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1.
合成了一种新的三桥连双铁 (III)配合物 [Fe2 (IDB) 2 (O) (CH3CO2 ) 2 ]Cl2 ·CH3OH ,IDB为N ,N’ -di(2’ -benzimidazolylmethyl)imine,利用单晶X射线衍射及其它谱学方法对所合成配合物进行了表征。每个双核单元的两个铁原子均通过一个氧原子和两个醋酸根连接 ,每个铁原子同时还与位于桥氧原子对位的三齿配体IDB重脂肪链上氮原子相结合 ,每个铁 (III)中心为一变形八面体结构。对该新化合物的拉曼光谱进行了研究并对一些谱峰进行了归属 相似文献
2.
三桥连双铁(Ⅲ)配合物[Fe2(IDB)2(O)(CH3CO2)2]Cl2·CH3OH的晶体结构及其傅立叶变换拉曼光谱 总被引:1,自引:1,他引:0
合成了一种新的三桥连双铁(Ⅲ)配合物[Fe2(IDB)2(O)(CH3CO2)2]Cl2·CH3OH,IDB为N,N'-di(2'-benzimidazolyl
methyl) imine,利用单晶x射线衍射及其它谱学方法对所合成配合物进行了表征.每个双核单元的两个铁原子均通过一个氧原子和两个醋酸根连接,每个铁原子同时还与位于桥氧原子对位的三齿配体IDB重脂肪链上氮原子相结合,每个铁(Ⅲ)中心为一变形八面体结构.对该新化合物的拉曼光谱进行了研究并对一些谱峰进行了归属. 相似文献
3.
Mono- and binuclear iron(III) complexes with the general formula [FeXL] and [LFe-Y-FeL](BPh4)2 have been prepared and their spin states of the iron atom in the complexes has been investigated by means of the temperature-dependent Mössbauer spectroscopy and magnetic measurements, where X is a methyl-substituted pyridine, L denotes a quinquedentate Schiff-base derived from salicylaldehyde with N-(2-aminoethyl)-1,3-propanediamine and Y denotes bridged ligands such as pyrazine(pyr), 4,4′-pyridine(bpy), 4,4′-vinylenepyridine(vipy). On the basis of the Mössbauer and magnetic data, it was concluded that the spintransition characteristics depends on the methyl substituent of pyridine and the bridged ligand. 相似文献
4.
采用基于密度泛函理论的第一性原理方法研究了氢原子和氢分子在纯铁表面和锰原子掺杂表面的吸附与解离行为.研究结果表明,氢原子可在纯铁(001)表面稳定吸附,吸附能按照顶位,桥位和心位依次增强;而溶质原子锰降低了氢原子距离表面的位置并强化了氢原子的吸附行为.氢分子在纯铁表面的吸附解离行为取决于氢分子距离模型表面的初始距离和初始空间构型.氢分子平行于纯铁(001)表面时,距离心位1.2?发生解离,而桥位、顶位均不会发生解离;氢分子垂直放置时,距离桥位0.6?、顶位1.0?发生解离,心位不会发生解离.氢分子平行于锰掺杂纯铁(001)表面时,距离桥位0.6?、顶位0.7?、心位1.2?发生解离;氢分子垂直放置时,距离桥位、心位0.8?发生解离,而顶位放置氢分子不发生解离.归纳可知,锰溶质原子掺杂会增加铁基体表面氢原子和氢分子的吸附作用并促进氢分子发生分解. 相似文献
5.
本文采用密度泛函理论方法研究了Fe2O3上AsH3的催化氧化反应机理.该反应以Fe2O3中的两个Fe原子为不同的活性中心进行研究,每个活性中心均设计了3个步骤. AsH3分子依次与3个O2分子在催化剂上相互作用分别形成中间体H3AsO2、H3AsO4及最终产物H3AsO6.研究发现,当氧化反应发生在1号铁原子(Fe1)附近,其速度控制步骤活化自由能垒为49.99 kcal/mol;当氧化反应发生在2号铁原子(Fe2)附近,其活化自由能垒为21.20 kcal/mol,与直接氧化(50.14 kcal/mol)相比大大降低.可见AsH3在Fe2O3上的催化氧化反应更易发生在Fe2附近. 相似文献
6.
Using an accurate density-function method, we explore the coexistence of the magnetism and conductivity in
bis(ethylenediselena)-tetrathiafulvalene (BEST) with the paramagnetic hexacyanoferrate(III) [Fe(CN)6]3- or the photochromic nitroprusside
anion [Fe(CN)5NO]2-. The total and partial densities of states, and
the atomic spin magnetic moments are calculated and discussed. It is found
that the up- and down-spin total densities of states (DOS) are continuous in
the vicinity of the Fermi level, there is overlap between the HOMO and LUMO
in the up-spin subbands and the down-spin subbands, which reveals that these
types of compounds have conductive properties. From the total and partial
densities of states and atomic spin magnetic moments, it is shown that the
spin magnetic moments of
(BEST)4[Fe(CN)6] is mainly assembled at
the iron atom and the cyanogen radical, and the spontaneous magnetic moments
for (BEST)2[Fe(CN)5NO] come from iron atom, cyanogen and nitric
oxide radical. To our best knowledge, it is the first theoretical study on the
coexistence of the magnetism and conductivity of these compounds. 相似文献
7.
Spin-crossover (SCO) magnets can act as one of the most possible building blocks in molecular spintronics due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, the electronic structures and transport properties through SCO magnet Fe(II)-N4S2 complexes sandwiched between gold electrodes are explored by performing extensive density functional theory calculations combined with non-equilibrium Green''s function formalism. The optimized Fe-N and Fe-S distances and predicted magnetic moment of the SCO magnet Fe(II)-N4S2 complexes agree well with the experimental results. The reversed spin transition between the HS and LS states can be realized by visible light irradiation according to the estimated SCO energy barriers. Based on the obtained transport results, we observe nearly perfect spin- filtering effect in this SCO magnet Fe(II)-N4S2 junction with the HS state, and the corresponding current under small bias voltage is mainly contributed by the spin-down electrons, which is obviously larger than that of the LS case. Clearly, these theoretical findings suggest that SCO magnet Fe(II)-N4S2 complexes hold potential applications in molecular spintronics. 相似文献
8.
Sergej Rackwitz Juliusz A. Wolny Kai Muffler Hans-J?rg Krüger Sabine Reh Harald Kelm Alexander I. Chumakov Volker Schünemann 《Hyperfine Interactions》2012,206(1-3):63-66
An IR microscope has been installed at the beamline ID18 at the ESRF in Grenoble, France in order to obtain nuclear inelastic scattering (NIS) data and IR spectra simultaneously. This setup combines the advantages of both spectroscopic methods. The applicability of the installed setup to the study of the spin crossover (SCO) phenomenon in polynuclear iron complexes has been shown. 相似文献
9.
S. Sakshath K. Jenni L. Scherthan P. Würtz M. Herlitschke I. Sergeev C. Strohm H.-C. Wille R. Röhlsberger J. A. Wolny V. Schünemann 《Hyperfine Interactions》2017,238(1):89
A novel sample environment enabling optical pump – nuclear resonance probe experiments has been installed at the beamline P01, Petra III, DESY Hamburg. This set-up has been used to investigate optically induced spin state changes of spin crossover (SCO) complexes by nuclear resonant scattering immediately after excitation by an optical laser pulse. Here, we report the technical details as well as first results of the experiments performed at 290 K and 80 K on the SCO complexes [Fe (NH2trz)3]Cl2 and [Fe(PM-BiA)2(NCS)2], respectively. The 57Fe-enriched SCO complexes were excited by a 531 nm laser with a pulse length <?100 ps. Evaluation of the nuclear forward scattering data clearly indicate the presence of high spin (HS) states when the complexes are excited by laser pulses and a pure low spin (LS) state in the absence of any laser pulse. Furthermore, the dependence of the optically excited HS-fraction has been determined as a function of the average optical power. 相似文献
10.
K.B. Yatsimirskii V.V. Nemoshkalenko Yu.P. Nazarenko V.G. Aleshin V.V. Zhilinskaya N.A. Tomashevsky 《Journal of Electron Spectroscopy and Related Phenomena》1977,10(3):239-245
A number of iron pentacyanide complexes of the Naitn [Fe(CN)5X] type have been synthesized. The compounds have been examined by X-ray photoelectron (ESCA) and Mössbauer spectroscopies. The influence of the nature of ligand X upon the properties of iron- (II) pentacyanide complexes has been studied. The donor properties of dinitrogen as a ligand have been compared with those of other nitrogen-containing ligands. A correlation has been established between the ESCA and Mössbauer data. 相似文献
11.
Two novel ternary rare earth perchlorate complexes had been synthesized by using bis(benzoylmethyl) sulfoxide as first ligand (L=C6H5COCH2SOCH2COC6H5), salicylic acid as second ligand (L′=C6H4OHCOO−). The compounds were characterized by elemental analysis, TG-DSC and molar conductivities in DMF solution. The composition was suggested as [REL5L′](ClO4)2·nH2O (RE=Tb, Dy; n=6, 8 ). Based on IR, 1HNMR and UV spectra, it showed that the first ligand, bis(benzoylmethyl) sulfoxide (L), bonded with Tb(III), Dy(III) ions by the oxygen atom of sulfinyl group. The second ligand, salicylic acid group (L′), not only bonded with RE(III) ions by one oxygen atom of carboxyl group but also bonded with RE(III) ions by oxygen atom of phenolic hydroxyl group. In bis(benzoylmethyl) sulfoxide system, fluorescent spectra of the complexes showed that the luminescence of Tb(III), Dy(III) ions was enhanced by the second ligand salicylic acid. The ternary complexes had stronger fluorescence than the binary ones where only bis(benzoylmethyl) sulfoxide acted as ligand. Phosphorescent spectra of the two ligands indicated that the coordination of salicylic acid resulted in the matching extent increasing between the triplet state of ligand and excited state of the rare earths. The relationship between fluorescence lifetime and fluorescence intensity was also discussed. 相似文献
12.
The iron phosphonates, tris (methyl methylphosphonate) iron (III) [Fe(MMP)3]; tris (ethylphosphonate) iron (III) [Fe(EEP)3]; and tris (isopropyl methylphosphonate) iron (III) [Fe(EEP)3]; have been obtained and studied previously by infrared spectroscopy and elemental analysis.1 The infrared obsorption spectra of the iron phosphonate compounds exhibited bands which could be assigned to functional groups of the phosphonate ligand; however, the role played by the iron atom in the molecule was unknown. In the present article, the results of Mössbauereffect spectroscopy are used to provide evidence for the interaction of the iron with the phosphonate esters. 相似文献
13.
Anupama Kamath Sandeep P. Netalkar Dhoolesh Gangaram Kokare Krishna Naik Vidyanand K. Revankar 《Journal of luminescence》2012,132(10):2763-2768
A tetranucleating compartmental Schiff base ligand system has been derived from 2,6-diformyl-4-methylphenol, p-phenylenediamine and 2-aminomethylbenzimidazole. Phenoxide bridged later first row transition metal(II) complexes of this ligand have been prepared by conventional sequential route. Ligand and complexes were characterized by routine physicochemical characterizations. The mutual influence of metal centers in terms of cooperative effect on the electronic, magnetic, electrochemical and structural properties was investigated. The Schiff-bases exhibit fluorescence originating from intraligand (π→π?) transitions. Metal mediated fluorescence enhancement is observed on complexation with Zn(II), whereas metal mediated fluorescence quenching occurs in all other complexes. 相似文献
14.
Holger Kämpf Daniel Daunke Frank W. Heinemann Andreas Grohmann 《Applied Physics A: Materials Science & Processing》2008,93(2):303-311
Octahedral iron(II) complexes of a unique pyridine-derived tetrapodal pentadentate polyamine ligand, 2,6-C5H3N(CMe[CH2NH2]2)2, show temperature-dependent spin crossover (SCO) depending on the nature of a sixth monodentate ligand L (imidazol or pyridine
derivative). For L = 1-methylimidazol, the redox behaviour of the complex, as determined by cyclic voltammetry, suggests an
accompanying ligand exchange. Pyridine-4-thiol and the disulphides: 4-(2-methyldisulphanyl)pyridine, 4-(2-hexadecyldisulphanyl)pyridine
and 1,2-bis([pyridine-4-yl]methyl)disulphane, were studied as mono-dentate ligands L, with a view to enable chemisorption
of iron(II) complexes on a gold surface. In the case of pyridine-4-thiol, the participation of the thiolate functional group
in iron coordination is difficult to suppress, whereas the disulphides enter into yet unrecorded redox chemistry with iron(II),
yielding a di-iron(III) complex containing a persulphide bridge (S
22−). 相似文献
15.
Assembled complex, Fe(bpa)2(NCX)2 (bpa=1,2-bis(4-pyridyl)ethane; X=S, Se, BH3) enclathrated diphenylmethane. The skeletons were interpenetrating structures for NCS and NCSe complexes, while 2D grid structure
was obtained for NCBH3 complex. The assembled iron complexes showed spin-crossover phenomena by enclathrating diphenylmethane. The ratio of spin
transition and the transition temperature depended on the assembled structure. 相似文献
16.
Stphane Loridant Mathieu Digne Marlne Daniel Thierry Huard 《Journal of Raman spectroscopy : JRS》2007,38(1):44-52
Fe(III)–nitrilotriacetate(NTA) aqueous solutions are used in various redox desulfurization processes. The nature of stable Fe–NTA complexes depends highly on parameters such as [Fe(III)] concentration, NTA/Fe ratio and pH value. These complexes can be characterized by potentiometric measurements or UV‐vis spectroscopy, but only at rather low concentrations. Using synthesis of solids, Raman spectra of these solids and ab initio calculations, a rational determination of the nature of complexes stable in water at high iron concentrations was proposed from the position sensitivity of the main low wavenumber band to the coordination sphere of iron cations. This band was assigned to ν(Fe N) stretching vibrations from ab initio calculations. Depending on the pH and NTA/Fe ratio of the prepared solutions, different species were identified from the Raman spectra. The present methodology can be extended to other metal–ligand systems to elucidate the nature of stable complexes in aqueous solution. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
17.
W.L. Zhou E.E. Carpenter J. Lin A. Kumbhar J. Sims C.J. O'Connor 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):289-292
Pure metal iron nanoparticles are unstable in the air. By a coating iron on nanoparticle surface with a stable noble metal,
these air-stable nanoparticles are protected from the oxidation and retain most of the favorable magnetic properties, which
possess the potential application in high density memory device by forming self-assembling nanoarrays. Gold-coated iron core-shell
structure nanoparticles (Fe/Au) synthesized using reverse micelles were characterized by transmission electron microscopy
(TEM). The average nanoparticle size of the core-shell structure is about 8 nm, with about 6 nm diameter core and 1∼2 nm shell.
Since the gold shell is not epitaxial growth related to the iron core, the morié pattern can be seen from the overlapping
of iron core and gold shell. However, the gold shell lattice can be seen by changing the defocus of TEM. An energy dispersive
X-ray spectrum (EDS) also shows the nanoparticles are air-stable. The magnetic measurement of the nanoparticles also proved
successful synthesis of gold coated iron core-shell structure. The nanoparticles were then assembled under 0.5 T magnetic
field and formed parallel nanobands with about 10 μm long. Assembling two dimensional ordered nanoarrays are still under going.
Received 29 November 2000 相似文献
18.
A series of organotin(IV) complexes of composition R3Sn[O2CC6H4{N= C(H)C6H3-2-OH(N=NC6H4R)}-p] (R = Ph or Bz; R = H, 2-CH3, 3-CH3, 4-CH3) have been investigated by 119Sn Mössbauer, 1H, 13C, 119Sn NMR and IR spectroscopic techniques. 119Sn Mössbauer data indicated a distorted tetrahedral geometry for the triphenyltin(IV) complexes while the tribenzyltin complexes exhibit a distorted trigonal bipyramidal coordination geometry with equatorial benzyl groups and the axial positions occupied by an O atom from the carboxylate ligand and the O atom from the water ligand. The 119Sn-NMR chemical shifts confirm that the Sn atom in triorganotin complexes is four-coordinate in CDCl3 solution. 相似文献
19.
Darko Hanzel D. Hanzel H. Bilinski T. A. Himdan M. Miljak V. Vancina 《Hyperfine Interactions》1990,53(1-4):339-343
Mössbauer data as well as infrared and magnetic susceptibility results indicate that Fe(III)-phthalates are high spin ferric complexes with a combination of trinuclear oxo-bridged and monomer structures. Values obtained for the isomer shift and quadrupole splitting parameters suggest that different counter ions, such as OH, NO3, and Na, leave the Fe(III) ions in two very distorted octahedral arrangements, although they scarcely affect the electron densities at the iron nuclei. 相似文献
20.
M. R. Press S. N. Khanna P. Jena M. J. Puska 《Zeitschrift für Physik B Condensed Matter》1990,81(2):281-289
Using the density functional theory and the embedded cluster model, we have calculated the energetics of carbon-vacancy complexes in Fe as a function of distance separating the carbon atom(s) and the vacancy along different crystallographic directions. Carbon is found to prefer off-center sites from the vacancy and maintains a constant distance of approximately 3.35a
0 from the nearest Fe atom(s) independent of its direction from the vacancy center. This distance agrees closely with that in stoichiometric Fe3C. Our results suggest that the equilibrium site of carbon is one where it is coordinated to three Fe atoms in its nearest neighbor shell. Further decoration of vacancies by more than one carbon atom has been found to be energetically favorable. The binding of carbon to iron atoms is not caused by charge transfer between the atoms, but rather has a magnetic origin. Positron lifetimes at vacancies and vacancy-carbon complexes have also been calculated for various configurations. Our results are in general agreement with experiment. 相似文献