline films can be prepared by annealing at temperatures above 700 C. Surface morphology and pore size of spin coated films are controlled by the amount of PEG in the sol. The film thickness is around 120 nm after three coating cycles. (authors)

  12. Sequential spectrofluorimetric determination of free and total glycerol in biodiesel in a multicommuted flow system

    Silva, Sidnei G. [Universidade de Sao Paulo, Instituto de Quimica, Sao Paulo (Brazil); Morales-Rubio, Angel; Guardia, Miguel de la [Universidad de Valencia, Department of Analytical Chemistry, Burjassot, Valencia (Spain); Rocha, Fabio R.P. [Universidade de Sao Paulo, Centro de Energia Nuclear na Agricultura, Piracicaba (Brazil)

    2011-07-15

    A new procedure for spectrofluorimetric determination of free and total glycerol in biodiesel samples is presented. It is based on the oxidation of glycerol by periodate, forming formaldehyde, which reacts with acetylacetone, producing the luminescent 3,5-diacetyl-1,4-dihydrolutidine. A flow system with solenoid micro-pumps is proposed for solution handling. Free glycerol was extracted off-line from biodiesel samples with water, and total glycerol was converted to free glycerol by saponification with sodium ethylate under sonication. For free glycerol, a linear response was observed from 5 to 70 mg L{sup -1} with a detection limit of 0.5 mg L{sup -1}, which corresponds to 2 mg kg{sup -1} in biodiesel. The coefficient of variation was 0.9% (20 mg L{sup -1}, n = 10). For total glycerol, samples were diluted on-line, and the linear response range was 25 to 300 mg L{sup -1}. The detection limit was 1.4 mg L{sup -1} (2.8 mg kg{sup -1} in biodiesel) with a coefficient of variation of 1.4% (200 mg L{sup -1}, n = 10). The sampling rate was ca. 35 samples h{sup -1} and the procedure was applied to determination of free and total glycerol in biodiesel samples from soybean, cottonseed, and castor beans. (orig.)

  13. Photooxidation of Furfural with Phthalocyanine-sensitized TiO2 Particle Under Xenon Lamp

    2007-01-01

    Copper phthalocyanine was selected as the photosensitizer to sensitize TiO2 in this experiment with furfural as the target pollutant. The composite catalysts (TiO2/CuPC) obtained showed a great activity under a xenon lamp. By experiments, the optimal preparation conditions of the composite catalysts were set as follows: the CuPC loading mass fraction was 1.5% , the mass fraction of acetylacetone was 0. 3% , and the stirring time was 10 h. UV-Vis diffuse reflectance spectra, XRD, and BET were used to characterize the properties of the composite catalysts, which showed that after loading CuPC on TiO2, the composite catalyst retained the same crystal structure as pure TiO2 and the wavelength range of its absorption spectrum was broadened to 600-700 nm while its surface area was smaller than that of the pure TiO2. Under the optimal conditions, 20 mg/L furfural solution was degraded by nearly 90% and TOC by about 70%. When the catalyst was reused 6 times, the activity of the catalyst was still retained by about 75%.

  14. Solution-processed nickel compound as hole collection layer for efficient polymer solar cells

    We demonstrated efficient bulk heterojunction polymer solar cells (PSCs) by inserting a solution-processable hole collection layer (HCL) between the indium tin oxide (ITO) electrode and photoactive layer. The HCL was prepared by spin-coating nickel acetylacetonate (Ni(acac)2) isopropanol solution on ITO, and then baking in air at 180 °C for 10 min followed by UV ozone treatment, which was marked as a-Ni(acac)2. The a-Ni(acac)2 HCL shows suitable energy levels, high hole mobility of 4.09  ×  10−3 cm2 V−1·s−1, and high transparency with light transmittance better than poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) in the wavelength range 550–800 nm. The PSCs with a-Ni(acac)2 HCL showed improved performance compared with the PSCs without or with traditional PEDOT:PSS HCL. The power conversion efficiency of the PSC based on PBDTTT-C-T:PC70BM with a-Ni(acac)2 HCL reached 7.84% under the illumination of AM 1.5 G, 100 mW cm−2. (paper)

  15. Synthesis and activation of Pt nanoparticles with controlled size for fuel cell electrocatalysts

    Liu, Zhufang; Reichert, W. Matthew; Nikles, David E. [Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487-0336 (United States); Shamsuzzoha, Mohammad; Ada, Earl T. [Central Analytical Facility, The University of Alabama, Tuscaloosa, AL 35487-0336 (United States)

    2007-02-10

    Well-dispersed Pt nanoparticles with controlled size and narrow size distribution were prepared by polyalcohol reduction of platinum acetylacetonate, using oleylamine as a capping agent. The particle size was varied from 3.5 nm to 11.5 nm by decreasing the amount of oleylamine added in the synthesis. Size selection of the as-prepared particles by solvent fractionation yielded nearly monodispersed Pt particles. The as-prepared particles were loaded on a carbon support by physical deposition, but showed no electrocatalytic activity due to the oleylamine bound to the particle surface. The particles were activated for electrocatalysis after heating the particles in air at 185 C for 5 h, conditions that gave no particle-sintering and no oxidation. Cyclic voltammetry showed that the particles after the heat treatment in air were electrocatalytically active for methanol oxidation. The smaller 3.5 nm and 4.0 nm Pt particles had a higher intrinsic activity for methanol oxidation, but a lower tolerance to CO poisoning, compared with 6.0 nm, 9.5 nm and 11.5 nm particles. CO-stripping results suggest that CO is more easily oxidized on larger Pt particles. (author)

  16. Combined sol–gel and carbothermal synthesis of ZrC–TiC powders for composites

    The TiC–ZrC binary compound of nanostructured powders was synthesised by combination of sol–gel and carbothermal reduction. The polymeric precursor of the blend was produced by sol–gel process from titanium tetrabutoxide, zirconium tetrabutoxide and benzene-1.4-diol; then carbothermally reduced to the TiC–ZrC blend at 1600 °C in an inert environment. The chemical reactions occurring in the system were monitored by infrared spectrometry. Stable alkoxide solution was obtained by adding acetylacetone to avoid premature gelation of the metal alkoxide mixture. A solid solution of ZrTiC2 was produced by spark plasma sintering at temperature of 2000 °C. - Highlights: • A polymeric precursor of TiC–ZrC blend was synthesised by sol–gel process. • The polymeric precursor synthesis was studied by infrared spectroscopy. • TiC–ZrC powder blend was carbothermally reduced from polymeric precursor. • TiC–ZrC powder blend was sintered to ZrTiC2 solid solution by spark plasma sintering. • Sintered ZrTiC2 have good mechanical properties

  17. Sol-gel based sensor for selective formaldehyde determination

    We report the development of transparent sol-gels with entrapped sensitive and selective reagents for the detection of formaldehyde. The sampling method is based on the adsorption of formaldehyde from the air and reaction with β-diketones (for example acetylacetone) in a sol-gel matrix to produce a yellow product, lutidine, which was detected directly. The proposed method does not require preparation of samples prior to analysis and allows both screening by visual detection and quantitative measurement by simple spectrophotometry. The detection limit of 0.03 ppmv formaldehyde is reported which is lower than the maximum exposure concentrations recommended by both the World Health Organisation (WHO) and the Occupational Safety and Health Administration (OSHA). This sampling method was found to give good reproducibility, the relative standard deviation at 0.2 and 1 ppmv being 6.3% and 4.6%, respectively. Other carbonyl compounds i.e. acetaldehyde, benzaldehyde, acetone and butanone do not interfere with this analytical approach. Results are provided for the determination of formaldehyde in indoor air.

  18. Sol-gel based sensor for selective formaldehyde determination

    Bunkoed, Opas [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Davis, Frank [Cranfield Health, Cranfield University, Bedford MK43 0AL (United Kingdom); Kanatharana, Proespichaya, E-mail: proespichaya.K@psu.ac.th [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thavarungkul, Panote [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Higson, Seamus P.J., E-mail: s.p.j.higson@cranfield.ac.uk [Cranfield Health, Cranfield University, Bedford MK43 0AL (United Kingdom)

    2010-02-05

    We report the development of transparent sol-gels with entrapped sensitive and selective reagents for the detection of formaldehyde. The sampling method is based on the adsorption of formaldehyde from the air and reaction with {beta}-diketones (for example acetylacetone) in a sol-gel matrix to produce a yellow product, lutidine, which was detected directly. The proposed method does not require preparation of samples prior to analysis and allows both screening by visual detection and quantitative measurement by simple spectrophotometry. The detection limit of 0.03 ppmv formaldehyde is reported which is lower than the maximum exposure concentrations recommended by both the World Health Organisation (WHO) and the Occupational Safety and Health Administration (OSHA). This sampling method was found to give good reproducibility, the relative standard deviation at 0.2 and 1 ppmv being 6.3% and 4.6%, respectively. Other carbonyl compounds i.e. acetaldehyde, benzaldehyde, acetone and butanone do not interfere with this analytical approach. Results are provided for the determination of formaldehyde in indoor air.

  19. Elaboration and characterization of sol-gel derived ZrO2 thin films treated with hot water

    We describe the preparation and characterization of zirconia (ZrO2) thin films via sol-gel route by spin-coating method. By utilizing alkoxides Zr[O(CH2)3CH3]4 in the presence of ethanol (EtOH), nitric acid and acetylacetone as a chelating agent, a stable sol of ZrO2 was obtained. Smooth surface morphology with nano-cracks was exhibited for all ZrO2 thin films being fabricated. The film thickness varied from 39 to 206 nm depending on the molar ratio of EtOH during the sol preparation and also annealing temperature applied. All ZrO2 films possess high optical transmittance. Refractive index of the thin film was ranging from 1.6 to 2.4 depending on molar ratio of EtOH and annealing temperature. Tetragonal phase of ZrO2 was formed after annealed at 400 °C. Crystallinity of ZrO2 was enhanced by increasing molar ratio of EtOH. Crystallite size of tetragonal ZrO2 was ranged from 3.0 to 9.9 nm. A hot-water treatment reduced the film thickness and further improved crystallinity of the sol-gel derived oxide.

  20. Microporous polytetrafluoroethylene tube separator for the determination of beryllium by flow injection - or suction-flow -solvent extraction followed by inductively coupled plasma atomic emission spectrometry

    A dual-tube separator was constructed for the purpose of flow injection - or suction-flow-solvent extraction followed by inductively coupled plasma atomic emission spectrometry. It consisted of an inner microporous polytetrafluoroethylene (PTFE) tube (1 mm i.d., 10 cm long, porosity 70%) and an outer PTFE tube (3 mm i.d.). This system was used for the determination of beryllium in alloys by extraction as the acetylacetonate into carbon tetrachloride. The phase separation was complete at an organic flow-rate of 0.2-6.2 ml min-1 and an aqueous flow-rate of up to 6.2 ml min-1. With a sample volume of 0.5 ml (50 p.p.b. Be) and sample and organic flow-rates of 1.2 and 0.7 ml min-1, respectively, the relative standard deviation (n = 10) was 1.3% and the sampling rate was 25 h-1. The sensitivity was enhanced about 2.6-fold compared with that obtained by the direct nebulisation of an aqueous solution. (author)

  1. Fabrication and kinetics study of nano-Al/NiO thermite film by electrophoretic deposition.

    Zhang, Daixiong; Li, Xueming

    2015-05-21

    Nano-Al/NiO thermites were successfully prepared as film by electrophoretic deposition (EPD). For the key issue of this EPD, a mixture solvent of ethanol-acetylacetone (1:1 in volume) containing 0.00025 M nitric acid was proved to be a suitable dispersion system for EPD. The kinetics of electrophoretic deposition for both nano-Al and nano-NiO were investigated; the linear relation between deposition weight and deposition time in short time and parabolic relation in prolonged time were observed in both EPDs. The critical transition time between linear deposition kinetics and parabolic deposition kinetics for nano-Al and nano-NiO were 20 and 10 min, respectively. The theoretical calculation of the kinetics of electrophoretic deposition revealed that the equivalence ratio of nano-Al/NiO thermites film would be affected by the behavior of electrophoretic deposition for nano-Al and nano-NiO. The equivalence ratio remained steady when the linear deposition kinetics dominated for both nano-Al and nano-NiO. The equivalence ratio would change with deposition time when deposition kinetics for nano-NiO changed into parabolic kinetics dominated after 10 min. Therefore, the rule was suggested to be suitable for other EPD of bicomposites. We also studied thermodynamic properties of electrophoretic nano-Al/NiO thermites film as well as combustion performance. PMID:25950271

  2. Synthesis and Characterization of Dinuclear Metal Complexes Stabilized by Tetradentate Schiff Base Ligands

    Eid A. Abdalrazaq

    2010-01-01

    Full Text Available Problem statement: The synthesis, spectroscopic properties and theoretical calculations of acetylacetonimine and acetylacetanilidimine Schiff-base ligands, L1H and L2H, respectively and their dinuclear complexes of the type [M2LnCl2(H2O2], where n = 1 or 2, M = Co(II, Ni(II, Cu(II, Zn(II and Cd(II are described. Approach: The new tetradentate dianion Schiff base ligand which was used as stabilizers for the complexes were prepared by condensation of hydrazine with acetylacetone or acetylacetanilide. The dinuclear complexes of theses ligands were synthesized by treating an ethanolic solution of the prepared ligand with hydrated metal salts in molar ratio of 1:2 (L:M. Results: The ligand and their dinuclear metal complexes were characterized by CHN elemental analysis, FT-IR, UV-Vis, 1HNMR (for the ligands, conductivity, magnetic susceptibility and theoretical calculation by using MM2 modeling program. Conclusion: The reaction of these ligands in a 1:2 (L:M afford dinuclear M(II metal complexes with tetrahedral arrangement around Co(II, Zn(II and Cd(II and square planar around Ni(II and Cu(II.

  3. Size dependence of the magnetic relaxation and specific power absorption in iron oxide nanoparticles

    Lima, E. [CONICET and Instituto de Nanociencia y Nanotecnologia and Centro Atomico Bariloche (Argentina); Torres, T. E. [University of Zaragoza, Instituto de Nanociencia de Aragon (INA) and Departamento de Fisica de la Materia Condensada and Laboratorio de Microscopias Avanzadas (LMA) (Spain); Rossi, L. M. [Instituto de Quimica, Universidade de Sao Paulo (Brazil); Rechenberg, H. R. [Instituto de Fisica, Universidade de Sao Paulo (Brazil); Berquo, T. S. [Institute of Rock Magnetism, University of Minnesota (United States); Ibarra, A. [University of Zaragoza, INA and LMA (Spain); Marquina, C. [CSIC, Universidad de Zaragoza, Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales de Aragon (ICMA) (Spain); Ibarra, M. R. [University of Zaragoza, INA and Departamento de Fisica de la Materia Condensada and LMA (Spain); Goya, G. F., E-mail: goya@unizar.es [University of Zaragoza, INA and Departamento de Fisica de la Materia Condensada (Spain)

    2013-05-15

    In this study, magnetic and power absorption properties of a series of iron oxide nanoparticles with average sizes Left-Pointing-Angle-Bracket d Right-Pointing-Angle-Bracket ranging from 3 to 23 nm were reported. The nanoparticles were prepared by thermal decomposition of Iron(III) acetylacetonate in organic media. From the careful characterization of the magnetic and physicochemical properties of these samples, the specific power absorption (SPA) values experimentally found were numerically reproduced, as well as their dependence with particle size, using a simple model of Brownian and Neel relaxation at room temperature. SPA experiments in ac magnetic fields (H{sub 0} = 13 kA/m and f = 250 kHz) indicated that the magnetic and rheological properties played a crucial role determining the heating efficiency at different conditions. A maximum SPA value of 344 W/g was obtained for a sample containing nanoparticles with Left-Pointing-Angle-Bracket d Right-Pointing-Angle-Bracket = 12 nm and dispersion {sigma} = 0.25. The observed SPA dependence with particle diameter and their magnetic parameters indicated that, for the size range and experimental conditions of f and H studied in this study, both Neel and Brown relaxation mechanisms are important to the heat generation observed.

  4. Preparation and in vitro evaluation of folate-receptor-targeted SPION–polymer micelle hybrids for MRI contrast enhancement in cancer imaging

    Polymer–SPION hybrids were investigated for receptor-mediated localization in tumour tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) prepared by high-temperature decomposition of iron acetylacetonate were monodisperse (9.27 ± 3.37 nm), with high saturation magnetization of 76.8 emu g−1. Amphiphilic copolymers prepared from methyl methacrylate and PEG methacrylate by atom transfer radical polymerization were conjugated with folic acid (for folate-receptor specificity). The folate-conjugated polymer had a low critical micellar concentration (0.4 mg l−1), indicating stability of the micellar formulation. SPION–polymeric micelle clusters were prepared by desolvation of the SPION dispersion/polymer solution in water. Magnetic resonance imaging of the formulation revealed very good contrast enhancement, with transverse (T2) relaxivity of 260.4 mM−1 s−1. The biological evaluation of the SPION micelles included cellular viability assay (MTT) and uptake in HeLa cells. These studies demonstrated the potential use of these nanoplatforms for imaging and targeting. (paper)

  5. Preparation and in vitro evaluation of folate-receptor-targeted SPION-polymer micelle hybrids for MRI contrast enhancement in cancer imaging

    Mahajan, Shveta; Koul, Veena; Choudhary, Veena; Shishodia, Gauri; Bharti, Alok C.

    2013-01-01

    Polymer-SPION hybrids were investigated for receptor-mediated localization in tumour tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) prepared by high-temperature decomposition of iron acetylacetonate were monodisperse (9.27 ± 3.37 nm), with high saturation magnetization of 76.8 emu g-1. Amphiphilic copolymers prepared from methyl methacrylate and PEG methacrylate by atom transfer radical polymerization were conjugated with folic acid (for folate-receptor specificity). The folate-conjugated polymer had a low critical micellar concentration (0.4 mg l-1), indicating stability of the micellar formulation. SPION-polymeric micelle clusters were prepared by desolvation of the SPION dispersion/polymer solution in water. Magnetic resonance imaging of the formulation revealed very good contrast enhancement, with transverse (T2) relaxivity of 260.4 mM-1 s-1. The biological evaluation of the SPION micelles included cellular viability assay (MTT) and uptake in HeLa cells. These studies demonstrated the potential use of these nanoplatforms for imaging and targeting.

  6. APCVD Transition Metal Oxides - Functional Layers in "Smart windows"

    Gesheva, K. A.; Ivanova, T. M.; Bodurov, G. K.

    2014-11-01

    Transition metal oxides (TMO) exhibit electrochromic effect. Under a small voltage they change their optical transmittance from transparent to collored (absorbing) state. The individual material can manifest its electrochromic properties only when it is part of electrochromic (EC) multilayer system. Smart window is controlling the energy of solar flux entering the building or car and makes the interiors comfortable and energy utilization more effective. Recently the efforts of material researchers in this field are directed to price decreasing. APCVD technology is considered as promissing as this process permits flowthrough large-scale production process. The paper presents results on device optimization based on WO3-MoO3 working electrode. Extensive research reveals that WO3-MoO3 structure combines positive features of single oxides: excellent electrochromic performance of WO3 and better kinetic properties of MoO3 deposition. The achieved color efficiency of APCVD WO3-MoO3 films is 200cm2/C and optical modulation of 65-70% are practically favorable electrochromic characteristics. To respond to low cost requirement, the expensive hexacarbonyl can be replaced with acetylacetonate. We have started with this precursor to fabricate mixed WxV1-xO3 films. The films possess excellent surface coverage and high growth-rate. CVD deposition of VO2, a promissing thermochromic thin film material is also presented.

  7. Structural and Luminescence Properties of Lu2O3:Eu3+ F127 Tri-Block Copolymer Modified Thin Films Prepared by Sol-Gel Method

    María Luz Carrera Jota

    2013-02-01

    Full Text Available Lu2O3:Eu3+ transparent, high density, and optical quality thin films were prepared using the sol-gel dip-coating technique, starting with lutetium and europium nitrates as precursors and followed by hydrolysis in an ethanol-ethylene glycol solution. Acetic acid and acetylacetonate were incorporated in order to adjust pH and as a sol stabilizer. In order to increment the thickness of the films and orient the structure, F127 Pluronic acid was incorporated during the sol formation. Structural, morphological, and optical properties of the films were investigated for different F127/Lu molar ratios (0–5 in order to obtain high optical quality films with enhanced thickness compared with the traditional method. X-ray diffraction (XRD shows that the films present a highly oriented cubic structure beyond 1073 K for a 3-layer film, on silica glass substrates. The thickness, density, porosity, and refractive index evolution of the films were investigated by means of m-lines microscopy along with the morphology by scanning electron microscope (SEM and luminescent properties.

  8. Preparation and properties of YSZ-doped YBCO films grown by the TFA-MOD method

    YBa2Cu3O7-δ (YBCO) films with Zr doping have been prepared successfully by the trifluoroacetate metal-organic deposition (TFA-MOD) method through dissolving Zr acetylacetonate in the precursor solution. Yttria-stabilized zirconia (YSZ) nanoparticles were detected in the doped YBCO films by x-ray diffraction (XRD) and scanning electron microscopy (SEM). From the analysis of XRD ω and ψ scans, the doped films have better out-of-plane and in-plane textures than those of the un-doped YBCO film. Although the doped YBCO films have a lower critical transition temperature (Tc) than that of un-doped YBCO film, a very significant enhancement of critical current density (Jc) is displayed as compared to the un-doped film at high applied fields. A high Jc near 106 A cm-2 at 1 T and a Jc of 105 A cm-2 at 5 T were observed in 6% doped Zr film, which are 5 times and 25 times the Jc values of the un-doped film in the same applied fields, respectively, indicating an optimal defect density created by 6% Zr doping.

  9. Synthesis, characterization, single crystal X-ray determination, fluorescence and electrochemical studies of new dinuclear nickel(II) and oxovanadium(IV) complexes containing double Schiff base ligands

    Shafaatian, Bita; Ozbakzaei, Zahra; Notash, Behrouz; Rezvani, S. Ahmad

    2015-04-01

    A series of new bimetallic complexes of nickel(II) and vanadium(IV) have been synthesized by the reaction of the new double bidentate Schiff base ligands with nickel acetate and vanadyl acetylacetonate in 1:1 M ratio. In nickel and also vanadyl complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:1 metals to ligands stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The nickel and vanadyl complexes exhibited distorted square planar and square pyramidal coordination geometries, respectively. The emission spectra of the ligands and their complexes were studied in methanol. Electrochemical properties of the ligands and their metal complexes were also investigated in DMSO solvent at 150 mV s-1 scan rate. The ligands and metal complexes showed both quasi-reversible and irreversible processes at this scan rate. The Schiff bases and their complexes have been characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis and conductometry. The crystal structure of the nickel complex has been determined by single crystal X-ray diffraction.

  10. One-step hydrothermal synthesis of highly water-soluble secondary structural Fe{sub 3}O{sub 4} nanoparticles

    Yang Xiwen [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Jiang Wei, E-mail: yangxw0610@yahoo.cn [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu Li; Chen Binghua; Wu Shixi; Sun Danping; Li Fengsheng [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2012-07-15

    Magnetite nanoparticles (MNPs) were prepared using the ferric acetylacetonate as the sole iron source in a facile hydrothermal route, while poly(acrylic acid) (PAA) was chosen as the stabilizer via one-step functionalized MNPs for better hydrophilic properties. The orthogonal was used in the paper for the experimental parameters optimization, including the solvent, the reaction time, the amount of stabilizer and the presynthesis. The obtained highly water dispersible MNPs with uniform size from about 50 to about 100 nm was individually composed of many monodisperse magnetite crystallites approximately 6 nm in size. And the MNPs show high magnetic properties, whose magnetite content was up to 76.76% and the saturation magnetization was 39.0 emu/g. Later the formation mechanism of MNPs was also discussed. Thus the MNPs proved to be very promising for biomedical applications. - Highlights: Black-Right-Pointing-Pointer MNPs are prepared in a low-temperature hydrothermal synthesis procedure. Black-Right-Pointing-Pointer Synthesis of MNPs is hybridized with their in situ surface functionalization. Black-Right-Pointing-Pointer Each of the secondary structural MNPs is composed of monodisperse primary particles. Black-Right-Pointing-Pointer The resulting MNPs show good magnetic properties combining that of primary one. Black-Right-Pointing-Pointer The size of MNPs is controllable and the mechanism is elaborated.

  11. Preparation and characterization of oil-soluble In2O3 nanoparticles and In2O3-SnO2 nanocomposites and their calcined thin films

    Wang, Li-ping; Xu, Xu-dong; Wang, Jia-xing

    2015-05-01

    Oil-soluble In2O3 nanoparticles and In2O3-SnO2 nanocomposites were prepared in oleylamine via decomposition of metal acetylacetonate precursors. Thin films of In2O3 and In2O3-SnO2 were obtained by spin-coating solutions of the oil-soluble In2O3 nanoparticles and In2O3-SnO2 nanocomposites onto substrates and then calcining them. Transmission electron microspectroscopy, scanning electron microspectroscopy, atomic force microspectroscopy, X-ray diffraction, ultraviolet-visible absorption, and photoluminescence spectroscopy were used to investigate the properties of the nanoparticles and thin films. The In2O3 nanoparticles were cubic-phased spheres with a diameter of ~8 nm; their spectra exhibited a broad emission peak centered at 348 nm. The In2O3-SnO2 nanocomposites were co-particles composed of smaller In2O3 particles and larger SnO2 particles; their spectra exhibited a broad emission peak at 355 nm. After the In2O3-SnO2 nanocomposites were calcined at 400°C, the obtained thin films were highly transparent and conductive, with a thickness of 30-40 nm; the surfaces of the thin films were smooth and crack-free.

  12. Magnetic and rheological properties of monodisperse Fe{sub 3}O{sub 4} nanoparticle/organic hybrid

    Hayashi, Koichiro; Sakamoto, Wataru [Division of Nanomaterials Science, EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Yogo, Toshinobu [Division of Nanomaterials Science, EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)], E-mail: yogo@esi.nagoya-u.ac.jp

    2009-03-15

    Fe{sub 3}O{sub 4} nanoparticle/organic hybrids were synthesized via hydrolysis using iron (III) acetylacetonate at {approx}80 deg. C. The synthesis of Fe{sub 3}O{sub 4} was confirmed by X-ray diffraction, selected-area diffraction, and X-ray photoelectron spectroscopy. Fe{sub 3}O{sub 4} nanoparticles in the organic matrix had diameters ranging from 7 to 13 nm depending on the conditions of hydrolysis. The saturation magnetization of the hybrid increased with an increase in the particle size. When the hybrid contained Fe{sub 3}O{sub 4} particles with a size of less than 10 nm, it exhibited superparamagnetic behavior. The blocking temperature of the hybrid containing Fe{sub 3}O{sub 4} particles with a size of 7.3 nm was 200 K, and it increased to 310 K as the particle size increased to 9.1 nm. A hybrid containing Fe{sub 3}O{sub 4} particles of size greater than 10 nm was ferrimagnetic, and underwent Verwey transition at 130 K. Under a magnetic field, a suspension of the hybrid in silicone oil revealed the magnetorheological effect. The yield stress of the fluid was dependent on the saturation magnetization of Fe{sub 3}O{sub 4} nanoparticles in the hybrid, the strength of the magnetic field, and the amount of the hybrid.

  13. Effect of solvent on the extraction of lanthanides with picrolonic acid

    Ali, A.; Saeed, M.M. [Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad (Pakistan). Chemistry Div.; Rehman, H. [Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad (Pakistan). Central Analytical Facility Div.; Anwar, J. [Punjab Univ., Lahore (Pakistan). Inst. of Chemistry

    2010-07-01

    Extraction of Eu(III), Tb(III) and Lu(III), as representatives of lanthanides, has been studied with picrolonic acid [1-p-nitrophenyl-3-methyl-4-nitro-5-pyrazolone (HPA)] as extractant in various solvents such as acetylacetone (ACAC), 1-octanol (ONL), n-hexanol (HNL), 1-butanol (nBNL), 2-butanol (iBNL), cyclohexanone (CHN), n-butyl ether (BE), di(1,2-dichloroethyl)ether (DCEE), diisobutylketone (DIBK), benzene and toluene from aqueous solution of pH 1-2, having ionic strength of 0.01 mol dm{sup -3} (K{sup +}/H{sup +}, Cl{sup -}). The composition of the extracted adduct has been determined as M(PA){sub 3} except in DCEE where it is M(PA){sub 3}.(HPA). Extraction constants (log K{sub ex}) were calculated and on the basis of log K{sub ex}, the role of diluents in the extraction process has been discussed. The solvents with respect to their extractability of the rare earth metal ions can be arranged in the order ACAC > DIBK > BE> DCEE > ONL > HNL > CHN. (orig.)

  14. Progammed synthesis of magnetic mesoporous silica coated carbon nanotubes for organic pollutant adsorption

    Tong, Yue; Zhang, Min; Xia, Peixiong; Wang, Linlin; Zheng, Jing; Li, Weizhen; Xu, Jingli

    2016-05-01

    Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis method and were characterized by TEM, XRD, FTIR, TGA, N2 adsorption-desorption and VSM. The well-designed mesoporous magnetic nanotubes had a large specific area, a highly open mesoporous structure and high magnetization. Firstly, SiO2-coated maghemite/CNTs nanoparticles (CNTs/Fe3O4@SiO2 composites) were synthesized by the combination of high temperature decomposition process and an sol-gel method, in which the iron acetylacetonate as well as TEOS acted as the precursor for maghemite and SiO2, respectively. The CNTs/Fe3O4@SiO2 composites revealed a core-shell structure, Then, CNTs/Fe3O4@mSiO2 was obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure. The resulting composites show not only a magnetic response to an externally applied magnetic field, but also can be a good adsorbent for the organic pollutant in the ambient temperature.

  15. Realistic prediction of solid pharmaceutical oxidation products by using a novel forced oxidation system.

    Ueyama, Eiji; Tamura, Kousuke; Mizukawa, Kousei; Kano, Kenji

    2014-04-01

    This study investigated a novel solid-state-based forced oxidation system to enable a realistic prediction of pharmaceutical product oxidation, a key consideration in drug development and manufacture. Polysorbate 80 and ferric(III) acetylacetonate were used as an organic hydroperoxide source and a transition metal catalyst, respectively. Homogeneous solutions of target compounds and these reagents were prepared in a mixed organic solvent. The organic solvent was removed rapidly under reduced pressure, and the oxidation of the resulting dried solid was investigated. Analysis of the oxidation products generated in test compounds by this proposed forced oxidation system using HPLC showed a high similarity with those generated during more prolonged naturalistic drug oxidation. The proposed system provided a better predictive performance in prediction of realistic oxidative degradants of the drugs tested than did other established methods. Another advantage of this system was that the generation of undesired products of hydrolysis, solvolysis, and thermolysis was prevented because efficient oxidation was achieved under mild conditions. The results of this study suggest that this system is suitable for a realistic prediction of oxidative degradation of solid pharmaceuticals. PMID:24497072

  16. Aluminium-doped zinc oxide films prepared by an inorganic sol-gel route

    Silva, Rodrigo F.; Zaniquelli, Maria E.D

    2004-02-02

    Thin films of aluminium-doped zinc oxide have been formed on glass using an inorganic sol-gel route and the dip-coating process. The films were formed by the thermal decomposition of a stable precursor colloidal sol prepared by an ethanolic reflux of Zn(CH{sub 3}COO){sub 2}{center_dot}2H{sub 2}O and Al(NO{sub 3}){sub 3}{center_dot}9H{sub 2}O. Lactic acid was used as hydrolysis catalyst and acetylacetone and diethanolamine were added to improve film homogeneity. Thermal analysis was used to investigate the chemical processes during firing of the sols. Atomic force microscopy data revealed morphological changes in the temperature range 200-500 deg. C. The importance of sample firing after each transfer step was evidenced by the quartz crystal microbalance technique. A red shift of the absorption edge was observed for thicker films and the transmittance of the samples decreased with increasing film thickness.

  17. Characterization of fine grain Ba0.995Y0.005TiO3 ceramics obtained from gel-precursor nanopowder.

    Cernea, Marin; Monnereau, Odile; Llewellyn, Philip; Vasile, Eugeniu

    2007-03-01

    Using an acetate-alkoxide sol-gel route in which the precursors are barium acetate, yttrium isopropoxide and titanium diisopropoxide bis-acetylacetonate, we prepared a ferroelectric material with the formula: Ba1-xYxTiO3, x = 0.005. SEM analysis showed a polymeric microstructure of the gel due to the chelated titanium alkoxide precursor used as starting materials. The evolution of the structure and microstructure of the precursor gel heated at temperatures up to 1000 degrees C was studied by various techniques. The powder obtained by heating the gel at 1100 degrees C presented a homogeneous structure consisting of submicronic particles (approximately 200 nm). XRD and SAED analyses revealed that Ba0.995Y0.005TiO3 nanocrystals of about 5-10 nm appeared at 600 degrees C, together with BaCO3. The presence of barium carbonate was identified also by IR spectroscopy and thermal analyses. The ceramics obtained from the as-prepared powder presented good dielectric properties (capacitance = 840 pF/dielectric constant = 3860 and dielectric loss (tandelta) = 0.078 at Curie temperatures of 120-121 degrees C). PMID:17450868

  18. Vanadia-silica and vanadia-cesium-silica catalysts for oxidation of SO2

    Pârvulescu, Vasile I.; Paun, Christina; Pârvulescu, Viorica;

    2004-01-01

    Mesoporous vanadia-silica catalysts have been prepared by three different sol-gel procedures using tetraethylorthosilicate (TEOS), vanadyl acetylacetonate (VAA), or VOCl3 and in some cases quaternary ammonium salts ((CH3)(3)C14H29N+Br- or (C10H21)(4)N+Br-) as surfactants. According to procedure A......, TEOS and VAA were concomitantly hydrolyzed, in procedure B TEOS was prehydrolized and vanadium precursor was added to the silica sol, and in procedure C both TEOS and vanadium precursors were separately prehydrolized. The sol-gel procedures were controlled by checking the effect of the hydrolysis p...... calcination of the V/Cs catalysts vanadia is dissolved in a sulfate containing molten salt. The activity of these catalysts for the oxidation of SO2 was tested in a gas containing 2% SO2, 19% O-2, 79% N-2 in the temperature range 523-823 K. Similar experiments with gases containing 10% H2O in the feed or with...

  19. Cu2ZnSnSe4 nanocrystals capped with S2− by ligand exchange: utilizing energy level alignment for efficiently reducing carrier rec ombination

    2014-01-01

    In this work, we employed a convenient one-step synthesis method for synthesizing Cu2ZnSnSe4 (CZTSe) nanocrystals (NCs) in an excess selenium environment. This excess selenium situation enhanced the reaction of metal acetylacetonates with selenium, resulting in the burst nucleation of NCs at relatively low temperatures. The phase morphology and surface and optoelectronic properties of NCs before and after ligand exchange were discussed in depth. It was found that pure tetragonal-phase structure CZTSe NCs with approximately 1.7-eV bandgap could be synthesized. The removal of large organic molecules on CZTSe NCs after ligand exchange by S2− decreased the resistivity. The bandgap of the films after ligand exchange by 550°C selenization was also decreased due to better crystallinity. For potential application in CZTSe solar cells, we constructed an energy level diagram to explain the mutual effect between the absorption layer and CdS layer. Using cyclic voltammetry (CV) measurement, we found that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of CZTSe films shifted down after ligand exchange. After energy level alignment at the CdS/CZTSe interface, a type I band alignment structure was more conveniently formed after ligand exchange. This structure acted as the barrier against injection electrons from ZnO to the CZTSe layer, and recombination would subsequently be depressed. PMID:24994951

  20. Cu2ZnSnSe4 nanocrystals capped with S(2-) by ligand exchange: utilizing energy level alignment for efficiently reducing carrier rec ombination.

    Wang, Xia; Kou, Dong-Xing; Zhou, Wen-Hui; Zhou, Zheng-Ji; Wu, Si-Xin; Cao, Xuan

    2014-01-01

    In this work, we employed a convenient one-step synthesis method for synthesizing Cu2ZnSnSe4 (CZTSe) nanocrystals (NCs) in an excess selenium environment. This excess selenium situation enhanced the reaction of metal acetylacetonates with selenium, resulting in the burst nucleation of NCs at relatively low temperatures. The phase morphology and surface and optoelectronic properties of NCs before and after ligand exchange were discussed in depth. It was found that pure tetragonal-phase structure CZTSe NCs with approximately 1.7-eV bandgap could be synthesized. The removal of large organic molecules on CZTSe NCs after ligand exchange by S(2-) decreased the resistivity. The bandgap of the films after ligand exchange by 550°C selenization was also decreased due to better crystallinity. For potential application in CZTSe solar cells, we constructed an energy level diagram to explain the mutual effect between the absorption layer and CdS layer. Using cyclic voltammetry (CV) measurement, we found that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of CZTSe films shifted down after ligand exchange. After energy level alignment at the CdS/CZTSe interface, a type I band alignment structure was more conveniently formed after ligand exchange. This structure acted as the barrier against injection electrons from ZnO to the CZTSe layer, and recombination would subsequently be depressed. PMID:24994951

  1. Facile one-pot synthesis of polytypic (wurtzite-chalcopyrite) CuGaS2

    Vahidshad, Yaser; Mirkazemi, Seyed Mohammad; Tahir, Muhammad Nawaz; Zad, Azam Iraji; Ghasemzadeh, Reza; Tremel, Wolfgang

    2016-03-01

    In this investigation, monodisperse CuGaS2 nanoparticles intended for use as visible-light-absorbing materials were synthesized using a facile one-step heating method that involved dissolving the precursors copper chloride, gallium acetylacetonate, and thiourea in a solvent consisting of either oleylamine alone or a combination of oleylamine, oleic acid, and 1-octadecene. The shapes of the resulting nanoparticles were either elongated, polygonal, or a mixture of both, depending on whether the crystal structure of the nanoparticles was predominantly wurtzite, predominantly chalcopyrite, or a more balanced mixture of both wurtzite and chalcopyrite (i.e., the nanoparticles were polytypic: both wurtzite and chalcopyrite phases were present). The crystal structure of the synthesized nanoparticles was found to be influenced by the temperature and the solvent applied during synthesis. X-ray diffraction data for the nanoparticles indicated that applying a temperature of 270 °C or using oleylamine, oleic acid solvent, and 1-octadecene during synthesis tended to yield a chalcopyrite phase, whereas applying a somewhat lower temperature (210 °C) or using oleylamine alone during synthesis tended to result in a wurtzite phase. The chemical states of the compounds obtained at different temperatures and using various solvents, as well as their crystal structures, morphologies, and optical properties were characterized via X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectroscopy, and photoluminescence.

  2. White organic light emitting devices with phosphorescent iridium complex as RGB dopants%以iridium磷光为红绿蓝染料的白光器件研究

    宋瑞丽; 段羽; 陈淑芬; 赵毅; 侯晶莹; 刘式墉

    2008-01-01

    以磷光染料iridium (III) bis [(4,6-di-fluoropheny)-pyridinato-N,C2′] picolinate(Flrpic)掺在4.4′-bis (9-carbazolyl)-2,2′-dimethyl-biphenyl(CDBP)中作为蓝光发光层,tris (2-Phenylpyridine) iridium(Irlppy)3和bis (1-phenyl-isoquinoline) acetylacetonate iridium (III)(Ir(piq)2)(acac)共掺在4,4′-N,N′-dicarbazole-biphenyl(CBP)中作为绿光和红光发光层,制备了高效白光器件.通过控制染料的浓度和发光层的厚度调节颜色,实现白光发射.器件的最大亮度为17 V时37 100 cd/m2,最大效率为5 V时7.37 lm/W.当亮度从1 000 cd/m2 到30 000 cd/m2色坐标由(0.41,0.42) 变到(0.37,0.39).

  3. Efficient white organic light-emitting devices based on blue, orange, red phosphorescent dyes

    Chen Ping; Duan Yu; Xie Wenfa; Zhao Yi; Hou Jingying; Liu Shiyong [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Zhang Liying; Li Bin, E-mail: chenping0329@gmail.co, E-mail: syliu@jlu.edu.c [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)

    2009-03-07

    We demonstrate efficient white organic light-emitting devices (WOLEDs) based on an orange phosphorescent iridium complex bis(2-(2-fluorphenyl)-1,3-benzothiozolato-N, C{sup 2'})iridium(acetylacetonate) in combination with blue phosphorescent dye bis[(4, 6-difluorophenyl)-pyridinato-N,C{sup 2})](picolinato) Ir(III) and red phosphorescent dye bis[1-(phenyl)isoquinoline] iridium (III) acetylanetonate. By introducing a thin layer of 4, 7-diphenyl-1,10-phenanthroline between blue and red emission layers, the diffusion of excitons is confined and white light can be obtained. WOLEDs with the interlayer all have a higher colour rendering index (>82) than the device without it (76). One device has the maximum current efficiency of 17.6 cd A{sup -1} and a maximum luminance of 39 050 cd m{sup -2}. The power efficiency is 8.7 lm W{sup -1} at 100 cd m{sup -2}. Furthermore, the device has good colour stability and the CIE coordinates just change from (0.394, 0.425) to (0.390, 0.426) with the luminance increasing from 630 to 4200 cd m{sup -2}.

  4. Facile synthesis and functionalization of manganese oxide nanoparticles for targeted T1-weighted tumor MR imaging.

    Luo, Yu; Yang, Jia; Li, Jingchao; Yu, Zhibo; Zhang, Guixiang; Shi, Xiangyang; Shen, Mingwu

    2015-12-01

    We report the polyethyleneimine (PEI)-enabled synthesis and functionalization of manganese oxide (Mn3O4) nanoparticles (NPs) for targeted tumor magnetic resonance (MR) imaging in vivo. In this work, monodispersed PEI-coated Mn3O4 NPs were formed by decomposition of acetylacetone manganese via a solvothermal approach. The Mn3O4 NPs with PEI coating were sequentially conjugated with fluorescein isothiocyanate, folic acid (FA)-linked polyethylene glycol (PEG), and PEG monomethyl ether. Followed by final acetylation of the remaining PEI surface amines, multifunctional Mn3O4 NPs were formed and well characterized. We show that the formed multifunctional Mn3O4 NPs with a mean diameter of 8.0 nm possess good water-dispersibility, colloidal stability, and cytocompatibility and hemocompatibility in the given concentration range. Flow cytometry and confocal microscopic observation reveal that the multifunctional Mn3O4 NPs are able to target FA receptor-overexpressing cancer cells in vitro. Importantly, the FA-targeted Mn3O4 NPs can be used as a nanoprobe for efficient T1-weighted MR imaging of cancer cells in vitro and the xenografted tumor model in vivo via an active FA-mediated targeting pathway. With the facile PEI-enabled formation and functionalization, the developed PEI-coated Mn3O4 NPs may be modified with other biomolecules for different biomedical imaging applications. PMID:26454057

  5. Structural models of vanadate-dependent haloperoxidases and their reactivity

    Mannar R Maurya

    2006-11-01

    Vanadium(V) complexes with hydrazone-based ONO and ONN donor ligands that partly model active-site structures of vanadate-dependent haloperoxidases have been reported. On reaction with [VO(acac)2] (Hacac = acetylacetone) under nitrogen, these ligands generally provide oxovanadium(IV) complexes [VO(ONO)X] (X = solvent or nothing) and [VO(acac)(ONN)], respectively. Under aerobic conditions, these oxovanadium(IV) species undergo oxidation to give oxovanadium(V), dioxovanadium (V) or -oxobis{oxovanadium(V)} species depending upon the nature of the ligand. Anionic and neutral dioxovanadium(V) complexes slowly deoxygenate in methanol to give monooxo complexes [VO(OMe)(MeOH)(ONO)]. The anionic complexes [VO2(ONO)]- can also be converted in situ on acidification to oxohydroxo complexes [VO(OH)(HONO)]+ and to peroxo complexes [VO(O2)(ONO)]-, and thus to the species assumed to be intermediates in the haloperoxidases activity of the enzymes. In the presence of catechol (H2cat) and benzohydroxamic acid (H2bha), oxovanadium (IV) complexes, [VO (acac)(ONN)] gave mixed-chelate oxovanadium(V) complexes [VO(cat)(ONN)] and [VO(bha)(ONN)] respectively. These complexes are not very stable in solution and slowly convert to the corresponding dioxo species [VO2(ONN)] as observed by 51V NMR and electronic absorption spectroscopic studies.

  6. Reactive polymers: part I - Novel polystyrene-anchored copper (II), nickel (II), cobalt (II), iron (III), zinc (II), cadmium (II), molybdenum (VI) and uranium (VI) complexes of the chelating resin containing thiosemicarbazone

    A new chelating resin containing thiosemicarbazone has been synthesized by the reaction of aldehydopolystyrene and thiosemicarbazide. The polystyrene bound thiosemicarbazone reacts with salicylaldehyde leading to the formation of a new Schiff base chelating resin which reacts with sodium monochloroacetate and gives the polymer bound S-acetatothiosemicarbazone. The new chelating resin forms complexes of the types PS-LCuX·S, PS-LNiX·3S, PS-LHNi(acac)2, PS-LCoX·3S, PS-LFeX2·2S, PS-LZnX·S, PS-LCdX·S, PS-LMoO2(acac) and PS-LUO2X·S (where PS-LH = polymeranchored ligand; S = DMF or CH3OH; X=Cl or CH3COO- and acacH = acetylacetone). The chelating resins and complexes have been characterized by elemental analysis, IR and electronic spectra and magnetic measurements. The Cu(II), Ni(II), Co(II), and Fe(III) complexes are paramagnetic while the Zn(II), Cd(II), Mo(VI) and U(VI) complexes are diamagnetic. The IR data indicate the thioenolization of the ligand in the complexes (except in PS-LHNi(acac)2 where it behaves as a neutral bidentate ligand). (author). 24 refs., 2 tabs

  7. Catalysis effect on curing catalysis of HTPB-IPDI binder system%催化剂对HTPB-IPDI黏合剂体系的固化催化作用研究

    常双君; 杨雪芹; 赵芦奎

    2011-01-01

    In order to reduce the curing temperature of HTPB-IPDI binder system and shorten curing time,the catalysis effects of three kinds of catalysts,ferric-acetylacetonate (Fe( AA)3) ,dibutyltin dilaurate (T-12) and triphenyl bismuth. ( TPB ) on the curing catalysis of HTPB-IPDI binder system are investigated. The experimental results show that the pot life of HTPB-IPDI binder system may reach 6 h as the TPB quality percent is 0. 05%. TPB is an ideal curing catalyst of HTPB-IPDI binder system.%为了降低黏合剂端羟基聚丁二烯( HTPB)和固化剂异佛尔酮二异氰酸酯(IPDI)的固化反应温度,提高生产效率,缩短固化时间,研究了二月桂酸二丁基锡(T-12)、乙酰丙酮铁(Fe(AA)3)和三苯基铋(TPB)3类催化剂对HTPB -IPDI黏合剂体系固化催化作用的影响.实验结果表明,加入TPB质量分数为0.05%时,其适用期可以达到6h,TPB是HTPB -IPDI黏合剂体系比较理想的固化催化剂.

  8. Organ weight changes in mice after long-term inhalation exposure to manganese oxides nanoparticles

    Zeman, T.; Buchtová, M.; Dočekal, B.; Míšek, I.; Navrátil, J.; Mikuška, P.; Šerý, O.; Večeřa, Z.

    2015-05-01

    Recently, it has been proven that manganese from inhaled particles of manganese compounds can accumulate in the internal organs of laboratory animals. Nevertheless, there were only a few researches dealing with changes in body morphology induced by inhalation of these particles, even though results of some studies indicate existence of such changes. The aim of our research was to assess the effect of inhaled manganese oxides nanoparticles on weight of internal organs. For this purpose a long-term inhalation experiment on laboratory mice was performed, during which the mice were exposed to MnO.Mn2O3 nanoparticles in concentration 2 × 106 particles/cm3 for 17 weeks, 24 hours a day, 7 days a week. Manganese oxides nanoparticles were synthesized continuously via aerosol route in a hot wall tube flow reactor using thermal decomposition of metal organic precursor manganese(II)acetylacetonate in the flow tube reactor at temperature 750 °C in the presence of 30 vol% of oxygen. It was proven that inhaled nanoparticles can influence the weight of internal organs of mice. Moreover, it was discovered that the resulting change in weight of selected organs is disproportional. The mice from the experimental group had statistically significantly lighter kidneys, liver and spleen and heavier pancreas compared to the mice from the control group.

  9. Synthesis of Al2O3 thin films using laser assisted spray pyrolysis (LASP)

    Dhonge, Baban P.; Mathews, Tom; Tripura Sundari, S.; Krishnan, R.; Balamurugan, A. K.; Kamruddin, M.; Subbarao, R. V.; Dash, S.; Tyagi, A. K.

    2013-01-01

    The present study reports the development of a laser assisted ultrasonic spray pyrolysis technique and synthesis of dense optical alumina films using the same. In this technique ultrasonically generated aerosols of aluminum acetylacetonate dissolved in ethanol and a laser beam (Nd:YAG, CW, 1064 nm) were fed coaxially and concurrently through a quartz tube on to a hot substrate mounted on an X-Y raster stage. At the laser focused spot the precursor underwent solvent evaporation and solute sublimation followed by precursor vapor decomposition giving rise to oxide coating, the substrate is rastered to get large surface area coating. The surface morphology revealed coalescence of particles with increase in laser power. The observed particle sizes were 17 nm for films synthesized without laser and 18, 21 and 25 nm for films made with laser at 25, 38 and 50 W, respectively. Refractive index of the films synthesized increased from 1.56 to 1.62 as the laser power increased from 0 to 50 W. The stoichiometry of films was studied using XPS and the increase in interfacial layer thickness with laser power was observed from dynamic SIMS depth profiling and ellipsometry.

  10. Structural diversity in binuclear complexes of alkaline earth metal ions with 4,6-diacetylresorcinol

    Shebl, Magdy; Khalil, Saied M. E.; Taha, A.; Mahdi, M. A. N.

    2012-11-01

    A new series of binuclear and mixed-ligand complexes with the general formula: [M 2(LO)yClz]; where M = Mg(II), Ca(II), Sr(II) and Ba(II); H2L = 4,6-diacetylresorcinol, the secondary ligand L' = acetylacetone (acac), 8-hydroxyquinoline (8-HQ) or 2,2'-bipyridyl (Bipy), n = 0-2, m = 1, 2, x = 0, 1, 2, 4, y = 0, 2, 4, 5 and z = 0-2; have been synthesized. They have been characterized by the analytical and spectral methods (IR, 1H NMR and mass) as well as TGA and molar conductivity measurements. The spectroscopic and conductance data suggested that the H2L ligand behaves as a neutral, monobasic or dibasic tetradentate ligand, depending on the basicity of the secondary ligand, through the two phenolic and two carbonyl groups. Binuclear octahedral geometry has been assigned to all of the prepared complexes in various molar ratios 2:2; 2:2:2; 1:2:1 and 1:2:4 (L:M:L'). Molecular orbital calculations were performed for the ligands and their complexes using Hyperchem 7.52 program on the bases of PM3 level and the results were correlated with the experimental data. The ligand and some of its alkaline metal(II) complexes showed antibacterial activity towards some of Gram-positive and Gram-negative bacteria, yeast (Candida albicans) and fungus (Aspergillus fumigatus).

  11. Mixed-ligand Al complex-a new approach for more high efficient OLEDs

    Petrova, Petia K., E-mail: petia@clf.bas.bg [Institute of Optical Materials and Technologies ' Acad. J. Malinowski' , Bulgarian Academy of Sciences, Acad. G Bonchev st., bl. 109, 1113 Sofia (Bulgaria); Tomova, Reni L.; Stoycheva-Topalova, Rumiana T. [Institute of Optical Materials and Technologies ' Acad. J. Malinowski' , Bulgarian Academy of Sciences, Acad. G Bonchev st., bl. 109, 1113 Sofia (Bulgaria); Kaloyanova, Stefka S.; Deligeorgiev, Todor G. [Applied Organic Chemistry, Faculty of Chemistry, University of Sofia, Sofia 1164 (Bulgaria)

    2012-02-15

    The mixed-ligand Aluminum bis(8-hydroxyquinoline) acetylacetonate (Alq{sub 2}Acac) complex was presented and its performance as electroluminescent and electron transporting layer for OLED was studied. The photophysical properties of the novel complex were investigated and compared with the properties of the parent Alq{sub 3}. Highly efficient OLED based on the mixed-ligand Al complex was developed with two times higher luminescence and efficiency compared to the identical OLED based on the conventional Alq{sub 3} The better performance of the devices make the novel Al complex a very promising material for OLEDs. - Highlights: Black-Right-Pointing-Pointer A novel electroluminescent Alq{sub 2}Acac complex is presented as material for OLED. Black-Right-Pointing-Pointer Electroluminescent emission of Alq{sub 2}Acac is very similar to that of commercial Alq{sub 3}. Black-Right-Pointing-Pointer Devices with Alq{sub 2}Acac show better characteristics compared to those with Alq{sub 3}.

  12. Hybrid chemical vapour and nanoceramic aerosol assisted deposition for multifunctional nanocomposite thin films

    Warwick, Michael E.A.; Dunnill, Charles W.; Goodall, Josie; Darr, Jawwad A.; Binions, Russell, E-mail: uccarbi@ucl.ac.uk

    2011-07-01

    Hybrid atmospheric pressure chemical vapour and aerosol assisted deposition via the reaction of vanadium acetylacetonate and a suspension of preformed titanium dioxide or cerium dioxide nanoparticles, led to the production of vanadium dioxide nanocomposite thin films on glass substrates. The preformed nanoparticle oxides used for the aerosol were synthesised using a continuous hydrothermal flow synthesis route involving the rapid reaction of a metal salt solution with a flow of supercritical water in a flow reactor. Multifunctional nanocomposite thin films from the hybrid deposition process were characterised using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The functional properties of the films were evaluated using variable temperature optical measurements to assess thermochromic behaviour and methylene blue photodecolourisation experiments to assess photocatalytic activity. The tests show that the films are multifunctional in that they are thermochromic (having a large change in infra-red reflectivity upon exceeding the thermochromic transition temperature) and have significant photocatalytic activity under irradiation with 254 nm light.

  13. Okadaic Acid, a Bioactive Fatty Acid from Halichondria okadai, Stimulates Lipolysis in Rat Adipocytes: The Pivotal Role of Perilipin Translocation

    Nen-Chung Chang

    2013-01-01

    Full Text Available Lipid metabolism in visceral fat cells is correlated with metabolic syndrome and cardiovascular diseases. Okadaic-acid, a 38-carbon fatty acid isolated from the black sponge Halichondria okadai, can stimulate lipolysis by promoting the phosphorylation of several proteins in adipocytes. However, the mechanism of okadaic acid-induced lipolysis and the effects of okadaic acid on lipid-droplet-associated proteins (perilipins and beta-actin remain unclear. We isolated adipocytes from rat epididymal fat pads and treated them with isoproterenol and/or okadaic acid to estimate lipolysis by measuring glycerol release. Incubating adipocytes with okadaic acid stimulated time-dependent lipolysis. Lipid-droplet-associated perilipins and beta-actin were analyzed by immunoblotting and immunofluorescence, and the association of perilipin A and B was found to be decreased in response to isoproterenol or okadaic acid treatment. Moreover, okadaic-acid treatment could enhance isoproterenol-mediated lipolysis, whereas treatment of several inhibitors such as KT-5720 (PKA inhibitor, calphostin C (PKC inhibitor, or KT-5823 (PKG inhibitor did not attenuate okadaic-acid-induced lipolysis. By contrast, vanadyl acetylacetonate (tyrosine phosphatase inhibitor blocked okadaic-acid-dependent lipolysis. These results suggest that okadaic acid induces the phosphorylation and detachment of lipid-droplet-associated perilipin A and B from the lipid droplet surface and thereby leads to accelerated lipolysis.

  14. Facile synthesis of palladium nanoparticles supported on multi-walled carbon nanotube for efficient hydrogenation of biomass-derived levulinic acid

    Yan, Kai, E-mail: kyan@lakeheadu.ca; Lafleur, Todd [Lakehead University, Department of Chemistry (Canada); Liao, Jiayou [Tianjin University, School of Chemical Engineering and Technology (China)

    2013-09-15

    Different loading of palladium (Pd) nanoparticles were successfully fabricated on multi-walled carbon nanotubes using Pd acetylacetonate as the precursor via a simple liquid impregnation method. The crystal phase, morphology, textural structure and the chemical state of the resulting Pd nanoparticles (Pd/CNT) catalysts were studied and the characterization results indicated that the uniform dispersion of small Pd nanoparticles with the size range of 1.0-4.5 nm was achieved. The synthesized Pd/CNT catalysts exhibited efficient performance for the catalytic hydrogenation of biomass-derived levulinic acid into biofuel {gamma}-valerolactone. In comparison with the commercial 5 wt% Pd/C and the 5 wt% Pd/CNT catalyst prepared by Pd nitrate precursor, much higher activities were achieved, whereas the biofuel {gamma}-valerolactone was highly produced with 56.3 % yield at 57.6 % conversion of levulinic acid on the 5 wt% Pd/CNT catalyst under mild conditions. The catalyst developed in this work may be a good candidate for the wide applications in the hydrogenation.

  15. Synthesis of Some Novel Heterocyclic and Schiff Base Derivatives as Antimicrobial Agents

    Mohamed E. Azab

    2015-10-01

    Full Text Available Treatment of 2,3-diaryloxirane-2,3-dicarbonitriles 1a–c with different nitrogen nucleophiles, e.g., hydrazine, methyl hydrazine, phenyl hydrazine, hydroxylamine, thiosemicarbazide, and/or 2-amino-5-phenyl-1,3,4-thiadiazole, afforded pyrazole, isoxazole, pyrrolotriazine, imidazolothiadiazole derivatives 2–5, respectively. Reacting pyrazoles 2a–c with aromatic aldehydes and/or methyl glycinate produced Schiff’s bases 7a–d and pyrazolo[3,4-b]-pyrazinone derivative 8, respectively. Treating 7 with ammonium acetate and/or hydrazine hydrate, furnished the imidazolopyrazole and pyrazolotriazine derivatives 9 and 10, respectively. Reaction of 8 with chloroacetic acid and/or diethyl malonate gave tricyclic compound 11 and triketone 12, respectively. On the other hand, compound 1 was reacted with active methylene precursors, e.g., acetylacetone and/or cyclopentanone producing adducts 14a,b which upon fusion with ammonium acetate furnished the 3-pyridone derivatives 15a,b, respectively. Some of newly synthesized compounds were screened for activity against bacterial and fungal strains and most of the newly synthesized compounds showed high antimicrobial activities. The structures of the new compounds were elucidated using IR, 1H-NMR, 13C-NMR and mass spectroscopy.

  16. Chemical vapor deposition and analysis of thermally insulating ZrO{sub 2} layers on injection molds

    Atakan, Burak; Khlopyanova, Victoria; Mausberg, Simon; Kandzia, Adrian; Pflitsch, Christian [Thermodynamik (IVG) and Cenide, Universitaet Duisburg-Essen, Lotharstr. 1, 47057 Duisburg (Germany); Mumme, Frank [Kunststoff-Institut Luedenscheid, Karolinenstrasse 8, 58507 Luedenscheid (Germany)

    2015-07-15

    High quality injection molding requires a precise control of cooling rates. Thermal barrier coating (TBC) of zirconia with a thickness of 20-40 μm on polished stainless steel molds could provide the necessary insulating effect. This paper presents results of zirconia deposition on stainless steel substrates using chemical vapor deposition (CVD) aiming to provide the process parameters for the deposition of uniform zirconia films with such a thickness. The deposition was performed with zirconium (IV) acetylacetonate (Zr(C{sub 5}H{sub 7}O{sub 2}){sub 4}) as precursor and synthetic air as co-reactant, which allows deposition at temperatures below 600 C. The experiments were carried out in a hot-wall reactor at pressures between 7.5 mbar and 500 mbar and in a temperature range from 450 C to 600 C. Important growth parameters were characterized and growth rates between 1 and 2.5 μm/h were achieved. Thick and well adhering zirconia layers of 38 μm could be produced on steel within 40 h. The transient heat transfer rate upon contact with a hot surface was also evaluated experimentally with the thickest coatings. These exhibit a good TBC performance. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Synthesis and characterization of thin films of Pd/TiO2 with possible applications in photo catalysis

    In this paper the synthesis and study of thin films of titanium oxide is reported, as well as those that were surface modified with palladium nanoparticles Pd/TiO2. First, the TiO2 films are grown on substrates of soda-lime glass using chemical sol-gel route and the repeated immersion procedure. The salt precursor titanium oxy-acetylacetonate to 0.2 M, in the solvent 2-methoxyethanol and monoethanolamine was used as stabilizer. The number of used immersions gave an average thickness estimate for these films of 172.8 nm. Second, the series of Pd/TiO2 films surface modified were obtained from a solution of palladium nitrate dehydrate at low concentration, with the same procedure. The films grown TiO2 and those surface-modified films were characterized in its structure by X-ray diffraction, morphology by scanning electron microscopy, the topography with atomic force microscopy, optical properties by UV-Vis, among others. Photoluminescence properties and/or possible applications in photo catalysis are reported in this paper. (Author)

  18. Ruthenium nanoparticles decorated curl-like porous carbons for high performance supercapacitors

    Lou, Bih-Show; Veerakumar, Pitchaimani; Chen, Shen-Ming; Veeramani, Vediyappan; Madhu, Rajesh; Liu, Shang-Bin

    2016-01-01

    The synthesis of highly dispersed and stable ruthenium nanoparticles (RuNPs; ca. 2-3 nm) on porous activated carbons derived from Moringa Oleifera fruit shells (MOC) is reported and were exploited for supercapacitor applications. The Ru/MOC composites so fabricated using the biowaste carbon source and ruthenium acetylacetonate as the co-feeding metal precursors were activated at elevated temperatures (600-900 oC) in the presence of ZnCl2 as the pore generating and chemical activating agent. The as-prepared MOC carbonized at 900 oC was found to possess a high specific surface area (2522 m2 g-1) and co-existing micro- and mesoporosities. Upon incorporating RuNPs, the Ru/MOC nanocomposites loaded with modest amount of metallic Ru (1.0-1.5 wt%) exhibit remarkable electrochemical and capacitive properties, achiving a maximum capacitance of 291 F g-1 at a current density of 1 A g-1 in 1.0 M H2SO4 electrolyte. These highly stable and durable Ru/MOC electrodes, which can be facily fabricated by the eco-friendly and cost-effective route, should have great potentials for practical applications in energy storage, biosensing, and catalysis.

  19. by ligand exchange: utilizing energy level alignment for efficiently reducing carrier rec ombination

    Wang, Xia; Kou, Dong-Xing; Zhou, Wen-Hui; Zhou, Zheng-Ji; Wu, Si-Xin; Cao, Xuan

    2014-05-01

    In this work, we employed a convenient one-step synthesis method for synthesizing Cu2ZnSnSe4 (CZTSe) nanocrystals (NCs) in an excess selenium environment. This excess selenium situation enhanced the reaction of metal acetylacetonates with selenium, resulting in the burst nucleation of NCs at relatively low temperatures. The phase morphology and surface and optoelectronic properties of NCs before and after ligand exchange were discussed in depth. It was found that pure tetragonal-phase structure CZTSe NCs with approximately 1.7-eV bandgap could be synthesized. The removal of large organic molecules on CZTSe NCs after ligand exchange by S2- decreased the resistivity. The bandgap of the films after ligand exchange by 550°C selenization was also decreased due to better crystallinity. For potential application in CZTSe solar cells, we constructed an energy level diagram to explain the mutual effect between the absorption layer and CdS layer. Using cyclic voltammetry (CV) measurement, we found that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of CZTSe films shifted down after ligand exchange. After energy level alignment at the CdS/CZTSe interface, a type I band alignment structure was more conveniently formed after ligand exchange. This structure acted as the barrier against injection electrons from ZnO to the CZTSe layer, and recombination would subsequently be depressed.

  20. Electroless plating of ultrathin palladium films: self-initiated deposition and application in microreactor fabrication

    Muench, Falk; Oezaslan, Mehtap; Svoboda, Ingrid; Ensinger, Wolfgang

    2015-10-01

    We present new electroless palladium plating reactions, which can be applied to complex-shaped substrates and lead to homogeneous, dense and conformal palladium films consisting of small nanoparticles. Notably, autocatalytic and surface-selective metal deposition could be achieved on a wide range of materials without sensitization and activation pretreatments. This provides a facile and competitive route to directly deposit well-defined palladium nanofilms on e.g. carbon, paper, polymers or glass substrates. The reactions proceed at mild conditions and are based on easily accessible chemicals (reducing agent: hydrazine; metal source: PdCl2; ligands: ethylenediaminetetraacetic acid (EDTA), acetylacetone). Additionally, the water-soluble capping agent 4-dimethylaminopyridine (DMAP) is employed to increase the bath stability, to ensure the formation of small particles and to improve the film conformity. The great potential of the outlined reactions for micro- and nanofabrication is demonstrated by coating an ion-track etched polycarbonate membrane with a uniform Pd film of approximately 20 nm thickness. The as-prepared membrane is then employed as a highly miniaturized flow reactor, using the reduction of 4-nitrophenol with NaBH4 as a model reaction.

  1. Effect of Fluorine Substitution on Photovoltaic Properties of Alkoxyphenyl Substituted Benzo[1,2-b:4,5-b']dithiophene-Based Small Molecules.

    Qiu, Beibei; Yuan, Jun; Xiao, Xuxian; He, Dingjun; Qiu, Lixia; Zou, Yingping; Zhang, Zhi-guo; Li, Yongfang

    2015-11-18

    Two new small molecules, C3T-BDTP and C3T-BDTP-F with alkoxyphenyl-substituted benzo[1,2-b:4,5-b']dithiophene (BDT) and meta-fluorinated-alkoxyphenyl-substituted BDT as the central donor blocks, respectively, have been synthesized and used as donor materials in organic solar cells (OSCs). With the addition of 0.4% v/v 1,8-diiodooctane (DIO), the blend of C3T-BDTP-F/PC71BM showed a higher hole mobility of 8.67 × 10(-4) cm(2) V(-1) s(-1) compared to that of the blend of C3T-BDTP/PC71BM. Two types of interlayers, zirconium acetylacetonate (ZrAcac) and perylene diimide (PDI) derivatives (PDINO and PDIN), were used to further optimize the performance of OSCs. With a device structure of ITO/PEDOT:PSS/donor:PC71BM/PDIN/Al, the OSCs based on C3T-BDTP delivered a satisfying power conversion efficiency (PCE) of 5.27% with an open circuit voltage (V(oc)) of 0.91 V, whereas the devices based on C3T-BDTP-F showed an enhanced PCE of 5.42% with a higher V(oc) of 0.97 V. PMID:26517574

  2. Series of dinuclear and tetranuclear lanthanide clusters encapsulated by salen-type and β-diketionate ligands: single-molecule magnet and fluorescence properties.

    Sun, Wen-Bin; Han, Bing-Lu; Lin, Po-Heng; Li, Hong-Feng; Chen, Peng; Tian, Yong-Mei; Murugesu, Muralee; Yan, Peng-Fei

    2013-10-01

    Three dinuclear [Ln2H2OL(1)2(acac)2]·solvent (1, Ln = Gd, solvent = 2CH2Cl2; 2, Ln = Tb, no solvent; 3, Ln = Er, solvent = (C2H5)2O), and two tetranuclear lanthanide clusters [Ln4(μ3-OH)2L(2)2(acac)6]·2(solvent) (4, Ln = Tb, solvent = CH3OH; 5, Ln = Dy, solvent = CH3CN) were characterized in terms of structure, fluorescence and magnetism. The dinuclear lanthanide complexes were constructed by a rigid salen-type ligand H2L(1) = N,N'-bis(salicylidene)-o-phenylenediamine and β-diketonate (acac = acetylacetonate) ligands, while the tetranuclear clusters were formed from the flexible ligand H2L(2) = N,N'-bis(salicylidene)-1,2-ethanediamine. Crystal structure analysis indicates that the rigid ligand favors the double-decker sandwich structure (Ln2L(1)2), in which the two lanthanide ions have different coordination numbers and geometry, while the more flexible ligand (H2L(2)) leads to planar tetranuclear clusters. The relationship between their respective magnetic anisotropy and ligand-field geometries and their fluorescence properties was investigated. The Dy and Tb-containing clusters exhibit typical visible fluorescence properties, and single-molecule magnet behavior is seen in complex 5. PMID:23887476

  3. Suspension chemistry and electrophoretic deposition of zirconia electrolyte on conducting and non-conducting substrates

    Das, Debasish; Basu, Rajendra N., E-mail: rnbasu@cgcri.res.in

    2013-09-01

    Graphical abstract: - Highlights: • Stable suspension of yttria stabilized zirconia (YSZ) obtained in isopropanol medium. • Suspension chemistry and process parameters for electrophoretic deposition optimized. • Deposited film quality changed with iodine and water (dispersants) concentration. • Dense YSZ film (∼5 μm) fabricated onto non-conducting porous NiO-YSZ anode substrate. - Abstract: Suspensions of 8 mol% yttria stabilized zirconia (YSZ) particulates in isopropanol medium are prepared using acetylacetone, iodine and water as dispersants. The effect of dispersants concentration on suspension stability, particle size distribution, electrical conductivity and pH of the suspensions are studied in detail to optimize the suspension chemistry. Electrophoretic deposition (EPD) has been conducted to produce thin and dense YSZ electrolyte films. Deposition kinetics have been studied in depth and good quality films on conducting substrate are obtained at an applied voltage of 15 V for 3 min. YSZ films are also fabricated on non-conducting NiO-YSZ anode substrate using a steel plate on the reverse side of the substrate. Upon co-firing at 1400 °C for 6 h a dense YSZ film of thickness ∼5 μm is obtained. Such a half cell (anode + electrolyte) can be used to fabricate a solid oxide fuel cell on applying a suitable cathode layer.

  4. Suspension chemistry and electrophoretic deposition of zirconia electrolyte on conducting and non-conducting substrates

    Graphical abstract: - Highlights: • Stable suspension of yttria stabilized zirconia (YSZ) obtained in isopropanol medium. • Suspension chemistry and process parameters for electrophoretic deposition optimized. • Deposited film quality changed with iodine and water (dispersants) concentration. • Dense YSZ film (∼5 μm) fabricated onto non-conducting porous NiO-YSZ anode substrate. - Abstract: Suspensions of 8 mol% yttria stabilized zirconia (YSZ) particulates in isopropanol medium are prepared using acetylacetone, iodine and water as dispersants. The effect of dispersants concentration on suspension stability, particle size distribution, electrical conductivity and pH of the suspensions are studied in detail to optimize the suspension chemistry. Electrophoretic deposition (EPD) has been conducted to produce thin and dense YSZ electrolyte films. Deposition kinetics have been studied in depth and good quality films on conducting substrate are obtained at an applied voltage of 15 V for 3 min. YSZ films are also fabricated on non-conducting NiO-YSZ anode substrate using a steel plate on the reverse side of the substrate. Upon co-firing at 1400 °C for 6 h a dense YSZ film of thickness ∼5 μm is obtained. Such a half cell (anode + electrolyte) can be used to fabricate a solid oxide fuel cell on applying a suitable cathode layer

  5. Chemical speciation and equilibria of some nucleic acid compounds and their iron(III) complexes

    Masoud, Mamdouh S.; Abd El-Kaway, Marwa Y.; Hindawy, Ahmed M.; Soayed, Amina A.

    The pH effect on electronic absorption spectra of some biologically active nucleic acid constituents have been studied at room temperature and the mechanism of ionization was explained. These compounds are of two categories (pyrimidines: [barbital; 5,5'-diethyl-barbituric acid], [SBA; 4,6-dihydroxy-2-mercapto-pyrimidin], [NBA; 5-nitro-2,4,6(1H,3H,5H)-pyrimidine trione] and [TU; 2,3-dihydro-2-thioxo-pyrimidin-4(1H)-one]) and (purines: [adenine; 6-amino purine], its [Schiff bases derived from adenine-acetylacetone; (Z)-4-(7H-purin-6-ylimino)pentan-2-one) and adenine-salicylaldehyde; 2-((7H-purin-6-ylimino) methyl) phenol] and its [Azo derived from adenine-resorcinol; 4-((7H-purin-6-yl)-diazenyl) benzene-1,3-diol]. The phenomena of tautomerization assigned different tautomers. Different spectrophotometric methods are applied to evaluate the pK's values that explained with their molecular structures. The interaction of Fe3+ with some selected pyrimidines (barbital, NBA and SBA) was explained using familiar six spectrophotometric methods. The data typified the existence of different absorbing species with the different stoichiometries 1:1, 1:2, 1:3 and 2:3. The stability constant of the complexes was computed. More approach was deduced to assign the existence of different species applying the distribution diagrams.

  6. Research on Raman-scattering and Fabrication of Multilayer Thin Film with Different Structures and Components Based on Pt/Ti/Si3N4/SiO2/Si Substrate

    Qiu-lin Tan; Wen-dong Zhang; Chen-yang Xue; Jun Liu; Jun-hong Li; Ji-jun Xiong

    2009-01-01

    Using the same conditions and various starting materials, such as lead acetate trihydrate, tetrabulyl titanate, zirconium n-butoxide, and acetylacetone, two kinds of solid precursors, lead zirconate titanate (PZT, Zr/Ti=15/85) and lead titanate (PT), were fabricated. With three different combinations, namely, PZT, PT/PZT-PZT/PT, and PT/PZT/-/PZT/PT, three multilayer thin films were deposited on three Pt-Ti-Si3N4-SiO2-Si substrates by a modified sol-gel process. The fabrication process of the thin films is discussed in detail. We found that there is a large built-in stress in the thin film, which can be diminished by annealing at 600 ℃, when the gel is turned into solid material through drying and sintering. The Raman scattering spectra of the films with different compositions and structures were investigated. With the help of X-ray diffraction (XRD) analyzer and Raman scattering spectra analyzer, it was found that the thin films with the PT/PZT-PZT/PT structure have reasonable crystallinity and less residual stress. XRD testing shows that the diffraction pattern of the multilayer film results from the superimposition of the PZT and PT patterns. This leads to the conclusion that the PT/PZT-PZT/PT multilayer thin film has a promising future in pyroelectric infrared detectors with high performance.

  7. Star-like PtCu nanoparticles supported on graphene with superior activity for methanol electro-oxidation

    The synthesis of stars-like PtCu nanoparticles is reported using copper (II) chloride dihydrate(CuCl2·2H2O) instead of copper(II) acetylacetonate [Cu(acac)2] as Cu precursor for the first time. Transmission electron microscopy (TEM) electron microscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used to characterize the stars-like PtCu nanoparticles. Both cyclic voltammetry and chronoamperometry results demonstrate that these stars-like PtCu nanoparticles exhibit significantly high catalytic activity toward the methanol oxidation reaction in comparison with the Pt catalyst. Furthermore, the stars-like PtCu nanoparticles supported on graphene (rGO) show about 2.3 times higher durability than the Pt/rGO catalyst in the accelerated ageing test. All results suggest the stars-like PtCu nanoparticles supported on rGO is promising for portable applications in direct methanol fuel cells and any other catalysis fields

  8. Composition-dependent electrocatalytic activity of palladium-iridium binary alloy nanoparticles supported on the multiwalled carbon nanotubes for the electro-oxidation of formic acid.

    Bao, Jianming; Dou, Meiling; Liu, Haijing; Wang, Feng; Liu, Jingjun; Li, Zhilin; Ji, Jing

    2015-07-22

    Surface-functionalized multiwalled carbon nanotubes (MWCNTs) supported Pd100-xIrx binary alloy nanoparticles (Pd100-xIrx/MWCNT) with tunable Pd/Ir atomic ratios were synthesized by a thermolytic process at varied ratios of bis(acetylacetonate) palladium(II) and iridium(III) 2,4-pentanedionate precursors and then applied as the electrocatalyst for the formic acid electro-oxidation. The X-ray diffraction pattern (XRD) and transmission electron microscope (TEM) analysis showed that the Pd100-xIrx alloy nanoparticles with the average size of 6.2 nm were uniformly dispersed on the MWCNTs and exhibited a single solid solution phase with a face-centered cubic structure. The electrocatalytic properties were evaluated through the cyclic voltammetry and chronoamperometry tests, and the results indicated that both the activity and stability of Pd100-xIrx/MWCNT were strongly dependent on the Pd/Ir atomic ratios: the best electrocatalytic performance in terms of onset potential, current density, and stability against CO poisoning was obtained for the Pd79Ir21/MWCNT. Moreover, compared with pure Pd nanoparticles supported on MWCNTs (Pd/MWCNT), the Pd79Ir21/MWCNT exhibited enhanced steady-state current density and higher stability, as well as maintained excellent electrocatalytic activity in high concentrated formic acid solution, which was attributed to the bifunctional effect through alloying Pd with transition metal. PMID:26132867

  9. Plasma enhanced chemical vapor deposition of thin ZnO layers on glass substrates

    The plasma enhanced chemical vapor deposition (PECVD) is a powerful and flexible instrument for depositing thin layers, nanocomposites or nanostructures. In this work ZnO layers were grown by metal-organic PECVD (RF – 13.56 MHz) on glass substrates coated with ZnO seed films. Zn acetylacetonate was used as a precursor and oxygen as oxidant. The influence of the oxygen content in gas mixture on the morphology, optical and electrical properties of the deposited layers was studied. ZnO film properties were investigated by scanning electron microscopy (SEM), UV-VIS optical spectrophotometry and current-voltage (I-V) measurements. The results obtained show that the oxygen content in the deposition atmosphere influences the morphology, the optical properties and the electrical resistivity of the obtained ZnO layers. Nanorods with good alignment, vertically orientated to the surface of glass substrate can be observed in the layers deposited at low content of O2 in plasma at substrate temperature of 400°C

  10. Novel composite Zr/PBI-O-PhT membranes for HT-PEFC applications

    Mikhail S. Kondratenko

    2013-08-01

    Full Text Available Novel composite membranes for high temperature polymer-electrolyte fuel cells (HT-PEFC based on a poly[oxy-3,3-bis(4′-benzimidazol-2″-ylphenylphtalide-5″(6″-diyl] (PBI-O-PhT polymer with small amounts of added Zr were prepared. It was shown in a model reaction between zirconium acetylacetonate (Zr(acac4 and benzimidazole (BI that Zr-atoms are capable to form chemical bonds with BI. Thus, Zr may be used as a crosslinking agent for PBI membranes. The obtained Zr/PBI-O-PhT composite membranes were examined by means of SAXS, thermomechanical analysis (TMA, and were tested in operating fuel cells by means of stationary voltammetry and impedance spectroscopy. The new membranes showed excellent stability in a 2000-hour fuel cell (FC durability test. The modification of the PBI-O-PhT films with Zr facilitated an increase of the phosphoric acid (PA uptake by the membranes, which resulted in an up to 2.5 times increased proton conductivity. The existence of an optimal amount of Zr content in the modified PBI-O-PhT film was shown. Larger amounts of Zr lead to a lower PA doping level and a reduced conductivity due to an excessively high degree of crosslinking.

  11. Utilization of water/alcohol-soluble polyelectrolyte as an electron injection layer for fabrication of high-efficiency multilayer saturated red-phosphorescence polymer light-emitting diodes by solution processing

    Wang, Lei; Liang, Bo; Huang, Fei; Peng, Junbiao; Cao, Yong

    2006-10-01

    Highly efficient multilayer red polymer light-emitting diodes were fabricated by solution process-ing from iridium complex, bis(1-(3-(9,9-dimethyl-fluorene-2-yl)phenyl)isoquinoline-C2,N ') iridium(III)acetylacetonate, doped into polyfluorene as a host and with a water/alcohol-soluble polymer, poly[(9,9-bis(3'-((N ,N-dimethyl)-N-ethylammonium)propyl)-2,7-fluorene)-2,7-(9,9-dioctylfluorene)-4,7-(2,1,3-benzoselenadiazole)]dibromide (PFN) as electron injection layer. The device with the structure ITO /PEDOT-PSS(50nm)/PVK(40nm)/PFO:PBD:Ir(DMFPQ)2acac(2%,75nm)/PFN(20nm)/Ba(4.5nm)/Al(150nm) showed an external quantum efficiency of 18.0% and luminance efficiency of 9.8Cd/A at a current density of 1.1mA/cm2, a peak emission at λmax=636nm, and Commission International de I'Eclairage coordinates of (0.665, 0.319). The efficiency remained as high as QE =11.1%, and LE =6.0cd/A, at a current density of 100mA/cm2, and a luminance of 6140cd/m2.

  12. Synthesis and characterization of magnetically active carbon nanofiber/iron oxide composites with hierarchical pore structures

    Polyacrylonitrile (PAN) solution containing the iron oxide precursor iron (III) acetylacetonate (AAI) was electrospun and thermally treated to produce electrically conducting, magnetic carbon nanofiber mats with hierarchical pore structures. The morphology and material properties of the resulting multifunctional nanofiber mats including the surface area and the electric and magnetic properties were examined using various characterization techniques. Scanning electron microscopy images show that uniform fibers were produced with a fiber diameter of ∼600 nm, and this uniform fiber morphology is maintained after graphitization with a fiber diameter of ∼330 nm. X-ray diffraction (XRD) and Raman studies reveal that both graphite and Fe3O4 crystals are formed after thermal treatment, and graphitization can be enhanced by the presence of iron. A combination of XRD and transmission electron microscopy experiments reveals the formation of pores with graphitic nanoparticles in the walls as well as the formation of magnetite nanoparticles distributed throughout the fibers. Physisorption experiments show that the multifunctional fiber mats exhibit a high surface area (200-400 m2 g-1) and their pore size is dependent on the amount of iron added and graphitization conditions. Finally, we have demonstrated that the fibers are electrically conducting as well as magnetically active.

  13. Synthesis and characterization of magnetically active carbon nanofiber/iron oxide composites with hierarchical pore structures

    Panels, Jeanne E.; Lee, Jinwoo; Park, Kang Yeol; Kang, Seung Yeon; Marquez, Manuel; Wiesner, Ulrich; Lak Joo, Yong

    2008-11-01

    Polyacrylonitrile (PAN) solution containing the iron oxide precursor iron (III) acetylacetonate (AAI) was electrospun and thermally treated to produce electrically conducting, magnetic carbon nanofiber mats with hierarchical pore structures. The morphology and material properties of the resulting multifunctional nanofiber mats including the surface area and the electric and magnetic properties were examined using various characterization techniques. Scanning electron microscopy images show that uniform fibers were produced with a fiber diameter of ~600 nm, and this uniform fiber morphology is maintained after graphitization with a fiber diameter of ~330 nm. X-ray diffraction (XRD) and Raman studies reveal that both graphite and Fe3O4 crystals are formed after thermal treatment, and graphitization can be enhanced by the presence of iron. A combination of XRD and transmission electron microscopy experiments reveals the formation of pores with graphitic nanoparticles in the walls as well as the formation of magnetite nanoparticles distributed throughout the fibers. Physisorption experiments show that the multifunctional fiber mats exhibit a high surface area (200-400 m2 g-1) and their pore size is dependent on the amount of iron added and graphitization conditions. Finally, we have demonstrated that the fibers are electrically conducting as well as magnetically active.

  14. Cobalt- and iron-based nanoparticles hosted in SBA-15 mesoporous silica and activated carbon from biomass: Effect of modification procedure

    Tsoncheva, Tanya; Genova, Izabela; Paneva, Daniela; Dimitrov, Momtchil; Tsyntsarski, Boyko; Velinov, Nicolay; Ivanova, Radostina; Issa, Gloria; Kovacheva, Daniela; Budinova, Temenujka; Mitov, Ivan; Petrov, Narzislav

    2015-10-01

    Ordered mesoporous silica of SBA-15 type and activated carbon, prepared from waste biomass (peach stones), are used as host matrix of nanosized iron and cobalt particles. The effect of preparation procedure on the state of loaded nanoparticles is in the focus of investigation. The obtained materials are characterized by Boehm method, low temperature physisorption of nitrogen, XRD, UV-Vis, FTIR, Mossbauer spectroscopy and temperature programmed reduction with hydrogen. The catalytic behaviour of the samples is tested in methanol decomposition. The dispersion, oxidative state and catalytic behaviour of loaded cobalt and iron nanoparticles are successfully tuned both by the nature of porous support and the metal precursor used during the samples preparation. Facile effect of active phase deposition from aqueous solution of nitrate precursors is assumed for activated carbon support. For the silica based materials the catalytic activity could be significantly improved when cobalt acetylacetonate is used during the modification. The complex effect of pore topology and surface functionality of different supports on the active phase formation is discussed.

  15. Control of the nanocrystalline zirconia structure through a colloidal sol-gel process

    Gossard, A.; Grasland, F.; Le Goff, X.; Grandjean, A.; Toquer, G.

    2016-05-01

    A simple method to synthesize tetragonal zirconia stabilized at ambient temperature is developed and allows the monitoring of the tetragonal-monoclinic transition via a colloidal sol-gel process. By increasing the pH of an aqueous solution consisted of a zirconium precursor and a complexing agent (acetylacetone), a colloidal sol and then a gel can be formed under slightly acidic condition. After a drying step, tetragonal zirconia is easily obtained with an adequate thermal treatment at low temperature. The tetragonal-monoclinic transition occurs when the calcination temperature is increased. The relationship between the crystallite size, the crystallographic structure and the thermal treatment has been investigated by X-Ray Diffraction and the behaviour of the system from the gel state to the final powder has been studied by using Small Angle X-Ray Scattering and thermal analysis techniques. We demonstrate that compared to a chemical precipitation route, this colloidal sol-gel process allows the nanostructure of the material to be controlled due to the formation of primary nanoparticles. The presence of these nanoparticles makes possible the specific determination of the zirconia crystallographic phase through an accurate control of the nanostructure during the thermal treatment.

  16. Pt-free carbon-based fuel cell catalyst prepared from spherical polyimide for enhanced oxygen diffusion

    Nabae, Yuta; Nagata, Shinsuke; Hayakawa, Teruaki; Niwa, Hideharu; Harada, Yoshihisa; Oshima, Masaharu; Isoda, Ayano; Matsunaga, Atsushi; Tanaka, Kazuhisa; Aoki, Tsutomu

    2016-01-01

    The development of a non-precious metal (NPM) fuel cell catalyst is extremely important to achieve globalization of polymer electrolyte fuel cells due to the cost and scarcity of platinum. Here, we report on a NPM cathode catalyst prepared by the pyrolysis of spherical polyimide nanoparticles that contain small amounts of Fe additive. 60 nm diameter Fe-containing polyimide nanoparticles were successfully synthesized by the precipitation polymerization of pyromellitic acid dianhydride and 1,3,5-tris(4-aminophenyl)benzene with Fe(acac)3 (acac = acetylacetonate) as an additive. The particles were subsequently carbonized by multistep pyrolysis to obtain the NPM catalyst while retaining the small particle size. The catalyst has good performance and promising durability for fuel cell applications. The fuel cell performance under a 0.2 MPa air atmosphere at 80 °C of 1.0 A cm−2 at 0.46 V is especially remarkable and better than that previously reported. PMID:26987682

  17. Supercritical fluid extraction of thorium and uranium ions from solid and liquid materials with fluorinated β-diketones and tributyl phosphate

    A recent report shows that trivalent lanthanide and uranyl ions can be extracted by supercritical CO2 containing the fluorinated β-diketone, 2,2-dimethyl-6,6,7,7,8,8,8-hyptafluoro-3,5-octanedione (FOD). Extraction and separation of actinides by supercritical fluids are of particular interest today because of potential applications to nuclear waste analysis and management. This paper describes the conditions of extracting thorium and uranium ions from solid and liquid materials by supercritical CO2 containing different β-diketones. The synergistic extraction of the actinides by mixed ligands involving β-diketones and tributyl phosphate (TBP) in supercritical CO2 is also reported. Synergistic extraction is another approach to improve the efficiencies of ligands of SFE of actinides. Potential applications of this new extraction technique for the separation of actinides from environmental samples are discussed. The five β-diketones tested for the extraction of uranyl and Th(IV) ions in supercritical carbon dioxide are given as follows: acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, thienoyltrifluoroacetylacetone, and FOD. 12 refs., 5 tabs

  18. Supercritical fluid extraction of thorium from tissue paper matrix employing β-diketones

    Various β-diketones viz. acetylacetone (AA), trifluoroacetylacetone (TFA), hexafluoroacetylacetone (HFA), thenoyltrifluoroacetylacetone (TTA) and heptafluorobutanoylpivaroylmethane (FOD) were evaluated as chelating agents for the supercritical fluid extraction of thorium from tissue paper matrix. In-situ chelation mode was found to be more effective than online chelation mode. A combination of tributyl phosphate (TBP) and β-diketones further enhanced the extraction efficiency. The extraction efficiency trend observed in all the cases was: TTA>FOD>HFA>TFA>AA. A correlation was observed between extraction efficiency and degree of fluorination in the side arms of β-diketones. This could be attributed to the fact that in supercritical CO2, higher fluorination results in higher percentage of enol content, greater dissociation into enolate ion and higher solubility and stability of β-diketones as well as of Th-β-diketone chelates. Highest extraction efficiency with TTA was probably due to the presence of aromatic thenoyl group. The spectra of the extracted Th-chelates displayed peaks in the visible region, which shifted towards UV region with increasing fluorination. In the Th-TTA chelate spectrum, red shift was observed. (orig.)

  19. Controlled synthesis and characteristics of antireflection coatings of TiO2 produced from a organometallic colloid

    Highlights: → Titanium dioxide antireflection coating was made by a less used titanium colloidal precursor solution. → Sol-gel spin-coating process was used to make thin films on silicon substrates. → Various process parameters have been studied and their effect on physical, structural and optical properties was investigated. → Application of the coating on silicon solar cells showed an enhancement more than 20% in Jsc in comparison to the cell devoid of the coating. - Abstract: Antireflection titanium dioxide (TiO2) coatings have been developed on monocrystalline silicon by a sol-gel spin-coating process using titanium di-isopropoxidebis(acetylacetonate) colloidal precursor solution. The effect of titanium content in the precursor, spin rate, sintering duration and temperature have been studied and their effect on coating thickness and optical properties (i.e., refractive index and reflectivity) were investigated. The influence of post-deposition sintering temperature on the optical characteristics, composition and the microstructure of the coatings have been evaluated by UV-vis spectroscopy, ellipsometry, X-ray photoelectron spectroscopy, atomic force microscopy and X-ray diffraction techniques. Solar cells made on silicon wafers with TiO2 as antireflection layer showed enhancement of more than 20% in short circuit current density in comparison to a cell devoid of the TiO2 coating.

  20. Ruthenium nanoparticles decorated curl-like porous carbons for high performance supercapacitors.

    Lou, Bih-Show; Veerakumar, Pitchaimani; Chen, Shen-Ming; Veeramani, Vediyappan; Madhu, Rajesh; Liu, Shang-Bin

    2016-01-01

    The synthesis of highly dispersed and stable ruthenium nanoparticles (RuNPs; ca. 2-3 nm) on porous activated carbons derived from Moringa Oleifera fruit shells (MOC) is reported and were exploited for supercapacitor applications. The Ru/MOC composites so fabricated using the biowaste carbon source and ruthenium acetylacetonate as the co-feeding metal precursors were activated at elevated temperatures (600-900 (o)C) in the presence of ZnCl2 as the pore generating and chemical activating agent. The as-prepared MOC carbonized at 900 (o)C was found to possess a high specific surface area (2522 m(2) g(-1)) and co-existing micro- and mesoporosities. Upon incorporating RuNPs, the Ru/MOC nanocomposites loaded with modest amount of metallic Ru (1.0-1.5 wt%) exhibit remarkable electrochemical and capacitive properties, achiving a maximum capacitance of 291 F g(-1) at a current density of 1 A g(-1) in 1.0 M H2SO4 electrolyte. These highly stable and durable Ru/MOC electrodes, which can be facily fabricated by the eco-friendly and cost-effective route, should have great potentials for practical applications in energy storage, biosensing, and catalysis. PMID:26818461

  1. Synthesis of magnetic cobalt ferrite nanoparticles with controlled morphology, monodispersity and composition: the influence of solvent, surfactant, reductant and synthetic conditions.

    Lu, Le T; Dung, Ngo T; Tung, Le D; Thanh, Cao T; Quy, Ong K; Chuc, Nguyen V; Maenosono, Shinya; Thanh, Nguyen T K

    2015-12-14

    In our present work, magnetic cobalt ferrite (CoFe2O4) nanoparticles have been successfully synthesised by thermal decomposition of Fe(III) and Co(II) acetylacetonate compounds in organic solvents in the presence of oleic acid (OA)/ oleylamine (OLA) as surfactants and 1,2-hexadecanediol (HDD) or octadecanol (OCD-ol) as an accelerating agent. As a result, CoFe2O4 nanoparticles of different shapes were tightly controlled in size (range of 4-30 nm) and monodispersity (standard deviation only at ca. 5%). Experimental parameters, such as reaction time, temperature, surfactant concentration, solvent, precursor ratio, and accelerating agent, in particular, the role of HDD, OCD-ol, and OA/OLA have been intensively investigated in detail to discover the best conditions for the synthesis of the above magnetic nanoparticles. The obtained nanoparticles have been successfully applied for producing oriented carbon nanotubes (CNTs), and they have potential to be used in biomedical applications. PMID:26542630

  2. Application of exciplex in the fabrication of white organic light emitting devices with mixed fluorescent and phosphorescent layers

    Yang, Dan; Duan, Yahui; Yang, Yongqiang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science & Engineering, Jilin University, Changchun 130012 (China); Hu, Nan [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science & Engineering, Jilin University, Changchun 130012 (China); Changchun University of Science and Technology, Changchun 130012 (China); Wang, Xiao [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science & Engineering, Jilin University, Changchun 130012 (China); Sun, Fengbo [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science & Engineering, Jilin University, Changchun 130012 (China); Changchun University of Science and Technology, Changchun 130012 (China); Duan, Yu, E-mail: duanyu@jlu.edu.cn [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science & Engineering, Jilin University, Changchun 130012 (China)

    2015-10-15

    In this study, a highly efficient fluorescent/phosphorescent white organic light-emitting device (WOLED) was fabricated using exciplex light emission. The hole-transport material 4,4',4''-tris(N-carbazolyl)triphenylamine (TCTA), and electron-transport material, 4,7-diphenyl-1,10-phenanthroline (Bphen), were mixed to afford a blue-emitting exciplex. The WOLED was fabricated with a yellow phosphorescent dye, Ir(III) bis(4-phenylthieno [3,2-c] pyridinato-N,C{sup 2'}) acetylacetonate (PO-01), combined with the exciplex. In this structure, the energy can be efficiently transferred from the blend layer to the yellow phosphorescent dye, thus improving the efficiency of the utilization of the triplet exciton. The maximum power efficiency of the WOLED reached a value 9.03 lm/W with an external quantum efficiency of 4.3%. The Commission Internationale de I'Eclairage (CIE) color coordinates (x,y) of the device were from (0.39, 0.45) to (0.27, 0.31), with a voltage range of 4–9 V. - Highlights: • An exciplex/phosphorescence hybrid white OLED was fabricated for the first time with blue/orange complementary emitters. • By using exciplex as the blue emitter, non-radiative triplet-states on the exciplex can be harvested for light-emission by transferring them to low triplet-state phosphors.

  3. A critical assessment of the specific role of microwave irradiation in the synthesis of ZnO micro- and nanostructured materials.

    Baghbanzadeh, Mostafa; Skapin, Srečo D; Orel, Zorica Crnjak; Kappe, C Oliver

    2012-04-27

    A rapid, microwave-assisted hydrothermal method has been developed to access ultrafine ZnO hexagonal microrods of about 3-4 μm in length and 200-300 nm in width by using a 1:5 zinc nitrate/urea precursor system. The size and morphology of these ZnO materials can be influenced by subtle changes in precursor concentration, solvent system, and reaction temperature. Optimized conditions involve the use of a 1:3 water/ethylene glycol solvent system and 10 min microwave heating at 150 °C in a dedicated single-mode microwave reactor with internal temperature control. Carefully executed control experiments ensuring identical heating and cooling profiles, stirring rates, and reactor geometries have demonstrated that for these preparations of ZnO microrods no differences between conventional and microwave dielectric heating are observed. The resulting ZnO microrods exhibited the same crystal phase, primary crystallite size, shape, and size distribution regardless of the heating mode. Similar results were obtained for the ultrafast preparation of ZnO nanoparticles with diameters of approximately 20 nm, synthesized by means of a nonaqueous sol-gel process at 200 °C from a Zn(acac)(2) (acac=acetylacetonate) precursor in benzyl alcohol. The specific role of microwave irradiation in enhancing these nanomaterial syntheses can thus be attributed to a purely thermal effect as a result of higher reaction temperatures, more rapid heating, and a better control of process parameters. PMID:22454084

  4. A simple route utilizing surfactant-assisted templating sol-gel process for synthesis of mesoporous Dy2O3 nanocrystal.

    Sreethawong, Thammanoon; Chavadej, Sumaeth; Ngamsinlapasathian, Supachai; Yoshikawa, Susumu

    2006-08-01

    A simple route of combined sol-gel process with surfactant-assisted templating technique was successfully employed for the first time to synthesize nanocrystalline mesoporous Dy(2)O(3) with narrow monomodal pore size distribution under mild conditions. The nanocrystalline Dy(2)O(3) with monomodal mesoporous characteristic was ultimately achieved by controlling the hydrolysis and condensation steps of dysprosium n-butoxide modified with acetylacetone in the presence of laurylamine hydrochloride surfactant aqueous solution. The synthesized material was methodically characterized by thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), N(2) adsorption-desorption, Brunauer-Emmett-Teller (BET) surface area analysis, and Barrett-Joyner-Halenda (BJH) pore size distribution analysis. The particle size of the synthesized Dy(2)O(3) in nanosized range obtained from the SEM and HRTEM micrographs was in good accordance with the crystallite size estimated from the XRD result. The N(2) adsorption-desorption result exhibited hysteresis pattern with single loop, indicating the existence of monomodal mesopore. The extremely narrow pore size distribution with mean pore diameter in the mesopore region of the synthesized Dy(2)O(3) was also confirmed by the BJH result. PMID:16647076

  5. Kinetics and mechanism of interaction of some bioactive ligands with cis-diaqua(cis-1,2-diaminocyclohexane)platinum(II) in aqueous medium

    P Karmakar; S Ray; S Mallick; B K Bera; A Mandal; S Mondal; A K Ghosh

    2013-09-01

    The substitution reaction of cis-[Pt(cis-dach)(H2O)2]2+ (where `dach’ is cis-1,2-diaminocyclohexane) with 2-thiouracil (S, N), 1,2-cyclohexanedionedioxime (N, N) and acetylacetone (O, O) were studied in aqueous solution in 0.10 M NaClO4 under pseudo-first order conditions as a functions of concentration, pH and temperature using UV-Vis spectrophotometry. The substitution reaction proceeds via rapid outer sphere association complex formation, followed by two slow consecutive steps. The first of these involves ligand-assisted deaquation, while second involves chelation as the second aqua ligand is displaced. The association equilibrium constant (KE) for the outer sphere complex formation has been evaluated together with rate constants for the two subsequent steps. The rate constants increase with increasing ligand concentration and the evaluated activation parameters for all reactions suggest an associative substitution mechanism for both the aqua ligand substitution processes. The product of the reaction has been characterized by IR, NMR and ESI-MS spectral analysis; which throws more light on the mechanistic behaviour of platinum(II) antitumour complexes.

  6. Influence of the utilized precursors on the morphology and properties of YBa{sub 2}Cu{sub 3}O{sub 7−y} superconducting nanostructures

    Alikhanzadeh-Arani, Sima [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Almasi-Kashi, Mohammad [Department of Physics, University of Kashan, Kashan, 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of)

    2013-05-15

    Highlights: ► YBa{sub 2}Cu{sub 3}O{sub 7−x} (Y-123) nanoparticles was synthesized by solid state processing. ► Inorganic precursor was used in the synthesis of YBa{sub 2}Cu{sub 3}O{sub 7−x}. ► The effect of calcinations on morphology and particle size were investigated. -- Abstract: In order to prevent agglomeration of high temperature ceramic material, the solid state processing based on new and appropriate yttrium complex precursors without applying surfactant has been suggested. These have been prepared by a reaction of yttrium acetate with three coordination compositions, acetylacetone, 2-hydroxo-1-naphthaldehyde and salicylaldehyde, for forming yttrium complex types. It was found that the size and morphology of products are clearly dependent on the type of utilized precursor because the organic ligands around yttrium center in these novel precursors act like a protecting agent. Magnetic susceptibility measurements showed that T{sub c} of the superconducting nanoparticles is from 82 K to 88.4 K. The crystalline structures of the nanoparticles remained in orthorhombic symmetry. Characterizations of specimens were performed using scanning electron microscopy and transmission electron microscopy, supported by other techniques including XRD diffraction, energy dispersive X-ray, FT-IR spectrum and magnetic susceptibility measurements.

  7. Effects of ferrite catalyst concentration and water vapor on growth of vertically aligned carbon nanotube

    Thanh Cao, Thi; Chuc Nguyen, Van; Thanh Tam Ngo, Thi; Le, Trong Lu; Loc Nguyen, Thai; Tran, Dai Lam; Obraztsova, Elena D.; Phan, Ngoc Minh

    2014-12-01

    In this study Fe3O4 nanoparticles were used as catalysts for the growth of vertically aligned carbon nanotubes (VA-CNTs) by chemical vapor deposition (CVD). The effect of catalyst concentration and water vapor during the CVD process on the properties of the VA-CNTs was investigated. Monodisperse Fe3O4 nanoparticles (4.5-9.0 nm diameter) prepared by thermal decomposition of iron acetylacetonate compounds were spin-coated on clean silicon substrates which served as a platform for VA-CNTs growth. The results indicated that the length, density and growth rate of CNTs were strongly affected by the catalyst concentration. CNTs grown at 0.026 g ml-1 Fe3O4 catalyst had greater length, density and growth rates than those obtained at 0.01 and 0.033 g ml-1 Fe3O4 catalyst. Addition of water during the CVD process had drastically improved CNTs growth. The length and growth rate of obtained CNTs were 40 μm and 1.33 μm min-1, respectively. The results provided insights into the role of Fe3O4 catalyst and water vapor during VA-CNTs growth process by CVD method and the obtained information might serve as a starting point for further optimization of VA-CNTs synthesis.

  8. Preparation of magnetic carbon nanotubes with hierarchical copper silicate nanostructure for efficient adsorption and removal of hemoglobin

    Zhang, Min; Wang, Yongtao; Zhang, Yanwei; Ding, Lei; Zheng, Jing; Xu, Jingli

    2016-07-01

    The controllable synthesis of materials with the desired structure and dimensionality is of great significance in material science. In this work, the hierarchical CNTs/Fe3O4@copper silicate (CNTs/Fe3O4@CuSilicate) composites were synthesized via a simple chemical conversion route by using CNTs/Fe3O4@SiO2 nanocables as template. Firstly, magnetic CNTs composites (CNTs/Fe3O4) were synthesized by the high temperature decomposition process using the iron acetylacetonate as raw materials. Then a layer of SiO2 can be easily coated on the magnetic CNTs by the stöber method, which were then converted into CNTs/Fe3O4@CuSilicate composites by hydrothermal reaction between the silica shell and copper ions in alkaline solution. The resulting CNTs/Fe3O4@CuSilicate composites hold merits such as magnetic responsivity, good dispersibility, and large specific surface area. Moreover, the CNTs/Fe3O4@copper silicate composites have strong affinity toward bovine hemoglobin (BHb), which were successfully applied to convenient, efficient, and fast removal of abundant proteins (HHb and HSA) in human blood.

  9. Highly efficient inverted top emitting organic light emitting diodes using a transparent top electrode with color stability on viewing angle

    We report a highly efficient phosphorescent green inverted top emitting organic light emitting diode with excellent color stability by using the 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile/indium zinc oxide top electrode and bis(2-phenylpyridine)iridium(III) acetylacetonate as the emitter in an exciplex forming co-host system. The device shows a high external quantum efficiency of 23.4% at 1000 cd/m2 corresponding to a current efficiency of 110 cd/A, low efficiency roll-off with 21% at 10 000 cd/m2 and low turn on voltage of 2.4 V. Especially, the device showed very small color change with the variation of Δx = 0.02, Δy = 0.02 in the CIE 1931 coordinates as the viewing angle changes from 0° to 60°. The performance of the device is superior to that of the metal/metal cavity structured device

  10. Photoluminescence studies of organic phosphor coated diffusing surface using blue inorganic light-emitting diode as excitation source

    We report the studies on photoluminescence (PL) of organic phosphor coated on a diffusing surface using a blue inorganic light-emitting diode (LED) array as an excitation source. The organic phosphor composite coated diffuser was used to scatter the directional blue light from the LED array. Some of the blue light is absorbed by the organic phosphor composite and the phosphor molecules are excited and re-emit light at longer wavelengths due to the PL process. The output light consists of scattered blue light plus phosphor generated broadband yellow light, thus making white light. The diffuser was made up of a plastic substrate coated with an organic composite of small molecule fluorescent material zinc(II)bis(8-hydroxyquinoline) (Znq2) doped with different percentages of electro-phosphorescent metal complex iridium(III)bis(2-methyldibenzo-[f, h] quinoxaline) (acetylacetonate) ([Ir(MDQ)2(acac)]). By means of changing the concentration and the thickness of the phosphor composite material the colour coordinates of white light were achieved. The CIE coordinates and correlated colour temperature were calculated for various thicknesses and phosphor composite concentrations and the results are reported. (paper)

  11. Interfacial reactions and microstructure of BaTiO{sub 3} films prepared using fluoride precursor method

    Fujihara, Shinobu; Schneller, Theodor; Waser, Rainer

    2004-01-15

    Interfacial reactions of BaF{sub 2} and TiO{sub 2} were investigated in preparing BaTiO{sub 3} thin films using a fluoride precursor method. Trifluoroacetate solutions were prepared from barium acetate, titanium tetraisopropoxide (TTIP), and trifluoroacetic acid (TFA, CF{sub 3}COOH) with additives such as water and acetylacetone. The solutions were deposited on platinized Si wafers by spin-coating, were pyrolysed at 400 deg. C in air and were finally heated typically at 700 deg. C in a water vapor atmosphere. The perovskite BaTiO{sub 3} phase was obtained although a small portion of BaF{sub 2} remained unreacted. Thus, the films were characterized as the mixture of BaTiO{sub 3}, BaF{sub 2}, and amorphous TiO{sub 2}. Influence of the solution chemistry on the phase evolution and microstructure was examined in order to discuss the reaction pathway of the perovskite phase.

  12. Preparation and photoluminescence enhancement in terbium(III ternary complexes with β-diketone and monodentate auxiliary ligands

    Devender Singh

    2016-12-01

    Full Text Available A series of new solid ternary complexes of terbium(III ion based on β-diketone ligand acetylacetone (acac and monodentate auxiliary ligands (aqua/urea/triphenylphosphineoxide/pyridine-N-oxide had been prepared. The structural characterizations of synthesized ternary compounds were studied by means of elemental analysis, infrared (IR, and proton nuclear magnetic resonance (NMR spectral techniques. The optical characteristics were investigated with absorption as well as photoluminescence spectroscopy. Thermal behavior of compounds was examined by TGA/DTA analysis and all metal complexes were found to have good thermal stability. The luminescence decay time of complexes were also calculated by monitoring at emission wavelength corresponding to 5D4 → 7F5 transition. A comparative inspection of the luminescent behavior of prepared ternary compounds was performed in order to determine the function of auxiliary ligands in the enhancement of luminescence intensity produced by central terbium(III ion. The color coordinates values suggested that compounds showed bright green emission in visible region in electromagnetic spectrum. Complexes producing green light could play a significant role in the fabrication of efficient light conversion molecular devices for display purposes and lightning systems.

  13. Phase- and morphology-controlled synthesis of cobalt sulfide nanocrystals and comparison of their catalytic activities for hydrogen evolution

    Pan, Yuan; Liu, Yunqi; Liu, Chenguang

    2015-12-01

    Colalt sulfide nanocrystals (NCs), including dandelion-like Co9S8 and sphere-like Co3S4, have been synthesized via a thermal decomposition approach using cobalt acetylacetonate as the cobalt source, 1-dodecanethiol as the sulfur source and oleic acid or oleylamine as the high boiling organic solvent. It is found that the molar ratio of the Co:S precursor and the species of solvent play an important role in the control of phase and morphology of cobalt sulfide nanostructures. The phase structure and morphology of the as-synthesized nickel sulfide NCs are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), energy dispersive spectrum (EDS) mapping, X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption. Then we further compare the electrocatalytic activity and stability of as-synthesized cobalt sulfide NCs for hydrogen evolution reaction (HER). The results show that sphere-like Co3S4 exhibits better electrocatalytic activity than the dandelion-like Co9S8 NCs for HER, which can be attributed to the difference of phase structure and morphology. The sphere-like Co3S4 NCs have large surface area and high electrical conductivity, both are beneficial to enhance the catalytic activity. This study indicates that the crystalline phase structure and morphology of cobalt sulfide NCs are important for designing HER electrocatalysts with high efficiency and good stability.

  14. Preparation and the optical nonlinearity of surface chemistry improved titania nanoparticles in poly(methyl methacrylate)-titania hybrid thin films

    With 800-nm, 120-fs laser pulses, optical nonlinearity has been studied in a series of thin films containing poly(methyl methacrylate) (PMMA), filled with surfactant acetylacetone (Acac) capped TiO2 nanoparticles, which were synthesized by a simple in situ sol-gel/polymerization process, assisted by spin coating and multi-step baking. The resulting nanohybrid thin films have highly optical transparency and demonstrate a unique nonlinear optical (NLO) response. The highest nonlinear refractive index (n2) is observed up to 6.55 x 10-2 cm2 GW-1 in the nanohybrid thin film of 60 wt% Ti(OBu)4 in PMMA, with a negligible two-photon absorption (TPA), as confirmed by the Z-scan technique. The titanium precursor loading combined with the nature of the capping molecules are used to influence the ability of nanoparticles to nonlinear optical response. Indeed, the ligands at the nanoparticles' surface can not only control the extent of the interaction between the organic molecules and the embedded nanoparticles but also influence the optical nonlinearities of nanoparticles.

  15. Characterization and microstructure of highly preferred oriented lead barium titanate thin films on MgO (100) by sol-gel process

    Highly preferred oriented lead barium titanate (Pb1-x,Ba x)TiO3 thin film, with particular emphasis on (Pb0.5,Ba0.5)TiO3, can be obtained by spin-coating on MgO (100) substrate by using the precursor sol, which was synthesized from acetylacetone chelating with titanium isopropoxide and ethylene glycol as a solvent, in the sol-gel process. Film thickness, pyrolysis temperature and heating rate were studied systemically to investigate their influences on the formation of preferred oriented thin films. The highly preferred (001)/(100) oriented thin film could be obtained by the pyrolysis of wet film at 500 deg. C and annealing at 600 deg. C at a slow heating rate of 5 deg. C/min. It is confirmed that the tetragonal perovskite structure of the titanate ceramic decreases with an increase of Ba content in (Pb1-x,Ba x)TiO3. The (001)/(100) oriented films were synthesized from all compositions between x = 0.2 and x = 0.8, at a crystallization temperature of 600 deg. C. In particular, for the Ba content in the range of x = 0.5∼0.6, highly preferred (001)/(100) planes were observed

  16. Study on the effects of complex ligands in the synthesis of TiO{sub 2} nanorod arrays using the sol-gel template method

    Attar, A Sadeghzadeh; Mirdamadi, Sh [Department of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Ghamsari, M Sasani; Hajiesmaeilbaigi, F [Solid State Lasers Research Group, Laser and Optics Research School, Tehran 11365-8486 (Iran, Islamic Republic of); Katagiri, K; Koumoto, K [Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan)], E-mail: mirdamadi@iust.ac.ir

    2008-08-07

    This work reports the effects of complex ligands on the synthesis of TiO{sub 2} nanorod arrays prepared by the improved sol-gel template method. In this method, the obtained TiO{sub 2} sols from the sol-gel process were injected by a syringe into the templates and then the samples were immediately immersed into boiling TiO{sub 2}-sol solutions. Densely and directionally aligned anatase nanorods of about 80-130 nm diameter and a length of several micrometres were successfully fabricated using an optimal molar ratio of the TiO{sub 2} sol. The results show that the molar ratio of the TiO{sub 2} sol plays an important role in the morphology and structure of TiO{sub 2} nanorods. The reaction between titanium alkoxide and acetylacetone leads to the formation of complex compounds, which can prevent the precipitation of undesired phases from the highly reactive precursors. These complex ligands can be removed after annealing at various temperatures, which depend on the molar ratio of the TiO{sub 2} sol.

  17. Synthesis and preservation of graphene-supported uranium dioxide nanocrystals

    Ma, Hanyu; Wang, Haitao; Burns, Peter C.; McNamara, Bruce K.; Buck, Edgar C.; Na, Chongzheng

    2016-07-01

    Graphene-supported uranium dioxide (UO2) nanocrystals are potentially important fuel materials. Here, we investigate the possibility of synthesizing graphene-supported UO2 nanocrystals in polar ethylene glycol compounds by the polyol reduction of uranyl acetylacetone under boiling reflux, thereby enabling the use of an inexpensive graphene precursor graphene oxide into a one-pot process. We show that triethylene glycol is the most suitable solvent with an appropriate reduction potential for producing nanometer-sized UO2 crystals compared to monoethylene glycol, diethylene glycol, and polyethylene glycol. Graphene-supported UO2 nanocrystals synthesized with triethylene glycol show evidence of heteroepitaxy, which can be beneficial for facilitating heat transfer in nuclear fuel particles. Furthermore, we show that graphene-supported UO2 nanocrystals synthesized by polyol reduction can be readily stored in alcohols, impeding oxidation from the prevalent oxygen in air. Together, these methods provide a facile approach for preparing and storing graphene-supported UO2 nanocrystals for further investigation and development under ambient conditions.

  18. Separations Science Data Base: an abstractor's manual

    The Separations Science Data Base, designed specifically for the retrieval of information needed in chemical separations problems (i.e., how to perform a given separation under given conditions), is described. The procedure for entering records into the data base is given. The initial entries are concerned primarily with liquid-liquid extraction and liquid-solid ion exchange methods for metal ions and salts; however, the data base is constructed so that almost any separations process can be accommodated. Each record is indexed with information provided under the following fields: author; title; publication source; date of publication; organization performing and/or sponsoring the work; brief abstract of the work; abstract number if the work has been so referenced, and/or abstractor's initials; type of separation system used (e.g., flotation); specific or generic name of the separation agent used (e.g., acetylacetone); list of substances separated (e.g., gold, copper); qualitative description of the supporting medium or matrix containing the substances before separation (e.g., nitrate); type of literature where the article was printed (e.g., book); and type of information that the article contains. Each of these fields may be searched independently of the others (or in combination), and the last six fields contain specific key words that are listed on the input form. Definitions are provided for the 39 information terms

  19. Chromium and Ruthenium-Doped Zinc Oxide Thin Films for Propane Sensing Applications

    Maximino Avendaño-Alejo

    2013-03-01

    Full Text Available Chromium and ruthenium-doped zinc oxide (ZnO:Cr and (ZnO:Ru thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III acetylacetonate and Ruthenium (III trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8 atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr and ruthenium (Ru, the sensing characteristics of undoped ZnO films are reported as well.

  20. Alternative synthesis of CuFeSe2 nanocrystals with magnetic and photoelectric properties.

    Wang, Wenliang; Jiang, Jun; Ding, Tao; Wang, Chunde; Zuo, Jian; Yang, Qing

    2015-02-01

    Monodisperse CuFeSe2 nanocrystals of high quality have been successfully synthesized for the first time using a hot-solution injection method from the reaction of metallic acetylacetonates with diphenyl diselenide (Ph2Se2) in oleylamine with addition of oleic acid at 255 °C for 90 min. The characterizations of X-ray diffraction, electron microscopy, and compositional analysis reveal that the resulting CuFeSe2 nanocrystals are of tetragonal phase with a stoichiometric composition. The CuFeSe2 nanocrystals exhibit well-defined quasi-cubic shape with an average size of ∼18 nm, and their shape can be tuned from quasi-cubes to quasi-spheres by adjusting the reaction parameters. Magnetic measurement reveals that the as-synthesized CuFeSe2 nanocrystals are ferromagnetic and paramagnetic at 4 and 300 K, respectively. Additionally, the current-voltage (I-V) behavior of the CuFeSe2 nanocrystals suggests that they are promising candidates for application in optoelectronics and solar energy conversion. PMID:25562289

  1. Surface modification of magnetite nanoparticle with azobenzene-containing water dispersible polymer

    We here report the synthesis of magnetite nanoparticle (MNP) grafted with poly (ethylene glycol) methyl ether methacrylate (PEGMA)-azobenzene acrylate (ABA) statistical copolymer via atom transfer radical polymerization (ATRP) for drug entrapment and photocontrolled release. MNP was synthesized via thermal decomposition of iron (III) acetylacetonate in benzyl alcohol and surface functionalized to obtain ATRP initiating sites. Molar compositions of the copolymer on MNP surface were systematically varied (100:0, 90:10, 70:30, and 50:50 of PEGMA:ABA, respectively) to obtain water dispersible particles with various amounts of azobenzene. The presence of polymeric shell on MNP core was evidenced by transmission electron microscopy (TEM). Drug loading and entrapment efficiencies as well as drug release behavior of the copolymer–MNP complexes were investigated. It was found that when percent of ABA in the copolymers was increased, entrapment and loading efficiencies of prednisolone model drug were enhanced. Releasing rate and percent of the released prednisolone of the complex exposed in UV light were slightly enhanced as compared to the system without UV irradiation. This copolymer–MNP complex with photocontrollable drug release and magnetic field-directed properties is warranted for further studies for potential uses as a novel drug delivery vehicle.

  2. Co-immobilization of laccase and mediator through a self-initiated one-pot process for enhanced conversion of malachite green.

    Sun, Hongfei; Huang, Wenguang; Yang, Hua; Zhang, Shujuan

    2016-06-01

    Laccase is a green biocatalyst. It works with molecular oxygen and produces water as the only by-product. However, its practical application is far less than satisfactory due to the low stability/poor reusability of free laccase and the potential secondary pollution caused by dissolved mediators. To address those bottlenecks in laccase-based catalysis, a novel biocatalyst (Immo-LMS) was fabricated by simultaneously immobilizing both laccase and a mediator (acetylacetone, abbreviated as AA) into a hydrogel through the laccase-AA initiated polymerization. This self-initiated immobilization process avoided the forced conformational change of laccase in the passive embedding to pre-existing carriers. Resulting from the effective cooperation of laccase and AA, the Immo-LMS had the highest substrate conversion quantity to malachite green, followed by the sole immobilized laccase and the immobilized laccase with an external mediator. Besides the improved activity, the Immo-LMS showed enhanced stability. The good performance of the Immo-LMS suggests that the co-immobilization of laccase and mediator through the self-initiated one-pot process was a promising strategy for the immobilization of laccase, which is expected to be helpful to cut down the running cost as well as the potential toxicity that come from mediators in the practical application of laccase. PMID:26971065

  3. Synthesis and characterization of Fe0.6Zn0.4Fe2O4 ferrite magnetic nanoclusters using simple thermal decomposition method

    Sharifi, Ibrahim; Zamanian, Ali; Behnamghader, Aliasghar

    2016-08-01

    This paper presents experimental results regarding the effect of the quantity of solvent on formation of the Fe-Zn ferrite nanoparticles during thermal decomposition. A ternary system of Fe0.6Zn0.4Fe2O4 has been synthesized by a thermal decomposition method using metal acetylacetonate in high temperature boiling point solvent and oleic acid. The X-ray diffraction study was used to determine phase purity, crystal structure, and average crystallite size of iron-zinc ferrite nanoparticles. The average crystallite size of nanoparticles was increased from 13 nm to 37 nm as a result of reducing the solvent from 30 ml to 10 ml in a synthesis batch. The diameter of particles and morphology of the particles were determined by transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM). Mid and far Fourier transform infrared (FT-IR) measurement confirmed monophasic spinel structure of ferrite. Furthermore, the DC magnetic properties of the samples were studied using the vibrating sample magnetometer (VSM). The largest Fe-Zn ferrite nanoparticles exhibited a relatively high saturation magnetization of 96 emu/g. Moreover, Low-field AC susceptibility measurement indicated blocking temperature of nanoparticles around 170-200 K.

  4. A novel polymeric herbicide based on phenoxyacetic acid derivatives

    Wimol Klaichim

    2009-01-01

    Full Text Available A novel polymeric herbicide based on phenoxyacetic acid derivatives was prepared by the reaction of epoxidised liquid natural rubber (ELNR with 2,4-dichlorophenoxyacetic acid (2,4-D or 2-methyl-4-chlorophenoxyacetic acid(MCPA. The liquid natural rubber (LNR was firstly obtained from the degradation of natural rubber latex with tert-butyl hydroperoxide and cobalt acetylacetonate at 65oC for 72 hrs. The epoxidised liquid natural rubber was prepared from thereaction of LNR with formic acid and hydrogen peroxide at 50oC for 6 hrs. The reaction of epoxidised liquid natural rubber with 2,4-D or MCPA using triethylamine as a catalyst in toluene was performed at 70, 80, and 90oC for 6, 9, 12, 18, and 24hrs. The polymeric herbicides obtained were characterized and the grafting percentage of 2,4-D or MCPA onto liquid natural rubber were also determined by FT-IR and 1H-NMR spectroscopy. It was found that the grafting percentage increased with increasing amount of reactants, temperature, and reaction time. The release of 2,4-D and MCPA from polymeric herbicides was investigated in pH 6, 7, and 8 buffers at room temperature. The results show that the slowest release of 2,4-D and MCPA was found to be constant at pH 7 for 14 and 10 days, respectively.

  5. Zinc oxide films impurified with Ti and prepared by the Sol-gel method

    Titanium-doped zinc oxide thin films have been prepared on silicon substrate using the Sol-Gel technique. The structural, morphology, electrical and optical properties of such thin films were studied as a function of titanium concentration (0.5, 1 and 1.5 %) and the thin films thickness. Zinc acetate dihydrate and titanium (VI)-oxy acetylacetonate were used as precursor materials, using 2-methoxyethanol and monoethanolamine as via. The X-ray diffraction spectra show polycrystalline films in all the cases. It can see for all the thin films a preferential growth along the (002) planes where the titanium concentration and also the thin films thickness play an important rule. No structural changes are observed at all. The surface morphology studied shows as the grain size decreases when thin thickness is increases. For titanium concentration of 0.5, 1 and 1.5 % values the grains size increase also. The thin films thickness for titanium concentration of 1.5 % was 500 nm (4v), 400 nm (3v), 180 nm (2v) and 130 nm (1v), values obtained from cross-section micrographs. Highly resistive samples are obtained for substrate soda-lime even showing high transmittance. Better physical properties are required for gas sensors or semitransparent electrodes and other possible applications. (Author)

  6. Study of immobilized catalysts--1. Magnetic properties and X-ray photoelectron (PHE) spectra of cobalt complexes immobilized on polymeric supports

    Ivleva, I.N.; Pomogailo, A.D.; Echmaev, S.B.; Ioffe, M.S.; Golubeva, N.D.; Borodko, Y.G.

    1979-10-01

    Polyethylene (PE) or polypropylene supports modified by organic ligands, including polyacrylic acid, poly-4-vinyl-pyridine (PVP), or polyvinylimidazole, grafted (gr) by the gas-phase radiation polymerization technique were treated by cobalt(II) chloride or acetylacetonate in ethanol at 50/sup 0/C to contain 0.7-2.76% by wt cobalt. X-ray PHE spectra and magnetic moment measurements on all the samples suggested that the immobilization of Co(II) compounds on the modified polymeric surfaces did not change the valent state of Co, which was present as paramagnetic Co(II) complexes with tetrahedral ligand coordination. The catalytic activity of the PE/gr(PVP-CoCl/sub 2/)+Al(C/sub 2/H/sub 5/)/sub 2/Cl Ziegler systems in isoprene polymerization depended on the order of component addition. In the absence of isoprene, Al(C/sub 2/H/sub 5/)/sub 2/Cl reduces Co(II) to the catalytically active diamagnetic Co(I) and the inactive ferromagnetic Co(0) formed at 1:1. Treatment of the PE/gr(PVP-CoCl/sub 2/) system with isoprene before adding Al(C/sub 2/H/sub 5/)/sub 2/Cl produced a much more active catalytic system that contained mainly diamagnetic Co(I). Apparently, isoprene forms an intermediate m-complex with the immobilized PVP-CoCl/sub 2/, which is then reduced to the active Co(I) species.

  7. Synthesis, crystal structure and thermal decomposition of [La2(CH3CH2COO)6.(H2O)3].3.5H2O precursor for high-k La2O3 thin films deposition

    Lanthanum acetylacetonate La(C5H7O2)3.xH2O has been used in the preparation of the precursor solution for the deposition of polycrystalline La2O3 thin films on Si(1 1 1) single crystalline substrates. The precursor chemistry of the as-prepared coating solution, precursor powder and precursor single crystal have been investigated by Fourier Transformed Infrared Spectroscopy (FTIR), differential thermal analysis coupled with quadrupole mass spectrometry (TG-DTA-QMS) and X-ray diffraction. The FTIR and X-ray diffraction analyses have revealed the complex nature of the coating solution due to the formation of a lanthanum propionate complex. The La2O3 thin films deposited by spin coating on Si(1 1 1) substrate exhibit good morphological and structural properties. The films heat treated at 800 oC crystallize in a hexagonal phase with the lattice parameters a = 3,89 A and c = 6.33 A, while at 900 oC the films contain both the hexagonal and cubic La2O3 phase.

  8. Facile synthesis of palladium nanoparticles supported on multi-walled carbon nanotube for efficient hydrogenation of biomass-derived levulinic acid

    Different loading of palladium (Pd) nanoparticles were successfully fabricated on multi-walled carbon nanotubes using Pd acetylacetonate as the precursor via a simple liquid impregnation method. The crystal phase, morphology, textural structure and the chemical state of the resulting Pd nanoparticles (Pd/CNT) catalysts were studied and the characterization results indicated that the uniform dispersion of small Pd nanoparticles with the size range of 1.0–4.5 nm was achieved. The synthesized Pd/CNT catalysts exhibited efficient performance for the catalytic hydrogenation of biomass-derived levulinic acid into biofuel γ-valerolactone. In comparison with the commercial 5 wt% Pd/C and the 5 wt% Pd/CNT catalyst prepared by Pd nitrate precursor, much higher activities were achieved, whereas the biofuel γ-valerolactone was highly produced with 56.3 % yield at 57.6 % conversion of levulinic acid on the 5 wt% Pd/CNT catalyst under mild conditions. The catalyst developed in this work may be a good candidate for the wide applications in the hydrogenation

  9. Effects of the addition of H{sub 2}O and NH{sub 4}OH in the optical and structural properties of the thin films of Y{sub 2}O{sub 3} deposited by pyrolytic spray; Efectos de la adicion de H{sub 2}O y NH{sub 4}OH en las propiedades opticas y estructurales de las peliculas delgadas de Y{sub 2}O{sub 3} depositadas por rocio pirolitico

    Alarcon F, G.; Carvajal V, R.; Aguilar F, M. [CICATA-IPN, Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico); Falcony, C. [CINVESTAV, A.P. 14-740, 07000 Mexico D.F. (Mexico)] [and others

    2005-07-01

    In this work we studied the optical and structural properties of yttrium oxide thin films deposited by spray pyrolysis. Yttrium acetylacetonate was used as raw material and N, N-DMF was used as solvent. The films were deposited on Si (100) and Si (111) substrates at temperatures of 400, 450, 500 and 550 C. The optical and structural characteristics of the films were dramatically improved when a mist of H{sub 2}O and/or NH{sub 4}0H was simultaneously added during deposition of the films. A refraction index up to 1.88, and deposition rates lower than 10 A/sec were obtained in the films. Infrared spectroscopy measurements indicate that the films resulted free from -OH bonds. X-ray diffraction patterns reveal that the films were polycrystalline. In addition, the relative chemical composition of the films was determined by Energy Dispersive Spectroscopy and the surface morphology was analyzed in the Atomic Force Microscope. (Author)

  10. Zinc oxide films impurified with Ti and prepared by the Sol-gel method; Peliculas de oxido de zinc impurificadas con Ti y preparadas por el metodo Sol-gel

    Tirado G, S. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Cazares R, J.M.; Maldonado, A. [CINVESTAV-IPN, A.P. 14-740, 07000 Mexico D.F. (Mexico)

    2006-07-01

    Titanium-doped zinc oxide thin films have been prepared on silicon substrate using the Sol-Gel technique. The structural, morphology, electrical and optical properties of such thin films were studied as a function of titanium concentration (0.5, 1 and 1.5 %) and the thin films thickness. Zinc acetate dihydrate and titanium (VI)-oxy acetylacetonate were used as precursor materials, using 2-methoxyethanol and monoethanolamine as via. The X-ray diffraction spectra show polycrystalline films in all the cases. It can see for all the thin films a preferential growth along the (002) planes where the titanium concentration and also the thin films thickness play an important rule. No structural changes are observed at all. The surface morphology studied shows as the grain size decreases when thin thickness is increases. For titanium concentration of 0.5, 1 and 1.5 % values the grains size increase also. The thin films thickness for titanium concentration of 1.5 % was 500 nm (4v), 400 nm (3v), 180 nm (2v) and 130 nm (1v), values obtained from cross-section micrographs. Highly resistive samples are obtained for substrate soda-lime even showing high transmittance. Better physical properties are required for gas sensors or semitransparent electrodes and other possible applications. (Author)

  11. Combustion synthesized indium-tin-oxide (ITO) thin film for source/drain electrodes in all solution-processed oxide thin-film transistors

    Tue, Phan Trong; Inoue, Satoshi; Takamura, Yuzuru; Shimoda, Tatsuya

    2016-06-01

    We report combustion solution synthesized (SCS) indium-tin-oxide (ITO) thin film, which is a well-known transparent conductive oxide, for source/drain (S/D) electrodes in solution-processed amorphous zirconium-indium-zinc-oxide TFT. A redox-based combustion synthetic approach is applied to ITO thin film using acetylacetone as a fuel and metal nitrate as oxidizer. The structural and electrical properties of SCS-ITO precursor solution and thin films were systematically investigated with changes in tin concentration, indium metal precursors, and annealing conditions such as temperature, time, and ambient. It was found that at optimal conditions the SCS-ITO thin film exhibited high crystalline quality, atomically smooth surface (RMS ~ 4.1 Å), and low electrical resistivity (4.2 × 10-4 Ω cm). The TFT using SCS-ITO film as the S/D electrodes showed excellent electrical properties with negligible hysteresis. The obtained "on/off" current ratio, subthreshold swing factor, subthreshold voltage, and field-effect mobility were 5 × 107, 0.43 V/decade, 0.7 V, and 2.1 cm2/V s, respectively. The performance and stability of the SCS-ITO TFT are comparable to those of the sputtered-ITO TFT, emphasizing that the SCS-ITO film is a promising candidate for totally solution-processed oxide TFTs.

  12. Design of a compact ultrahigh vacuum-compatible setup for the analysis of chemical vapor deposition processes

    Optimizing thin film deposition techniques requires contamination-free transfer from the reactor into an ultrahigh vacuum (UHV) chamber for surface science analysis. A very compact, multifunctional Chemical Vapor Deposition (CVD) reactor for direct attachment to any typical UHV system for thin film analysis was designed and built. Besides compactness, fast, easy, and at the same time ultimately clean sample transfer between reactor and UHV was a major goal. It was achieved by a combination of sample manipulation parts, sample heater, and a shutter mechanism designed to fit all into a NW38 Conflat six-ways cross. The present reactor design is versatile to be employed for all commonly employed variants of CVD, including Atomic Layer Deposition. A demonstration of the functionality of the system is provided. First results of the setup (attached to an Omicron Multiprobe x-ray photoelectron spectroscopy system) on the temperature dependence of Pulsed Spray Evaporation-CVD of Ni films from Ni acetylacetonate as the precursor demonstrate the reactor performance and illustrate the importance of clean sample transfer without breaking vacuum in order to obtain unambiguous results on the quality of CVD-grown thin Ni films. The widely applicable design holds promise for future systematic studies of the fundamental processes during chemical vapor deposition or atomic layer deposition

  13. Design of a compact ultrahigh vacuum-compatible setup for the analysis of chemical vapor deposition processes

    Weiss, Theodor; Nowak, Martin; Mundloch, Udo; Zielasek, Volkmar; Kohse-Höinghaus, Katharina; Bäumer, Marcus

    2014-10-01

    Optimizing thin film deposition techniques requires contamination-free transfer from the reactor into an ultrahigh vacuum (UHV) chamber for surface science analysis. A very compact, multifunctional Chemical Vapor Deposition (CVD) reactor for direct attachment to any typical UHV system for thin film analysis was designed and built. Besides compactness, fast, easy, and at the same time ultimately clean sample transfer between reactor and UHV was a major goal. It was achieved by a combination of sample manipulation parts, sample heater, and a shutter mechanism designed to fit all into a NW38 Conflat six-ways cross. The present reactor design is versatile to be employed for all commonly employed variants of CVD, including Atomic Layer Deposition. A demonstration of the functionality of the system is provided. First results of the setup (attached to an Omicron Multiprobe x-ray photoelectron spectroscopy system) on the temperature dependence of Pulsed Spray Evaporation-CVD of Ni films from Ni acetylacetonate as the precursor demonstrate the reactor performance and illustrate the importance of clean sample transfer without breaking vacuum in order to obtain unambiguous results on the quality of CVD-grown thin Ni films. The widely applicable design holds promise for future systematic studies of the fundamental processes during chemical vapor deposition or atomic layer deposition.

  14. Preparation and Characterization of TiO2/CdS Layers as Potential Photoelectrocatalytic Materials

    Teofil-Danut Silipas

    2011-01-01

    Full Text Available The TiO2/CdS semiconductor composites were prepared on
    indium tin oxide (ITO substrates in di®erent mass proportions via wet-chemical techniques using bi-distilled water, acetyl-acetone, poly-propylene-glycol and Triton X-100 as additives. The composite layers were annealed in normal conditions at the temperature of 450±C, 120 min. with a rate of temperature increasing of 5±C/min. The structural and optical properties of all the TiO2/CdS ayers were characterized by X-ray di®raction, UV-VIS spectroscopy, spectrofluorimetry and FT/IR microscopy. The microstructural properties of the deposited TiO2/CdS layers can be modi¯ed by varying the mass proportions of TiO2:CdS. The good crystallinity level and the high optical adsorption of
    the TiO2/CdS layers make them attractive for photoelectrochemical cell applications.

  15. Integration of atomic layer deposition-grown copper for advanced interconnect applications

    Wu, Liqi

    While copper damascene processes currently utilize physically vapor deposited (PVD) Cu seed layers, the continued scaling of interconnect feature sizes in advanced nanoelectronic devices requires the development of a more conformal, controllable Cu seed layer technology for use with electrochemically deposited (ECD) copper interconnects. Atomic layer deposition (ALD) is a promising alternative because of its excellent conformality and precise thickness control capability. In this research, a self-limiting plasma-enhanced ALD (PEALD) Cu process, employing Cu(II) acetylacetonate (Cu(acac)2) and atomic hydrogen, was employed to deposit high quality PEALD Cu films. In addition, substrate surface hydrogen plasma treatments prior to PEALD Cu growth were observed to enhance Cu nucleation, decrease Cu surface roughness, and reduce Cu resistivity. The performance characteristics of ECD/PEALD-grown Cu interconnects were compared with those of a conventional ECD/PVD Cu stack. Finally, void-free electroplated Cu was demonstrated on 60 and 35 nm patterned via structures using both ALD Ru/TaN and conventional PVD Ta/TaN liner/barrier structures coupled with PEALD Cu seed layers. The film properties and resulting integration characteristics suggest that PEALD Cu is a promising approach for advanced seed layer applications in CMOS metallization.

  16. New approach towards the polyol route to fabricate MFe2O4 magnetic nanoparticles: The use of MCl2 and Fe(acac)3 as chemical precursors

    Solano, Eduardo; Yáñez, Ramón; Ricart, Susagna; Ros, Josep

    2015-05-01

    A new more efficient approach of the polyol route to generate MFe2O4 (M=Mn, Fe, Co, Ni, Cu, Zn) nanoparticles in triethylene glycol (TREG) is presented. The selected thermal procedure is based on the Fe metalorganic precursor (iron(III) acetylacetonate) decomposition in presence of an inorganic transition metal chloride salt (MCl2, M=Mn, Fe, Co, Ni, Cu, Zn) to produce high quality polar dispersible nanoparticles with lower production cost. In addition, the nanoparticles are stabilized by ionic (from the Cl-) and steric (TREG as capping ligand) effects inducing into the nanoparticles an extraordinary stability in different polar solvents. As result of this optimized methodology, the colloidal polar dispersible nanoparticles present a size around 10 nm with an adequate size dispersion demonstrated by analyzing transmission electron microscopy (TEM) images. X-ray powder diffraction (XRPD) results corroborate the absence of secondary phases and the high crystalline degree obtained for the spinel structure, fact proved by using synchrotron X-ray diffraction. The high magnetic performance at low and room temperature of the nanoparticles studied by magnetometry proves the high internal crystal order of the spinel. Parallel to this, the influence of the heating ramp and annealing time in the thermal procedure were also investigated for the CuFe2O4 case, where a relationship between these two parameters and the final size and their associated diameter distribution was found, allowing a possible size control of the final ferrite magnetic nanoparticles synthesized.

  17. TREG coated iron oxide nanoparticles as contrast agent for MRI in-vivo use

    Gutierrez-Garcia, Eric; Hidalgo-Tobon, Silvia; Lopez, Ciro; Gonzalez-Rodriguez, Roberto; Coffer, Jeffery; De Celis Alonso, Benito; Dies Suarez, Pilar; Obregon, Manuel; Perez-Pena, Mario; Platas-Neri, Diana; Mendez-Rojas, Miguel

    2014-11-01

    Super-paramagnetic iron oxide nanoparticles (SPIONs) are of interest due to their great potential applications in diverse fields such as biomedicine. In this work we have prepared SPION nanoparticles using the polyol technique and characterized the magnetic properties of them for MRI in-vivo use. Nanoparticle preparation: All reagents were purchased from commercial sources (Sigma-Aldrich, St. Louis, USA) Iron (III) acetylacetonate, [Fe(acac)3], was used as the iron oxide precursor and thermally decomposed at high temperatures in triethyleneglycol (TREG). Nano-sized magnetite particles were prepared by an adaptation of the method proposed by Wei Cai et al[1-3]. A healthy rabbit was scanned on a clinical 1.5 T Philips MR scanner. Images were taken in 2D mode with a mFFE sequence. Relaxation time T2 was obtained from the MR images using a Matlab algorithm where the signal intensity decay was calculated at each image and then adjusted to a mono-exponential curve. Images were obtained before contrast injection, 24 hours and 36 hours following SPIONs administration. Signal decay at different Echo times for the prepared magnetic SPIONs, before and after contrast injection was measured. It was visualized a concentration of the agent contrast in brain and liver and the results were compared with images obtained from histopathology.

  18. Effect of Counterion on the Solvatochromic Properties of Heteroleptic Chelate Copper(II Complexes

    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.

  19. Combined sol–gel and carbothermal synthesis of ZrC–TiC powders for composites

    Umalas, Madis [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia); Estonian Nanotechnology Competence Centre, Riia 142, 51014, Tartu (Estonia); Hussainova, Irina, E-mail: irina.hussainova@ttu.ee [Department of Materials Engineering, Tallinn University of Technology, Ehitajate 5, 19086, Tallinn (Estonia); ITMO University, Kronverksky 49, St. Petersburg, 197101 (Russian Federation); Reedo, Valter [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia); Young, Der-Liang [Department of Materials Engineering, Tallinn University of Technology, Ehitajate 5, 19086, Tallinn (Estonia); Cura, Erkin; Hannula, Simo-Pekka [Department of Materials Science and Engineering, Aalto University, School of Chemical Technology, POB 16200, Aalto, 00076 (Finland); Lõhmus, Rünno [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia); Estonian Nanotechnology Competence Centre, Riia 142, 51014, Tartu (Estonia); Lõhmus, Ants [Institute of Physics, University of Tartu, Riia 142, 51014, Tartu (Estonia)

    2015-03-01

    The TiC–ZrC binary compound of nanostructured powders was synthesised by combination of sol–gel and carbothermal reduction. The polymeric precursor of the blend was produced by sol–gel process from titanium tetrabutoxide, zirconium tetrabutoxide and benzene-1.4-diol; then carbothermally reduced to the TiC–ZrC blend at 1600 °C in an inert environment. The chemical reactions occurring in the system were monitored by infrared spectrometry. Stable alkoxide solution was obtained by adding acetylacetone to avoid premature gelation of the metal alkoxide mixture. A solid solution of ZrTiC{sub 2} was produced by spark plasma sintering at temperature of 2000 °C. - Highlights: • A polymeric precursor of TiC–ZrC blend was synthesised by sol–gel process. • The polymeric precursor synthesis was studied by infrared spectroscopy. • TiC–ZrC powder blend was carbothermally reduced from polymeric precursor. • TiC–ZrC powder blend was sintered to ZrTiC{sub 2} solid solution by spark plasma sintering. • Sintered ZrTiC{sub 2} have good mechanical properties.

  20. Enhanced efficiency in single-host white organic light-emitting diode by triplet exciton conversion

    The authors observe that the external quantum efficiency (EQE) of the Iridium (III) bis(4-phenylthieno [3,2-c]pyridinato-N,C2′)acetylacetonate (PO-01) based yellow organic light-emitting diode (OLED) is significantly increased by uniformly co-doping Iridium (III)bis[(4,6-difluorophenyl)-pyridinato-N,C2−] (FIrpic) and PO-01 into the same wide band-gap host of N,N′-dicarbazolyl-3, 5-benzene (mCP). Detailed investigation indicates that the efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. Compared to the control device, which has maximum EQE of 10.5%, an improved maximum EQE of 13.2% is obtained in the optimization white device based on FIrpic and PO-01 emission according to this principle. This work makes it easier for a single host white OLED to simultaneously harvest high efficiency in both blue and yellow units. Comprehensive experimental results show that this phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices. -- Highlights: • This work makes easier for a single host white OLED to harvest high efficiency in both blue and yellow units. • Efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. • This phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices

  1. Efficient triplet exciton confinement of white organic light-emitting diodes using a heavily doped phosphorescent blue emitter

    We demonstrated efficient white electrophosphorescence with a heavily doped phosphorescent blue emitter and a triplet exciton blocking layer (TEBL) inserted between the hole transporting layer (HTL) and the emitting layer (EML). We fabricated white organic light-emitting diodes (WOLEDs) (devices A, B, C, and D) using a phosphorescent red emitter; bis(2-phenylquinolinato)-acetylacetonate iridium III (Ir(pq)2acac) doped in the host material; N,N'-dicarbazolyl-3,5-benzene (mCP) as the red EML and the phosphorescent blue emitter; bis(3,5-Difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) doped in the host material; p-bis(triphenylsilyly)benzene (UGH2) as the blue EML. The properties of device B, which demonstrate a maximum luminous efficiency and external quantum efficiency of 26.83 cd/A and 14.0%, respectively, were found to be superior to the other WOLED devices. It also showed white emission with CIEx,y coordinates of (x = 0.35, y = 0.35) at 8 V. Device D, which has a layer of P-type 4,4',4''-tri(N-carbazolyl)triphenylamine (TCTA) material between the HTL and TEBL, was compared with device A to determine the 430 nm emission peak.

  2. Pt-free carbon-based fuel cell catalyst prepared from spherical polyimide for enhanced oxygen diffusion

    Nabae, Yuta; Nagata, Shinsuke; Hayakawa, Teruaki; Niwa, Hideharu; Harada, Yoshihisa; Oshima, Masaharu; Isoda, Ayano; Matsunaga, Atsushi; Tanaka, Kazuhisa; Aoki, Tsutomu

    2016-03-01

    The development of a non-precious metal (NPM) fuel cell catalyst is extremely important to achieve globalization of polymer electrolyte fuel cells due to the cost and scarcity of platinum. Here, we report on a NPM cathode catalyst prepared by the pyrolysis of spherical polyimide nanoparticles that contain small amounts of Fe additive. 60 nm diameter Fe-containing polyimide nanoparticles were successfully synthesized by the precipitation polymerization of pyromellitic acid dianhydride and 1,3,5-tris(4-aminophenyl)benzene with Fe(acac)3 (acac = acetylacetonate) as an additive. The particles were subsequently carbonized by multistep pyrolysis to obtain the NPM catalyst while retaining the small particle size. The catalyst has good performance and promising durability for fuel cell applications. The fuel cell performance under a 0.2 MPa air atmosphere at 80 °C of 1.0 A cm‑2 at 0.46 V is especially remarkable and better than that previously reported.

  3. Towards Clarifying the Role of O2 during the Phthalocyanine Synthesis.

    Wang, Kang; Pan, Houhe; Jiang, Jianzhuang

    2015-12-01

    The role of O2 within the synthesis of phthalocyanines (Pcs) has remained unclear in the past century. Here, we demonstrate that O2 , in cooperation with the solvent n-pentanol, participates in the cyclic tetramerization of phthalonitriles over the half-sandwich complex template [Lu(Pc)(acac)] (acac=acetylacetonate) and terminates the reaction at the stage of uncyclized isoindole oligomeric derivatives rather than the phthalocyanine chromophores, resulting in the isolation of the heteroleptic (phthalocyaninato)(triisoindole-1-one) lutetium double-decker complexes [(Pc)Lu(TIO-I)] (TIO-I=3,4,7,8,11,12-sexi(2,6-diisopropylphenoxy)-15-[4,5-di(2,6-diisopropylphenoxy)-2-cyanobenzimidamido]triisoindole-1-one) and [(Pc)Lu(TIO-II)] (TIO-II=3,4,7,8,11,12-sexi(2,6-dimethylphenoxy)-15-[4,5-di(2,6-dimethylphenoxy)-2-cyanobenzimidamido]triisoindole-1-one) with the help of bulky substituents at the phthalonitrile periphery and an unsubstituted phthalocyanine ligand in the double-decker skeleton. Nevertheless, the cyclic tetramerization of the phthalonitriles was revealed to be sensitive to O2 with the reaction progression also depending on the oxygen concentration/content, leading to the O2 -senstive and -dependent nature for the isolation of phthalocyanine derivatives. PMID:26526528

  4. Simultaneous observation of low temperature 4f-4f and 3d-3d emission spectra in a series of Cr(III)(ox)Ln(III) assembly

    Subhan, M A; Suzuki, T; Choi, J H; Kaizaki, S

    2003-01-01

    We report here the low temperature emission spectra in the heterometal dinuclear 3d-4f assembled molecular system [(acac) sub 2 Cr sup I sup I sup I (mu-ox)Ln sup I sup I sup I (HBpz sub 3) sub 2] (Cr(ox)Ln:acac sup - =acetylacetonate, ox sup 2 sup - =oxalate, HBpz sub 3 sup - =hydrotris(pyrazol-1-yl)borate; Ln=La, Nd, Ho, Er , Tm and Yb) in comparison with those of Na[Cr(acac) sub 2 (ox)] and [(HBpz sub 3) sub 2 Ln(mu-ox)Ln(HBpz sub 3) sub 2](Ln=Nd and Er). From 10 to 150 K the Cr(ox)Ln complexes show a broad emission band around 800 nm from the sup 2 E state of Cr(III) moiety. At room temperature no sup 2 E- sup 4 A sub 2 emission was observed in the Cr(ox)Ln except for the La and Lu complexes. On warming from 10 to 300 K rapid quenching of the sup 2 E- sup 4 A sub 2 emission of Cr(III) is suggested to result from the energy transfer from Cr to Ln in the Cr(ox)Ln. The excitation spectra and the life-time were also measured with monitoring the 4f-4f emission peaks of the Cr(ox)Yb complex.

  5. Multi-Directional Growth of Aligned Carbon Nanotubes Over Catalyst Film Prepared by Atomic Layer Deposition

    Zhou Kai

    2010-01-01

    Full Text Available Abstract The structure of vertically aligned carbon nanotubes (CNTs severely depends on the properties of pre-prepared catalyst films. Aiming for the preparation of precisely controlled catalyst film, atomic layer deposition (ALD was employed to deposit uniform Fe2O3 film for the growth of CNT arrays on planar substrate surfaces as well as the curved ones. Iron acetylacetonate and ozone were introduced into the reactor alternately as precursors to realize the formation of catalyst films. By varying the deposition cycles, uniform and smooth Fe2O3 catalyst films with different thicknesses were obtained on Si/SiO2 substrate, which supported the growth of highly oriented few-walled CNT arrays. Utilizing the advantage of ALD process in coating non-planar surfaces, uniform catalyst films can also be successfully deposited onto quartz fibers. Aligned few-walled CNTs can be grafted on the quartz fibers, and they self-organized into a leaf-shaped structure due to the curved surface morphology. The growth of aligned CNTs on non-planar surfaces holds promise in constructing hierarchical CNT architectures in future.

  6. Metal-organic chemical vapour deposition of lithium manganese oxide thin films via single solid source precursor

    Oyedotun K.O.

    2015-12-01

    Full Text Available Lithium manganese oxide thin films were deposited on sodalime glass substrates by metal organic chemical vapour deposition (MOCVD technique. The films were prepared by pyrolysis of lithium manganese acetylacetonate precursor at a temperature of 420 °C with a flow rate of 2.5 dm3/min for two-hour deposition period. Rutherford backscattering spectroscopy (RBS, UV-Vis spectrophotometry, X-ray diffraction (XRD spectroscopy, atomic force microscopy (AFM and van der Pauw four point probe method were used for characterizations of the film samples. RBS studies of the films revealed fair thickness of 1112.311 (1015 atoms/cm2 and effective stoichiometric relationship of Li0.47Mn0.27O0.26. The films exhibited relatively high transmission (50 % T in the visible and NIR range, with the bandgap energy of 2.55 eV. Broad and diffused X-ray diffraction patterns obtained showed that the film was amorphous in nature, while microstructural studies indicated dense and uniformly distributed layer across the substrate. Resistivity value of 4.9 Ω·cm was obtained for the thin film. Compared with Mn0.2O0.8 thin film, a significant lattice absorption edge shift was observed in the Li0.47Mn0.27O0.26 film.

  7. Fabrication of copper nanorods by low-temperature metal organic chemical vapor deposition

    ZHANG Ying; Frank Leung-Yuk Lam; HU Xijun; YAN Zifeng

    2006-01-01

    Copper nanorods have been synthesized in mesoporous SBA-15 by a low-temperature metal organic chemical vapor deposition (MOCVD)employing copper (Ⅱ) acetylacetonate, Cu(acac)2,and hydrogen as a precursor and reactant gas, respectively. The hydrogen plays an important role in chemical reduction of oganometallic precursor which enhances mass transfer in the interior of the SBA-15 porous substrate. Such copper nanostructures are of great potentials in the semiconductor due to their unusual optical, magnetic and electronic properties.In addition, it has been found that chemically modifying the substrate surface by carbon deposition is crucial to such synthesis of copper nanostructures in the interior of the SBA-15, which is able to change the surface properties of SBA-15 from hydrophilic to hydrophobic to promote the adsorption of organic cupric precursor. It has also been found that the copper nanoparticles deposited on the external surface are almost eliminated and the copper nanorods are more distinct while the product was treated with ammonia. This approach could be achieved under a mild condition: a low temperature (400℃) and vacuum (2 kPa) which is extremely milder than the conventional method. It actually sounds as a foundation which is the first time to synthesize a copper nanorod at a mild condition of a low reaction temperature and pressure.

  8. Microstructure, optical and optoelectrical properties of mesoporous nc-TiO2 films by hydrolysis-limited sol-gel process with different inhibitors

    Mesoporous nanocrystalline titania (nc-TiO2) films were synthesized by sol-gel route using poly (alkylene oxide) block copolymer as template and tetrabutyl orthotitanate as titanium source. Influence of acetylacetone (AcAc), glacial acetic acid, HCl and AcAc-HCl as inhibitors on hydrolysis/condensation reaction was investigated. The mesopore structure, crystalline phase and optical characteristics were analyzed by N2 adsorption, X-ray diffraction, transmission electron microscopy and UV-VIS-NIR spectrum. Photoaction measurements were performed on dye-sensitized solar cells (DSSCs) using the mesoporous nc-TiO2 as photoanodes. The results show that the formed films are anatase phase and mesoporous structure. Different restraining mechanisms of these inhibitors to hydrolysis/condensation process lead to different mesoporous structure whose specific surface area (SBET) varies from 34 to 176 m2/g, and crystal size is from 5.6 to 38.2 nm. The mesoporous photoanode with high SBET and large crystalline grains may be responsible for increasing conversion efficiency of the DSSCs.

  9. Effect of humidity and UV-assistance on the preparation of erbium doped alumina by aerosol MOCVD process

    Salhi, Rached, E-mail: salhi_rached@yahoo.fr [Laboratoire des Materiaux et du Genie Physique, CNRS UMR 5628, INP Grenoble-Minatec, 3 parvis Louis Neel BP 257, 38 016 Grenoble Cedex 1 (France); Laboratoire de chimie industrielle, Ecole Nationale d' Ingenieur de Sfax, University of Sfax BP W 3038 Sfax (Tunisia); Jimenez, Carmen; Chaudoueet, Patrick [Laboratoire des Materiaux et du Genie Physique, CNRS UMR 5628, INP Grenoble-Minatec, 3 parvis Louis Neel BP 257, 38 016 Grenoble Cedex 1 (France); Maalej, Ramzi [Laboratoire de Physique Appliquee, Departement de Physique, Faculte des Sciences de Sfax, University of Sfax, 3018 Sfax (Tunisia); Fourati, Mohieddine; Deschanvres, Jean-Luc [Laboratoire des Materiaux et du Genie Physique, CNRS UMR 5628, INP Grenoble-Minatec, 3 parvis Louis Neel BP 257, 38 016 Grenoble Cedex 1 (France)

    2012-01-15

    The effect of deposition temperature, relative humidity of carrier gas and UV-assistance on the growth of Erbium-doped aluminium oxide films has been studied. The films were prepared from aluminium acetylacetonate (Al(C{sub 5}H{sub 7}O{sub 2}){sub 3}) and erbium (III) Tris(2,2,6,6-tetramethyl-3,5-heptanedionate) (Er(TMHD){sub 3}) by UV and aerosol-assisted metal-organic chemical vapour deposition, using air with controlled humidity as carrier gas. Amorphous transparent films were deposited between 350 and 460 Degree-Sign C. It was observed that UV assistance allows a large decrease down to 5 kJ/mol of the activation energy of the deposition reaction for deposition temperatures lower than 420 Degree-Sign C. More over, depositing under high air humidity induced higher deposition rate, lower level of organic contamination and higher film density. Under these conditions Er-doped aluminium oxide films with a refractive index value of 1.71 were obtained at 460 Degree-Sign C.

  10. A study of Cu/ZnO/Al2O3 methanol catalysts prepared by flame combustion synthesis

    Jensen, Joakim Reimer; Johannessen, Tue; Wedel, Stig;

    2003-01-01

    examined by X-ray powder diffraction, determination of the specific surface area by the BET-method, determination of the copper dispersion in the reduced catalyst by a novel N2O-method, by transmission electron microscopy, and by test of the catalytic properties in a catalytic micro-reactor. A low peak......The flame combustion synthesis of Cu/ZnO/Al2O3 catalysts for the synthesis of methanol from CO, CO2 and H2 is investigated. The oxides are generated in a premixed flame from the acetyl-acetonate vapours of Cu, Zn and Al mixed with the fuel and air prior to combustion. The flame-generated powder is...... is used in the assessment of the phase composition of the particles. The specific surface area varies from 100 m2/g or a little below for samples without Al to several hundred m2/g for the respective compositions of pure Al2O3 and ZnAl2O4. Copper dispersion after reduction varies from 1.8 to 14...

  11. Secondary brown carbon formation via the dicarbonyl imine pathway: nitrogen heterocycle formation and synergistic effects.

    Kampf, C J; Filippi, A; Zuth, C; Hoffmann, T; Opatz, T

    2016-07-21

    Dicarbonyls are known to be important precursors of so-called atmospheric brown carbon, significantly affecting aerosol optical properties and radiative forcing. In this systematic study we report the formation of light-absorbing nitrogen containing compounds from simple 1,2-, 1,3-, 1,4-, and 1,5-dicarbonyl + amine reactions. A combination of spectrophotometric and mass spectrometric techniques was used to characterize reaction products in solutions mimicking atmospheric particulates. Experiments with individual dicarbonyls and dicarbonyl mixtures in ammonium sulfate and glycine solutions demonstrate that nitrogen heterocycles are common structural motifs of brown carbon chromophores formed in such reaction systems. 1,4- and 1,5-dicarbonyl reaction systems, which were used as surrogates for terpene ozonolysis products, showed rapid formation of light-absorbing material and products with absorbance maxima at ∼450 nm. Synergistic effects on absorbance properties were observed in mixed (di-)carbonyl experiments, as indicated by the formation of a strong absorber in ammonium sulfate solutions containing acetaldehyde and acetylacetone. This cross-reaction oligomer shows an absorbance maximum at 385 nm, relevant for the actinic flux region of the atmosphere. This study demonstrates the complexity of secondary brown carbon formation via the imine pathway and highlights that cross-reactions with synergistic effects have to be considered an important pathway for atmospheric BrC formation. PMID:27334793

  12. Production and characterization of 166Ho polylactic acid microspheres.

    Yavari, Kamal; Yeganeh, Ehsan; Abolghasemi, Hossein

    2016-01-01

    Microsphere and particle technology with selective transport of radiation represents a new generation of therapeutics. Poly-L-lactic acid (PLLA) microspheres loaded with holmium-166 acetylacetonate ((166)Ho-PLLA-MS) are novel microdevices. In this research, (165)HoAcAc-PLLA microparticles were prepared by the solvent evaporation technique. Microspheres were irradiated at Tehran Research Reactor. The diameter and surface morphologies were characterized by particle sizer and scanning electron microscopy before and after irradiation. The complex stability, radiochemical purity, and in vivo biodistribiotion were checked in the final solution up to 3 days. In this study, (166)Ho-PLLA spherical particles with a smooth surface and diameter of 20-40 µm were obtained, which were stable in vitro and in vivo studies. Neutron irradiation did not damage the particles. The ease with which the PLLA spheres could be made in the optimal size range for later irradiation and their ability to retain the (166)Ho provided good evidence for their potential use in radioembolization. PMID:26691104

  13. Preparation and electrochemical properties of RuO2-containing activated carbon nanofiber composites with hollow cores

    RuO2-containing activated carbon nanofibers with hollow cores (PMRu-ACNFs) are prepared through one-step electrospinning using polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), and ruthenium(III) acetylacetonate followed by thermal treatment. The porous PMRu-ACNF composites exhibit an improved morphological structure and textual properties due to the increased surface area, unique nanotexture, and presence of several functional groups such RuO2 in the ACNFs. Electrochemical measurements of PMRu-ACNF reveal a maximum specific capacitance of 180 Fg−1 and high energy densities of 20-14 Whkg−1 in the power density range of 400 to 10,000 W kg−1 in aqueous KOH electrolyte. In contrast, the ACNF electrodes show a lower specific capacitance and the energy density rapidly drops to 2 Whkg−1 at power densities of 4,000 Wkg−1. Therefore, the PMRu-ACNF composite electrodes may be more suitable as supercapacitors than regular ACNFs are, due to the synergistic effect between the electric double-layer capacitance of porous ACNFs and the pseudocapacitance of RuO2

  14. Carborane tuning on iridium complexes: redox-switchable second-order NLO responses.

    Wang, Jiao; Wang, Wen-Yong; Fang, Xin-Yan; Qiu, Yong-Qing

    2015-04-01

    Much effort has been devoted to investigating the molecular geometries, electronic structures, redox properties and nonlinear optical (NLO) properties of Ir complexes involving o-, m- or p-carborane groups by density functional theory (DFT) methods. Switchable second-order NLO properties were induced by redox processes involving these complexes, and it was found that mainly the coordination bonds of Ir complexes changed during the oxidation process. Our calculations revealed that oxidation reactions have a significant influence on the second-order NLO response owing to the change in charge transfer pattern. The β tot values of oxidized species are at least ∼9 times larger for set I and ∼5 times larger for set II than those of the corresponding parent complexes. Introduction of carborane groups into ppy (phenylpyridine) ligands can enhance the second-order NLO response by 1.2- 1.6 times by a metal-to-ligand charge transfer (MLCT) transition between the Ir atom and carborane. The β tot of complex 2 [(ppy)2Ir(phen)](+) (phen = phenanthroline) is 3.3 times larger than that of complex 1 (ppy)2Ir(acce) (acce = acetylacetonate), which is caused by ligand-to-ligand charge transfer (LLCT) between ppy ligands and the ancillary ligand. Therefore, it can be concluded that the second-order NLO response can be effectively enhanced by oxidation reactions. PMID:25791353

  15. Synthesis and characterization of thin films of Pd/TiO{sub 2} with possible applications in photo catalysis; Sintesis y caracterizacion de peliculas delgadas de Pd/TiO{sub 2} con posibles aplicaciones en fotocatalisis

    Tirado G, S. [IPN, Escuela Superior de Fisica y Matematicas, U. P. Adolfo Lopez Mateos Edif. 9, San Pedro Zacatenco, 07738 Mexico D. F. (Mexico); Valenzuela Z, M. A., E-mail: tirado@esfm.ipn.mx [IPN, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Laboratorio de Catalisis y Materiales, U. P. Adolfo Lopez Mateos Edif. 8, San Pedro Zacatenco, 07738 Mexico D. F. (Mexico)

    2015-10-15

    In this paper the synthesis and study of thin films of titanium oxide is reported, as well as those that were surface modified with palladium nanoparticles Pd/TiO{sub 2}. First, the TiO{sub 2} films are grown on substrates of soda-lime glass using chemical sol-gel route and the repeated immersion procedure. The salt precursor titanium oxy-acetylacetonate to 0.2 M, in the solvent 2-methoxyethanol and monoethanolamine was used as stabilizer. The number of used immersions gave an average thickness estimate for these films of 172.8 nm. Second, the series of Pd/TiO{sub 2} films surface modified were obtained from a solution of palladium nitrate dehydrate at low concentration, with the same procedure. The films grown TiO{sub 2} and those surface-modified films were characterized in its structure by X-ray diffraction, morphology by scanning electron microscopy, the topography with atomic force microscopy, optical properties by UV-Vis, among others. Photoluminescence properties and/or possible applications in photo catalysis are reported in this paper. (Author)

  16. Microspheres of polyester loaded with Holmium-165: effect of gamma irradiation on the polymeric structure

    Azevedo, Mariangela de Burgos M. de; Pires, Geovanna; Lira, Rafael A. de; Geraldes, Adriana N.; Nascimento, Nanci; Melo, Vitor Hugo Soares de, E-mail: mbmazevedo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Kodama, Yasko [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia

    2011-07-01

    Biodegradable polymers containing radioactive isotopes have potential applications as delivery vehicles of beta radiation to the cancer tumors by brachytherapy. 166-Ho is an example of such radioisotope emitting high-energy beta particles, and also its gamma rays allow nuclear imaging in everywhere is applied. Among the biodegradable polymers, different types of poly(lactide) have been investigated in our laboratory, and poly(L-lactide) (PLLA) was used as substrate to prepare microparticles loaded with holmium acetylacetonate HoAcAc (PLLA-HoAcAc-MP). The aim of this study was to evaluate the stability of these microparticles to gamma radiation. The PLLA-HoAcAc-MP were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP, and their stability studied out with gamma radiation of 25, 50 and 100 kGy doses. MP were characterized before and after irradiation by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and con focal laser scanning microscopy (CLSM). Preliminary results showed that gamma radiation did not damage morphologically the prepared PLLA-HoAcAc-MP in the dose range studied, and this procedure may be an important tool for knowing the stabilities of the polymers studied as MP for possible application in brachytherapy. (author)

  17. ZnO THIN FILMS PREPARED BY SPRAY-PYROLYSIS TECHNIQUE FROM ORGANO-METALLIC PRECURSOR

    Martin Mikulics

    2012-07-01

    Full Text Available Presented experiments utilize methanolic solution of zinc acetyl-acetonate as a precursor and sapphire (001 as a substrate for deposition of thin films of ZnO. The X-ray diffraction analysis revealed polycrystalline character of prepared films with preferential growth orientation along c-axis. The roughness of prepared films was assessed by AFM microscopy and represented by roughness root mean square (RMS value in range of 1.8 - 433 nm. The surface morphology was mapped by scanning electron microscopy showing periodical structure with several local defects. The optical transmittance spectrum of ZnO films was measured in wavelength range of 200-1000 nm. Prepared films are transparent in visible range with sharp ultra-violet cut-off at approximately 370 nm. Raman spectroscopy confirmed wurtzite structure and the presence of compressive stress within its structure as well as the occurrence of oxygen vacancies. The four-point Van der Pauw method was used to study the transport prosperities. The resistivity of presented ZnO films was found 8 × 10–2 Ω cm with carrier density of 1.3 × 1018 cm–3 and electron mobility of 40 cm2 V–1 s–1.

  18. Sensing Characteristics of Flame-Spray-Made Pt/ZnO Thick Films as H2 Gas Sensor

    Nittaya Tamaekong

    2009-08-01

    Full Text Available Hydrogen sensing of thick films of nanoparticles of pristine, 0.2, 1.0 and 2.0 atomic percentage of Pt concentration doped ZnO were investigated. ZnO nanoparticles doped with 0.2–2.0 at.% Pt were successfully produced in a single step by flame spray pyrolysis (FSP technique using zinc naphthenate and platinum(II acetylacetonate as precursors dissolved in xylene. The particle properties were analyzed by XRD, BET, SEM and TEM. Under the 5/5 (precursor/oxygen flame condition, ZnO nanoparticles and nanorods were observed. The crystallite sizes of ZnO spheroidal and hexagonal particles were found to be ranging from 5 to 20 nm while ZnO nanorods were seen to be 5–20 nm wide and 20–40 nm long. ZnO nanoparticles paste composed of ethyl cellulose and terpineol as binder and solvent respectively was coated on Al2O3 substrate interdigitated with gold electrodes to form thin films by spin coating technique. The thin film morphology was analyzed by SEM technique. The gas sensing properties toward hydrogen (H2 was found that the 0.2 at.% Pt/ZnO sensing film showed an optimum H2 sensitivity of ~164 at hydrogen concentration in air of 1 volume% at 300 °C and a low hydrogen detection limit of 50 ppm at 300 °C operating temperature.

  19. One-pot synthesis and self-assembly of colloidal copper(I) sulfide nanocrystals

    A simple one-pot method is developed to prepare size- and shape-controlled copper(I) sulfide (Cu2S) nanocrystals by thermolysis of a mixed solution of copper acetylacetonate, dodecanethiol and oleylamine at a relatively high temperature. The crystal structure, chemical composition and morphology of the as-obtained products are characterized by powder x-ray diffraction (PXRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The morphology and size of the Cu2S nanocrystals can be easily controlled by adjusting the reaction parameters. The Cu2S nanocrystals evolve from spherical to disk-like with increasing reaction temperature. The spherical Cu2S nanocrystals have a high tendency to self-assemble into close-packed superlattice structures. The shape of the Cu2S nanodisks changes from cylinder to hexagonal prism with prolonged reaction time, accompanied by the diameter and thickness increasing. More interestingly, the nanodisks are inclined to self-assemble into face-to-face stacking chains with different lengths and orientations. This one-pot approach may extend to synthesis of other metal sulfide nanocrystals with different shapes and sizes.

  20. One-pot synthesis and self-assembly of colloidal copper(I) sulfide nanocrystals

    Tang Aiwei; Qu Shengchun; Cao Jie; Wang Zhanguo [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Li Kai [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Hou Yanbing; Teng Feng; Wang Yongsheng, E-mail: qsc@semi.ac.cn, E-mail: fteng@bjtu.edu.cn [Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing JiaoTong University, Beijing 100044 (China)

    2010-07-16

    A simple one-pot method is developed to prepare size- and shape-controlled copper(I) sulfide (Cu{sub 2}S) nanocrystals by thermolysis of a mixed solution of copper acetylacetonate, dodecanethiol and oleylamine at a relatively high temperature. The crystal structure, chemical composition and morphology of the as-obtained products are characterized by powder x-ray diffraction (PXRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The morphology and size of the Cu{sub 2}S nanocrystals can be easily controlled by adjusting the reaction parameters. The Cu{sub 2}S nanocrystals evolve from spherical to disk-like with increasing reaction temperature. The spherical Cu{sub 2}S nanocrystals have a high tendency to self-assemble into close-packed superlattice structures. The shape of the Cu{sub 2}S nanodisks changes from cylinder to hexagonal prism with prolonged reaction time, accompanied by the diameter and thickness increasing. More interestingly, the nanodisks are inclined to self-assemble into face-to-face stacking chains with different lengths and orientations. This one-pot approach may extend to synthesis of other metal sulfide nanocrystals with different shapes and sizes.

  1. Metal organic chemical vapor deposition of environmental barrier coatings for the inhibition of solid deposit formation from heated jet fuel

    Mohan, Arun Ram

    for the deposition of metal and metal oxide functional coatings by MOCVD. Alumina was chosen as a candidate for metal oxide coating because of its thermal and phase stability. Platinum was chosen as a candidate to utilize the oxygen spillover process to maintain a self-cleaning surface by oxidizing the deposits formed during thermal stressing. Two metal organic precursors, aluminum trisecondary butoxide and aluminum acetylacetonate, were used as precursors to coat tubes of varying diameters. The morphology and uniformity of the coatings were characterized by electron microscopy and energy-dispersive x-ray spectroscopy. The coating was characterized by x-ray photoelectron spectroscopy to obtain the surface chemical composition. This is the first study conducted to examine the application of MOCVD to coat internal surfaces of tubes with varying diameters. In the third part of the study, the metal oxide coatings, alumina from aluminum acetylacetonate, alumina from aluminum trisecondary butoxide, zirconia from zirconium acetylacetonate, tantalum oxide from tantalum pentaethoxide and the metal coating, platinum from platinum acetylacetonate were deposited by MOCVD on AISI304. The chemical composition and the surface acidity of the coatings were characterized by x-ray photoelectron spectroscopy. The morphology of the coatings was characterized by electron microscopy. The coated substrates were tested in the presence of heated Jet-A in a flow reactor to evaluate their effectiveness in inhibiting the solid deposit formation. All coatings inhibited the formation of metal sulfides and the carbonaceous solid deposits formed by metal catalysis. The coatings also delayed the accumulation of solid carbonaceous deposits. In particular, it has been confirmed that the surface acidity of the metal oxide coatings affects the formation of carbonaceous deposits. Bimolecular addition reactions promoted by the Bronsted acid sites appear to lead to the formation of carbonaceous solid

  2. Functional doped metal oxide films. Zinc oxide (ZnO) as transparent conducting oxide (TCO) titanium dioxide (TiO{sub 2}) as thermographic phosphor and protective coating

    Nebatti Ech-Chergui, Abdelkader

    2011-07-29

    Metalorganic chemical vapor deposition (MOCVD) was used in the present work. Un-doped and Al-doped ZnO films were developed using two reactors: Halogen Lamp Reactor (HLR) (a type of Cold Wall Reactor) and Hot Wall Reactor (HWR), and a comparison was made between them in terms of the film properties. Zinc acetylacetonate was used as precursor for ZnO films while aluminum acetylacetonate was used for doping. The amount of Al doping can be controlled by varying the gas flow rate. Well ordered films with aluminum content between 0 and 8 % were grown on borosilicate glass and silicon. The films obtained are 0.3 to 0.5 {mu}m thick, highly transparent and reproducible. The growth rate of ZnO films deposited using HLR is less than HWR. In HLR, the ZnO films are well oriented along c-axis ((002) plane). ZnO films are commonly oriented along the c-axis due to its low surface free energy. On the other hand, the HWR films are polycrystalline and with Al doping these films aligned along the a-axis ((100) plane) which is less commonly observed. The best films were obtained with the HLR method showing a minimum electrical resistivity of 2.4 m{omega}cm and transmittance of about 80 % in the visible range. The results obtained for Al-doped films using HLR are promising to be used as TCOs. The second material investigated in this work was un-doped and doped titanium dioxide (TiO{sub 2}) films- its preparation and characterization. It is well known that thermographic phosphors can be used as an optical method for the surface temperature measurement. For this application, the temperature-dependent luminescence properties of europium (III)-doped TiO{sub 2} thin films were studied. It was observed that only europium doped anatase films show the phosphorescence. Rutile phase do not show phosphorescence. The films were prepared by the sol-gel method using the dip coating technique. The structures of the films were determined by X-ray diffraction (XRD). The excitation and the emission

  3. Sol-Gel Process for Making Pt-Ru Fuel-Cell Catalysts

    Narayanan, Sekharipuram; Valdez, Thomas; Kumta, Prashant; Kim, Y.

    2005-01-01

    A sol-gel process has been developed as a superior alternative to a prior process for making platinum-ruthenium alloy catalysts for electro-oxidation of methanol in fuel cells. The starting materials in the prior process are chloride salts of platinum and ruthenium. The process involves multiple steps, is time-consuming, and yields a Pt-Ru product that has relatively low specific surface area and contains some chloride residue. Low specific surface area translates to incomplete utilization of the catalytic activity that might otherwise be available, while chloride residue further reduces catalytic activity ("poisons" the catalyst). In contrast, the sol-gel process involves fewer steps and less time, does not leave chloride residue, and yields a product of greater specific area and, hence, greater catalytic activity. In this sol-gel process (see figure), the starting materials are platinum(II) acetylacetonate [Pt(C5H7O2)2, also denoted Pt-acac] and ruthenium(III) acetylacetonate [Ru(C5H7O2)3, also denoted Ru-acac]. First, Pt-acac and Ru-acac are dissolved in acetone at the desired concentrations (typically, 0.00338 moles of each salt per 100 mL of acetone) at a temperature of 50 C. A solution of 25 percent tetramethylammonium hydroxide [(CH3)4NOH, also denoted TMAH] in methanol is added to the Pt-acac/Ruacac/ acetone solution to act as a high-molecular-weight hydrolyzing agent. The addition of the TMAH counteracts the undesired tendency of Pt-acac and Ru-acac to precipitate as separate phases during the subsequent evaporation of the solvent, thereby helping to yield a desired homogeneous amorphous gel. The solution is stirred for 10 minutes, then the solvent is evaporated until the solution becomes viscous, eventually transforming into a gel. The viscous gel is dried in air at a temperature of 170 C for about 10 hours. The dried gel is crushed to make a powder that is the immediate precursor of the final catalytic product. The precursor powder is converted to the

  4. Hypoxia-sensitive bis(2-(2'-benzothienyl)pyridinato-N,C3')iridium[poly(n-butyl cyanoacrylate]/chitosan nanoparticles and their phosphorescence tumor imaging in vitro and in vivo

    Zeng, Yun; Zhang, Shaojuan; Jia, Menghui; Liu, Yang; Shang, Jin; Guo, Youmin; Xu, Jianhua; Wu, Daocheng

    2013-11-01

    A new hypoxia-sensitive coordination compound, bis(2-(2'-benzothienyl)pyridinato-N,C3')iridium[poly(n-butyl cyanoacrylate)], hereafter denoted as (btp)2Ir(PBCA), is synthesized and characterized by 13C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). (btp)2Ir(PBCA)/chitosan [(btp)2Ir(PBCA)/CS] nanoparticles (NPs) with a core-shell structure are prepared by a two-step fabrication process. The size distributions of these NPs are measured with a Malvern size analyzer, and their morphology is observed by transmission electron microscopy (TEM). The functional groups on the surface are confirmed by FTIR. Phosphorescence spectra are obtained and lifetimes are determined with a spectrophotofluorometer and a time-correlated single photon counting (TCSPC) apparatus, respectively. HeLa and CT26 cell lines are used to examine the cytotoxicity by the MTT assay, as well as to determine the imaging capability of the samples in air and nitrogen atmospheres, respectively. Tumor-bearing mouse models of colon adenocarcinoma are used for tumor imaging in vivo, and the imaging effect is evaluated with a Maestro 2 fluorescence imaging system. Compared with the hypoxia-associated probe bis(2-(2'-benzothienyl)pyridinato-N,C3')iridium(acetylacetonate) (BTP), the phosphorescence lifetime of (btp)2Ir(PBCA)/CS NPs significantly decreases, but the hypoxia-sensitivity increases after preparation of NPs. Apart from the significantly lower cytotoxicity, (btp)2Ir(PBCA)/CS NPs also enhance the tumor imaging effect by more than 10 times, maintaining the phosphorescence signal in tumor tissue for over 24 h and significantly decreasing the phosphorescence signal in normal tissue in vivo compared with the BTP probe.A new hypoxia-sensitive coordination compound, bis(2-(2'-benzothienyl)pyridinato-N,C3')iridium[poly(n-butyl cyanoacrylate)], hereafter denoted as (btp)2Ir(PBCA), is synthesized and characterized by 13C nuclear magnetic resonance (NMR) and Fourier transform

  5. One-step thermolysis synthesis of two-dimensional ultrafine Fe3O4 particles/carbon nanonetworks for high-performance lithium-ion batteries

    Zhang, Wanqun; Li, Xiaona; Liang, Jianwen; Tang, Kaibin; Zhu, Yongchun; Qian, Yitai

    2016-02-01

    To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ~3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h g-1 is achieved at a 1 C rate and is maintained without decay up to 500 cycles (1 C = 1 A g-1). Even at the high current density of 5 C and 10 C, the 2D Fe3O4/carbon nanonetworks maintain a reversible capacity of 845 and 647 mA h g-1 after 500 discharge/charge cycles, respectively. In comparison with other reported Fe3O4-based anodes, the 2D Fe3O4/carbon nanonetwork electrode is one of the most attractive of those in energy storage applications.To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ~3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h

  6. Cathode materials produced by spray flame synthesis for lithium ion batteries

    Hamid, NoorAshrina Binti A.

    2013-07-03

    Lithium ion batteries are one of the most enthralling rechargeable energy storage systems for portable application due to their high energy density. Nevertheless, with respect to electromobility innovation towards better electrochemical properties such as higher energy and power density is required. Altering the cathode material used in Li-ion batteries is favorable since the mass- and volume performance is closely related to the cathode electrode mass. Instead of using LiCoO{sub 2} as cathode electrode, LiFePO{sub 4} has gained serious attention as this material owns a high theoretical capacity of 170 mAh g{sup -1}. It is non-toxic, cheap and consists of abundant materials but suffers from low electronic and ionic conductivity. Utilization of nanotechnology methods in combination with composite formation is known to cure this problem effectively. In this work, a new combination of techniques using highly scalable gas-phase synthesis namely spray-flame synthesis and subsequent solid-state reaction has been used to synthesize nanocomposite LiFePO{sub 4}/C. At first this work deals with the formation and characterization of nanosize FePO{sub 4} from a solution of iron(III)acetylacetonate and tributyl phosphate in toluene using spray-flame synthesis. It was shown that a subsequent solid state reaction with Li{sub 2}CO{sub 3} and glucose yielded a LiFePO{sub 4}/C nanocomposite with very promising electrochemical properties. Based on these initial findings the influence of two synthesis parameter - carbon content and annealing temperature - was investigated towards the physicochemical properties of LiFePO{sub 4}/C. It was shown that an annealing temperature of 700 C leads to high purity composite materials consisting of crystalline LiFePO{sub 4} with crystallite sizes well below 100 nm and amorphous carbon consisting of disordered and graphite-like carbon. Variation of glucose amount between 10 and 30 wt% resulted in carbon contents between 2.1 and 7.3 wt%. In parallel

  7. A thermolysis approach to simultaneously achieve crystal phase- and shape-control of ternary M-Fe-O metal oxide nanoparticles

    Huang, Chih-Chia; Chang, Chich-Neng; Yeh, Chen-Sheng

    2011-10-01

    Significant studies have achieved beautiful control in particle size, while the shape- and phase-control synthesis of nanoparticles remains an open challenge. In this study, we have developed a generalized methodology to selectively prepare either NaCl-type (reduced form) or spinel-type ferrite (oxidized form) M-Fe-O (M = Mn, Co) crystallites with high reproducibility. A two-step heating process was able to control formation of two types of crystal phase, either a thermodynamic spinel-type under air or a kinetic-control of NaCl-type (rock salt structure) under Ar in a cubic morphology. On the other hand, the three-step heating procedure in air obtained the spinel-type with a thermodynamic equilibrium octahedral shape exclusively. Either using metal acetates (M(ac)2) or metal acetylacetonates (M(acac)2) as the starting precursors (M = Mn, Co) can be introduced to prepare NaCl-type (reduced form) or spinel-type ferrite (oxidized form) crystallites with identical experimental parameters, including precursor concentration, reaction temperature, reaction time, and heating rate. The oleic acid molecule, reaction temperature, and heating rate employed in the synthesis were carefully examined and found acting as determined roles behind the reaction processes. Apart from the previous literature reports as shape-directed and/or stabilizing agents, the oleic acid molecule played an additional phase-tuning role.Significant studies have achieved beautiful control in particle size, while the shape- and phase-control synthesis of nanoparticles remains an open challenge. In this study, we have developed a generalized methodology to selectively prepare either NaCl-type (reduced form) or spinel-type ferrite (oxidized form) M-Fe-O (M = Mn, Co) crystallites with high reproducibility. A two-step heating process was able to control formation of two types of crystal phase, either a thermodynamic spinel-type under air or a kinetic-control of NaCl-type (rock salt structure) under Ar in a

  8. Experimental setup and analytical methods for the non-invasive determination of volatile organic compounds, formaldehyde and NOx in exhaled human breath

    Different analytical devices were tested and evaluated for their suitability of breath gas analysis by examining the physiological parameters and chemical substances in the exhaled breath of ten healthy probands during light cycling in dependence of methanol-rich nutrition. The probands exercised under normal breathing conditions on a bicycle ergometer. Breath air was exhaled into a glass cylinder and collected under steady-state conditions. Non-invasively measured parameters were pulse rate, breath frequency, temperature, relative humidity, NOx, total volatile organic compounds (TVOCPAS), carbon dioxide (CO2), formaldehyde, methanol, acetaldehyde, acetone, isoprene and volatile organic compounds (VOCs). Methanol rich food and beverages strongly influenced the concentration of methanol and other organic substances in human breath. On the other hand, nutrition and smoking had no clear effect on the physical conditions of the probands. The proton transfer reaction mass spectrometry (PTR-MS) method was found to be very suitable for the analysis of breath gas but the m/z 31, if assigned to formaldehyde, is sensitive to interferences. The time vs. concentration curves of nitric oxide showed sudden peaks up to 120 ppb in most of the measurements. In one case a strong interference of the NOx signal was observed. The time resolved analysis of exhaled breath gas is of high capability and significance for different applications if reliable analytical techniques are used. Some compounds like nitric oxide (NO), methanol, different VOCs as well as sum parameters like TVOCPAS are especially suitable as markers. Formaldehyde, which is rapidly metabolized in the human body, could be measured reliably as a trace component by the acetylacetone (acac) method but not by PTR-MS.

  9. 分光光度法测定甲醛甲酚溶液中甲醛的含量%Measurement of Formaldehyde in Formaldehyde and Cresol Solution by Spectrophotometry

    贡雪芃; 黄丽华; 施春阳

    2011-01-01

    目的 建立甲醛甲酚溶液中甲醛的含量测定方法.方法 利用甲醛与乙酰丙酮及铵离子反应,生成黄紫色化合物,采用分光光度法进行测定.结果 确定检测波长为413 nm,甲醛量在4.39~30.73 μg范围内线性关系良好(R2=0.999 9),平均回收率99.4%,RSD=1.4%.结论 该方法准确、精密、稳定,专属性强,具有较好的耐用性,能够很好测定甲醛甲酚溶液中甲醛的含量.%Objective To set up a method for detecting formaldehyde in formaldehyde and cresol solution. Methods Based on a yellow-purple complex with a specific absorption wavelength at 413 nm yielded by reacting with NH+4 and acetylacetone, the formaldehyde in formaldehyde and cresol solution was measured by spectrophotometry. Results There was a good linearization between the absorbency from UV and formaldehyde within 4. 39 ~ 30. 73 μg , FT = 0. 999 9. The average recovery was 99.4% and RSD 1. 4%. Conclusion The method is accurate, simple, rapid, specific and can be used to measure formaldehyde in formaldehyde and cresol solution.

  10. Preparation of ZnO:CeO2-x thin films by AP-MOCVD: Structural and optical properties

    The growth of columnar CeO2, ZnO and ZnO:CeO2-x films on quartz and AA6066 aluminum alloy substrates by economic atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) is reported. A novel and efficient combination of metal acetylacetonate precursors as well as mild operating conditions were used in the deposition process. The correlation among crystallinity, surface morphology and optical properties of the as-prepared films was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and UV-vis spectroscopy. The synthesized films showed different crystallographic orientations depending on the ZnO and CeO2 lattice mismatch, cerium content and growth rate. The CeO2 films synthesized in this work showed plate-like compact structures as a result of the growth process typical of CVD. Both pure and ZnO:CeO2-x films were obtained with a hexagonal structure and highly preferred orientation with the c-axis perpendicular to both substrates under the optimal deposition conditions. The microstructure was modified from dense, short round columns to round structures with cavities ('rose-flower-like' structures) and the typical ZnO morphology by controlling the cerium doping the film and substrate nature. High optical transmittance (>87%) was observed in the pure ZnO films. As for the ZnO:CeO2-x films, the optical transmission was decreased and the UV absorption increased, which subsequently was affected by an increase in cerium content. This paper assesses the feasibility of using ZnO:CeO2-x thin films as UV-absorbers in industrial applications. - Graphical abstract: TEM micrographs and their corresponding SAED pattern obtained for the as-deposited ZnO-CeO2-x thin films for a Zn/Ce metallic ratio 16:9.

  11. Hybrid white organic light-emitting devices based on phosphorescent iridium–benzotriazole orange–red and fluorescent blue emitters

    We demonstrate that high color purity or efficiency hybrid white organic light-emitting devices (OLEDs) can be generated by integrating a phosphorescent orange–red emitter, bis[4-(2H-benzotriazol-2-yl)-N,N-diphenyl-aniline-N1,C3] iridium acetylacetonate, Ir(TBT)2(acac) with fluorescent blue emitters in two different emissive layers. The device based on deep blue fluorescent material diphenyl-[4-(2-[1,1′;4′,1″]terphenyl-4-yl-vinyl)-phenyl]-amine BpSAB and Ir(TBT)2(acac) shows pure white color with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.33,0.30). When using sky-blue fluorescent dopant N,N′-(4,4′-(1E,1′E)-2,2′-(1,4-phenylene)bis(ethene-2,1-diyl) bis(4,1-phenylene))bis(2-ethyl-6-methyl-N-phenylaniline) (BUBD-1) and orange–red phosphor with a color-tuning phosphorescent material fac-tris(2-phenylpyridine) iridium (Ir(ppy)3 ), it exhibits peak luminance yield and power efficiency of 17.4 cd/A and 10.7 lm/W, respectively with yellow-white color and CIE color rendering index (CRI) value of 73. - Highlights: ► An iridium-based orange–red phosphor Ir(TBT)2(acac) was applied in hybrid white OLEDs. ► Duel- and tri-emitter WOLEDs were achieved with either high color purity or efficiency performance. ► Peak luminance yield of tri-emitter WOLEDs was 17.4 cd/A with yellow-white color and color rendering index (CRI) value of 73.

  12. Linker dependence of interfacial electron transfer rates in Fe(II)-polypyridine sensitized solar cells

    Dye-sensitized solar cells (DSSCs) convert solar energy to electricity employing dye molecules attached to a semiconductor surface. Some of the most efficient DSSCs use Ru-based chromophores. Fe-based dyes represent a cheaper and more environmentally friendly alternative to these expensive and toxic dyes. The photoactive state of Fe-based chromophores responsible for charge-separation at the dye-semiconductor interface is, however, deactivated on a sub-picosecond time scale via the intersystem crossing (ISC) into a manifold of low-lying photo-inactive quintet states. Therefore, development of Fe-based dyes capable of fast interfacial electron transfer (IET) leading to efficient charge separation on a time scale competitive with the ISC events is important. This work investigates how linker groups anchoring a prototypical Fe-based dye [Fe(bpy-L)2(CN)2] (bpy = 2,2′-bipyridine, L = linker group) onto the TiO2 semiconductor surface influence the IET rates in the dye–semiconductor assemblies. Linker groups investigated include carboxylic acid, phosphonic acid, hydroxamate, catechol, and acetylacetonate. We employ time-dependent density functional theory (TD-DFT) to obtain absorption spectra of [Fe(bpy-L)2(CN)2] with each linker, and quantum dynamics simulations to investigate the IET rates between the dye and the (101) TiO2 anatase surface. For all attachments, TD-DFT calculations show similar absorption spectra with two main bands corresponding to the metal-to-ligand charge transfer transitions. The quantum dynamics simulations predict that the utilization of the hydroxamate linker instead of the commonly used carboxylic acid linker will lead to a more efficient IET and better photon-to-current conversion efficiencies in Fe(II)-polypyridine sensitized solar cells. (paper)

  13. Separations systems data base: a users' manual. Revision I

    A separations systems data base (SEPSYS), designed specifically for the retrieval of information needed in chemical separations problems (i.e., how to perform a given separation under given conditions), is described. Included are descriptions of the basic methods of searching and retrieving information from the data base, the procedure for entering records into the data base, a listing of additional references concerning the computer information process, and an example of a typical record. The initial entries are concerned primarily with liquid-liquid extraction and liquid-solid ion exchange methods for metal ions and salts; however, the data base is constructed so that almost any separation process can be accommodated. Each record is indexed with information provided under the following fields: author; title; publication source; data of publication; organization sponsoring the work; brief abstract of the work; abstract number if the work has been so referenced, and/or abstractors initials; type of separation system used (e.g., flotation); specific or generic name of the separation agent used (e.g., acetylacetone); list of substances separated (e.g., gold, copper); qualitative description of the supporting medium or matrix containing the substances before separation (e.g., nitrate); type of literature where the record was printed (e.g., book); and type of information that the article contains. Each of these fields may be searched independently of the others (or in combination), and the last six fields contain specific key words that are listed in the report. Definitions are provided for the 36 information terms

  14. A new route for the synthesis of titanium silicalite-1

    Graphical abstract: Well-prepared TS-1 was synthesized by an innovative procedure using inexpensive reagents such as fumed silica and TPABr as structure-directing agent. This is the first time when highly crystalline TS-1 is obtained in basic medium, using sodium hydroxide as HO− ion source required for the crystallization process. Hydrolysis of titanium source has been prevented by titanium complexation with acetylacetone before structuring gel. Highlights: ► TS-1 was obtained using cheap reagents as fumed silica and tetrapropylammonium bromide. ► First time NaOH was used as source of OH− ions required for crystallization process. ► The hydrolysis Ti alkoxides was controlled by Ti complexation with 2,4-pentanedione. -- Abstract: A new and efficient route using inexpensive reagents such as fumed silica and tetrapropylammonium bromide is proposed for the synthesis of titanium silicalite-1. High crystalline titanium silicalite-1 was obtained in alkaline medium, using sodium hydroxide as HO− ion source required for the crystallization process. Hydrolysis of titanium source with formation of insoluble oxide species was prevented by titanium complexation with before structuring gel. The final solids were fully characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared, ultraviolet-visible diffuse reflectance, Raman and atomic absorption spectroscopies, as well as nitrogen sorption analysis. It was found that a molar ratio Ti:Si of about 0.04 in the initial reaction mixture is the upper limit to which well formed titanium silicalite-1 with channels free of crystalline or amorphous material can be obtained. Above this value, solids with MFI type structure containing both Ti isomorphously substituted in the network and extralattice anatase nanoparticles inside of channels is formed.

  15. Ultrasonic spray-pyrolyzed CuCrO2 thin films

    Sánchez-Alarcón, R. I.; Oropeza-Rosario, G.; Gutierrez-Villalobos, A.; Muro-López, M. A.; Martínez-Martínez, R.; Zaleta-Alejandre, E.; Falcony, C.; Alarcón-Flores, G.; Fragoso, R.; Hernández-Silva, O.; Perez-Cappe, E.; Mosqueda Laffita, Yodalgis; Aguilar-Frutis, M.

    2016-05-01

    In this paper the optical, structural and electrical properties of CuCrO2 thin films deposited by ultrasonic spray pyrolysis at temperatures from 400 to 600 °C in steps of 50 °C are presented. Copper and chromium acetylacetonates were chosen as sources of Cu and Cr, respectively, and N,N-dimethylformamide was used as the solvent. X-ray results confirmed that the films as deposited showed the CuCrO2 phase without any post-deposition thermal annealing. The surface morphology was observed to be mirror like, and as the films were deposited at different temperatures, they gradually revealed the presence of small crystallites. The best film’s optical percentage transmission (in the visible region), about 58%, was obtained in films deposited at 450 °C, and the highest band gap energy (3.17 eV) was measured in films deposited at 400 °C. The electrical properties of the films were obtained by the Hall effect. A hole concentration in the range 1019-1021 cm-3, conductivity as high as 35 S cm-1, and mobility lower than 1 cm2 V-1 s-1 were obtained in the films. p-type conductivity was confirmed using the hot point probe arrangement, and the Seebeck coefficient was estimated. The hole conductivity is thought to be due to excess oxygen in the films. Finally, the minimum energy required to transfer carriers from acceptor level to the valence band in the films was estimated by impedance spectroscopy.

  16. Size-controlled synthesis of monodisperse nickel nanoparticles and investigation of their magnetic and catalytic properties

    Pan, Yuan; Jia, Rongrong; Zhao, Jinchong; Liang, Jilei; Liu, Yunqi, E-mail: liuyq@upc.edu.cn; Liu, Chenguang

    2014-10-15

    Graphical abstract: - Highlights: • Monodisperse nickel nanoparticles (NPs) with different size were synthesized via the thermal decomposition approach. • The size of nickel NPs can easily be controlled by changing synthetic conditions. • The possible growth mechanism of nickel NPs was proposed. • The as-synthesized nickel NPs exhibited superparamagnetism characteristics at room temperature, and the saturation magnetization increased significantly with increasing size of the nickel NPs. • The dehydrogenation reaction of cyclohexane on nickel NPs was structure sensitive reaction. - Abstract: Monodisperse nickel nanoparticles (NPs) with different size were synthesized via the thermal decomposition approach using nickel acetylacetonate as precursors and trioctylphosphine as surfactant in oleylamine. The structure and morphology of as-synthesized nickel NPs were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and selected area electron diffraction (SAED). The surface states of as-synthesized nickel NPs were characterized by Fourier transform infrared (FT-IR) spectra. The textural properties of as-synthesized nickel NPs were characterized by N{sub 2} adsorption–desorption. The size of as-synthesized nickel NPs was found to be easily controlled by changing synthetic conditions, including P:Ni precursor ratio, reaction temperature, reaction time and oleylamine quantity, and the possible growth mechanism of nickel NPs was proposed. In addition, the magnetic measurements showed that the as-synthesized nickel NPs exhibited superparamagnetism characteristics at room temperature, and the saturation magnetization increased significantly with the increase in nickel NPs’ size. Finally, the size-dependent catalytic properties of nickel NPs for cyclohexane dehydrogenation reaction were studied. The results demonstrated that the catalytic activity can be enhanced by decreasing the size of NPs, which indicated that the dehydrogenation

  17. Structural, optical, and magnetic properties of Cu- and Ni-codoped CdO dilute magnetic nanocrystalline semiconductor: effect of hydrogen post-treatment

    Dakhel, A.A. [University of Bahrain, Department of Physics, College of Science, Sakhir (Bahrain); Bououdina, M. [University of Bahrain, Department of Physics, College of Science, Sakhir (Bahrain); University of Bahrain, Nanotechnology Centre, Sakhir (Bahrain)

    2015-06-15

    Cadmium oxide codoped with Cu and Ni ions powders was synthesised by thermal co-decomposition of a mixture of cadmium, copper, and nickel acetylacetonates. The mass ratio of Cu/Cd was fixed, while the Ni/Cd mass ratio was varied systematically. The purpose of the present study is to prepare powders having room-temperature ferromagnetic (RT-FM) properties. X-ray fluorescence (XRF) and X-ray diffraction (XRD) confirm the purity and the formation of single nanocrystalline structure of the as-prepared powders. The energy bandgap of the as-prepared powders was found to vary slightly and then increases by 3.96-38.02 % after post-H{sub 2}-treatment. Magnetic measurements reveal that all as-prepared doped CdO powders gained partial (RT-FM) properties. Furthermore, the created RT-FM is dependent on the Ni% doping level. After annealing under H{sub 2} gas, a strong enhancement of RT-FM was observed, especially for 1.2 % Ni-doping-level powder where the whole powder became ferromagnetic with coercivity, remanence, and saturation magnetisation of 249.2 Oe, 4.52 memu/g, and 14.57 memu/g, respectively, representing an increase by ∝241.3, 1062, and 1700 %, respectively, in comparison with the as-prepared sample. Thus, it was proved, for the first time, the possibility of producing of codoped CdO with RT-FM, where the magnetic characteristics can be tailored by doping and post-treatment under H{sub 2} atmosphere, thus a new potential candidate for dilute magnetic semiconductor (DMS). (orig.)

  18. Indium tin oxide thin films elaborated by sol-gel routes: The effect of oxalic acid addition on optoelectronic properties

    Single layer indium tin oxide (ITO) thin films were deposited on glass using modified sol-gel formulations. The coating sols were prepared using indium (InCl3∙ 4H2O) and tin salts (SnCl4∙ 5H2O). The stable sols were obtained using ethanol (C2H5OH) and acetylacetone (C5H8O2) as solvents and by the addition of oxalic acid dihydrate (C2H2O4∙ 2H2O) in different amounts. The effect of oxalic acid content in the sol formulation and post-coating calcination treatment (in air at 300–600 °C) on electrical/optical properties of ITO films have been reported. It was shown that film formation efficiency, surface coverage and homogeneity were all enhanced with oxalic acid addition. Oxalic acid modification also leads to a significant improvement in electrical conductivity without affecting the film thickness (45 ± 3 nm). ITO films exhibiting high transparency (≈ 93%, visible region) with a sheet resistance as low as 3.8 ± 0.4 kΩ/sqr have been formed by employing coating sols with optimized oxalic acid amount. The mechanisms and factors affecting the functional performance of oxalic acid-modified films have been thoroughly discussed and related to the microstructural and chemical characteristic of the films achieved by oxalic acid addition. - Highlights: • A solution-based method for processing indium tin oxide (ITO) thin film is reported. • Oxalic acid (OAD) modification leads to a highly compacted film microstructure. • Bulk resistivity of a single layer OAD-modified ITO film was determined as 0.02 Ωcm. • Thin films with transparency values higher than 90% were produced

  19. The Effect of Precursor Ligands and Oxidation State in the Synthesis of Bimetallic Nano-Alloys

    LaGrow, Alec P.

    2015-05-12

    The characteristics of bimetallic nanomaterials are dictated by their size, shape and elemental distribution. Solution synthesis is widely utilized to form nanomaterials, such as nanoparticles, with controlled size and shape. However, the effects of variables on the characteristics of bimetallic nanomaterials are not completely understood. In this study, we used a continuous-flow synthetic strategy to explore the effects of the ligands and the oxidation state of a metal precursor in a shape-controlled synthesis on the final shape of the nanomaterials and the elemental distribution within the alloy. We demonstrate that this strategy can tune the size of monodisperse PtM (M=Ni or Cu) alloy nanocrystals ranging from 3 to 16 nm with an octahedral shape using acetylacetonate or halide precursors of Pt(II), Pt(IV) and Ni or Cu (II). The nanoparticles formed from halide precursors showed an enrichment of platinum on their surfaces, and the bromides could oxidatively etch the nanoparticles during synthesis with the O2/Br- pair. The two nanocrystal precursors can be uti-lized independently and can control the size with a trend of Pt(acac)2

  20. Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

    Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface. PMID:27001452

  1. Chemical vapor deposition (CVD) of uranium for alpha spectrometry

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  2. Thermodynamic modeling to analyse composition of carbonaceous coatings of MnO and other oxides of manganese grown by MOCVD

    Sukanya Dhar; A Varade; S A Shivashankar

    2011-02-01

    Equilibrium thermodynamic analysis has been applied to the low-pressure MOCVD process using manganese acetylacetonate as the precursor. ``CVD phase stability diagrams” have been constructed separately for the processes carried out in argon and oxygen ambient, depicting the compositions of the resulting films as functions of CVD parameters. For the process conduced in argon ambient, the analysis predicts the simultaneous deposition of MnO and elemental carbon in 1:3 molar proportion, over a range of temperatures. The analysis predicts also that, if CVD is carried out in oxygen ambient, even a very low flow of oxygen leads to the complete absence of carbon in the film deposited oxygen, with greater oxygen flow resulting in the simultaneous deposition of two different manganese oxides under certain conditions. The results of thermodynamic modeling have been verified quantitatively for lowpressure CVD conducted in argon ambient. Indeed, the large excess of carbon in the deposit is found to constitute a MnO/C nanocomposite, the associated cauliflower-like morphology making it a promising candidate for electrode material in supercapacitors. CVD carried out in oxygen flow, under specific conditions, leads to the deposition of more than one manganese oxide, as expected from thermodynamic analysis (and forming an oxide–oxide nanocomposite). These results together demonstrate that thermodynamic analysis of the MOCVD process can be employed to synthesize thin films in a predictive manner, thus avoiding the inefficient trial-and-error method usually associated with MOCVD process development. The prospect of developing thin films of novel compositions and characteristics in a predictive manner, through the appropriate choice of CVD precursors and process conditions, emerges from the present work.

  3. Microspheres of poly(ε-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho2O3. Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  4. Hybrid white organic light-emitting devices based on phosphorescent iridium-benzotriazole orange-red and fluorescent blue emitters

    Xia, Zhen-Yuan, E-mail: xiazhenyuan@hotmail.com [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237 (China); Su, Jian-Hua [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237 (China); Chang, Chi-Sheng; Chen, Chin H. [Display Institute, Microelectronics and Information Systems Research Center, National Chiao Tung University, Hsinchu, Taiwan 300 (China)

    2013-03-15

    We demonstrate that high color purity or efficiency hybrid white organic light-emitting devices (OLEDs) can be generated by integrating a phosphorescent orange-red emitter, bis[4-(2H-benzotriazol-2-yl)-N,N-diphenyl-aniline-N{sup 1},C{sup 3}] iridium acetylacetonate, Ir(TBT){sub 2}(acac) with fluorescent blue emitters in two different emissive layers. The device based on deep blue fluorescent material diphenyl-[4-(2-[1,1 Prime ;4 Prime ,1 Double-Prime ]terphenyl-4-yl-vinyl)-phenyl]-amine BpSAB and Ir(TBT){sub 2}(acac) shows pure white color with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.33,0.30). When using sky-blue fluorescent dopant N,N Prime -(4,4 Prime -(1E,1 Prime E)-2,2 Prime -(1,4-phenylene)bis(ethene-2,1-diyl) bis(4,1-phenylene))bis(2-ethyl-6-methyl-N-phenylaniline) (BUBD-1) and orange-red phosphor with a color-tuning phosphorescent material fac-tris(2-phenylpyridine) iridium (Ir(ppy){sub 3} ), it exhibits peak luminance yield and power efficiency of 17.4 cd/A and 10.7 lm/W, respectively with yellow-white color and CIE color rendering index (CRI) value of 73. - Highlights: Black-Right-Pointing-Pointer An iridium-based orange-red phosphor Ir(TBT){sub 2}(acac) was applied in hybrid white OLEDs. Black-Right-Pointing-Pointer Duel- and tri-emitter WOLEDs were achieved with either high color purity or efficiency performance. Black-Right-Pointing-Pointer Peak luminance yield of tri-emitter WOLEDs was 17.4 cd/A with yellow-white color and color rendering index (CRI) value of 73.

  5. Catalytic nanomedicine technology: copper complexes loaded on titania nanomaterials as cytotoxic agents of cancer cell.

    Lopez, Tessy; Ortiz-Islas, Emma; Guevara, Patricia; Gómez, Esteban

    2013-01-01

    The anticancer properties of pure copper (II) acetate and copper (II) acetylacetonate, alone and loaded on functionalized sol-gel titania (TiO(2)), were determined in four different cancer cell lines (C6, RG2, B16, and U373), using increasing concentrations of these compounds. The copper complexes were loaded onto the TiO(2) network during its preparation by the solgel process. Once copper-TiO(2) materials were obtained, these were characterized by several physical-chemical techniques. An in vitro copper complex-release test was developed in an aqueous medium at room temperature and monitored by ultraviolet spectroscopy. The toxic effect of the copper complexes, alone and loaded on TiO(2), was determined using a cell viability 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, when cancer cells were treated with increasing concentrations (15.75-1000 mg/mL) of these. Characterization studies revealed that the addition of copper complexes to the TiO(2) sol-gel network during its preparation, did not generate changes in the molecular structure of the complexes. The surface area, pore volume, and pore diameter were affected by the copper complex additions and by the crystalline phases obtained. The kinetic profiles of both copper complexes released indicated two different stages of release: The first one was governed by first-order kinetics and the second was governed by zero-order kinetics. The cell viability assay revealed a cytotoxic effect of copper complexes, copper-TiO(2), and cisplatin in a dose-dependent response for all the cell lines; however, the copper complexes exhibited a better cytotoxic effect than the cisplatin compound. TiO(2) alone presented a minor cytotoxicity for C6 and B16 cells; however, it did not cause any toxic effect on the RG2 and U373 cells, which indicates its high biocompatibility with these cells. PMID:23413123

  6. Obtention of zirconia films stabilized with Yttria via pyrolysis spray: study of the solvent influence; Obtencao de filmes de zirconia estabilizada com itria via spray pirolise: estudo da influencia do solvente

    Halmenschlager, Cibele Melo; Vieira, Ramaugusto da Porciuncula; Takimi, Antonio Shigueaki; Bergmann, Carlos Perez; Silva, Aline Lima da; Malfatti, Celia de Fraga [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais (PPGEM). Lab. de Materiais Ceramicos (LACER)]. E-mail: cibelemh@yahoo.com.br

    2008-07-01

    Yttria-stabilized-zirconia (YSZ) has been object of many studies, due to its great chemical stability and excellent ionic conduction in high temperature. This material has been studies with an intention of to be used with electrolyte of oxide solid fuel cells, which work in high temperature. The aim of the present work was to evaluate the influence of the solvent on the elaboration of crystalline films of YSZ via spray pyrolysis. The film was prepared by spray pyrolysis with zirconium acetylacetonate (Zr(C{sub 6}H{sub 7}O{sub 2}){sub 4}) and yttrium chloride (YCl{sub 3}.6H{sub 2}O), dissolved in different solvents: ethanol (C{sub 2}H{sub 6}O), ethanol (C{sub 2}H{sub 6}O) + propyleneglycol (C{sub 3}H{sub 8}O{sub 2}) with volume ratio (1:1) and ethanol (C{sub 2}H{sub 6}O) + diethylene glycol butyl ether (C{sub 8}H{sub 18}O{sub 3}) with volume ratio of 1:1. A disk of steel 316L was used as substrate. The amorphous film was deposited in the substrate heated at 280 deg C {+-} 50 deg C. After deposition from thermal treatment at 700 deg C the amorphous film was changed into Yttria-stabilized-zirconia film. The thermal behavior of the films has been studied by both (DTA/TGA) thermogravimetric and mass spectroscopy analyses. The morphology and crystalline phase of the films was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The YSZ film obtained after heat treatment was dense and crystalline, however, the analyses indicate a significant influence of the solvent and of the substrate temperature during the deposition process on the film morphology.(author)

  7. A Facile Synthesis of MPd (M=Co, Cu) Nanoparticles and Their Catalysis for Formic Acid Oxidation

    Mazumder, Vismadeb [Brown University; Chi, Miaofang [ORNL; Mankin, Max [Brown University; Liu, Yi [Brown University; Metin, Onder [Ataturk University; Sun, Daohua [Xiamen University, China; More, Karren Leslie [ORNL; Sun, Shouheng [Brown University

    2012-01-01

    Monodisperse CoPd nanoparticles (NPs) were synthesized and studied for catalytic formic acid (HCOOH) oxidation (FAO). The NPs were prepared by coreduction of Co(acac)2 (acac = acetylacetonate) and PdBr2 at 260 C in oleylamine and trioctylphosphine, and their sizes (5-12 nm) and compositions (Co10Pd90 to Co60Pd40) were controlled by heating ramp rate, metal salt concentration, or metal molar ratios. The 8 nm CoPd NPs were activated for HCOOH oxidation by a simple ethanol wash. In 0.1 M HClO4 and 2 M HCOOH solution, their catalytic activities followed the trend of Co50Pd50 > Co60Pd40 > Co10Pd90 > Pd. The Co50Pd50 NPs had an oxidation peak at 0.4 V with a peak current density of 774 A/gPd. As a comparison, commercial Pd catalysts showed an oxidation peak at 0.75 V with peak current density of only 254 A/gPd. The synthesis procedure could also be extended to prepare CuPd NPs when Co(acac)2 was replaced by Cu(ac)2 (ac = acetate) in an otherwise identical condition. The CuPd NPs were less active catalysts than CoPd or even Pd for FAO in HClO4 solution. The synthesis provides a general approach to Pd-based bimetallic NPs and will enable further investigation of Pd-based alloy NPs for electro-oxidation and other catalytic reactions.

  8. Synthesis and catalytic properties of iron - cerium phosphates with surfactant Síntese e propriedades catalíticas de ferro-fosfato de cério com surfactante

    H. Onoda

    2013-03-01

    Full Text Available Iron phosphate was prepared from iron nitrate and phosphoric acid with a surfactant, pentaethylene glycol mono dodecyl ether. The chemical composition of the obtained samples was estimated from ICP and XRD measurements. Particle shape and size distribution were observed by SEM images and laser diffraction / scattering methods. Further, the catalytic activity was studied with the decomposition of the complex between formaldehyde, ammonium acetate, and acetylacetone. The peaks of FePO4 were observed in XRD patterns of samples prepared in Fe/Ce=10/0 and then heated at 600 ºC. Other samples were amorphous in XRD patterns. Iron-cerium phosphates had high catalytic activity for the decomposition of the complex.Fosfato de ferro foi preparado a partir do nitrato de ferro e ácido fosfórico com um surfactante éter monododecil pentaetileno glicol. A composição química das amostras obtidas foi estimada a partir de medidas por ICP e DRX. A distribuição e forma das partículas foram observadas por imagens de MEV e o pelo método de espalhamento de laser. A atividade catalítica foi estudada com a decomposição do complexo entre formaldeido, acetato de amônio e acetilacetona. Os picos de FePO4 foram observados nos padrões de DRX das amostras preparadas Fe/Ce=10/0 e então aquecidas a 600 ºC. Outras amostras foram de padrões de DRX amorfo. Ferro-fosfatos de cério tiveram alta atividade catalítica para a decomposição do complexo.

  9. Study of atomic layer deposition of indium oxy-sulfide films for Cu(In,Ga)Se{sub 2} solar cells

    Bugot, Cathy, E-mail: cathy-externe.bugot@edf.fr [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP, UMR 7174 CNRS-EDF-Chimie Paristech), Chatou (France); Schneider, Nathanaelle [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP, UMR 7174 CNRS-EDF-Chimie Paristech), Chatou (France); Bouttemy, Muriel; Etcheberry, Arnaud [Institut Lavoisier de Versailles, UMR 8180 (CNRS-UVSQ), Versailles (France); Lincot, Daniel; Donsanti, Frédérique [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP, UMR 7174 CNRS-EDF-Chimie Paristech), Chatou (France)

    2015-05-01

    This paper explores the growth mechanism of plasma enhanced atomic layer deposition of In{sub 2}(S,O){sub 3} films. The films were deposited using indium acetylacetonate (In(acac){sub 3}), hydrogen sulfide (H{sub 2}S) and Ar/O{sub 2} plasma as oxygen precursor. The films were characterized using X-ray reflectometry, spectrophotometry, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. To understand the growth mechanism and especially the interactions between Ar/O{sub 2} plasma and In{sub 2}(S,O){sub 3} growing film, in-situ analyses were performed using quadrupole mass spectrometry. In-situ qualitative analysis revealed good correlation between the species detected in vapor phase and thin film properties. High concentrations of atomic and molecular oxygen were measured in the vapor phase during O{sub 2} plasma pulses. Significant decrease of these species could be observed by varying the plasma power from 2600 to 300 W, while the optical band gap remained at high values (> 2.6 eV). The analysis of the O{sub 2}-free/Ar plasma process showed that some of these oxygen species originate either from the indium precursor or from the substrate surface. This study explains the high oxygen content of the films, and allows us to reduce and control it. Generally, this report provides keys to understand the effect of plasma reactivity for the elaboration of oxide based materials. - Highlights: • In{sub 2}(S,O){sub 3} films were synthesized by plasma enhanced atomic layer deposition. • Growth mechanism was studied via gas phase analysis by Quadrupole Mass Spectrometry. • Good correlation between the vapor phase species and thin films properties was observed. • The film compositions and band gaps can be controlled by varying the plasma power.

  10. Remedial action of matrices contaminated by cobalt with supercritical CO{sub 2}: contribution to the understanding of the complex formation mechanisms and to the diphasic transfers; Rehabilitation de matrices contaminees par du cobalt a l'aide du CO{sub 2} supercritique: contribution a la comprehension des mecanismes de complexation et de transferts diphasiques

    Gervais, F

    2001-10-15

    The treatment of polluted soils by supercritical CO{sub 2} extraction seems to be an interesting alternative to the existing depollution techniques. The main interest of this process is the low effluents volume generated during the treatment. The extraction of metals or radionuclides by this technique requires their preliminary complexation by complexing or chelating agents. The {beta}-diketones and the dithiocarbamates (fluorinated or not) have been chosen for this study. The first part of this study deals with the study of the phenomena which govern the chemical equilibria in an aqueous phase simulating a soil solution. The complexing tests reveal a very slow cobalt acetylacetonate formation velocity and this complex presents a well-marked absorbent character. On the other hand the formation of the complex between cobalt and dithiocarbamate is instantaneous and the complex formed is very hydrophobic. The mass transfers between an aqueous phase and an extracting phase (hexane and supercritical CO{sub 2}) applied to ligands and preformed complexes are studied too in this work. CO{sub 2} seems to have a superior affinity to those of the hexane for the fluorinated {beta}-diketones, ligand or complex, contrarily to hexane. This tendency is confirmed by in-situ solubility measurements of fluorinated or non fluorinated commercial complexes, by X-ray absorption spectroscopy. Nevertheless, globally, the cobalt-{beta}-diketones complexes are rather absorbent because of their partial hydration. This type of ligand is then not necessarily adapted to cobalt extraction by supercritical CO{sub 2} of an aqueous phase. On the other hand, the dithiocarbamates being hydrophobic, their distribution coefficient is higher than those given by the {beta}-diketonates in hexane or in supercritical CO{sub 2}. The metals extraction of a liquid matrix seems then more promising with this ligands family. (O.M.)

  11. A series of dinuclear Dy(iii) complexes bridged by 2-methyl-8-hydroxylquinoline: replacement on the periphery coordinated β-diketonate terminal leads to different single-molecule magnetic properties.

    Zhang, Wan-Ying; Tian, Yong-Mei; Li, Hong-Feng; Chen, Peng; Sun, Wen-Bin; Zhang, Yi-Quan; Yan, Peng-Fei

    2016-03-01

    A series of HMq-bridged dinuclear dysprosium complexes, namely, [Dy(acac)2(CH3OH)]2(μ-HMq)2 (1), [Dy(DBM)2]2(μ-HMq)2(n-C6H14) (2), [Dy(hmac)2]2(μ-HMq)2 (3) and [Dy(hfac)3]2(μ-HMq)2 (4) (HMq = 2-methyl-8-hydroxyquinoline, acac = acetylacetone, DBM = dibenzoylmethane, hmac = hexamethylacetylacetonate and hfac = hexafluoroacetylacetonate), were structurally and magnetically characterized. X-ray crystallographic analyses of the structures reveal that HMq serves as the effective bridge to link two Dy(iii) centers by means of the phenoxyl oxygen and nitrogen atoms and the periphery β-diketonate ligands complete the coordination sphere by bidentate oxygen atoms. The different substituents on the β-diketonate terminal lead to different coordination models mostly due to the steric hindrance of these substituents, and the electron-withdrawing or donating effects likely influence the strength of the ligand fields and the Dy(iii) ion anisotropy. Measurements of alternating-current (ac) susceptibility on complexes 1-4 reveal that complexes 3 and 4 display significant zero-field single-molecule magnetic (SMM) behavior with barrier energy Ueff/kB = 14.8 K, τ0 = 1.8 × 10(-5) s and Ueff/kB = 9.2 K, τ0 = 1.7 × 10(-5) s, respectively, whereas 1 and 2 exhibit field-induced SMM behavior, and these differences are attributed to the alteration on the periphery β-diketonate ligands. Their distinct slow magnetic relaxation behaviors were related to their different individual Dy(iii) ion magnetic anisotropy and intramolecular coupling, which were confirmed by ab initio calculations. PMID:26905041

  12. Synthesis, spectroscopic studies, molecular modeling and antimicrobial activity of binuclear Co(II) and Cu(II) complexes of 4,6-diacetylresorcinol

    Shebl, Magdy; Khalil, Saied M. E.; Taha, A.; Mahdi, M. A. N.

    2013-09-01

    Reactions of 4,6-diacetylresorcinol with different cobalt(II) and copper(II) salts viz., OAc-, Cl-, NO3- and SO42-, yielded a new series of binuclear metal complexes. Reactions of the ligand with these metal ions in the presence of a secondary ligand (L‧) [O,O-donor; acetylacetone, N,O-donor; 8-hydroxyquinoline or N,N-donor; 1,10-phenanthroline and N,N,N‧,N‧-tetramethylethylenediamine] in 1:2:2 (L:M:L‧) molar ratio yielded mixed-ligand complexes with different molar ratios. The metal complexes were characterized by elemental and thermal analyses, IR, electronic, ESR and mass spectra as well as conductivity and magnetic susceptibility measurements. The analytical and spectroscopic data suggested that the H2L ligand behaves as a neutral, monobasic or dibasic tetradentate ligand, depending on the type of the anion and secondary ligand used, through the two phenolic and two carbonyl groups. Electronic spectra, magnetic and conductivity measurements showed that all complexes are octahedral with non-electrolytic nature. The profile of ESR spectra of copper(II) complexes suggested the octahedral geometry and the spin Hamiltonian parameters of the complexes were calculated and discussed. Molecular orbital calculations were performed for metal complexes using Hyperchem 7.52 program on the bases of PM3 level and the results correlated with the experimental data. The free ligand and some of its metal complexes showed antimicrobial activity towards some of Gram-positive and Gram-negative bacteria, yeast (Candida albicans) and fungus (Aspergillus fumigatus).

  13. Vanadium-induced formation of thiadiazole and thiazoline compounds. Mononuclear and dinuclear oxovanadium(v) complexes with open-chain and cyclized thiosemicarbazone ligands.

    Rubcić, Mirta; Milić, Dalibor; Horvat, Gordan; Dilović, Ivica; Galić, Nives; Tomisić, Vladislav; Cindrić, Marina

    2009-11-28

    Reactions of the salicylaldehyde 4-phenylthiosemicarbazone (H(2)L) with selected vanadium(iv) and vanadium(v) precursors ([VO(acac)(2)], [VO(OAc)(2)], VOSO(4), [V(2)O(4)(acac)(2)]) were investigated under aerobic conditions in different alcohols (methanol, ethanol, propanol). In all examined cases mononuclear alkoxo vanadium(v) complexes [VOL(OR)] (1) (OR = OMe, OEt, OPr) were isolated as major products. On prolonged standing, mother liquids afforded dinuclear vanadium(v) complexes [V(2)O(3)(L(cycl))(2)(OR)(2)] (3) (OR = OMe, OEt, OPr), where L(cycl)(-) represents 1,3,4-thiadiazole ligand, formed by vanadium-induced oxidative cyclization of H(2)L. When [VO(acac)(2)] or [V(2)O(4)(acac)(2)] were used as precursors, in addition to products 1 and 3, a thiazoline derivative HL(acac)(cycl) (2) was isolated. This compound, formed by a reaction between acetylacetone and H(2)L, represented the second type of cyclic product. The products were characterized by IR and NMR spectroscopies, TG analysis, and in some cases by single-crystal X-ray diffraction. To the best of our knowledge, compounds [V(2)O(3)(L(cycl))(2)(OR)(2)] represent the first structurally characterized dinuclear vanadium(v) complexes with a thiadiazole moiety acting as a bridging ligand. Complexes 1 and 3, when dissolved in an appropriate alcohol, underwent substitution of the alkoxo ligand as confirmed by XRPD. The kinetics of reactions in methanolic solutions was qualitatively studied by UV-Vis and ESMS spectrometries. Under the experimental conditions applied, a relatively slow formation of the mononuclear complex [VOL(OMe)] and an even slower formation of the cyclic species 2 were observed, whereas the presence of dinuclear compound [V(2)O(3)(L(cycl))(2)(OMe)(2)] in the reaction mixture could not be detected. PMID:19885541

  14. Synthesis and fabrication of Y{sub 2}O{sub 3}:Tb{sup 3+} and Y{sub 2}O{sub 3}:Eu{sup 3+} thin films for electroluminescent applications: Optical and structural characteristics

    Alarcón-Flores, G., E-mail: alar_fbeto@yahoo.com [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, IPN, Legaría 694, Irrigación, C.P. 11500, México D.F. (Mexico); García-Hipólito, M. [Instituto de Investigaciones en Materiales, UNAM, Apdo. Postal 70-360, Delegación Coyoacán, C.P. 04150, México D.F. (Mexico); Aguilar-Frutis, M. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, IPN, Legaría 694, Irrigación, C.P. 11500, México D.F. (Mexico); Carmona-Téllez, S. [Instituto de Física, UNAM, Coyoacán, C.P. 04150, México D.F. (Mexico); Martinez-Martinez, R. [Universidad Tecnológica de la Mixteca, Carretera Acatlima Km 2.5, Huajuapan de León Oaxaca, C.P. 69000, México (Mexico); Campos-Arias, M.P. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, IPN, Legaría 694, Irrigación, C.P. 11500, México D.F. (Mexico); Zaleta-Alejandre, E. [Universidad Autónoma del Estado de Hidalgo-Escuela Superior de Apan, Carretera Apan-Calpulalpan Km. 8, C.P. 43920, Apan, Hidalgo (Mexico); and others

    2015-01-15

    Terbium, europium and yttrium β diketonates have been synthesized from acetylacetone and inorganic metal salts and used as precursors for the deposition of Tb{sup 3+} or Eu{sup 3+} doped Y{sub 2}O{sub 3} polycrystalline films by the ultrasonic spray pyrolysis technique. The films were deposited on c-Si substrates at temperatures in the 400–550 °C range. The optical and structural characterization of these films as a function of substrate temperature and Tb{sup 3+} and Eu{sup 3+} concentration was carried out by means of photoluminescence (PL), cathodoluminescence (CL), infrared (IR), ellipsometry, and UV–visible spectroscopy and atomic force microscopy (AFM), energy dispersive spectroscopy (EDS) and X ray diffraction (XRD) measurements respectively. The PL intensity from these films was found to depend on deposition temperature. Films deposited above 450 °C exhibited the characteristic PL peaks associated with either Tb{sup 3+} or Eu{sup 3+} intra electronic energy levels transitions. The most intense PL emission was found for dopant concentration of 10 at% for Tb{sup 3+} and at 8 at% for Eu{sup 3+} ions into precursor solution. In both cases concentration quenching of the PL emission was observed for concentrations above these values. The films had a refractive index (1.81), low average surface roughness (∼62 Å) and a UV–Vis. transmission of the order of 90 %T. - Highlights: • Terbium, europium and yttrium β diketonates have been synthesized. • Luminescent thin films of Y{sub 2}O{sub 3}:Tb{sup 3+} and Y{sub 2}O{sub 3}:Eu{sup 3+} were obtained. • Optical and structural characteristics of these thin films are presented. • The films had a refractive index (1.81) and low average surface roughness (∼62 Å)

  15. Exploitation of pulsed flows for on-line dispersive liquid-liquid microextraction: Spectrophotometric determination of formaldehyde in milk.

    Nascimento, Carina F; Brasil, Marcos A S; Costa, Susana P F; Pinto, Paula C A G; Saraiva, Maria Lúcia M F S; Rocha, Fábio R P

    2015-11-01

    Formaldehyde is often added to foods as a preservative, but it is highly toxic to humans, having been identified as a carcinogenic substance. It has also been used for the adulteration of milk in order to diminish the bacteria count and increase the shelf life of the product. Herein, we present a green dispersive liquid-liquid microextraction procedure in a flow-batch system for the determination of formaldehyde in milk. Pulsed flows were exploited for the first time to improve the dispersion of the extractant in the aqueous phase. The Hantzsch reaction was used for the derivatization of formaldehyde and the product was extracted with the ionic liquid (IL) trihexyltetradecylphosphonium chloride with methanol as the disperser. The flow-batch chamber was made of stainless steel with the facility for resistive heating to speed up the derivatization reaction. Spectrophotometric measurements were directly carried out in the organic phase using an optical fiber spectrophotometer. The limit of detection and coefficient of variation were 100 μg L(-1) and 3.1% (n=10), respectively, with a linear response from 0.5 to 5.0 mg L(-1), described by the equation A=0.088+0.116CF (mg L(-1)) in which A is absorbance and CF is formaldehyde concentration in mg L(-1). The estimated recoveries of formaldehyde from spiked milk samples ranged from 91% to 106% and the slopes of the analytical curves obtained with reference solutions in water or milk were in agreement, thus indicating the absence of matrix effects. Accuracy was demonstrated by the agreement of the results with those achieved by the reference fluorimetric procedure at the 95% confidence level. The proposed procedure allows for 10 extractions per hour, with minimized reagent consumption (120 μL of IL and 3.5 μL acetylacetone) and generation of only 6.7 mL waste per determination, which contribute to the eco-friendliness of the procedure. PMID:26452946

  16. Experimental setup and analytical methods for the non-invasive determination of volatile organic compounds, formaldehyde and NO{sub x} in exhaled human breath

    Riess, Ulrich; Tegtbur, Uwe [Hannover Medical School, Sports Physiology and Sports Medicine, Carl-Neuberg-Str. 1, 30625 Hannover (Germany); Fauck, Christian; Fuhrmann, Frank; Markewitz, Doreen [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54 E, 38108 Braunschweig (Germany); Salthammer, Tunga, E-mail: tunga.salthammer@wki.fraunhofer.de [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54 E, 38108 Braunschweig (Germany)

    2010-06-11

    Different analytical devices were tested and evaluated for their suitability of breath gas analysis by examining the physiological parameters and chemical substances in the exhaled breath of ten healthy probands during light cycling in dependence of methanol-rich nutrition. The probands exercised under normal breathing conditions on a bicycle ergometer. Breath air was exhaled into a glass cylinder and collected under steady-state conditions. Non-invasively measured parameters were pulse rate, breath frequency, temperature, relative humidity, NO{sub x}, total volatile organic compounds (TVOC{sub PAS}), carbon dioxide (CO{sub 2}), formaldehyde, methanol, acetaldehyde, acetone, isoprene and volatile organic compounds (VOCs). Methanol rich food and beverages strongly influenced the concentration of methanol and other organic substances in human breath. On the other hand, nutrition and smoking had no clear effect on the physical conditions of the probands. The proton transfer reaction mass spectrometry (PTR-MS) method was found to be very suitable for the analysis of breath gas but the m/z 31, if assigned to formaldehyde, is sensitive to interferences. The time vs. concentration curves of nitric oxide showed sudden peaks up to 120 ppb in most of the measurements. In one case a strong interference of the NO{sub x} signal was observed. The time resolved analysis of exhaled breath gas is of high capability and significance for different applications if reliable analytical techniques are used. Some compounds like nitric oxide (NO), methanol, different VOCs as well as sum parameters like TVOC{sub PAS} are especially suitable as markers. Formaldehyde, which is rapidly metabolized in the human body, could be measured reliably as a trace component by the acetylacetone (acac) method but not by PTR-MS.

  17. Metal oxide films on glass and steel substrates

    A variety of thin (10-1000nm) metal oxide films have been deposited on flat glass substrates by the pyrolysis of an aerosol of metal acetylacetonates in a suitable carrier. The optical characteristics and thickness of the films have been measured and particular interest has centered on the use of a novel pin on disc apparatus to measure the physical durability of such thin films. Characteristic friction/penetration force traces have been established for 1st Series transition metal oxide films and some ranking in terms of 'hardness' established. The use of SnO2 - coated glass for electrodes in a light modulator cell has been examined. The electrochromic behaviour of a silver matrix in DMSO electrolyte has been observed in a small glass cell and by cyclic voltammetry on a vitreous carbon electrode. Optimum conditions for practical light-shutter have been established and electrode processes elucidated. A corrosion study of mild steel in two different water/organic electrolytes of industrial importance has been carried out. Mechanisms to account for the corrosion observed have been presented. Support for the usual anodic reaction is presented Fe → Fe2+ + 2e but in the electrolyte operated at low pH film formation of a water soluble organic 'tar' has been confirmed and the proposed reaction Fe2+ + H2O → FeOH+ + H+ leads to a local increase in [H+] which accounts for the observed corrosion rate. In contrast, corrosion behaviour in the pH8 electrolyte supports the view that the rate limiting reduction reaction is possibly oxygen (or water) reduction although some contribution from an organic 'impurity' cannot be ruled out. Coatings of Fe3O4 on mild steel have been prepared by CVD using pneumatic spraying techniques and the corrosion behaviour of coated electrodes in organic-phosphate electrolyte (pH8) has been examined. (author)

  18. Quartz Crystal Microbalance Coated with Sol-gel-derived Thin Films as Gas Sensor for NO Detection

    S. J. O’Shea

    2003-10-01

    Full Text Available This paper presents the possibilities and properties of Indium tin oxide (ITO-covered quartz crystal as a NOx toxic gas-sensor. The starting sol-gel solution was prepared by mixing indium chloride dissolved in acetylacetone and tin chloride dissolved in ethanol (0-20% by weight. The ITO thin films were deposited on the gold electrodes of quartz crystal by spin-coating technique and subsequently followed a standard photolithography to pattern the derived films to ensure all sensors with the same sensing areas. All heat treatment processes were controlled below 500°C in order to avoid the piezoelectric characteristics degradation of quartz crystal (Quartz will lose its piezoelectricity at ~573°C due to the phase change from α to β. The electrical and structural properties of ITO thin films were characterized with Hall analysis system, TG/DTA, XRD, XPS, SEM and etc. The gas sensor had featured with ITO thin films of ~100nm as the receptor to sense the toxic gas NO and quartz crystal with frequency of 10MHz as the transducer to transfer the surface reactions (mass loading, etc into the frequency shift. A homemade setup had been employed to measure the sensor response under the static mode. The experimental results had indicated that the ITO-coated QCM had a good sensitivity for NO gas, ~12Hz/100ppm within 5mins. These results prove that the ITO-covered quartz crystals are usable as a gas sensor and as an analytical device.

  19. Preparation of zirconia coatings by hydrolysis of zirconium alkoxide with hydrogen peroxide

    Zirconia has gained a great deal of attention because of its superior properties of mechanical strength, chemical resistance, and ionic conductivity. Zirconia coatings and thin films are receiving attention as tribological and thermal barrier coatings for engines, high-reflective coatings, solid electrolytes for fuel cells, oxygen sensors, etc. The sol-gel coating method has several advantages, such as low processing temperatures, homogeneity, control of micro-structure, and good productivity compared to chemical vapor deposition and physical vapor deposition. However, there are few reports concerning the preparation of zirconia coatings and thin films by the sol-gel method. Up to the present, zirconia coatings have been prepared from zirconium propoxide (not heated), zirconium tetrabutoxide modified by acetylacetone and ethyl acetoacetate, zirconium diethoxydichloride (ZrCl2(OC2H5)2), and a hydrosol prepared from a zirconium oxychloride solution. Coatings of 8.8-mol%-yttria-doped zirconia were fabricated using a transparent and spinnable sol prepared by hydrolysis of zirconium alkoxide with hydrogen peroxide and nitric acid. The sol gave a crack-free coating film consisting of fine grains. The crystalline phase was cubic after heating of 1,000 and 1,200 C and cubic and tetragonal at 1,350 C, with the coating being highly oriented in the (111) plane, especially at 1,000 C. Activation energy of the coating films was higher than that of the bulk. Transmittance through a film thickness of about 0.3 μm on each side was 75%

  20. Structural characterization and DFT study of V(IV)O(acac)2 in imidazolium ionic liquids.

    Mota, Andreia; Hallett, Jason P; Kuznetsov, Maxim L; Correia, Isabel

    2011-09-01

    We report the structural characterization of vanadyl acetylacetonate in imidazolium room temperature ionic liquids--bbimNTf(2), bmimNTf(2), C(3)OmimNTf(2), bm(2)imNTf(2), bmimPF(6), bmimOTf, bmimBF(4), bmimMeCO(2), bmimMeSO(4), bmimMe(2)PO(4) and bmimN(CN)(2)--and organic solvents. The complex was characterized by visible electronic (Vis) and EPR spectroscopies. VO(acac)(2) shows solvatochromism in the selected ionic liquids and behaves as in organic solvents, evidencing coordination of the ionic liquid anion in the solvents with higher coordinating ability. The Lewis basicity order obtained for the IL anions was: PF(6)(-) < NTf(2)(-) < OTf(-)≈ MeCO(2)(-) < MeSO(4)(-) < BF(4)(-)≈ N(CN)(2)(-) < Me(2)PO(4)(-). The solvent effect on the spectroscopic data was tentatively examined using linear solvation energy relationships based on the Kamlet-Taft solvent scale (α, β and π*), however no suitable correlation was found with all data. The EPR characterization showed the presence of two isomers in bmimOTf, bmimMeCO(2) and bmimMe(2)PO(4), suggesting coordination of the ionic liquid anions in both equatorial and axial positions. The full geometry optimization of cis-/trans-VO(acac)(2)(OTf)(-) and cis-/trans-VO(acac)(2)(OTf)(mmim) structures was done at the B3P86/6-31G* level of theory. The calculations confirm that the anion OTf(-) is able to coordinate to VO(acac)(2) with the trans isomer being more stable than the cis by 4.8 kcal mol(-1). PMID:21789301