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1.
《Journal of Coordination Chemistry》2012,65(14):2325-2333
Complexes of Cr(III) and Mn(II) with N′,N″-bis(3-carboxy-1-oxopropanyl) 2-amino-N-arylbenzamidine (H2L1) and N′,N″-bis(3-carboxy-1-oxophenelenyl) 2-amino-N-arylbenzamidine (H2L2) have been synthesized and characterized by various physico-chemical techniques. The vibrational spectral data are in agreement with coordination of amide and carboxylate oxygen of the ligands with the metal ions. The electronic spectra indicate octahedral geometry around the metal ions, supported by magnetic susceptibility measurements. The thermal behavior of chromium(III) complexes shows that uncoordinated nitrate is removed in the first step, followed by two water molecules and then decomposition of the ligand; manganese(II) complexes show two waters removed in the first step, followed by removal of the ligand in subsequent steps. Kinetic and thermodynamic parameters were computed from the thermal data using Coats and Redfern method, which confirm first order kinetics. The thermal stability of metal complexes has been compared. X-ray powder diffraction determines the cell parameters of the complexes. 相似文献
2.
《Journal of Coordination Chemistry》2012,65(10):1677-1689
Reaction of 2-hydroxy-1-naphthaldehydebenzoylhydrazone(napbhH2) with manganese(II) acetate tetrahydrate and manganese(III) acetate dihydrate in methanol followed by addition of methanolic KOH in molar ratio (2 : 1 : 10) results in [Mn(IV)(napbh)2] and [Mn(III)(napbh)(OH)(H2O)], respectively. Activated ruthenium(III) chloride reacts with napbhH2 in methanolic medium yielding [Ru(III)(napbhH)Cl(H2O)]Cl. Replacement of aquo ligand by heterocyclic nitrogen donor in this complex has been observed when the reaction is carried out in presence of pyridine(py), 3-picoline(3-pic) or 4-picoline(4-pic). The molar conductance values in DMF (N,N-dimethyl formamide) of these complexes suggest non-electrolytic and 1 : 1 electrolytic nature for manganese and ruthenium complexes, respectively. Magnetic moment values of manganese complexes suggest Mn(III) and Mn(IV), however, ruthenium complexes are paramagnetic with one unpaired electron suggesting Ru(III). Electronic spectral studies suggest six coordinate metal ions in these complexes. IR spectra reveal that napbhH2 coordinates in enol-form and keto-form to manganese and ruthenium metal ions in its complexes, respectively. ESR studies of the complexes are also reported. 相似文献
3.
Laure-Marie Grand Sara J. Palmer Ray L. Frost 《Journal of Thermal Analysis and Calorimetry》2010,100(3):981-985
The hydrotalcite based upon manganese known as charmarite Mn4Al2(OH)12CO3·3H2O has been synthesised with different Mn/Al ratios from 4:1 to 2:1. Impurities of manganese oxide, rhodochrosite and bayerite at low concentrations were also produced during the synthesis. The thermal stability of charmarite was investigated using thermogravimetry. The manganese hydrotalcite decomposed in stages with mass loss steps at 211, 305 and 793 °C. The product of the thermal decomposition was amorphous material mixed with manganese oxide. A comparison is made with the thermal decomposition of the Mg/Al hydrotalcite. It is concluded that the synthetic charmarite is slightly less stable than hydrotalcite. 相似文献
4.
A. Czylkowska 《Journal of Thermal Analysis and Calorimetry》2012,110(3):1299-1308
Novel mixed-ligand complexes with empirical formula Ln(4-bpy)2(CCl3COO)3·nH2O [where Ln(III)?=?Dy, Ho, Er, Tm, Yb, Lu; 4-bpy?=?4,4??-bipyridine] were prepared and characterized by chemical and elemental analysis, infrared spectroscopy, and conductivity measurements (in methanol, dimethylformamide, and dimethyl sulfoxide). X-ray powder diffraction patterns indicate that the complexes are small crystalline compounds. IR spectra of complexes show that all carboxylate groups and 4-bpy are engaged in coordination of lanthanide ions. The thermal behavior of complexes was studied by means of TG, DTG, DTA techniques in the solid state under nonisothermal conditions in air atmosphere. During heating, the complexes decompose via intermediate products to the oxide Ln2O3. The combined TG?CFTIR technique was employed to study the decomposition pathway of the Ho(III) and Tm(III) complexes in flowing argon atmosphere. 相似文献
5.
Santanu Mandal Ashok Kumar Rout Anupam Ghosh Guillaume Pilet Debasis Bandyopadhyay 《Polyhedron》2009,28(17):3858-3862
Two new mononuclear complexes of manganese(III) viz. [MnL2(LH)2]ClO4 (1) and [MnL2(N3)]·0.5CH3OH (2) have been synthesized by reacting manganese perchlorate with furfurylamine and salicylaldehyde (plus sodium azide in 2) where L = (2-hydroxybenzyl-2-furylmethyl)imine, an asymmetric bidentate Schiff base formed in situ to bind the Mn(III) ion. The complexes have been characterized by elemental analysis, IR spectroscopy, TGA and single crystal X-ray diffraction studies. Structural studies reveal that the complexes 1 and 2 adopt an octahedral and a square pyramidal geometry, respectively. The antibacterial activity of the complexes has been tested against Gram(+) and Gram(?) bacteria. 相似文献
6.
S. De Angelis Curtis Krystyna Kurdziel S. Materazzi S. Vecchio 《Journal of Thermal Analysis and Calorimetry》2008,92(1):109-114
The crystal structure of a manganese(II) 1-allylimidazole complex ([Mn(1-AIm)3(NO3)2], where 1-Aim=1-allylimidazole), was characterized by X-ray diffraction (XRD) using SHELX-97. The thermal behaviour of the
complex was investigated by thermogravimetry (TG) coupled with an FTIR unit. The complex showed a multi-step decomposition
related to the release of the ligand molecules, followed by oxidation. The final residue at 1073 K was found to be manganese(II)
oxide. Evolved gas analysis allowed to prove the oxidative decomposition pattern of the examined complex, initially proposed
by the percentage mass loss data. Finally, a kinetic analysis of the oxidative decomposition steps was made using the Kissinger
equation, while the complex nature of the decomposition kinetics was revealed by the isoconversional Ozawa-Flynn-Wall method. 相似文献
7.
O. I. Gyrdasova V. N. Krasil’nikov E. V. Shalaeva M. V. Kuznetsov A. P. Tyutyunnik 《Russian Journal of Inorganic Chemistry》2012,57(1):72-78
Nanotubes of manganese-doped zinc oxide Zn1 − x
Mn
x
O (0 ≤ x ≤ 0.2) were synthesized by heating the Zn1 − x
Mn
x
(HCOO)(OCH2CH2O)1/2 precursor in air at 500°C. The precursor with extended crystals was synthesized by a solvothermal method based on heat treatment
of a mixture of Zn1 − x
Mn
x
(HCOO)2 · 2H2O with an ethylene glycol excess at 100–130°C. The tubular morphology of Zn1 − x
Mn
x
O particles was identified by transmission electron microscopy. Tubular quasi-one-dimensional particles were shown to have
a nanodispersed polycrystalline structure, the size of separate crystallites being from 5 to 20 nm. X-ray photoelectron spectroscopy
suggested that the manganese distribution on the outer surface layer of Zn1 − x
Mn
x
O nanotubes is nonuniform. 相似文献
8.
Zhong-Lu You Mei Zhang Dong-Mei Xian Hai-Hua Li Qian-Feng Weng 《Transition Metal Chemistry》2012,37(3):279-283
The mixed valence manganese(II/IV) complex, [MnIIL2(MeOH)2]·[MnIVL2(OAc)2]·2(MeOH) (1), and the chloride-bridged 1D polymeric manganese(III) complex, [MnIIIL2(μ-Cl)]n (2), where L is the deprotonated form of 2-ethoxy-6-[(2-phenylaminoethylimino)methyl]phenol (HL), have been prepared and structurally
characterized by single-crystal X-ray diffraction analysis and IR spectra. The Mn atoms in both complexes are octahedrally
coordinated. The self-assembly of the complex structures is apparently directed by the anions of the manganese salts. 相似文献
9.
MnO and Mn2O3 nanoparticles were prepared in air and argon atmosphere by thermal decomposition of nanocrystalline manganese carbonate synthesized by reaction of manganese(II) nitrate with glycerol. Samples were characterized using transmission electron microscopy, simultaneous thermal analysis and X-ray diffraction analysis. Average sizes of prepared nanoparticles were calculated from XRD patterns using Scherrer equation. Also, the conditions for decomposition of manganese carbonate were optimized to obtain optimal nanoparticle sizes. Due to suitable sizes of prepared nanoparticles and the initial material, this method can be used in a wide range of industrial applications. 相似文献
10.
《Journal of Coordination Chemistry》2012,65(10):1613-1622
Two manganese complexes, [Mn2(tptz)2Cl4] · CH3CN (1) and [Mn(tptz(ac)(N3)(H2O)] · H2O (2) (where tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazine, ac = acetate anion), were synthesized and characterized by elemental analyses, infrared spectra, and UV–Vis absorption spectral analyses. The structures of both the complexes were determined by single crystal X-ray diffraction analysis. Complex 1 is binuclear with chloro-bridged manganese ions at the Mn–Mn separation of 3.777(27) Å. Each manganese center in 1 is six coordinate with three nitrogens from a tridentate tptz, three chlorides (one terminal and two bridging), adopting a centrosymmetric distorted octahedral geometry. Various hydrogen bonds form 2-D spiral structures in 1 with Mn–Mn separation of 7.421(2) Å along a-axis and 9.121(2) Å along b-axis. Complex 2 is seven coordinate with pentagonal bipyramidal geometry. The metal center coordinates to three nitrogens from tptz, two oxygens from acetate, one nitrogen from azide, and one oxygen from water. It has a 1-D layered structure, where three independent molecules are linked by uncoordinated water present in the lattice. Magnetic susceptibility in the temperature range 5–300 K for 1 shows the presence of antiferromagnetic interaction between the local high-spin manganese(II) ions with J = ?0.17 cm?1. 相似文献
11.
The electronic structure of hexanuclear Mn(II,III) pivalate complexes with tetrahydrofuran and isonicotinamide are studied by X-ray photoelectron spectroscopy and X-ray emission spectroscopy. It is shown that when isonicotinamide substitutes for tetrahydrofuran the spin state of manganese ions is retained; the electron density increases on the manganese and oxygen atoms of the [Mn6(O)2Piv10] core. 相似文献
12.
《Journal of Coordination Chemistry》2012,65(9):1538-1545
Two new 1-D manganese(III) Schiff-base complexes bridged by dicyanamide (dca), [Mn(III)(5-Brsalen)(dca)] ? CH3OH (1) and [Mn(III)(3,5-Brsalen)(dca)] · CH3OH · CH3CN (2) (5-Brsalen = N,N′-ethylenebis(5-bromo salicylaldiminato) dianion; 3,5-Brsalen = N,N′-ethylenebis(3,5-dibromosalicylal diminato) dianion), have been synthesized and characterized. X-ray diffraction analyses reveal that the two complexes have 1-D chain structures constructed by μ 1,5-dca bridge. Magnetic susceptibility measurements exhibit weak antiferromagnetic exchange coupling in the complexes. 相似文献
13.
Katarína Homzová Katarína Győryová Zuzana Bujdošová Daniela Hudecová Mária Ganajová Zuzana Vargová Jana Kovářová 《Journal of Thermal Analysis and Calorimetry》2014,116(1):77-91
New zinc(II) 4-hydroxybenzoate complex compounds with general formula [Zn(4-OHbenz)2Ln]·xH2O, where 4-OHbenz = 4-hydroxybenzoate; L = isonicotinamide, N-methylnicotinamide, N,N-diethylnicotinamide, thiourea, urea, phenazone, theophylline, methyl-3-pyridylcarbamate; n = 2, 3; x = 0–3, 5, were synthesized and characterised by elemental analysis, thermal analysis and IR spectroscopy. The thermal behaviour of the prepared compounds was studied by TG/DTG and DTA methods in argon atmosphere. The thermal decomposition of hydrated compounds started with dehydration. During the thermal decomposition, organic ligand, carbon monoxide, carbon dioxide and phenol were evolved. The final solid product of the thermal decomposition was zinc or zinc oxide. The volatile gaseous product, solid intermediate products and the final product of thermal decomposition were identified by IR spectroscopy, mass spectrometry, qualitative chemical analyses and X-ray powder diffraction method. The antimicrobial activity of zinc(II) carboxylate compounds was tested against various strains of bacteria, yeasts and filamentous fungi (S. aureus, E. coli, C. parapsilosis, R. oryzae, A. alternata, M. gypseum). The presence of zinc in complexes led to the increase in their antimicrobial activity in comparison with free 4-hydroxybenzoic acid. 相似文献
14.
Summary New carbodithioate complexes of the oxovanadium(IV), manganese(II) and manganese(III) ions have been prepared and studied by i.r. and electronic spectral and variable temperature magnetic susceptibility (77K to room temperature) measurements. The carbodithioate ligands, 4-methylpiperazine-1-carbodithioate (4-MPipzcdt) and 4-phenylpiperazine-1-carbodithioate (4-PPipzcdt), were derived from heterocyclic secondary amines. The VO(4-MPipzcdt)2 and VO(4-PPipzcdt)2 complexes possess C
4v
symmetry; Mn(4-PPipzcdt)2 is tetrahedral and Mn(4-PPipzcdt)3 is octahedral. All exhibit abnormal room temperature magnetic moments and the variable temperature magnetic moments suggest antiferromagnetism for the oxovanadium(IV) and the manganese(II) complexes and the occurrence of low spin (3
T
1g
) high spin (5
E
g
) equilibrium in addition to antiferromagnetic interactions in the manganese(III) complex. The spin-spin exchange parameter (-2J) value for the VO(4-MPipzcdt)2 complex has been calculated using variable temperature magnetic susceptibility data. 相似文献
15.
L. Vikram B. Raju R. Ragul B. N. Sivasankar 《Journal of Thermal Analysis and Calorimetry》2008,93(3):987-991
Lighter and heavier lanthanide(III) ions react with dihydrazinium salts of ethylenediaminetetraacetic acid (H4edta) in aqueous
solution to yield hydrazinium lanthanide ethylenediaminetetraacetate hydrate, N2H5[Ln(edta)(H2O)3]·(H2O)5 where Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb and Dy. The numbers of water molecules present inside the coordination sphere have been confirmed
by X-ray single crystal studies. The presence of five water molecules as lattice water is clearly shown by the mass loss from
the TG analyses. Dehydration of a known amount (1 g) of each sample were carried out at constant temperature (100–110°C) for
about 5 min further confirms the number of non-coordinated water molecules. The complexes after the removal of lattice water
undergo multi-step decomposition to give respective metal oxide as the final product. The DTA shows endotherms for dehydration
and exotherms for the decomposition of the anhydrous complexes. The formation of the metal oxides was confirmed by X-ray powder
diffraction studies. 相似文献
16.
Different metal complexes of the general form M(OH)
n
(H2O)6–
n
have been studied for manganese and iron. Oxidation states considered for manganese are Mn(III), Mn(IV) and Mn(V) and for
iron Fe(II), Fe(III) and Fe(IV). Oxygen containing ligands are used throughout with varying numbers of hydroxyl and water
ligands. Some metal-oxo and some charged complexes were also studied. Large Jahn-Teller distortions were found for the Mn(III)
and Fe(IV) complexes. Consequences of these distortions are that water ligands have to be placed along the weak JT-axis and
that five-coordination by a loss of one of these water ligands is quite competitive with six-coordination in particular for
manganese. For Fe(II) and Fe(III) lower coordinations than six are preferred due to the presence of two repulsive e
g
electrons. For the metal-oxo complexes five-coordination is also preferred due to the strong trans effect from the oxo ligand.
All complexes studied have high-spin ground states. An interesting effect is that the spin is much more delocalized on the
ligands for the iron complexes than for the manganese complexes. This effect, which is chemically important for certain iron
enzymes, is rationalized by the large number of 3d electrons on iron. For manganese with only five 3d electrons no spin delocalization is needed to obtain the proper high-spin states.
Received: 4 February 1997 / Accepted: 24 February 1997 相似文献
17.
《Electrochemistry communications》2000,2(6):445-447
A new manganese dioxide pillared by vanadium oxide species has been synthesized hydrothermally from permanganate. It has the electrochemically active MnO2 layer structure, which has been extensively studied as a battery cathode. The vanadium oxide ions, together with the water molecules, reside in between the oxide sheets; dehydration occurs without structural change. The (VOy)0.1MnO2·nH2O has a rhombohedral structure, with hexagonal parameters a=2.843(6) Å, c=22.08(2) Å. It reacts readily with lithium with a capacity around 150 mAh g−1; the pillar ions do not appear to impede reaction. 相似文献
18.
《Journal of Coordination Chemistry》2012,65(19):3158-3171
Bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone(naohH4) interacts with manganese(II) acetate in methanol followed by addition of KOH giving [MnIV(naoh)(H2O)2]. Activated ruthenium(III) chloride reacts with naohH4 in methanol yielding [RuIII(naohH4)Cl(H2O)Cl2]. The replacement of aquo by heterocyclic nitrogen donor in these complexes has been observed when the reaction is carried out in presence of heterocyclic nitrogen donors such as pyridine(py), 3-picoline(3-pic) or 4-picoline(4-pic). The molar conductance values in DMF for these complexes suggest non-electrolytic nature. Magnetic moment values suggest +4 oxidation state for manganese in its complexes, however, ruthenium(III) complexes are paramagnetic with one unpaired electron. Electronic spectral studies suggest six coordinate metal ions. IR spectra reveal that naohH4 coordinates in enol-form and keto-form to manganese and ruthenium, respectively. ESR and cyclic voltammetric studies of the complexes have also been reported. 相似文献
19.
Reactions of manganese and zinc chloride with dimethoxyethane (DME) in the presence of (CH3)3SiCl and water resulted in [MnCl2(DME)]n (1) with a polymeric chain structure and in the molecular [ZnCl2(DME)]2 (2), respectively. The complexes 1 and 2 reacted with di(2-methoxyethyl) ether (abbreviated diglyme) in tetrahydrofuran (THF) solvent achieving binuclear [MnCl2(diglyme)]2 (3) and mononuclear [ZnCl2(diglyme)] (4), respectively. The complex [NiCl2(diglyme)]2 (5) was prepared by the reaction of nickel chloride hexahydrate, diglyme and (CH3)3SiCl in THF solvent. A distorted octahedral geometry was found for manganese and nickel ions in the complexes 1, 3 and 5. Linear chains of manganese ions linked by double chloride bridges are present in 1. Two bridging chlorides connect two manganese or nickel atoms into isostructural binuclear molecules 3 and 5, respectively. Two zinc ions in the complex 2 are in different environments, in a tetrahedral and in an octahedral one, while five-coordinate zinc ions are present in the mononuclear complexes 4. 相似文献
20.
Summary Hydroxamic acids show a degree of selectivity towards transition metal ions having symmetrical d-electron configuration, e.g. vanadium(V) (d0) and iron(III) (d65). Hydroxamato complexes of metal ions having unsymmetrical d-electron distribution are rare. Thus for manganese(III) (d4) only some thiohydroxamato complexes(1) have been characterised so far. In this communication we report on the first synthesis of a salicylhydroxamato complex of manganese(III). Such investigations are of interest because these higher valent manganese complexes are potentially models for the water-splitting complex present in photosystem II(2). 相似文献