Mn Acetate Research Articles

ChemInform Abstract: Manganese(III) Acetate Mediated Free‐Radical Phosphonylation of Flavones and Coumarins.

AbstractPhosphoryl radicals, generated by oxidation of diethyl phosphate with Mn(III) acetate, react selectively at the 3‐position to give products of biological interest.

Catalytic Oxidation of Benzene with Ozone Over Nanoporous Mn/MCM-48 Catalyst

The catalytic oxidation of a representative volatile organic compound, benzene, with ozone at a low temperature was investigated. A nanoporous MCM-48 material with a high specific surface area was used as the support for the catalytic oxidation for the first time. Mn, which has high activity at a low temperature, was used as the metal catalyst. To examine the effect of the Mn precursor, MCM-48 was impregnated with two different Mn precursors: Mn acetate and Mn nitrate. The characteristics of the synthesized catalysts were analyzed by Brunauer Emmett Teller surface area, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programmed reduction. MCM-48 impregnated with Mn acetate showed higher catalytic activity than MCM-48 impregnated with Mn nitrate. This result was attributed to the better dispersion within nanoporous MCM-48 and higher oxygen mobility of Mn oxides produced by Mn acetate. The catalytic activity was also shown to depend closely on the ozone concentration.

A convenient, high-yielding, chromatography-free method for the insertion of transition metal acetates into porphyrins

Presented is a quick and efficient method for the insertion of first-row transition metal acetates into 5,10,15,20-tetraphenyl porphyrin, utilizing Soxhlet extraction for the removal of the acetic acid by-product. High yields (>90%) and purity are achieved without requiring chromatographic purification. Basic Mn(III) and Fe(III) acetate may be used, as well as hydrated Co(II), Ni(II), and Cu(II) acetates as starting materials. In the case of Fe, an initial mixture of Fe(TPP)OAc and [Fe(TPP)]2O is formed, which can be quantitatively converted to Fe(TPP)OAc by treatment with acetic acid. The crystal structure of Fe(TPP)OAc is reported, and spectral data for all compounds is presented, including a correction of the literature UV–Vis data for Fe(TPP)OAc. Attempted metalation with basic Cr(III) acetate yielded a mixture of Cr(TPP)OAc and the oxo-bridged dimer. The latter cannot be converted to the desired acetate. No reaction occurred with vanadyl or titanyl acetate under the conditions used.

Syntheses, structures and properties of two manganese(II) metal–organic frameworks based on bromoisophthalate and bipyridyl-type co-ligands

Two new manganese(II) coordination polymers, [Mn 2 (bpe) 2 (4-Brip) 2 ] n ( 1 ) and {[Mn 3 (H 2 O) 2 (H-bpp) 2 (5-Brip) 4 ]·H 2 O} n ( 2 ), were prepared through hydrothermal reactions of Mn(II) acetate with H 2 -4-Brip or H 2 -5-Brip (H 2 -4/5-Brip = 4/5-bromoisopthaliac acid) and the bipyridyl-type co-ligands bpe or bpp (bpe = 1,2-bi(4-pyridyl)ethane and bpp = 1,3-bi(4-pyridyl)propane). The two complexes were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and X-ray single-crystal diffraction. Complex 1 has a complicated (3,5)-connected 3D 3-fold interpenetrating network with a Schläfli symbol of (4 2 .6 5 .8 3 )(4 2 .6), constructed of the ribbon-like chains having dimeric [Mn(COO)] 2 units bridged by 4-Brip. Complex 2 contains isophthalato-bridged trimanganese clusters as building units, which are linked by 5-Brip anions to form a 1D ladder-like chain with unidentate coordinated H-bpp decorated as pendants. And the chains are further linked by N H∙∙∙O and O H∙∙∙O hydrogen bonding to generate a 2D interlocked architecture. Dominant antiferromagnetic couplings were observed in complexes 1 and 2 . Two new manganese(II) coordination polymers were synthesized and characterized. Complex 1 exhibits a complicated 3D 3-fold interpenetrating network. Complex 2 possesses a 2D layer structure, and exists extensive hydrogen-bonding interactions. ► Two Mn(II) complexes were synthesized and characterized. ► Dominant antiferromagnetic couplings in 1 and 2 ► Compared with other isophthalate derivative complexes, the substituted groups have an effect on final structures.

Spectral and in vitro antimicrobial properties of 2-oxo-4-phenyl-6-styryl-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid transition metal complexes

2-oxo-4-phenyl-6-styryl-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid (ADP) was complexed with acetates of Mn(II), Ni(II), Cu(II) and Zn(II). The structures of the ligand and its metal complexes were characterized by microanalysis, IR, NMR, UV–vis spectroscopy, magnetic susceptibility and TGA–DTA analyses. Octahedral and square planar geometries were suggested for the complexes in which the central metal ion coordinated with O donors of ligand and acetate ions. Each ligand binds the metal using carboxylate oxygens. The ligand and complexes were evaluated for their antimicrobial activities against different species of pathogenic bacteria and fungi. The present novel pyrimidine containing complexes could constitute a new group of antibacterial and antifungal agents.

Use of X-ray Absorption Spectroscopy To Speciate Manganese in Airborne Particulate Matter from Five Counties Across the United States

The purpose of this study is to characterize manganese oxidation states and speciation in airborne particulate matter (PM) and describe how these potentially important determinants of PM toxicity vary by location. Ambient PM samples were collected from five counties across the US using a high volume sequential cyclone system that collects PM in dry bulk form segregated into "coarse" and "fine" size fractions. The fine fraction was analyzed for this study. Analyses included total Mn using ICP-MS and characterization of oxidation states and speciation using X-ray absorption spectroscopy (XAS). XAS spectra of all samples and ten standard compounds of Mn were obtained at the National Synchrotron Light Source. XAS data was analyzed using Linear Combination Fitting (LCF). Results of the LCF analysis describe differences in composition between samples. Mn(II) acetate and Mn(II) oxide are present in all samples, while Mn(II) carbonate and Mn(IV) oxide are absent. To the best of our knowledge, this is the first paper to characterize Mn composition of ambient PM and examine differences between urban sites in the US. Differences in oxidation state and composition indicate regional variations in sources and atmospheric chemistry that may help explain differences in health effects identified in epidemiological studies.

Catalytic oxidation of alkylbenzenes with ozone in acetic acid in the presence of strong acids

The oxidation of ethylbenzene with ozone in the acetic acid-sulfuric acid system in the presence of Mn(II) acetate and cumene in the acetic acid-trifluoroacetic acid system in the presence of Co(II) acetate has been studied. The main factors that affect the catalytic ozonation of alkylbenzenes are discussed. A redox catalysis mechanism is proposed. The kinetic characteristics of the main stages of the catalytic cycle have been determined.

Spectroscopic study on the interaction of ct-DNA with manganese Salen complex containing triphenyl phosphonium groups

The DNA binding properties of a bulky and hydrophobic Schiff base complex of manganese(III) [N,N′-bis(5-(triphenyl phosphonium methyl)salicylidene)-1,2-ethylene diamine chloride Mn(III) acetate] was examined by spectroscopic techniques. UV–vis titration data indicate both hypo and hyperchromic effect with addition of DNA to complex. A competitive binding study showed that the enhanced emission intensity of ethidium bromide (EB) in the presence of DNA was quenched by adding Mn Salen complex. This finding indicates that Mn Salen complex displaces EB from its binding site in DNA. Helix melting studies indicate improvement in the helix stability, and an increase in the melting temperature. The analysis of CD spectra represents the structural changes in DNA due to the binding of Mn Salen complex. The binding constant has been calculated using absorbance and fluorescence data. The results also represent that the binding process proceeds by strong electrostatic and hydrophobic interactions.

Catalytic ozone oxidation of benzene at low temperature over MnOx/Al-SBA-16 catalyst

The low-temperature catalytic ozone oxidation of benzene was investigated. In this study, Al-SBA-16 (Si/Al = 20) that has a three-dimensional cubic Im3m structure and a high specific surface area was used for catalytic ozone oxidation for the first time. Two different Mn precursors, i.e., Mn acetate and Mn nitrate, were used to synthesize Mn-impregnated Al-SBA-16 catalysts. The characteristics of these two catalysts were investigated by instrumental analyses using the Brunauer-Emmett-Teller method, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programmed reduction. A higher catalytic activity was exhibited when Mn acetate was used as the Mn precursor, which is attributed to high Mn dispersion and a high degree of reduction of Mn oxides formed by Mn acetate than those formed by Mn nitrate.

Mn(III)acetate-Induced Electron Transfer in Pentaammine Cobalt(III)Complexes of α-Amino Acids in Micellar Medium

A micellar catalyzed oxidation of pentaamminecobalt(III) complexes of α-amino acids by Mn(III)acetate in acidic medium yielding nearly 100% Co(II) and about 100% carbonyl compounds are ultimate products. The unbound amino acids yield about 100% of carbonyl compound in presence of micelles. The effect of variation of sulphuric acid has been carried. The decrease in UV-Visible absorbance at λ=502 nm for Co(III) complex corresponds to nearly 100% of the initial absorbance. In spite of the stoichiometry of Mn(III) to unbound ligand is 2:1, the ratio of Mn(III) to cobalt(III) complex is 1:1 accounting for about 100% reduction at the cobalt(III) centre. The kinetic and stoichiometric results have been accounted. A suitable mechanism consistent with the experimental findings has been proposed by involving a radical cation intermediate.

Comparative studies on manganese-based SOD mimetics, including the phosphate effect, by using global spectral analysis

Stopped-flow measurements have been successfully combined with time-resolved UV/vis spectroscopy and global spectral analysis of superoxide decay for the comparative study of catalytic activity of putative manganese SOD (superoxide dismutase) mimetics known in the literature. The SOD activity of the studied complexes decreases in the following order: a) M40403>Mn(III)TM-4-PyP5+>Mn(II)pyane >>EUK-113 at pH 7.4 (M40403=([manganese(II)dichlorido{(4R,9R,14R,19R)-3,10,13,20,26-pentaazatetracyclo[20.3.1.0.4,9014,19]hexacosa-1(26),-22(23),24-triene}], Mn(III)TM-4-PyP5+=Mn(III)meso-tetrakis(N-methylpyridinium-4-yl)porphyrin, Mn(II)Pyane=Mn(II)trans-2,13-dimethyl-3,6,9,12,18-pentaazabicyclo[12.3.1]-octadeca-1(18),14,16-triene, EUK-113=[manganese(III)acetato(6,6′-((1E,1′E)-(ethane-1,2-diylbis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenolate)]) in Hepes buffer (Hepes=4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid), b) Mn(III)TM-4-PyP5+>M40403≅Mn(II)pyane >>EUK-113 at pH 8.1 in Hepes buffer and c) Mn(III)TM-4-PyP5+≅Mn(II)pyane>MnCl2>M40403≅EUK-113 at pH 7.4 in phosphate buffer. MnCl2 in Hepes, Mn(III)TSPP3−, Mn(III)TBAP3−, Mn(III)acetate, Mn(II)lactate and Mn(II)EDTA do not exhibit SOD activity (Mn(III)TSPP3−=Mn(III)mesotetrakis(benzoic acid)porphyrin, Mn(III)TBAP3−=Mn(III)mesotetrakis(4-sulfonatophenyl)porphyrin). MnCl2 possess SOD activity that is comparable with those of other mimetics in the presence of phosphate. Our results demonstrate that phosphate anions, independent of ionic strength effect, influence the activity of manganese SOD mimetics, which is crucial for understanding and comparing their biological activity.

Synthetic, spectroscopic, magnetic, thermal, and antimicrobial approach towards new biocidal coordination polymers

AbstractO‐aminophenol was reacted with glutraldehyde to obtain Schiff base, which was then reacted with formaldehyde in slight acidic medium to generate phenolic groups. Now the substituted Schiff base was reacted with the transition metal acetates of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) to get polymeric metal complexes. Their structures have been elucidated on the basis of elemental analyses, 1H NMR spectra, 13C NMR spectra, magnetic measurements, thermogravimetric analyses, electronic spectra, and infrared spectra. The results are in accordance with an octahedral environment around the central metal ion. The polychelates of Mn(II), Co(II), Ni(II), and Cu(II) are paramagnetic while Zn(II) polychelate was found to be diamagnetic. The synthesized Schiff base acted as a uninegative bidentate ligand and bonding occurs through the hydroxyl oxygen and nitrogen atoms. The thermal behavior of these coordinating polymers was studied by TGA in nitrogen atmosphere up to the temperature range of 800°C. All the synthesized polychelates were also screened for their biocidal activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis (bacteria), Candida albicans, and Muller species (yeast) by using agar well diffusion method. All the metal polychelates show promising antimicrobial activities. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124:3971–3979, 2012

SnO 2–MnO 2 composite powders and their electrochemical properties

Nanosized cryptomelane manganese dioxide (MDO) and its SnO 2-coated product were prepared through a redox reaction between KMnO 4 and Mn(II) acetate. XRD analysis showed the cryptomelane-type structure for both materials. Chemical analysis detected the presence of K in parent and K and Sn in coated oxide. The coating was evidenced by TEM images, which display a thin layer of SnO 2 at the surface of nanosized MnO 2 particles. Vibrational spectroscopic measurements confirmed the integrity of the MnO 2 lattice. The net effect of the SnO 2 coating results in better electrochemical performance of the Li//MnO 2 cells.

Synthesis and Characterization of Cu(II), Ni(II), Co(II), Mn(II), and Cd(II) Transition Metal Complexes of Tridentate Schiff Base Derived from O-Vanillin and N-Aminopyrimidine-2-Thione

Monobasic tridentate Schiff base ligand having ONS donor sequence was prepared by condensing N-aminopyrimidine-2-thione with o-vanillin. The complexes were formed by reacting ligand and the metal acetates of Cu(II), Ni(II), Co(II), Mn(II), and Cd(II) in methanol to get a series of mononuclear and dinuclear complexes. The characterization of ligand and metal complexes were carried out by elemental analyses, conductivity measurements, magnetic susceptibility data, FTIR, UV-vis, NMR, and API-ES mass spectral data. The structure of the complexes was confirmed on the basis of elemental analyses, magnetic susceptibility, API-ES mass spectral data and thermal gravitational analysis (TGA).GRAPHICAL ABSTRACT

Investigation of the oxygen affinity of manganese(II), cobalt(II) and nickel(II) complexes with some tetradentate Schiff bases

Oxygen absorption–desorption processes for square planar Mn(II), Co(II) and Mn(II) complexes of tetradentate Schiff base ligands in DMF and chloroform solvents were investigated. The tetradentate Schiff base ligands were obtained by condensation reaction of ethylenediamine with salcyldehyde, o-hydroxyacetophenone or acetylacetone in the molar ratio 1:2. The square planar complexes were prepared by the reaction of the Schiff base ligands with Mn(II) acetate, Co(II) nitrate and Ni(II) nitrate in dry ethanol under nitrogen atmosphere. The sorption processes were undertaken in the presence and absence of (pyridine) axial-base in 1:1M ratio of (pyridine:metal(II) complexes). Complexes in DMF indicate significant oxygen affinity than in chloroform solvent. Cobalt(II) complexes showed significant sorption processes compared to Mn(II) and Ni(II) complexes. The presence of pyridine axial base clearly increases oxygen affinity.

New biocidal metal complexes of bisphenol-A formaldehyde polymer containing piperazine

The polymeric ligand (BFP) was synthesized by condensation of bisphenol-A, formaldehyde, and piperazine in alkaline medium at 70–80°C. The polymer–metal complexes were synthesized by the reaction of BFP with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) acetates in 1 : 0.5 (ligand : metal) molar ratio. All the synthesized polymers were characterized by elemental, spectral (infrared, 1H-NMR, and UV-Vis), magnetic moment measurements, and thermal (TGA) analysis. The ligand-field and nephelauxetic parameters have been determined from UV-Vis spectra using ligand-field theory. Elemental analyses indicate the association of water with metal for Mn(II), Co(II), and Ni(II), which is also supported by TGA. The antimicrobial activities of the synthesized polymers were studied by agar well diffusion methods against Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, and Shigella boydii. The antimicrobial activity and thermal stability of Cu(II)–polymer were higher than the other polymer–metal complexes due to the higher stability constant of Cu(II).

Synthesis, structure, and complexing ability of hetarylhydrazones of glyoxylic acid

Benzoxazolyl-, benzthiazolyl-, 2′-quinolinyl- and 1′-phthalazinylhydrazones of glyoxylic acid (H2L) and their complexes have been synthesized. The acid-base properties of the obtained hydrazones were studied by the methods of potentiometric titration and spectrophotometry. The hydrazones were shown to form mononuclear octahedral complexes M(HL)2 with Ni(II) and Mn(II) acetates, whereas with Zn(II) and Cu(II) acetates binuclear complexes M2L2 were formed. The nature of the exchange interaction between the Cu(II) ions is discussed.

New antimicrobial agents: The synthesis of Schiff base polymers containing transition metals and their characterization and applications

AbstractA new polymeric Schiff base containing formaldehyde and 2‐thiobarbituric acid moieties was synthesized by the condensation of a monomeric Schiff base derived from 2‐hydroxyacetophenone and hydrazine. Polymer–metal complexes were also synthesized by the reaction of the polymeric Schiff base with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) acetate. The polymeric Schiff base and its polymer–metal complexes were characterized with magnetic moment measurements, elemental analyses, and spectral techniques (infrared, 1H‐NMR, and ultraviolet–visible). The thermal behaviors of these coordination polymers were studied by thermogravimetric analysis in a nitrogen atmosphere up to 800°C. The thermal data revealed that all of the polymer–metal complexes showed higher thermal stabilities than the polymeric Schiff base and also ascribed that the Cu(II) polymer–metal complex showed better heat resistant properties than the other polymer–metal complexes. The antimicrobial activity was screened with the agar well diffusion method against various selected microorganisms, and all of the polymer–metal complexes showed good antimicrobial activity. Among all of the complexes, the antimicrobial activity of the Cu(II) polymer–metal complex showed the highest zone of inhibition because of its higher stability constant and may be used in biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Incorporation of Mn(II) and Fe(II) into Uranyl Carboxyphosphonates

Five heterobimetallic U(VI)/M(II) (M = Mn, Fe) carboxyphosphonates have been synthesized under mild hydrothermal conditions by reacting UO3, triethyl phosphonoacetate, with either Mn(II) or Fe(II) acetate. The manganese reactions yield Mn2[(UO2)6(PO3CH2CO2)3O3(OH)(H2O)2]·16H2O (MnUPAA-1) and [Mn(H2O)6][Mn(H2O)5Mn2(UO2)5(PO3CH2CO2)6(H2O)]·5.75H2O (MnUPAA-2). The addition of boric acid, which lowers the crystallization temperature, allows for the production of a third product, [Mn(H2O)4]2(UO2)3(PO3CH2CO2)2O2 (MnUPAA-3). The iron-containing reactions yield [Fe(H2O)6][UO2(PO3CH2CO2)]2·8H2O (FeUPAA-1) and [Fe(H2O)6][UO2(PO3CH2CO2)H2O]2·4H2O (FeUPAA-2). Four of these five compounds crystallize in low-symmetry space groups; whereas MnUPAA-1 crystallizes in the cubic space group Im3̅ and possesses a remarkably complex open-framework structure containing both UO7 pentagonal bipyramids and UO8 hexagonal bipyramids. MnUPAA-3 adopts a one-dimensional uranium oxide topology that contains both UO6 tetragonal bipyramids and UO7 pentagonal bipyramids. The remaining three compounds solely contain UO7 pentagonal bipyramids.

Investigation of electrochemical behavior of Mn–Co doped oxide electrodes for electrochemical capacitors

The electrochemical properties of nanocrystalline Co-doped Mn oxide electrodes were investigated to determine the relationship between physicochemical feature evolution and the corresponding electrochemical behavior of synthesized electrodes. Co-doped Mn oxide electrodes with a rod-like morphology and antifluorite-type structure were synthesized by anodic electrodeposition on Au coated Si substrates from a dilute solution of 0.01 M Mn acetate (Mn(CH 3COO) 2) and 0.001 M Co sulphate (CoSO 4). Electrochemical characterization of synthesized electrodes, with and without a conducting polymer (PEDOT) coating, was performed with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) at different scan rates. In addition, structural characterization of as-deposited and cycled electrodes was conducted using SEM, TEM and XPS. Capacitance values for all deposits increased with increasing scan rate to 100 mV s −1, and then decreased after 100 mV s −1. The Mn–Co oxide/PEDOT electrodes showed improved specific capacity and electrochemical cyclability relative to uncoated Mn–Co oxides. Mn–Co oxide/PEDOT electrodes with rod-like structures had high capacitances (up to 310 F g −1) at a scan rate of 100 mV s −1 and maintained their capacitance after 500 cycles in 0.5 M Na 2SO 4 (91% retention). Capacitance reduction for the deposits was mainly due to the loss of Mn ions by dissolution in the electrolyte solution.