Synthesis, structure and characterization of a novel asymmetrical half-sandwich binuclear iron carborane complex [eta(5)-C5H3 (t-Bu)(2)](2)Fe-2 (CO)(3)Se2C2B10H10

Halfsandwich iron dicarbonyl complex [eta(5)-C5H3(t-Bu)(2)]Fe(CO)(2)Cl(1) reacts with 1, 2-dilithium diseleno carborane Li(2)Se(2)C(2)B(10)H10 (2) to give a binuclear iron carborane complex [eta(5)-C5H3(t-Bu)(2)](2)Fe-2(CO)(3) Se2C2B10H10(3). The X-ray diffraction analysis of complex 3 reveals that one of the iron atoms is chiral.

Synthesis and structure of iron complex with 1,2-dithiolate-1,2-dicarba-closo-dodecaborane [Li(THF)(4)][Fe(S2C2B10H10)(2)(THF)]

The crystal of complex [Li(THF)(4)][Fe(S2C2B10H10)(2)(THF)] 3 belongs to monoclinic, space group P2(1) with a = 11.964(2), b = 16.527(3), c = 12.554(3) Angstrom,beta = 108.70(3)degrees, V= 2351.3(8) Angstrom(3), Z = 2, M-r = 835.95, D-c = 1.181 g/cm(3), mu (MoKalpha) = 5.30 cm(-1), f(000) = '874, R = 0.0622 and Rw 0.1538 for 1641 observed reflections with I > 2sigma(I). The ionic complex,of 3 contains the square pyramidal anion of [Fe(S2C2B10H10)(2)(THF)](-) and the tetrahedral cation of [Li(THF)(4)](+). The iron is 5-coordinated and located in the square pyramidal configuration. The iron atom and the four sulfur atoms are almost coplanar. The Lithium atom is coordinated with four oxygen atoms of four THF molecules and located in a tetrahedral configuration.

1,1 '-di(tert-butyl)metallocenium cations. The x-ray crystal structures of [M((C5H4Bu)-Bu-t)(2)]PF6 (M = Fe, Co) and [Co((C5H4Bu)-Bu-t)(2)](2)CoCl4

The hexafluorophosphate salts [Fe((C5H4Bu)-Bu-t)(2)]PF6 (1) and [Co((C5H4Bu)-Bu-t)(2)]PF6 (2) crystallize in isotypic structures with centrosymmetric cations which have a staggered (transoid) conformation of the exactly parallel ring Ligands (conformational angle tau = 180 degrees). The tetrachlorocobaltate salt, [CO((C5H4Bu)-Bu-t)(2)](2)CoCl4 (3), contains one almost eclipsed (tau = 140.4 degrees) and one almost staggered (tau = 101.4 degrees) cobaltocenium cation; in both cases, the cyclopentadienyl ring planes are slightly inclined (by alpha = 5.4 degrees and 4.1 degrees, respectively) to give more room to the tert-butyl substituents which are bent away from the metal in all three complexes 1 - 3.

Electrochemiluminescent determination of peroxydisulfate with Cr(bpy)(3)(3+) in purely aqueous solution

A novel method for the sensitive and selective determination of peroxydisulfate was proposed. It was based on an electrochemiluminescent method with Cr(bpy)(3)(3+). The applied potential was set at -0.5 V in Cr(bpy)(3)(3+) system which was much more positive than those in Ru(bpz)(3)(2+) and Ru(bpy)(3)(2+) systems. A linear calibration was obtained over the range of 7-100 mu mol l(-1) with a correlation coefficient of 0.993. The relative standard deviation was 2% for 10 replicate injections of 0.01 mol l(-1) S2O82- solution. The detection limit (S/N=3) was 1 mu mol l(-1). The method was successfully applied to determination of peroxydisulfate in phase transfer catalysis. (C) 2000 Elsevier Science B.V. All rights reserved.

一些含半夹心结构ⅥB族金属的1,1’-二硫(硒)二茂铁化合物的合成

CpCr(NO)(CO)_2与Fe(C_5H_4S)_2S反应,形成氧化-还原产物CpCr(NO)(SC_5H_4)_2Fe(1)。双杂核二茂铁化合物CpM(NO)(EC_5H_4)_2Fe[M=Mo,E=S(2a),Se(2b);M=W,E=S(4a),Se(4b)]、CpMo(NO)(SC_5H_4)_2Fe(3)、Cp_2Mo(SeC_5H_4)_2Fe(6)和Cp_2W(SC_5H_4)_2Fe(7)可通过Fe(C_5H_4ELi)_2·2THF(E=S,Se)与CpM(NO)I_2(M=Mo,W)、[CpMo(NO)I_2]_2或Cp_2MCl_2(M=Mo,W)反应制得。三核杂原子二茂铁化合物[CpCr(NO)_2]_2(EC_5H_4)_2Fe[E=S(8a),Se(8b)],由Fe(C_5H_4ELi)_2·2THF(E=S,Se)与二倍摩尔量的CpCr(NO)_2I反应制备。通过AgBF_4氧化2a得到二茂铁离子型化合物[CpMo(NO)(SC_5H_4)_2Fe]~+BF_4~-(5)。采用元素分析、红外光谱、~1H和~(13)C NMR谱以及EI-MS表征了所合成的新型化合物。

Gold-coated iron (Fe@Au) nanoparticles: Synthesis, characterization, and magnetic field-induced self-assembly

A unique reverse micelle method has been developed to prepare gold-coated iron (Fe@Au) nanoparticles. XRD, UV/vis, TEM, and magnetic measurements are utilized to characterize the nanocomposites. XRD only gives FCC patterns of gold for the obtained nanoparticles. The absorption band of the Fe@Au colloid shifts to a longer wavelength and broadens relative to that of the pure gold colloid. TEM results show that the average size of Fe@Au nanoparticles is about 10 nm, These nanoparticles are self-assembled into chains on micron scale under a 0.5 T magnetic field. Magnetic measurements show that the particles are superparamagnetic with a blocking temperature (T-B) of 42 K, At 300 K (above T-B), no coercivity (Hc) and remanence (M-r) is observed in the magnetization curve, while at 2K (below T-B) He and M, are observed to be 728 Oe and 4.12 emu/g, respectively, (C) 2001 Academic Press.

Study of energy transfer in KMgF3 : Eu-X (X = Gd, Cr, Ce) by the decay model of P-6(7/2) exited state of Eu2+

Energy transfer processes between Eu2+ and Gd3+, Cr3+, Ce3+ ions in KMgF3, which are difficult to study spectroscopically, have been investigated by using the proposed four-level decay model of the P-6(7/2) excited state of the Eu2+ ion. Gd3+ and Ce3+ transfer its energy to the vibronic transition of the P-6(7/2) --> S-8(7/2) transition of Eu2+, whereas Cr3+ receive energy from Eu2+ via the d-d interaction. The energy transfer from the Eu2+ 4f(6)5d level to the Ce3+ 4f5d state is observed spectroscopically, and the energy transfer mechanism is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

Analysis of mussel standard reference material by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry

A method for the analysis of mussel standard reference material by inductively coupled plasma atomic emission spectrometry( ICP-AES) and inductively coupled plasma mass spectrometry(ICP-MS) was developed. K, Na, Ca, Mg, P, Al, Fe, Zn, Mn and Sr were determined by ICP-AES and As, B, Cd, Co, Cr, Cu, Ga, Ge, Mn, Mo, Ni, Pb, Se, Sr, U and V by ICP-MS, The interference coefficients at the Mn-55, Se-78, Cu-63, Co-59, Ni-58, Ni-60, As-75, Se-77, V-51, Cr-53 and Cr-52 originating from polyatomic ion of the matrix elements (KO)-K-39-O-16, K-39(2), (ArNa)-Ar-40-Na-23, (CaO)-Ca-43-O-16, (CaO)-Ca-42-O-16, (CaO)-Ca-44-O-16, (PO2)-P-31-O-16, (ArCl)-Ar-40-Cl-35, (ArCl)-Ar-40-Cl-37, (ClO)-Cl-35-O-16, (ClO)-Cl-37-O-16 and (ArC)-Ar-40-C-12 were determined under the selected operation parameters. The major matrix elements, such as K, Na and Ca, result in the suppression of analytes signals. The apparent concentration at the significant biological element which was produced by the different digestion methods, (.) HNO3 + H2O2 (3 + 2), HNO3 + HClO4 (3 + 0.5) and HNO3 + H2SO4 (3 + 0.5),was determined. The sample digested by HNO3 + H2O2 did not give rise to interfere on the analyte, and the backgrounds of Se-77, Ga-69, Zn-67, As-75, V-51, Cr-53 and Cr-52 were increased by HNO3 + HClO4 digestion method, that affected the determination of these elements, especially the monoisotope As and V. Sample digested by HNO3 + H2SO4 increased the backgrounds at Cu-65, Zn-64 and Zn-67. Detection limits of ICP-AES are 0.001 similar to 0.75 mg/L and those of ICP-MS are 0.005 similar to 1.01 mu g/L. The relative standard derivations of ICP-AES and ICP-MS are 2.7% similar to 12.8%, 3.4% similar to 24.8%, respectively.

电感耦合等离子体光谱和质谱法分析贻贝标准物质

采用电感耦合等离子体光谱和质谱法分析了贻贝标准物质,光谱法测定K、Na、ca、Mg、P、Al、Fe、Zn、Nn和Sr,质谱法测定As、B、Cd、Co、Cr、Cu、Ca、Ce、Mn、Mo、Ni、Pb、Se、Sr、U和V。在优化的工作条件下,测定了来自基体元素K、Na、Ca、P、Cl和C的多原子离子~(39)K~(16)O、~(39)K_2、~(40)Ar~(23)Na、~(43)Ca~(16)O、~(42)Ca~(16)O、~(44)Ca~(16)O、~(31)P~(16)O_2、~(40)Ar~(37)Cl、~(35)Cl~(16)O、~(37)Cl~(16)O和~(40)Ar~(12)C对~(55)Mn、~(78)Se、~(63)Cu、~(59)Co、~(58)Ni、~(60)Ni、~(75)As、~(77)Se、~(51)V、~(53)Cr和~(52)Cr的干扰系数以及HNO_3+H_2O_2(3+2)、HNO_3+HClO_4(3+0.5)和HNO_3+H_2SO_4(3+0.5)等3种样品消解方法在一些生物重要元素的同位素处产生的表观浓度。光谱法的检出限0.001～0.75mg/L;质谱法的检出限0....

Study on the bond covalency and bond susceptibility in NdCr1-xMxO3 (M=Mn, Fe, Co)

Bond covalency, bond susceptibility and macroscopic linear susceptibility in NdCr1-xMxO3 (M=Mn, Fe, Co, 0.0 less than or equal to x less than or equal to 1.0) are investigated by complex chemical bond theory. The results indicate the bond covalencies are insensitive to the doping level. With the increasing doping level, the macroscopic linear susceptibilities increase for M=Mn, Fe, decrease for M=Co. The valence state of Cr can be strongly influenced by the properties of the doping ions.

Structure, electric and magnetic properties of new compounds CdYMWO7 (M = Cr and Mn)

Two new compounds with the formula of CdYMWO7 (M = Cr, Mn) were prepared by solid state reaction. They crystallized with orthorhombic structure with the cell parameters of a = 11.7200 Angstrom, b = 7.1779 Angstrom, c = 6.9805 Angstrom (CdYCrWO7), and a = 11.7960 Angstrom, b = 6.1737 Angstrom, c = 7.6530 Angstrom (CdYMnWO7). These compounds are insulators with high resistivities at room temperature. The temperature dependence of the magnetic susceptibility of CdYMWO7 (M = Cr and Mn) show Curie-Weiss Law's behaviors from 80 to 300 K. The magnetic moments at room temperature fit very well with those corresponding to Cr3+ and Mn3+ ions. This suggests that both Cr and Mn ions exist in + 3 oxidation state in CdYMWO7 compounds. (C) 1998 Elsevier Science Ltd. All rights reserved.

Mossbauer spectra of Fe-57 in a thick film of YBa2(Cu0.97Fe0.03)(3)O7-x irradiated by a large dose of gamma-rays

Mossbauer spectra of Fe-57 in a thick film YBa2(Cu0.97Fe0.03)(3)O7-x irradiated by a large dose of gamma-rays from Co-60 have been measured. The variation of the relative intensities of some subspectra of Fe-57 in the. Mossbauer spectra of the thick film YBa2(Cu0.97Fe0.03)(3)O7-x after irradiation can be observed. This variation indicates that the change of the coordination environment around some Fe atoms in the lattice occurs due to irradiation. The relative intensity of subspectrum D1(Fe) at the Cu(1) site decreases and that of subspectrum D4(Fe) at the Cu(1) site increases. This may be because of the possible oxygen atom hopping between the coordination environments of D1(Fe) and D4(Fe) in the lattice caused by irradiation. The effect of irradiation on the coordination environment around the Fe atom at the Cu(2) site is not appreciable. (C) 1997 Elsevier Science B.V.

层状La-Ba-Cu复合氧化物在CO还原NO反应中活性的研究

氮氧化物是严重的空气污染物,催化消除氮氧化物是环保催化研究的热点问题,在已有报道的催化剂体系中复合氧化物和含铜分子筛受到人们的普遍关注,文献中已有报道ABO_3(A=Ln;B=Cr,Mn,Fe,Co,Ni)型复合氧化物作为CO还原NO反应的催化剂.但迄今尚未见有合成LaCuO_3的报道,有关含铜复合氧化物作催化剂的大多是A_2BO_4型的.呈ABO_3结构的含铜复合氧化物只有成层状的超导体如YBa_2Cu_3O_7,本文为了探讨复合氧化物晶体结构对催化活性的影响,首次研究了3种层状ABO_3结构的La-Ba-Cu复合氧化物对CO还原NO反应的活性,发现它们均具有较高的活性,并首次提出了Ba离子在此反应中的作用.1 实验方法催化剂的制备和Cu价态分析见文献[4,5]CO还原NO反应在固定床流动反应体系中进行,反应管为内径6mm石英管,催化剂粒度为40～80目,用量0.2g,空速为7000h~(-1),原料气为NO7.5×10~(-3),CO8.0×10~(-3),He平衡.采用英国产的Pyc Pan气相色谱分析检测N_2O,CO_2,0.5nm分子筛色谱柱检测NO,CO转化率. H_2-TPR在自制装置上...

青海油菜蜂花粉酶解破壁前后营养成分的比较

对青海油菜蜂花粉及生物酶解破壁花粉的营养成分进行了分析和比较。结果表明，花粉经酶解破壁后，粗蛋白、粗脂肪、还原糖、核酸、总黄酮、灰份、多数氨基酸、维生素（A、B、C和K）及黄酮类化合物（原青花素、芦丁、槲皮素、异鼠李索）的含量得到了明显提高，而K、Na、Ca、Mg、Fe、Zn、Cu、Cr、Cd、Ni、Mn等矿质元素的含量无明显变化。青海油菜花粉经破壁后更有利于营养成分和活性成分的释放。

华北克拉通新生代玄武岩携带的地幔橄榄岩Fe同位素地球化学及含金云母地幔岩岩石学研究

In recent years, thanks to the improvement of analytical methods and the use of MC-ICP-MS, Fe isotope can be measured precisely. Fe isotope shows considerable variation both in biological and inorganic processes (from low T to high T) in nature, Therefore, Fe isotope has become one of the exciting frontier sciences and has favorable prospects of the application to the geosciences and life sciences. Based on a comprehensive review of available references in the related field, this study focuses on the development of techniques for high-precision measurement of iron isotope using MC-ICP-MS, and application of the techniques developed to study the Fe isotopes as well as major and trace element compositions of minerals (Ol, Opx, Cpx and Sp) from spinel peridotitic xenoliths from Cenozoic alkaline basalts to investigate Fe isotopic features of the lithospheric mantle beneath the North China Craton. The minerals from these xenoliths are similar to those off-cratonic peridotites world-wide, but are remarkably different from those on-cratonic peridotites and clinopyroxenes from these spinel lherzolites exhibit two types of chondrite-normalized REE patterns i.e. LREE-depleted and flat or spoon-shaped. It is noted that total abundances of REE in clinopyroxenes from these peridotites show a broad negative correlation with Cr# numbers of Cpx and Sp. The Fe isotope results show that the spinel peridotitic xenoliths have small but distinguishable Fe isotopic variations in minerals (generally Ol < Opx < Cpx) and samples, and the isotopic range in spinel is relatively large. Positive linear relationship with the ε57Fecpx/ε57Feopx ratio close to one unit has been observed between Fe isotopes of coexistent Opx and Cpx, indicating that the Cpx and Opx have generally reached Fe isotopic equilibrium. However, Fe isotopes between the Ol and Sp show apparent disequilibrium. The broadly negative correlation between mineral Fe isotopes and oxygen fugacity (fo2), metasomatic indexes such as spinel Cr#, (La/Yb) N and (La/Sm) N ratios of clinopyroxenes suggest that Fe isotopic variations in different minerals and peridotites were probably produced by melt-peridotite interaction. This study further confirms the previous observation that the lithospheric mantle has distinguishable and heterogeneous Fe isotopic variations at a scale of xenoliths. Mantle metasomatism that induces the interaction of the lithospheric mantle peridotite with metasomatic agent is a most potential mechanism for the Fe isotope fractionation in mantle peridotites. Therefore, Fe isotope could be a new and powerful tool to probe the evolution of the lithospheric mantle. We also report mineral compositions, clinopyroxene trace element concentrations and Sr-Nd isotopes for newly-discovered phlogopite-bearing spinel lherzolite and olivine clinopyroxenite xenoliths from three different localities （Hannuoba, Hebei Province; Jining Sangyitang, Inner Mongolia; Hebi, Henan Province）of the North China Craton. Systematic comparisons with phlogopite-free spinel lherzolite xenolith from the same locality reveals that the phlogopite-bearing peridotitic xenoliths have relatively higher Al2O3, CaO, Na2O, K2O, TiO2 contents and lower MgO contents than those phogopite-free counterparts. The former also has higher LREE concentrations, but relatively less radiogenic Sr-Nd isotopic ratios. This demonstrates that mantle metasomatism can not only enrich the basaltic components and trace element concentrations, but also make a decrease in Mg# of the peridotites and olivines and a relative depletion in Sr-Nd isotopes. 87Rb/86Sr-87Sr/86Sr isochrons of the phlogopite-bearing xenoliths indicate that mantle metasomatism happened in the Mesozoic and/or Cenozoic time. The metasomatic agent was derived from the asthenosphere. The result also manifests that the widespread similarity of the geochemical features such as major and trace elements and isotopic compositions in the Cenozoic lithospheric mantle beneath the North China Craton to those “oceanic” lithospheric mantle could be as a result of the ubiquitous presence of the interaction between the old refractory peridotites and the infiltrated asthenospheric melt, rather than the actually newly-accreted lithospheric mantle.