1834-30-6Relevant academic research and scientific papers
Synthesis and reactivity of haloacetato derivatives of iron(II) including the crystal and the molecular structure of [Fe(CF3COOH) 2(μ-CF3COO)2]n
Marchetti, Fabio,Melai, Bernardo,Pampaloni, Guido,Zacchini, Stefano
, p. 3378 - 3384 (2007)
The syntheses of haloacetates of iron(II) and their reactivity are described. The compound Fe(CF3COO)2, 1, crystallizes from CF3COOH/(CF3CO)2O solution as the polynuclear [Fe(CF3COO)2(CF3COOH)2] n, 2, which contains bridging trifluoroacetates and monodentate trifluoroacetic acid groups. Fe(CF3COO)2(DMF)x, as obtained from Fe(CO)5 and CF3COOH/(CF 3CO)2O in DMF, reacts with dioxygen at room temperature to give two μ3-oxo compounds, namely, [Fe3(μ 3-O)(CF3COO)6(DMF)3], 3, a Fe (II)-Fe(III)-Fe(III) derivative, and [Fe 4(μ3-O)2(μ2-CF 3COO)6(CF3COO)2(DMF)4], 4, containing Fe(III) atoms only, which have been characterized by X-ray diffraction methods. Iron(II) chloro- and bromoacetates can be isolated by exchange reactions of iron(II) acetate with chloro- and bromo-substituted acetic acids in moderate to good yields. The stability of iron(II) haloacetates decreases on increasing the atomic weight and the number of halogens on the α-carbon atom. The species Fe(CX3COO)2 (X = Cl, 7; Br, 8), in THF solution, slowly convert into [Fe3(μ3-O) (CCl3COO)6(THF)3], 11, or [Fe 3(μ3-O)(CBr3COO)6(THF) 3][FeBr4], 10, respectively. Likewise, when iron(II) acetate (or trifluoroacetate) is left for several hours in the presence of a variety of haloacetic acids in THF, selective formation of different species, depending on the nature of the starting compound and of the acid employed, is observed. The formation of these products is the result of C-X bond activation (X = Cl, Br) and haloacetato decomposition, which occurs with concomitant oxidation at the metal centers. Carboxylic acid degradation species (CH 2XCOOH, CX4, CX3H, CX2H2, X = Cl, Br) have been observed by GC-MS.
Electric properties of Co substituted Ni-Zn ferrites
Ghodake,Kambale,Salvi,Sawant,Suryavanshi
, p. 830 - 834 (2009)
Nanocrystalline Ni-Co-Zn ferrites have been synthesized by chemical co precipitation method, using oxalate precursors. The phase formation of the sintered ferrite was confirmed by X-ray diffraction study. The lattice parameter 'a' increases with the addit
A study of the effect of pyridine linkers on the viscosity and electrochromic properties of metallo-supramolecular coordination polymers
Pai, Sandesh,Schott, Marco,Niklaus, Lukas,Posset, Uwe,Kurth, Dirk G.
, p. 3310 - 3321 (2018)
We present the optical, electrochemical, and electrochromic properties of Fe(ii)-, Co(ii)- and Ru(ii)-based metallo-supramolecular polymers (MEPEs) self-assembled from rigid, π-conjugated bis-terpyridines with different numbers of pyridine linkers. By exc
Studies on initial permeability and loss factor in Ni-Zn ferrites synthesized by oxalate precursors
Chaudhari,Kambale,Patil,Sawant,Suryavanshi
, p. 1713 - 1719 (2010)
NiXZn1-XFe2O4 ferrites with (X = 0.28-0.40 in step of 0.2) have been synthesized by oxalate precursor method and investigated for their, initial permeability and loss factor measurements. Initial permeability has been observed to increase with the increase in Ni 2+ up to X = 0.32, beyond which it decreases. The variation of initial permeability has been explained by considering the factors such as grain size, saturation magnetization and anisotropy constant. Thermal variation of initial permeability reveals a peak height in μi-T curves which tends to increase with increase in Ni2+ content. μi-T curves also exhibit thermal hysteresis, which reveals the inverse relationship between the difference in heating and cooling curves at which hysteresis falls between Hopkinson peak and Tc with value of initial permeability. Loss factor values are small which is attributed to high density of the samples and processing techniques.
Crystal structure of iron(II) acetate
Weber, Birgit,Betz, Richard,Bauer, Wolfgang,Schlamp, Stephan
, p. 102 - 107 (2011)
In this paper the X-ray structure and magnetic properties of iron(II) acetate - starting material for the synthesis of a wide range of iron complexes - are presented. The compound crystallises in the space group Pbcn and was identified as 2D coordination polymer consisting of iron atoms and acetate moieties with all the iron atoms hexacoordinate and different coordination modes for the acetate moieties. Additional hydrogen bond contacts lead to a porous coordination polymer with 1D channels in the size of mesopores. Temperature dependent magnetic measurements confirm that the complex is a high-spin compound in the entire temperature range investigated with a room temperature magnetic moment of 5.4 μB. Field-dependent magnetisation measurements reveal a slightly sigmoidal curve progression typical for metamagnetism. Copyright
Thermoanalytical study of Cu-Mg-Zn ferrites
Bhosale,Choudhari,Sawant,Patil,Kulkarni,Kelkar
, p. 851 - 859 (1999)
Homogeneous solid solution oxalates of Fe2+, Cu2+, Mg2+ and Zn2+ metals were prepared by co-precipitation from respective metal acetate solutions with oxalic acid solution. The thermogravimetric (TG) analysis of
Synthesis, characterization and thermal analysis of [Fe(N2H4)2(CH3COO)2]
Jiji, E. R.,Aravindakshan, K. K.
, p. 65 - 72 (1995)
[Fe(N2H4)2(CH3COO)2] was synthesized and characterized for the first time by chemical analysis, magnetic measurements, electronic and IR spectral studies. Its thermal reactivity was ascertained by the
On the thermal stability of Co2Z hexagonal ferrites for low-temperature ceramic cofiring technologies
Kra?unovska,T?pfer
, p. 1370 - 1376 (2008)
Co2Z hexaferrite Ba3Co2Fe24O41 was prepared by a mixed oxalate co-precipitation route and the standard ceramic technology. XRD studies show that at T2Z-type ferrite of about μ=20 is stable up to several 100 MHz, with maximum losses μ′′ around 700 MHz. Addition of 3 wt% Bi2O3 as sintering aid shifts the temperature of maximum shrinkage down to 950 °C and enables sintering of Z-type ferrite powders at 950 °C. However, the permeability is reduced to μ=3. It is shown here for the first time that Co2Z ferrite is not stable under these conditions; partial thermal decomposition into other hexagonal ferrites is found by XRD studies. This is accompanied by a significant decrease of permeability. This shows that Co2Z hexagonal ferrite is not suitable for the fabrication of multilayer inductors for high-frequency applications via the low-temperature ceramic cofiring technology since the material is not compatible with the typical process cofiring temperature of 950 °C.
Magnetic properties of NiCuZn ferrites synthesized by oxalate precursor method
Ghodake,Ghodake,Sawant,Suryavanshi,Bakare
, p. 110 - 119 (2006)
Ni-Cu-Zn ferrites have been synthesized by employing co-precipitation technique using oxalate precursors. X-ray diffractograms did not show impurity phases, indicating single-phase formation of the ferrites. The diffractograms of oxalate complex decomposed at 650 °C show that ferritization is complete up to 650 °C. Lattice parameter a (A?) was found to decrease with the addition of Ni2+ which is attributed to ionic sizes of Ni2+ (0.69 A?), which replaces Cu2+ (0.72 A?). From the thermogravimetric studies it is observed that the experimentally observed total mass loss (%), agrees with theoretically calculated mass loss (%) indicating maintenance of requisite stoichiometry. Initial permeability (μi ) shows increase when Ni2+ is added up to x = 0.15 while for (x > 0.15), it decreases. The increase in initial permeability (μi) is attributed to monotonic increase in Ms, and K1 on addition of Ni2+. However, the microstructure and density (porosity) also influence μi variations. The decrease in μi is attributable to increase of K1. The composition with density 91.14% exhibits large μi which also tends to increase with temperature up to 60 °C. Thus its usable range extends up to 60 °C. This samples has Tc near to 160 °C.
Gold-Clip-Assisted Self-Assembly and Proton-Coupled Expansion–Contraction of a Cofacial FeIII–Porphyrin Cage
Wang, Yuanyuan,Ang, Pau Lin,Wong, Chun-Yuen,Yip, John H. K.
, p. 18623 - 18628 (2018)
A molecular cage {Au8(μ-PAnP)4[Fe(H2O)2(TPyP)]2(OTf)2}(OTf)8 (1) composed of two cofacial FeIII-porphyrin can be self-assembled from the gold clip [Au2(PAnP)Cl2] and Fe3+(H2O)2(TPyP)+ (PAnP=9,10-bis(diphenylphosphino)anthracene, TPyP=meso-tetra(4-pyridyl)porphyrinato). The height of the cage is 8.579(3) ?. The addition of a base to a solution of the cage leads to a contracted and twisted cage {[Au8(μ-PAnP)4[Fe2(μ-O)(TPyP)2]}(OTf)8 (2), which has a height of ≈4.4 ? and porphyrin–porphyrin torsional angle of ≈20°. The contracted cage can be synthesized independently from the gold clip and Fe2(μ-O)(TPyP)2. The spectroscopy and crystal structure of an unclipped analog of the contracted cage, {[AuPPh3)8[Fe2(μ-O)(TPyP)2]}(OTf)8 (3), supports the DFT-calculated structure of 2. NMR and UV/Vis titrations show that the expansion-untwisting and contraction-twisting of the cage is reversible.
