- Surfactant-assisted crystallization of porous Mn2O3 anode materials for Li-ion batteries
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MnCO3 precursors with different morphologies were crystallized using three kinds of surfactants as soft templates, i.e., cation surfactant cetyl trimethyl ammonium bromide (CTAB), anion surfactant sodium dodecyl sulfate (SDS) and neutral poly(vinyl pyrrolidone) (PVP). When PVP was used, the reaction manner was changed from only stirring at room temperature to a hydrothermal route. Under hydrothermal conditions, different ethanol/water ratios and sources of CO32- (NaHCO3 and urea) were used. Porous cubic, regular spherical and nut-like spherical Mn2O3 samples can be obtained by a simple post-annealing process. The correlation between the morphology of Mn2O3 and its performance as an anode material for Li-ion batteries was evaluated. The nut-like spherical Mn2O3 sample has the best cycling performance, with a specific discharge capacity of 925 mA h g-1 at a current density of 100 mA g-1 after 180 cycles. The sample composed of cubes and spheres has superior rate performance. The specific discharge capacity decreases with increasing current density from ~872 mA h g-1 at 100 mA g-1 to ~361 mA h g-1 at 2000 mA g-1.
- Li, Keyan,Shua, Fenfen,Guo, Xinwen,Xue, Dongfeng
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- Supramolecular Interactions Induced Chirality Transmission, Second Harmonic Generation Responses, and Photoluminescent Property of a Pair of Enantiomers from in Situ [2 + 3] Cycloaddition Synthesis
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Spontaneous resolutions from an in situ reaction especially for a Sharpless reaction are really rare. Here we display a new pair of enantiomeric compounds Δ- and Λ-[Mn(4-tzba)(bpy)2·H2O](bpy)·3H2O (labeled as Δ-1 and Λ-1 respectively) (4-tzba = 4-tetrazolbenzoic acid; bpy = 2,2′-bipyridine) from a Sharpless reaction. They crystallized in the P212121 chiral space group and demonstrated strong second harmonic generation (SHG) responses and red photoluminescence property. The chiral metal conformations were captured by the introduction of the distorted bpy and the in situ synthesized 4-tzba ligands. The hydrogen bonds connecting the 4-tzba and central metal play a crucial role in the chirality transmission, as well as the donor-acceptor type SHG nonlinear response.
- Gao, Ji-Xing,Xiong, Jian-Bo,Xu, Qing,Tan, Yu-Hui,Liu, Yi,Wen, He-Rui,Tang, Yun-Zhi
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- Topotactic reduction as a synthetic route for the preparation of low-dimensional Mn(II) oxide phases: The structure and magnetism of LaAMnO 4-x (A = Sr, Ba)
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Reaction of LaSrMnO4 with CaH2 at 420 °C yields LaSrMnO3.67(3). Raising the temperature to 480 °C yields the Mn(II) phase LaSrMnO3.50(2). Neutron powder diffraction data show both phases adopt body-centred orthorhombic crystal structures (LaSrMnO 3.67(3), Immm: a = 3.7256(1) A, b = 3.8227(1) A, c = 13.3617(4) A; LaSrMnO3.50(2), Immm: a = 3.7810(1) A, b = 3.7936(1) A, c = 13.3974(3) A) with anion vacancies located within the equatorial MnO2-x planes of the materials. Analogous reactivity is observed between LaBaMnO4 and CaH2 to yield body-centred tetragonal reduced phases (LaBaMnO3.53(3), I4/mmm: a = 3.8872(1)A, c = 13.6438(2) A). Low-temperature neutron diffraction and magnetisation data show that LaSrMnO3.5 and LaBaMnO3.5 exhibit three-dimensional antiferromagnetic order below 155 K and 135 K respectively. Above these temperatures, they exhibit two-dimensional antiferromagnetic order with paramagnetic behaviour observed above 480 K in both phases. The origin of the low dimensional magnetic order and ordering of the anion vacancies in the reduced phases is discussed.
- Kitchen, Helen J.,Saratovsky, Ian,Hayward, Michael A.
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- Synthesis, spectral characterization, density functional theory studies, and biological screening of some transition metal complexes of a novel hydrazide–hydrazone ligand of isonicotinic acid
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Novel Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) complexes (1–7) of hydrazide–hydrazone ligand (H2L) derived from the condensation of isonicotinic acid hydrazide with (Z)-N′-(2-nitrobenzylidene)-3-oxobutanehydrazide have been prepared. The ligand and its chelates were characterized based on elemental analysis, spectral, thermal analysis, molar conductance, and magnetic moment measurements. Besides, density functional theory (DFT) computations have been conducted to study structures and energetics of the ligand and its complexes. The IR spectra showed that the ligand was chelated with the metal ion in a monobasic tridentate manner using ONO donors in all complexes except Zn(II) complex (5) where the ligand binds with Zn(II) ion as a dibasic tridentate utilizing ONO donors. The magnetic moment and electronic spectral data revealed octahedral and square pyramidal geometries for complexes (1, 7) and (2, 4, 5), respectively, whereas a square planar geometry was suggested for 3. DFT studies show that the Cd(II) center reveals interesting structural deviations from regular octahedral geometry in the resulting hexa-coordinated complex [Cd(H2L)2].2H2O (6) assumes a trigonal prismatic (TP) structure for this complex. The antibacterial and antifungal activities of the ligand and its complexes have been investigated with different bacterial and fungal strains. The data revealed that Hg(II) complex (7) demonstrated a very good antibacterial and antifungal activity than others. Highlights: A new hydrazide–hydrazone ligand of isonicotinic acid was synthesized. Seven mononuclear Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) complexes of the new ligand were prepared and characterized by different tools. DFT studies have been carried out to study the structure of the ligand and its complexes. Antimicrobial activities of the ligand and its complexes were studied against a variety of bacterial and fungal strains by using disk diffusion method and results were compared with standard drugs.
- El-Nahas, Ahmed M.,Kashar, Tahani I.,Tolan, Dina A.,Yoshizawa, Kazunari
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- Synthesis, structure and catalytic promiscuity of a napthyl-pyrazole Mn(II) complex and structure–activity relationships
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The napthyl/pyridine-pyrazole-derived complexes, [Mn(L1)Cl2] (1), [Co(L1)Cl2] (2), [Cu(μ-Cl)(Cl)(L)]2 (3), [Cu2(L)2(N3)3(μ2-N3)] (4), and [Co(L2)Cl2] (5) (where L1 = bis-(3,5-dimethyl-pyrazol-1-ylmethyl)-napthalen-1-ylmethyl-amine (L1), L = 5-methyl-pyrazol-1-ylmethyl) -napthalen-1-ylmethyl-amine (L) and L2 = 2-[2-(3,5-dimethyl-pyrazol-1-yl)-1-methyl-ethyl]-pyridine), exhibited phenoxazinone synthase activity in methanol in the range 5–54 h?1. Binuclear copper(II) derivatives 3 and 4 show better catalytic activities than manganese(II) and cobalt(II) derivatives. The kinetic studies reveal that phenoxazinone chromophore is produced via a complex-substrate intermediate. Further, 3 and 4 show catecholase activity in methanol in the presence of oxygen. All the complexes showed potent antimicrobial activity against the tested strains of bacteria and fungi. Complex 1 was synthesized for the first time by mixing L1 and MnCl2 (1:1) and characterized by single-crystal X-ray crystallography, cyclic voltammetry, density functional theory, and thermogravimetry analysis. The present study suggests that napthyl/pyridyl-anchored pyrazole metal complexes are interesting scaffolds for the development of novel model compounds for biochemical reaction and efficient antimicrobial agents.
- Jana, Abhimanyu,Brand?o, Paula,Jana, Harekrishna,Jana, Atish Dipankar,Mondal, Gopinath,Bera, Pradip,Santra, Ananyakumari,Mahapatra, Ajit Kumar,Bera, Pulakesh
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- In situ X-ray absorption of Co/Mn/TiO2 catalysts for fischer-tropsch synthesis
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The reduction behavior of Co/TiO2 and Co/Mn/TiO2 catalysts for Fischer-Tropsch synthesis has been investigated by soft X-ray absorption spectroscopy (XAS). In situ XAS measurements of the L2,3 edges of Co and Mn have been carried out during reduction treatments of the samples in H2 at a pressure of 2 mbar and at temperatures up to 425?°C. The changes of Co and Mn 3d valences and the symmetries throughout the reduction have been determined by comparison with theoretical calculations based on the charge transfer multiplet code. Furthermore, bulk Co 3O4 has been reduced under the same conditions to evaluate the effect of TiO2 as a support on the reducibility of Co oxides. The average Co valence at the various temperatures has been determined from a linear combination of the reference spectra. It was found that the unsupported Co3O4 was easily reduced to Co0 at 425?°C, whereas the Co3O4 supported on TiO2 catalysts was only reduced to a mixture of CoO and Co0, even after 12 h reduction at 425?°C. The presence of Mn further retards the reduction of the supported Co3O4 particles. The MnIII ions were easily reduced to MnO at temperatures lower than 300 ?°C, and they remained in this oxidation state even after further temperature increase. In addition, catalytic tests in the Fischer-Tropsch synthesis reaction at a pressure of 1 bar indicate that the selectivity of these catalysts might be related to the extent of Co reduced after the activation treatment (i.e., the reduction with H2).
- Morales, Fernando,De Groot, Frank M.F.,Glatzel, Pieter,Kleimenov, Evgueni,Bluhm, Hendrik,Haì?vecker, Michael,Knop-Gericke, Axel,Weckhuysen, Bert M.
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- The synthesis of alkylmanganese(III) complexes. Crystal structure of MnMe(2-Me2NCH2C6H4)2
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Treatment of bis(3-N,N-dimethylaminopropyl)manganese(II) with methyllithium and subsequently with silver tetrafluoroborate gives bis(3-N,N-dimethylaminopropyl)methylmanganese(III) (1).The related complex bis(2-N,N-dimethylaminomethylphenyl)methylmanganese
- Latten, Jozef L.,Dickson, Ron S.,Deacon, Glen B.,West, Bruce O.,Tiekink, Edward R.T.
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- Thermal investigation of iron(III) and manganese(II, III) complexes of dianils derived from 6-formylkhellin: Synthesis, characterization
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Manganese and iron complexes of Schiff bases derived from 6-formylkhellin were prepared and characterized. Complexes of o-phenylenediamine derivative (ligand (I)) are monomeric or dimeric whereas those of p-phenylenediamine derivative (ligand (II)) are polymeric. The complexes obtained are characterized by a lower magnetic moment values. The complexes also have different solvent of crystallization with different nature of interaction. The thermal behaviour of the ligands and their metal complexes was investigated by means of DTA, TG, IR and X-ray diffraction spectroscopy. Ligand (I) shows different thermal behaviour from that of ligands (II) and (III). The complexes of ligand (II) give abnormal oxides as a final product during their thermal decomposition.
- Donia,El-Boraey,El-Samalehy
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- Microwave synthesis and inherent stabilization of metal nanoparticles in 1-methyl-3-(3-carboxyethyl)-imidazolium tetrafluoroborate
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The synthesis of Co-NPs and Mn-NPs by microwave-induced decomposition of the metal carbonyls Co2(CO)8 and Mn2(CO) 10, respectively, yields smaller and better separated particles in the functionalized IL 1-methyl
- Marquardt, Dorothea,Xie, Zailai,Taubert, Andreas,Thomann, Ralf,Janiak, Christoph
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- Kinetic study of the reaction of Mn(a6S5/2) with N2O from 448 to 620 K
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The gas phase reactivity of Mn(a6S5/2) with N2O in the temperature range 448-620 K is reported. Manganese atoms were produced by the photodissociation of 2-methylcyclopentadienyl manganese tricarbonyl and detected by laser-induced fluorescence. The reaction rate of the a6S5/2 state is very slow and temperature dependent. The rate constants are independent of total pressure indicating a bimolecular reaction. The rate constants are described in Arrhenius form by (2.05±0.45)×10-10 exp(-44.7±1.0 kJ/mol/RT) cm3 s-1.
- Campbell, Mark L.
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- Thermal analysis of manganese(II) complexes of general formula (Bu4N)2[MnBrnCl4-n]
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Thermal decomposition of compounds consisting of tetrahalogenomanganese(II) anions, [MnBrnCl4-n]2- (n = 0-4), and a tetrabutylammonium cation has been studied using the DSC, TG-FTIR, TG-MS and DTA techniques. The measureme
- Styczeń,Wyrzykowski,Gazda,Warnke
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- Electrodeposition and characterization of manganese coatings
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Manganese coatings of high quality are electrodeposited on steel substrates from simple sulfate solutions with addition of ammonium sulfate. Potentiodynamic scans and galvanostatic experiments are used to study manganese electrodeposition in a wide range of pH and current density. The effect of these variables on the microstructure, crystallography, mechanical, and corrosion-resistance properties of manganese deposits are investigated. It is found that ammonium sulfate enhances the reduction reaction of the manganese ion and provides a buffering effect. Two types of manganese deposits can be obtained depending on current density: crystalline films (type I, body-centered tetragonal γ-Mn) at low current density and amorphous films (type II) at high current density. Bright manganese films with (002) preferential orientation are electrodeposited at low pH. Type I structures show recrystallization at room temperature with phase transformation; the rate of phase transformation from γ-Mn to α-Mn (body-centered cubic) follows a Johnson-Mehl-Avrami kinetics. Crystalline films obtained at relatively high current density and low pH tend to have higher phase transformation rates. Amorphous films show good corrosion resistance both in acidic sodium sulfate/borate and sodium chloride electrolytes.
- Gong, Jie,Zangaria, Giovanni
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- Crystal structure and thermodecomposition kinetics of a three-dimensional supramolecular Mn complex with 8-hydroxyquinoline
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A three-dimensional supramolecular complex, [Mn(8-OHQ)3] ? CH3OH (8-OHQ is 8-hydroxyquinoline), C28H 22MnN3O4, was synthesized in methanol, and its crystal structure was determined by X-ray crystallography. The crystals are triclinic, space group P P 1, a = 10.823(2) A, b = 13.222(3) A, c = 17.283(3) A, α = 90.03(3)°, β = 93.15(3)°, γ = 92.58(3)°, V = 2467.0(8) A3, Z = 4, F(000) = 1072, ρ = 1.399 g/cm3, μ = 0.575 mm-1. Hydrogen bonds and intermolecular interactions, which are observed in the complex, stabilize its structure. The thermal decomposition kinetics of the complex was investigated under nonisothermal conditions using the Achar differential method and the Coats-Redfern integral method. Pleiades Publishing, Inc., 2006.
- Yang,Bi,Fan,Liu,Guo,Ai
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- Dioxygen Complexes of 3d Transition-Metal Atoms: Formation Reactions in the Gas Phase
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Reactions of ground-state 3d transition-metal atoms including Ti, Mn, Co, Ni, and Cu with molecular oxygen in Ar buffer gas have been investigated in the pressure range 5-700 Torr at 296 K.Attention has been given to termolecular association reactions in which mono(dioxygen) complexes are formed.A pulsed laser photolysis-laser fluorescence technique is used where metal atoms are produced by visible multiphoton dissociation of a volatile organometallic precursor in a static pressure reaction cell, and reactions of metal atoms are monitored by resonance fluorescence excitation at variable time delay following the photolysis pulse.The pres ent study completes a survey of the reactions of 3d transition-metal atoms with O2 under room temperature conditions, from which it emerges that reactivity with respect to complex formation is correlated with a dns1 valence electron configuration of the metal atom.Simplified RRKM calculations have been used to interpret termolecular rate constants for the association reactions in terms of a trend in the binding energies of the dioxygen complexes.
- Brown, Carl E.,Mitchell, S. A.,Hackett, Peter A.
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- Volatile and thermally stable mid to late transition metal complexes containing α-imino alkoxide ligands, a new strongly reducing coreagent, and thermal atomic layer deposition of Ni, Co, Fe, and Cr metal films
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Treatment of MCl2 (M = Cu, Ni, Co, Fe, Mn, Cr) with 2 equiv of α-imino alkoxide salts K(RR′COCNtBu) (R = Me, tBu; R′ = iPr, tBu) afforded M(RR′COCNtBu)2 or [Mn(RR′COCNtBu) 2]2 in 9-75% yields. These complexes combine volatility and high thermal stability and have useful atomic layer deposition (ALD) precursor properties. Solution reactions between Ni, Co, and Mn complexes showed that BH3(NHMe2) can reduce all to metal powders. ALD growth of Ni, Co, Fe, and Cr films is demonstrated. Mn film growth may be possible, but the films oxidize completely upon exposure to air.
- Kalutarage, Lakmal C.,Martin, Philip D.,Heeg, Mary Jane,Winter, Charles H.
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- Energetics of the manganese trimer and tetramer ions
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The binding energies of the manganese ions of trimer, Mn3+, and tetramer Mn4+, were determined via photodissociation experiments. In these experiments, the threshold energies were measured for the dissociation c
- Terasaki, Akira,Minemoto, Shinichirou,Kondow, Tamotsu
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- EQCM study of the electrodeposition of manganese in the presence of ammonium thiocyanate in chloride-based acidic solutions
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The influence of ammonium thiocyanate (NH4SCN) on the mechanism of manganese electrodeposition from a chloride-based acidic solution was investigated by cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The EQCM data were represented as plots dΔm dt-1 versus E, known as massograms. Because massograms are not affected by interference from the hydrogen evolution reaction, they clearly show the manganese reduction and oxidation processes. By comparing the voltammograms with their corresponding massograms, it was possible to differentiate mass changes due to faradaic processes from those due to non-faradaic processes. Morphology, chemical composition and structure of the manganese deposits formed in different potential ranges were analyzed by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD). The results showed that in the absence of NH4SCN, Mn(OH)2(s) is formed in the potential range -1.1 to -0.9 V due to the hydrogen evolution reaction in this region. At more cathodic potentials, the deposition of β-manganese and the inclusion of Mn(OH)2(s) into the deposit occur; both of these species underwent dissolution by non-faradaic processes during the anodic scan. In the presence of NH4SCN, the formation of α- and γ-manganese was observed. When the potential was ≤-1.8 V and [NH4SCN] exceeded 0.3 M, the α-manganese phase was favored.
- Díaz-Arista,Anta?o-López,Meas,Ortega,Chainet,Ozil,Trejo
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- Electrodeposition and characterization of manganese-bismuth system from chloride based acidic bath
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In this work, Mn-Bi system has been successfully electrodeposited on Cu/Si substrates from aqueous ammonium chloride containing electrolyte. A thermodynamic study of the electrolysis bath highlights the possible formation of manganese complexes (MnCl+,MnCl2,MnCl3-) and bismuth complexes (BiCl2+,BiCl2+,BiCl3,BiCl4-,BiCl52-,BiCl63-). The mechanism process involving Mn and Bi electrodeposition is investigated by cyclic voltammetry. Mn-Bi films can be grown under potentiostatic control. The physico-chemical, morphological and structural characterizations of the deposits were carried out by scanning electron microscopy (SEM) and X-rays analysis (XRD). The results reveal a granular surface quality and a heterogeneous chemical composition of the films. The energy dispersive spectroscopy (EDS) analysis reveals the presence of manganese and bismuth peaks whose relative intensities vary according to the imposed potential and the position on the sample. The X-rays diffraction analysis showed three different crystalline phases: α-manganese (body centred cubic system), γ-manganese (body centred tetragonal system) and bismuth (rhombohedral system).
- Benfedda,Benbrahim,Kadri,Chainet,Charlot,Coindeau
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- Free Radical-Mediated Heterogeneous Photocatalytic Reduction of Metal Ions in UV-Irradiated Titanium Dioxide Suspensions
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This paper describes the indirect photocatalytic reduction of four metal ions: Cd2+, Zn2+, Mn2+, and Tl+ using formate radical anions (CO2.-) generated in UV-irradiated aqueous TiO2 suspensions. Trends in the reactivity of these four metal ions are compared with corresponding rate constants reported in the literature for the homogeneous reactions of these metal ions with CO 2.- in aqueous media. In both cases, the reaction rates follow the same order: Cd2+ > Tl+ > Mn2+ > Zn2+. Using Tl+ as a model metal ion, a simple kinetics scheme is developed for the indirect reduction route, and the predictions from this model are shown to be in excellent agreement with experimental data.
- Somasundaram, Sashikala,Ming, Yong,Chenthamarakshan,Schelly, Zoltan A.,Rajeshwar, Krishnan
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- Experimental investigation of the Mg-Mn-Nd isothermal section at 450 °c
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The Mg-Mn-Nd isothermal section at 450°C was constructed experimentally using solid-solid diffusion couples and key alloys. Diffusion couples and key alloys were annealed at the same temperature for different annealing time periods to understand the diffusion behavior of the system components, and to achieve the phase equilibrium in the system. The phase relations and solubility limits were determined using scanning electron microscope coupled with wave/energy dispersive X-ray spectrometers, X-ray diffraction and metallography. No ternary compounds could be observed in this system at 450°C. The microstructures of the diffusion zones showed Mn either as a pure element or as a solute atom. However, microstructures of the annealed key alloys near the Mn-rich side showed the formation of Mn17Nd2 at 450°C. Other Mn binary compounds, Mn2Nd and Mn23Nd6, were observed only in the as-cast alloys, because they are not stable at 450°C. The experiments showed that Mn remained stationary in some diffusion zones forming Mn+(MgNd), Mn+(Mg3Nd) and Mn+Mg41Nd 5 two-phase regions. However, some of Mn atoms were diffusing in the system forming a continuous thin layer of pure Mn at the interface of pure Mg end-member, or to form (α-Nd)Mg,Mn, (MgNd) and (Mg 3Nd) ternary solid solutions. The solubility of Mn in these solutions was estimated as 3.0, 13.0 and 3.5 at.% Mn, respectively. Since Mn is in equilibrium with most of the phases in the system, the phase boundary lines are pointing toward Mn-rich corner except that of (α-Nd) Mg,Mn+(MgNd)+Mn17Nd2 three-phase field. This was confirmed based on the consistency of the results obtained from diffusion couples and key alloys.
- Mostafa, Ahmad,Medraj, Mamoun
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- Thermal analysis and vibrational spectroscopy of Mn(II)-urea-halide complexes: Comparative study of the metal-ligand bond strength
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The thermal study of Mn(II)-urea-halide complexes as a function of the metal-ligand bond strength is given. The results compared very well with those obtained from vibrational spectra. (C) 2000 Elsevier Science B.V.
- Keuleers,Janssens,Desseyn
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- Sodium azide as a reagent for solid state metathesis preparations of refractory metal nitrides
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Thermal initiation (.apprx.300°C) of a reaction between sodium azide and anhydrous metal chlorides (LaCl3, SmCl3, TiCl3, ZrCl4, HfCl4, VCl3, TaCl5, CrCl2, WCl6 and MnCl2) in sealed evacuated ampoules rapidly produces binary metal nitrides, dinitrogen and sodium chloride. The metalnitrides were purified by trituration with methanol and characterized b y powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and FT-IR.
- Hector, Andrew L.,Parkin, Ivan P.
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- Facile synthesis of MOF-derived Mn2O3 hollow microspheres as anode materials for lithium-ion batteries
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In this article, we report a facile and scalable route for the fabrication of Mn2O3 hollow microspheres by direct pyrolysis of Mn-based metal-organic frameworks at 450 °C with a heating rate of 10 °C min-1 in air. The effect of the heating rate on the morphology of the final samples has been also investigated. When evaluated as an anode material for LIBs, these Mn2O3 microspheres exhibited a reversible and stable capacity of 582 mA h g-1 after 60 cycles at a current density of 100 mA g-1. The improved capacity and excellent cycling stability of the as-prepared Mn2O3 microspheres could be attributed to the porous hollow structures, which can reduce diffusion length for lithium ions and electrons, and also can enhance structural integrity for buffering the volume expansion during the discharge/charge processes.
- Zheng, Fangcai,Xu, Shihao,Yin, Zhichen,Zhang, Yuanguang,Lu, Lu
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- Synthesis of orthorhombic LiMnO2 as a high capacity cathode for Li-ion battery by emulsion drying method
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Orthorhombic LiMnO2 was readily synthesized by calcination of an emulsion-dried powder precursor. The optimum synthesis condition to crystallize into zigzag layered β-NaMnO2 system was to calcine at 925 °C for 12 h in an Ar atmosphere. According to TEM observation, the prepared material from the emulsion-dried precursor consisted of highly ordered single crystalline particle. Li/LiMnO2 cell showed the capacity of about 173 mAh (g-oxide)-1 and excellent capacity retention upon cycling with help of cycle-induced spinel like phase, more than 155 mAh g-1 over 300 cycles at 25 °C.
- Myung, Seung-Taek,Komaba, Shinichi,Kumagai, Naoaki
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- Structural designing, spectral and computational studies of bioactive Schiff's base ligand and its transition metal complexes
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Transition metal complexes of Mn(II) and Ni(II) have been synthesized with novel bioactive Schiff's base ligand. Schiff's base ligand i.e. benzoylacetone-bis(2-amino-4-methylbenzothioazole) has been synthesized via condensation reaction between 2-amino-4-
- Gautam, Seema,Chandra, Sulekh,Rajor, Hament,Agrawal, Swati,Tomar, Praveen Kumar
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- Base-Free and Bisphosphine Ligand Dialkylmanganese(II) Complexes as Precursors for Manganese Metal Deposition
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The solid-state structures and the physical, solution magnetic, solid-state magnetic, and spectroscopic (NMR and UV/vis) properties of a range of oxygen- and nitrogen-free dialkylmanganese(II) complexes are reported, and the solution reactivity of these complexes toward H2 and ZnEt2 is described. The compounds investigated are [{Mn(μ-CH2SiMe3)2}8] (1), [{Mn(CH2CMe3)(μ-CH2CMe3)2}2{Mn(μ-CH2CMe3)2Mn}] (2), [Mn(CH2SiMe3)2(dmpe)] (3; dmpe = 1,2-bis(dimethylphosphino)ethane), [{Mn(CH2CMe3)2(μ-dmpe)}2] (4), [{Mn(CH2SiMe3)(μ-CH2SiMe3)}2(μ-dmpe)] (5), [{Mn(CH2CMe3)(μ-CH2CMe3)}2(μ-dmpe)] (6), [{Mn(CH2SiMe3)(μ-CH2SiMe3)}2(μ-dmpm)] (7; dmpm = bis(dimethylphosphino)methane), and [{Mn(CH2CMe3)(μ-CH2CMe3)}2(μ-dmpm)] (8). Syntheses for 1-4 have previously been reported, but the solid-state structures and most properties of 2-4 had not been described. Compounds 5 and 6, with a 1:2 dmpe/Mn ratio, were prepared by reaction of 3 and 4 with base-free 1 and 2, respectively. Compounds 7 and 8 were accessed by reaction of 1 and 2 with 0.5 equiv or more of dmpm per manganese atom. An X-ray structure of 2 revealed a tetrametallic structure with two terminal and six bridging alkyl groups. In the solid state, bisphosphine-coordinated 3-8 adopted three distinct structural types: (a) monometallic [LMnR2], (b) dimetallic [R2Mn(μ-L)2MnR2], and (c) dimetallic [{RMn(μ-R)}2(μ-L)] (L = dmpe, dmpm). Compound 3 exhibited particularly desirable properties for an ALD or CVD precursor, melting at 62-63 °C, subliming at 60°C (5 mTorr), and showing negligible decomposition after 24 h at 120°C. Comparison of variable-temperature solution and solid-state magnetic data provided insight into the solution structures of 2-8. Solution reactions of 1-8 with H2 yielded manganese metal, demonstrating the thermodynamic feasibility of the key reaction steps required for manganese(II) dialkyl complexes to serve, in combination with H2, as precursors for metal ALD or pulsed CVD. In contrast, the solution reactions of 1-8 with ZnEt2 yielded a zinc-manganese alloy with an approximate 1:1 Zn/Mn ratio.
- Price, Jeffrey S.,Chadha, Preeti,Emslie, David J. H.
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- Electrochemical codeposition of copper and manganese from room-temperature N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid
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The voltammetric behavior of N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid (BMP-TFSI) containing Cu(I), Mn(II), or mixtures of Cu(I) and Mn(II) as well as the electrodeposition of copper-manganese alloy coatings (Cu-Mn alloy
- Chen, Po-Yu,Deng, Ming-Jay,Zhuang, Ding-Xuan
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- Thermochemical study of gaseous salts of oxygen-containing acids: XV. Manganese molybdates and tungstates
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The existence of gaseous manganese molybdates and tungstates MnXO 4 and MnXO3 (X = Mo, W) was confirmed, and their standard enthalpies of formation and atomization were determined.
- Shugurov,Lopatin,Stolyarova
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- Manganese-based layered coordination polymer: Synthesis, structural characterization, magnetic property, and electrochemical performance in lithium-ion batteries
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Manganese-based layered coordination polymer ([Mn(tfbdc)(4,4′-bpy) (H2O)2], Mn-LCP) with microporous structure was synthesized by reaction of 2,3,5,6-tetrafluoroterephthalatic acid(H 2tfbdc) and 4,4′-bipyridine(4,4′-bpy) with manganese(II) acetate tetrahydrate in water solution. Mn-LCP was characterized by elemental analysis, IR spectra, thermogravimetric analysis, X-ray single-crystal structure analysis, and powder X-ray diffraction. Magnetic susceptibility data from 300 to 1.8K show that there is a weak antiferromagnetic exchange between Mn(II) ions in Mn-LCP. As anode material, the Mn-LCP electrode exhibits an irreversible high capacity in the first discharge process and a reversible lithium storage capacity of up to about 390 mA h/g from the fourth cycle. It might provide a new method for finding new electrode materials in lithium-ion batteries
- Liu, Qi,Yu, Lili,Wang, Ying,Ji, Yunzhou,Horvat, Josip,Cheng, Mei-Ling,Jia, Xiaoyan,Wang, Guoxiu
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- Tin-manganese alloy electrodeposits II. Corrosion performacne studies
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The corrosion performance of tin-manganese alloy electrodeposits either immersed in a quiescent sodium chloride solution or exposed to neutral salt spray (NSS) was studied. The results obtained were then compared with those for conventional pure zinc and zinc-nickel alloy electrodeposits with or without chromate passivation treatment. It was found that tin-manganese alloy electrodeposits provided much longer sacrificial protection against the corrosion of mild steel substrates than zinc-nickel alloy coatings, although they were inferior to pure zinc coatings. The prolonged sacrificial property was attributed to the high polarization resistance of tin-manganese alloy electrodeposits as revealed by linear polarization resistance techniques, which would only allow the corrosion and the consequent ennoblement of these coatings to proceed at a slow rate. The result of NSS tests indicated that tin-manganese alloy electrodeposits, with a time to red rust of about 1200 h, were as good as chromated zinc-nickel alloy coatings but far outperformed pure zinc coatings and nonchromated zinc-nickel coatings. The high corrosion resistance of tin-manganese alloy electrodeposits without any passivation treatment suggests that they may be an environmentally friendly replacement to zinc alloy coatings, which need toxic chromate conversion coatings for corrosion-resistance enhancement.
- Chen, Keming,Wilcox, Geoffrey D.
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- Studies of the reduction mechanism of selenium dioxide and its impact on the microstructure of manganese electrodeposit
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The influence of selenium dioxide (SeO2) on the microstructure and electrodeposition of manganese coatings obtained from a sulfate based neutral solution was investigated by material characterization methods and electrochemical techniques. The crystal structure and surface morphology of these coatings were studied by scanning electron microscopy (SEM) and powder X-ray diffraction spectroscopy (XRD), respectively. The SEM and XRD data showed that SeO2 could effectively accelerate phase transformation, and facilitate leveled and fine grain growth. The electrochemical results indicated that SeO2 could inhibit hydrogen evolution reaction and promote manganese deposition. The action of selenium dioxide in manganese deposition was found to be a reduction and adsorption mechanism. The process could be explained as following: First, Se (IV) was reduced to Se (0), and part of Se (0) future reduce to selenide, which then combined with the remainder Se (0) forming a complicate compound (multi-selenium ions).
- Sun, Yan,Tian, Xike,He, Binbin,Yang, Chao,Pi, Zhenbang,Wang, Yanxin,Zhang, Suxin
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- Decomposition behaviour of Mn(BH4)2 formed by ball-milling LiBH4 and MnCl2
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Manganese borohydride-based materials are of interest for hydrogen storage, as the Mn(BH4)2 compound has a theoretical hydrogen capacity of 9.53 wt.%. However, more needs to be known about the decomposition behaviour, in order to try to introduce reversibility. In this work, samples were prepared by ball-milling xLiBH4 and MnCl2 (where x = 2 or 3). The Mn(BH4)2 phase had XRD reflections consistent with the P3112 structure proposed by ?erny et al., and Raman spectroscopy indicted that the [BH4]- units were in an ionic tetrahedral configuration. The 3LiBH4 + MnCl2 sample contained excess LiBH4 which exhibited an orthorhombic to hexagonal phase change at 93 °C indicating partial substitution of Cl - for [BH4]-. Thermal decomposition of Mn(BH4)2 occurred between 130 and 181 °C for the 2LiBH4 + MnCl2 sample and 105-145 °C for 3LiBH 4 + MnCl2, with the concurrent evolution of hydrogen and diborane. Analysis of the decomposition products shows the formation of amorphous boron, and the probable formation of manganese metal (deduced from the presence of manganese oxide in a sample subsequently exposed to air).
- Liu, Ruixia,Reed, Daniel,Book, David
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- Synthesis, characterization, antimicrobial activity and DFT studies of 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione and its Mn(II), Co(II), Ni(II) and Zn(II) complexes
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A pyrimidine-based ligand, 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione (L), has been synthesized by the reaction of 2-aminopyrimidine with 2-hydroxy-1,4-napthoquinone. Reaction of the ligand with Ni(II), Co(II), Mn(II) and Zn(II) acetate gave the corresponding metal complexes which were characterized by spectroscopic techniques, (infrared, electronic), elemental analysis, room-temperature magnetometry, conductance measurements and thermogravimetry-differential scanning calorimetry (TG-DSC) analyses. The room-temperature magnetic data and electronic spectral measurements of the complexes gave evidence of 4-coordinate square planar/tetrahedral geometry. The thermal analyses values obtained indicated the monohydrate complexes. The antimicrobial screening of the compounds showed mild to very good results. The Mn(II) complex showed the best result within in the range of 11.5–29 mm. The electronic, structural and spectroscopic properties of the complexes were further discussed using density functional theory. Molecular docking studies showed significant binding affinity with the drug targets and the metal complexes have potentials to be used as drugs.
- Chioma, Festus,Ekennia, Anthony C.,Ibeji, Collins U.,Okafor, Sunday N.,Onwudiwe, Damian C.,Osowole, Aderoju A.,Ujam, Oguejiofo T.
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- FT-IR spectroscopic investigation of some Hofmann type complexes: M(1-phenylpiperazine)2Ni(CN)4 (M = Ni, Co, Cd, Pd or Mn)
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New Hofmann type complexes in the form of M(pp)2Ni(CN)4 (where pp = 1-phenylpiperazine and M = Ni, Co, Cd, Pd or Mn) have been prepared in powder form and their infrared spectra have been reported in the range of (4000-400) cm-1
- Senyel, Mustafa,Parlak, Cemal,Alver, Oezguer
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- Electrochemical behavior of manganese in chloride-bromide-ammonium electrolytes
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Halide-ammonium electrolytes were developed for electrochemical production of high-purity manganese.
- Kozin,Mashkova,Manilevich,Danil'tsev
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Read Online
- Structural Diversity and Trends in Properties of an Array of Hydrogen-Rich Ammonium Metal Borohydrides
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Metal borohydrides are a fascinating and continuously expanding class of materials, showing promising applications within many different fields of research. This study presents 17 derivatives of the hydrogen-rich ammonium borohydride, NH4BH4, which all exhibit high gravimetric hydrogen densities (>9.2 wt % of H2). A detailed insight into the crystal structures combining X-ray diffraction and density functional theory calculations exposes an intriguing structural variety ranging from three-dimensional (3D) frameworks, 2D-layered, and 1D-chainlike structures to structures built from isolated complex anions, in all cases containing NH4+ countercations. Dihydrogen interactions between complex NH4+ and BH4- ions contribute to the structural diversity and flexibility, while inducing an inherent instability facilitating hydrogen release. The thermal stability of the ammonium metal borohydrides, as a function of a range of structural properties, is analyzed in detail. The Pauling electronegativity of the metal, the structural dimensionality, the dihydrogen bond length, the relative amount of NH4+ to BH4-, and the nearest coordination sphere of NH4+ are among the most important factors. Hydrogen release usually occurs in three steps, involving new intermediate compounds, observed as crystalline, polymeric, and amorphous materials. This research provides new opportunities for the design and tailoring of novel functional materials with interesting properties.
- Cerny, Radovan,Cho, Young Whan,Grinderslev, Jakob B.,Jensen, Torben R.,Jepsen, Lars H.,Lee, Young-Su,Mller, Kasper T.
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p. 12733 - 12747
(2020/09/15)
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- Anti-hepatocellular carcinoma, antioxidant, anti-inflammation and antimicrobial investigation of some novel first and second transition metal complexes
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New coordination compounds of some selected metal ions from the first and second transition metals series with a Schiff base were synthesized and characterized. The Schiff base is derived from 4-Aminoantipyrine and 3-(hydroxyimino) butan-2-one. The compounds were characterized by different analysis tools like; elemental analysis, mass spectra, Fourier transform infrared (FTIR) as well as electronic spectra, magnetic measurements, molar conductance and thermal analysis technique. All complexes were formed with 1:1 (metal: ligand) stoichiometry except Mn (II) where 1:2 (Mn: ligand) is formed. Schiff base ligand interacted as a tridentate ligand by using the nitrogen atoms of the imine and the oximato groups and the carbonyl oxygen atom as donor groups with all studied metal ions except copper (II) and manganese (II) where the carbonyl oxygen is not shared in the coordination. These complexes show various physicochemical properties. X-ray powder diffraction shows different crystal systems; Cd (II) complex: hexagonal, Cu (II) complex: orthorhombic; and [Ni (II), Mn (II), Rh (III) & Pd (II)] complexes: monoclinic. All compounds showed potent cytotoxicity against the growth of human liver cancer cell lines. The square planar Pd (II) complex was more active than those of octahedral geometries of all other synthesized complexes. Cd (II) complex has the highest microbial growth inhibition than the rest of the prepared complexes. The docking active sites interactions were evaluated using the selected proteins EGFR tyrosine kinase and protein crystal structure of GlcN-O-P synthase. in vitro antioxidant assay revealed potent free radical scavenging activity of the three synthesized Cu (II), Pd (II) and Rh (III) complexes that exceeded the standard ascorbic acid. Pd (II) complex shows the most significant inhibition denaturation percent.
- Hassan, Safaa S.,Khalf-Alla, Perihan A.
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- Compound, thin film-forming material, and thin film manufacturing method
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A novel compound represented by the general formula (I) or (II) below: [in the formula, each of R1 and R2 independently represent a C1?12 hydrocarbon group, and Si(R3)3 is optionally substituted for a hydrogen atom in the hydrocarbon group; however, R1 and R2 are different groups; R3 represents a methyl or ethyl group; M represents a metal atom or silicon atom; and n is an integer from 1 to 4].
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(2019/04/26)
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- Structural Changes of Binary/Ternary Spinel Oxides During Ethanol Anaerobic Decomposition
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Several M-modified iron oxides of the spinel family have proven to be effective electron and O2? vectors for the production of hydrogen in the chemical-loop reforming of bio-alcohols. The present work is specifically focused on investigation of ethanol anaerobic decomposition over spinel oxides, which results in significant structural changes of the oxygen carrier material itself and corresponds to a first step of the chemical-loop reforming process. In particular, a series of binary/ternary M-modified ferrospinels were prepared by a co-precipitation method and tested in terms of both redox properties and intrinsic catalytic activity in addition to a complex ex situ study that encompasses the solid-state chemistry investigations of the fresh and reduced oxygen carrier materials. It was found that Co/Cu incorporation facilitates total/partial oxidation of ethanol, giving rise to high yields of H2, COx, and H2O; whereas Mn incorporation predominantly favored dehydrogenation and condensation reactions, leading to the formation of acetaldehyde and acetone. In addition, the incorporation of Mn contributed to significantly reduce the amount of coke formed; however, it caused a lower intrinsic reducibility, which was explained by the formation of a thermodynamically stable and hardly reducible layer of MnxFeyO solid solution.
- Vozniuk, Olena,Bazzo, Cristian,Albonetti, Stefania,Tanchoux, Nathalie,Bosselet, Fran?oise,Millet, Jean-Marc M.,Di Renzo, Francesco,Cavani, Fabrizio
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p. 2219 - 2230
(2017/06/27)
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- Synthesis, spectroscopic, coordination and biological activities of some transition metal complexes containing ONO tridentate Schiff base ligand
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The main target of this paper is to get an interesting data for the preparation and characterizations of metal oxide (MO) nanoparticles using H2L Schiff base complexes as precursors through the thermal decomposition procedure. Five Schiff base complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions were synthesized from 2-[(2-hydroxy-naphthalen-1-ylmethylene)-amino]-benzoic acid new adduct (H2L). Theses complexes were characterized using infrared, electronic, mass and 1H NMR spectroscopic techniques. The elemental analysis data was confirmed that the stoichiometry of (metal:H2L) is 1:1 molar ratio. The molar conductance indicates that all of complexes are non electrolytic. The general chemical formulas of these complexes is [M(L)(NH3)]·nH2O. All complexes are tetrahedral geometry. The thermal decomposition behavior of H2L hydrated and anhydrous complexes has been discussed using thermogravimetric analysis (TG/DTG) and differential thermal analyses (DTA) under nitrogen atmosphere. The crystalline phases of the reaction products were checked using X-ray diffractometer (XRD) and scanning electron microscopy (SEM).
- Belal,El-Deen,Farid,Zakaria, Rosan,Refat, Moamen S.
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p. 771 - 787
(2015/05/27)
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- Preparation of reduced iron powder using combined distribution of wood-charcoal by microwave heating
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In this paper, the influences of microwave heating with wood-charcoal as the reducing agent, on the reducing characterization of mill-scale were systematically investigated. The microstructures of the samples were characterized before and after microwave
- Ye, Qianxu,Zhu, Hongbo,Zhang, Libo,Ma, Ji,Zhou, Li,Liu, Peng,Chen, Jian,Chen, Guo,Peng, Jinhui
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p. 102 - 106
(2014/07/08)
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- Carbon monoxide oxidation by atmospheric oxygen on catalysts prepared by pyrolysis of transition metal β-diketonates on the synthetic foam ceramics
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The results of development of new catalytic systems for the carbon monoxide oxidation to dioxide are systematized. The catalysts were produced by gas-phase thermal decomposition of the transition metal acetylacetonates on the synthetic foam ceramics. The kinetic and activation parameters of the oxidation on the catalysts were studied and their relative activity was explored. The activity of catalysts at the oxidation with air oxygen were found to depend on the nature of the deposited metal and the carrier. A synergistic effect in the bimetallic copper catalysts was revealed.
- Didenkulova,Tsyganova,Shekunova,Aleksandrov
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p. 106 - 115
(2012/06/04)
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- Volatility and high thermal stability in mid- to late-first-row transition-metal diazadienyl complexes
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Treatment of MCl2 (M = Cr, Mn, Fe, Co, Ni) with 2 equiv of lithium metal and 1,4-di-tert-butyl-1,3-diazadiene (tBu2DAD) in tetrahydrofuran at ambient temperature afforded Cr(tBu2DAD) 2 (38%), Mn(tBu2DAD)2 (81%), Fe( tBu2DAD)2 (47%), Co(tBu2DAD)2 (36%), and Ni(tBu2DAD)2 (41%). Crystal structure determinations revealed monomeric complexes that adopt tetrahedral coordination environments and were consistent with tBu2DAD radical anion ligands. To evaluate the viability of M(tBu2DAD)2 (M = Cr, Mn, Fe, Co, Ni) as potential film growth precursors, thermogravimetric analyses, preparative sublimations, and solid-state decomposition studies were performed. Mn( tBu2DAD)2 is the most thermally robust among the series, with a solid-state decomposition temperature of 325 °C, a sublimation temperature of 120 °C/0.05 Torr, and a nonvolatile residue of 4.3% in a preparative sublimation. Thermogravimetric traces of all complexes show weight loss regimes from 150 to 225 °C with final percent residues at 500 °C ranging from 1.5 to 3.6%. Thermolysis studies reveal that all complexes except Mn(tBu2DAD)2 decompose into their respective crystalline metal powders under an inert atmosphere. Mn(tBu2DAD)2 may afford amorphous manganese metal upon thermolysis.
- Knisley, Thomas J.,Saly, Mark J.,Heeg, Mary Jane,Roberts, John L.,Winter, Charles H.
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p. 5010 - 5017
(2011/11/13)
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- Poly(pyrazolyl)aluminate complexes containing aluminum-hydrogen bonds
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The treatment of LiAlH4 with 2, 3, or 4 equiv of the 3,5-disubstituted pyrazoles Ph2pzH or iPr2pzH afforded [Li(THF)2][AlH2(Ph2pz)2] (97%), [Li(THF)][AlH(Ph2pz)3] (96%), [Li(THF)4] [Al(Ph2pz)4] (95%), and [Li(THF)][AlH(iPr 2pz)3] (89%). The treatment of ZnCl2 with [Li(THF)][AlH(Ph2pz)3] afforded Zn(AlH(Ph 2Pz)3)H (70%). X-ray crystal structures of these complexes demonstrated κ2 or κ3 coordination of the aluminum-based ligands to the Li or Zn ions. The treatment of [Li(THF)][AlH(Ph2pz)3] with MgBr2 or CoCl 2 in THF/Et2O solutions, by contrast, afforded the pyrazolate transfer products Mg2Br2(Ph2pz) 2(THF)3·2THF (25%) and Co2Cl 2(Ph2pz)2(THF)3·THF (23%) as colorless and blue crystalline solids, respectively. An analogous treatment of [Li(THF)][AlH(Ph2pz)3] with MCl2 (M = Mn, Fe, Ni, Cu) afforded metal powders and H2, illustrating hydride transfer from Al to M as a competing reaction path.
- Snyder, Christopher J.,Heeg, Mary Jane,Winter, Charles H.
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p. 9210 - 9212
(2011/10/31)
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- NUTRITIONAL FORMULATION
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The present invention relates to nutritional supplements that provide an adult with essential vitamins and minerals that may be lacking in the adult's diet and prevent chronic diseases, such as osteoporosis. A number of combinations of nutrients in set ratios are provided to increase the body's ability to absorb and use the nutrients. These combinations are important in helping the body reach the proper balance required for maximized function. Because adults over the age of 50 years have different nutritional needs, nutritional supplements specifically designed for them are also provided.
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- High temperature-pressure processing of mixed alanate compounds
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Mixtures of light-weight hydrides and elements were investigated to increase the understanding of the chemical reactions that take place between various materials. This report details investigations we have made into mixtures that include NaAlH4, LiAlH4, MgH2, Mg2NiH4, alkali(ne) hydrides, and early third row transition metals (V, Cr, Mn). Experimental parameters such as stoichiometry, heat from ball milling versus hand milling, and varying the temperature of high pressure molten state processing were studied to examine the effects of these parameters on the reactions of the complex metal hydrides.
- Berseth, Polly A.,Pittman, Jennifer,Shanahan, Kirk,Stowe, Ashley C.,Anton, Donald,Zidan, Ragaiy
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p. 2141 - 2145
(2009/02/05)
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- Stereoselective synthesis of (Z)-α-haloacrylic acid derivatives, and (Z)-haloallylic alcohols from aldehydes and trihaloesters or amides promoted by Rieke manganese
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A Mn*-promoted sequential process directed toward the synthesis of (Z)-α-halo-α,β-unsaturated esters or amides is described. In both cases, the process takes place with complete Z-stereoselectivity. In addition, (Z)-α-chloro-α,β-unsaturated ketones and carboxylic acids, and (Z)-haloallylic alcohols were readily prepared from (Z)-α-halo-α,β-unsaturated amides derived from morpholine, or esters. A mechanism has been proposed to explain the sequential process and the stereoselectivity observed. The Royal Society of Chemistry.
- Concellon, Jose M.,Rodriguez-Solla, Humberto,Diaz, Pamela
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p. 2934 - 2940
(2009/02/02)
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- Synthesis, spectroscopic and thermal studies of transition metal complexes derived from benzil and diethylenetriamine
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A macrocyclic ligand, bdta (where bdta = 3,6,9,12,15,18-hexaaza-1,2,10,11-tetraphenyl-2,9,11,18-tetraenecyclododecane) has been prepared by cyclocondensation of benzil with diethylenetriamine which efficiently encapsulates transition as well as pseudo-transition metal ions leading to the formation of M(bdta)Cl2 type complexes [where M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)]. The analytical, spectroscopic and magnetic moment data suggests an octahedral geometry for all the complexes. EPR spectra of Mn(II) and Cu(II) show considerable exchange interaction in the complex. They are non-conducting in DMSO. The TGA profile of the ligand and its complexes are identical and consists of two discreet stages. The voltammogram of Cu-complex exhibits a quasi-reversible one-electron transfer wave for Cu(II)/Cu(I) couple.
- Khan, Sadaf,Nami, Shahab A.A.,Siddiqi
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p. 269 - 274
(2008/02/13)
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- Heteroleptic tri-tert-butoxysilanethiolate complexes of manganese(II): Thermal studies
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The thermal behavior of Mn(II) silanethiolate series [Mn(SR) 2L(MeOH)n], where R=SSi(OBut)3, L=heterocyclic nitrogen base and n=0, 1 or 2 has been comparatively investigated using differential scanning calorimetry (DSC), t
- Kropidlowska, Anna,Strankowski,Gazda, Maria,Becker, Barbara
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p. 463 - 470
(2008/10/09)
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- Synthesis and characterization of 3,3′-bis(N-ferrocenyl methylene formylhydrazone)-2,2′-bipyridyl and its Cd(II), Hg(II), Cu(II), and Mn(II) Complexes
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In this article, 3,3′-bis(N-ferrocenylmethylene formylhydrazone)-2, 2′-bipyridyl and its Cd(II), Hg(II), Cu(II), and Mn(II) complexes have been synthesized and characterized by elemental analyses, IR, 1H NMR spectral, thermal analyses, and molar conductances. In the complexes, 3,3′-bis(N-ferrocenylmethylene formylhydrazone)-2,2′-bipyridyl coordinates to the transition metal ions using a methylenimine nitrogen, the amide oxygen in the enolic form, the pyridyl nitrogen, the acetate in a symmetrical bidentate manner, and one water molecule, all of which participate in coordination to form a binuclear complex. The ligand and the complexes are insoluble in common organic solvents and slightly soluble in strongly polar solvents such as DMF and DMSO.
- Wu, Ben-Lai,Liu, Cheng-Xiang,Yao, Ming-Xing,Zhang, Hong-Yun,Chen, Pei-Kun,Mao, Hong-Yan,Shen, Xiao-Qing,Liu, Shou-Chang
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p. 1709 - 1719
(2008/10/09)
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- Structurally Characterized Neutral Monoalkyl and -aryl Complexes of Manganese(II)
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The synthesis and X-ray crystal structures of the monomethyl and -phenyl manganese complexes [LMn(μ-Me)]2 (2) and LMnPh (3) (L = HC(CMeNAr)2, Ar = 2,6-iPr2C6H3) are reported. These complexes represent
- Chai, Jianfang,Zhu, Hongping,Fan, Hongjun,Roesky, Herbert W.,Magull, Joerg
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p. 1177 - 1179
(2008/10/09)
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- Nutritional supplement
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A nutritional supplement is provided that is designed to provide nutritional benefits as well as to assist the body with detoxification. By providing a supplement that serves both of these functions, the present invention may enable persons to improve their overall wellness.
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- Syntheses, molecular structures, and thermal decomposition of cyclopentadienyldicarbonylmanganese chalcogenide derivatives
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Transmetallation of the dichalcogenide complexes [CpMn(CO) 2]2(μ-X2) (X = S or Se) with M(CO) 5(thf) (M = Cr or W) afforded new heterometallic complexes CpMn(CO)2(μ-Se2)Cr(CO)5,
- Pasynskii,Grigoriev,Torubaev,Blokhin,Shapovalov,Dobrokhotova,Novotortsev
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p. 2689 - 2700
(2007/10/03)
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- Direct preparation of benzylic manganese reagents from benzyl halides, sulfonates, and phosphates and their reactions: Applications in organic synthesis
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The use of highly active manganese (Mn)*, prepared by the Rieke method, was investigated for the direct preparation of benzylic manganese reagents. The oxidative addition of the highly active manganese to benzylic halides was easily completed under mild conditions. Moreover, benzylic manganese sulfonates and phosphates were prepared by direct oxidative addition of Mn* to the carbon-oxygen bonds of benzylic sulfonates and phosphates. The resulting benzylic manganese reagents were found to undergo cross-coupling reactions with a variety of electrophiles. Most of these reactions were carried out in the absence of any transition metal catalyst under mild conditions. In addition, the use of highly active manganese was also studied for preparation of homo-coupled products of functionalized benzyl halides without transition metal catalysts. These useful approaches provided not only a facile synthetic route to the preparation of resoricinolic lipids but a facile synthesis of functionalized 4-benzylpyridines by regioselective and chemo selective γ-addition of benzylic group to N-alkoxycarbonylpyridinum salts.
- Suh, YoungSung,Lee, Jun-Sik,Kim, Seoung-Hoi,Rieke, Reuben D.
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- Thermal decomposition of triethanolamine and monoethanolethylenediamine complexes of some transition metal saccharinates
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The thermal decomposition behaviour of triethanolamine (TEA) and monoethanolethylenediamine (me-en) complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) saccharinates was studied under non-isothermal conditions by TG, DTA and DTG in dynamic nitrogen atmosphere. The decomposition of the TEA complexes proceeds via three main stages. The first stage involves exothermic removal of two CH2OH groups, due to degradation of uncoordinated ethanol groups of the TEA molecules, and the second and third stages correspond to formation of metal saccharinates and metals as the end products, respectively. All the me-en complexes show similar decomposition behaviour and, after evolution of two CH2OH groups, they progressively decompose through saccharinate intermediates and subsequently yield metals or metal oxides as the final residue. Tea complexes showed much higher thermal stability than their me-en analogues. A thermal decomposition mechanism for the metal complexes was suggested.
- Yilmaz,Topcu,Karadag
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p. 129 - 135
(2008/10/08)
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- Mono- and zerovalent manganese alkyl complexes supported by the α,α′-diiminato pyridine ligand: Alkyl stabilization at the expense of catalytic performance
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The mono- and zerovalent manganese alkyl complexes supported by the α,α′-diiminato pyridine ligand were analyzed. The reactivity pattern provides both activation of the vanadium metal and a two electron reduction pathway towards rare monovalent vanadium alkyls. The coordination geometry of manganese was identical to that of the Fe and Co supercatalysts with the same distorted square pyramidal arrangement.
- Reardon, Damien,Aharonian, Ghazar,Gambarotta, Sandro,Yap, Glenn P.A.
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p. 786 - 788
(2008/10/08)
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