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1.
T. Sato F. Ambe K. Endo M. Katada H. Sano 《Journal of Radioanalytical and Nuclear Chemistry》1995,190(2):257-261
The crystal structures of oxo-centered trineclear cobalt-iron chloroacetate complex [CoIIFe
2
III
O(CH2ClCO2)6(H2O)3]·3H2O (1) was compared with that of previously reported trinuclear iron complex [FeIIFe
2
III
O(CH2ClCO2)6(H2O)3]·3H2O (2) which has an isomorphous structure to 1. Compound 1 crystallizes in space group P21/n with Z=4 in a unit cell of a=14.826 (4) Å, b=4.536 (8) Å, c=14.000 (4) Å, =100.32 (2)0 and V=2968 (11) Å3. The structure was refined to R=0.75 and Rw=0.82. The coordination geometries of the three iron atoms are observed equivalent in 1 indicating a static disorder of the position among cobalt and iron atoms. Two distinct FeIII doublets observed in Mössbauer spectra of 1 become an indistinguishable broad doublet by dehydration of crystal water. On the other hand, no significant line-broadening is observed after the dehydration in complex 2. The results indicate that the dehydration in 2 induces a local environmental change reordering of an electronic configuration around iron atoms, whereas the remaining disordering is reflected in Mössbauer spectrum after the dehydration in 1. 相似文献
2.
3.
Complexes of the type (n-C
n
H2n
+1NH3)2SnX6 (0n 4 and X=Cl or Br) have been investigated with a variety of physico-chemical techniques. The structural phase transitions were found in some of these complexes. The temperature dependence of the Mössbauer spectral absorption area for (C2H5NH3)2SnCl6 and (C2H5NH3)2SnBr6 changed sharply at phase transition temperatures. The temperature dependences for (n-C4H9NH3)2SnCl6 and (n-C4H9NH3)2SnBr6 decreased gradually with an increase in temperature. The correlation between the temperature dependence of the spectral absorption area and the motion of n-C
n
H2n+1NH3
+ ions is discussed. 相似文献
4.
T. Sato K. Ishishita M. Katada M. Nakada K. Endo H. Sano 《Hyperfine Interactions》1992,70(1-4):1237-1240
Mixed-valence states of57Fe atoms produced after EC-decay of57Co in a series of trinuclear cobalt-iron halogenoacetate complexes, [CoIIFe 2 III O(CH3?nXnCO2)6(H2O)3] (0≤n≤3, X=Cl, Br, and I), were studied by comparing the results obtained by emission Mössbauer spectroscopy with those observed in absorption Mössbauer spectra of analogous trinuclear iron complexes, [FeIIFe 2 III O(CH3?nXnCO2)6(H2O)3]. Some of the emission Mössbauer spectra show a temperature-dependent mixed-valence state as found in the absorption Mössbauer spectra. Others show a somewhat different temperature dependence compared with the absorption Mössbauer spectra. The results were interpreted in terms of after-effects of the EC-decay. 相似文献
5.
Emission Mössbauer spectra of mixedvalence trinuclear complexes,57Co-labelled [CoFe2O(CH3CO2)6(H2O)3] and [CoFe2O(CH3CO2)6 (py)3]py were compared with that of [CoCr2O(CH3CO2)6 (py)3]py. It was found that the57Fe atoms produced in57Co-labelled [CoFe2O(CH3CO2)6(H2O)3] and [CoFe2O(CH3CO2)6 (py)3]py showed a temperature-dependent mixed-valence state as observed in the absorption Mössbauer spectra of [Fe3O(CH3CO2)6 (H2O)3] and [Fe3O(CH3CO2)6 (py)3]py, respectively, while57Co-labelled [CoCr2O(CH3CO2)6 (py)3]py showed a temperature-independent divalent iron/II/ state. The results indicate that the decayed atoms keep their position at the sites of original57Co atoms and that the valence electrons are transferred through the intramolcular bondings. 相似文献
6.
7.
Ohki Y Sunada Y Honda M Katada M Tatsumi K 《Journal of the American Chemical Society》2003,125(14):4052-4053
The [8Fe-7S] core of the P-clusters in nitrogenases is unique among the known [Fe-S] clusters which are essential to electron-transfer processes in nature. The [8Fe-7S] cluster has been thought unstable and to exist only in protein environments. We found that this unusual [8Fe-7S] structure can be self-assembled from the reaction of Fe(II) bis-amide, tetramethylthiourea, 2,4,6-triisopropylbenzenethiol, and elemental sulfur in a specific mole ratio. The structure of the complex isolated therefrom closely resembles that of the reduced form (PN) of the P-clusters, while the 6Fe(II)2Fe(III) oxidation state was manifested by the M?ssbauer study. 相似文献
8.
Chemical effects associated with6Li (n,α)T reaction in Lithium compounds were studied by observing a Mössbauer spectrum for the Mössbauer nuclides introduced in the lithium compounds. The large difference between the effects of lithium carbonate and oxalate was compared with the results obtained in the emission Mössbauer spectra of57Co-labelled triscarbonatocobaltate(III) and trisoxalatocobaltate(III), in which the former shows much less reducing effect on the produced57Fe species than the latter. 相似文献
9.
10.
A dependence of intramolecular valence delocalization on crystal form in mixed-valence trinuclear iron phenylacetate [Fe
2
III
FeIIO(PhCH2CO2)6(py)3] was found. This complex was obtained in two different crystal forms: a columnar and a needle crystal form. Mössbauer spectra of the columnar crystals show a temperature-dependent valence delocalization, while the needle crystals show a trapped mixed-valence state from a lower temperature up to room temperature. 相似文献