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7439-96-5Relevant articles and documents
Surfactant-assisted crystallization of porous Mn2O3 anode materials for Li-ion batteries
Li, Keyan,Shua, Fenfen,Guo, Xinwen,Xue, Dongfeng
, p. 5094 - 5100 (2015)
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.
Supramolecular Interactions Induced Chirality Transmission, Second Harmonic Generation Responses, and Photoluminescent Property of a Pair of Enantiomers from in Situ [2 + 3] Cycloaddition Synthesis
Gao, Ji-Xing,Xiong, Jian-Bo,Xu, Qing,Tan, Yu-Hui,Liu, Yi,Wen, He-Rui,Tang, Yun-Zhi
, p. 1559 - 1564 (2016)
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.
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)
Kitchen, Helen J.,Saratovsky, Ian,Hayward, Michael A.
, p. 6098 - 6105 (2010)
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.
Synthesis, spectral characterization, density functional theory studies, and biological screening of some transition metal complexes of a novel hydrazide–hydrazone ligand of isonicotinic acid
El-Nahas, Ahmed M.,Kashar, Tahani I.,Tolan, Dina A.,Yoshizawa, Kazunari
, (2021)
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.
Synthesis, structure and catalytic promiscuity of a napthyl-pyrazole Mn(II) complex and structure–activity relationships
Jana, Abhimanyu,Brand?o, Paula,Jana, Harekrishna,Jana, Atish Dipankar,Mondal, Gopinath,Bera, Pradip,Santra, Ananyakumari,Mahapatra, Ajit Kumar,Bera, Pulakesh
, p. 2636 - 2653 (2019)
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.
In situ X-ray absorption of Co/Mn/TiO2 catalysts for fischer-tropsch synthesis
Morales, Fernando,De Groot, Frank M.F.,Glatzel, Pieter,Kleimenov, Evgueni,Bluhm, Hendrik,Haì?vecker, Michael,Knop-Gericke, Axel,Weckhuysen, Bert M.
, p. 16201 - 16207 (2004)
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).
The synthesis of alkylmanganese(III) complexes. Crystal structure of MnMe(2-Me2NCH2C6H4)2
Latten, Jozef L.,Dickson, Ron S.,Deacon, Glen B.,West, Bruce O.,Tiekink, Edward R.T.
, p. 101 - 108 (1992)
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
Thermal investigation of iron(III) and manganese(II, III) complexes of dianils derived from 6-formylkhellin: Synthesis, characterization
Donia,El-Boraey,El-Samalehy
, p. 987 - 1000 (2003)
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.
Microwave synthesis and inherent stabilization of metal nanoparticles in 1-methyl-3-(3-carboxyethyl)-imidazolium tetrafluoroborate
Marquardt, Dorothea,Xie, Zailai,Taubert, Andreas,Thomann, Ralf,Janiak, Christoph
, p. 8290 - 8293 (2011)
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
Kinetic study of the reaction of Mn(a6S5/2) with N2O from 448 to 620 K
Campbell, Mark L.
, p. 7515 - 7517 (1996)
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.
