Electronic structure of HgBa2Ca(n-1)Cu(n)O(2n+2) (n = 1, 2, 3) superconductor parent compounds from periodic hybrid density functional theory

The electronic structure of HgBa(2)Ca(n) (-1)Cu(n)O(2n+2) (n = 1, 2, and 3) high T(c) superconductor parent compounds has been investigated by means of periodic hybrid density functional theory. Similar to other cuprates, these materials are predicted to exhibit an antiferromagnetic ground state with well localized S = 1/2 magnetic centers at the Cu(2+) sites. However, the presence of the HgO(2) structural units largely defines the nature of states dominating the energy range around Fermi energy. This results in a complex charge transfer character of the insulating gap which decreases when increasing the number of CuO(2) planes in the unit cell, to the point that in the HgBa(2)Ca(2)Cu(3)O(8) compound it becomes so small that one can claim that the resulting material is metallic. Nevertheless, the metallic character arises from the HgO(2) structural units and coexists with the antiferromagnetic order arising from the localized spins at the Cu(2+) sites.     

水热法制备具有光滑表面的球形Y2O3∶Eu3+发光材料

The spherical Y₂O₃∶Eu³⁺ luminescent particles with size of 0.5～3 μm and smooth surface were synthesized by hydrothermal method. The resulted Y₂O₃∶Eu³⁺ precursors and the calcined particles were characterized by differential thermal analysis (DTA) and thermogravimetric (TG) analysis, X-ray diffraction (XRD), Fourier-transform IR spectroscopy (FTIR), scanning electron microscopy (SEM) and photoluminescence spectra (PL). FTIR, TG-DTA, XRD measurements show that the precursors are crystal with hydroxyl and carbonate group, and the pure cubic yttria is obtained after annealing above 700 ℃. The SEM images indicate that the Y₂O₃∶Eu³⁺ particles are in spherical shape and with smooth surface. PL analysis shows that the particles present characteristic red emission of Eu³⁺.     

Two multi-copper-containing heteropolyoxotungstates constructed from the lacunary Keggin polyoxoanion and the high-nuclear spin cluster

Two novel high-nuclear copper-substituted polyoxometalates, Na16[Cu14(OH)4(H2O)16(SiW8O31)4].20.5H2O (1) and K10Na14[Cu10(H2O)2(N3)4(GeW9O34)2(GeW8O31)2].30H2O (2), containing 14 Cu2+ ions and 10 Cu2+ ions, respectively, have been obtained in aqueous solution and characterized by IR, UV, TG, element analysis, electrochemistry, and single-crystal X-ray analyses. The polyoxoanion framework of 1 is composed of four [beta-SiW8O31] units connected by 14 Cu2+ ions to constitute a tetrameric compound. In 2, two [beta-GeW8O31] anions and two [B-alpha-GeW9O34] anions are connected together by a [Cu10(N3)4O32(H2O)2] {Cu10(N3)4} cluster to construct a novel tetrameric compound. The results of the electrocatalytic experiments reveal that the reduced species of 1 and 2 have electrocatalytic activities for nitrate reduction.     

基于八钼酸盐杂化网络的离子热合成、晶体结构和光催化性质

采用离子热法合成了一个由八钼酸盐和过渡金属配合物构筑的新颖的三维(3D)自穿插网络的有机-无机杂化材料Cu₅^ⅠBBTZ₃H₂O[β-Mo^ⅤMo₇^ⅥO₂₆][1,BBTZ=1,4-二(三咪唑-1-乙基)苯]. 化合物1具有由3D聚圆环结构和(4,4)二维层构筑的3D自穿插框架结构. 通过单晶X射线衍射、 元素分析、 红外光谱和热重分析对化合物1的结构进行了表征, 并初步研究了其光催化产氢活性.     

高温超导体的Cu-O键型和氧上的部分电荷

多数钙钛矿型化合物是离子型绝缘体，而高温超导化合物则有金属电性，它们是以什么键型为主？对此等人[1]认为用共价或金属成键图像描述高温超导体在化学上更合理，Nepela等人[2]指出超导体临界温度（Tc）随阴离子平均电负性与阳离子平均电负性之差增大而升高．这意味着离子性较强的超导体有较高的人．杨频等问运用晶型键参数方法估算结果表明高温超导体属干部分离子性与部分共价性键．以上不同的结果都是基丁理论处理或估算得到的·本文试图在实验上通过比较不同成键特征的铜化合物的x光电子能潜（＊P8）来估计对高温超导性起重要作用的C…     

Valence of elements in HgBa2Can-1CunO2n+2+d (n=1, 2, 3, 4)

Valence of elements in HgBa2Can-1CunO2n+2+d (n=1, 2, 3, 4) (both argon and oxygen annealed samples) were calculated. The result indicated for both argon and oxygen annealed samples, Hg had the lowest valence for the highest Tc sample. For fixed n, the valence of Cu in oxygen annealed samples was larger than that in argon annealed samples, indicating that oxygen annealed samples produce more carriers than argon annealed samples.     

Thermal analysis of Y1−xCaxBa2Cu3O7−y

TG and DTA analysis of Y_1?xCa_xBa₂Cu₃O_7?y suggests that the stability of the 123 phase increases with increasing Ca contents. The O(1) in the Cu(1)-O chain is unstable but O(2) and O(3) in Cu(2)-O planes are very stable. There are hardly any oxygen vacancies in the Cu(2)-O plane. The replacement of Y by Ca does not make oxygen vacancies in Cu(2)-O planes but leads to an increase in the oxidation number of copper in Cu(2)-O planes.     

Co(III) complexes with N2(SO)2-type equatorial planar ligands similar to the active center of nitrile hydratase: role of the sulfenate group in the enzymatic reaction

In order to gain an understanding of the role of the sulfenyl group of nitrile hydratase (NHase), a new Co(III) complex with a sulfenyl-type ligand (LC=O:N2(SO)2), Na[CoIII(LC=O:N2(SO)2)(tBuNC)2] (2), was synthesized. The compound includes two amide groups, two sulfenate sulfurs in the equatorial plane, and two tBuNC molecules in the axial positions. Characterization of the compound was performed by UV-vis spectroscopic, IR spectral, thermogravimetric (TG), and X-ray structure analytical methods. The results are discussed in the context of Co(III) complexes containing the corresponding sulfur-type (LC=O:N2S2) (1) and sulfinyl-type ligands (LC=O:N2(SO2)2) (3). Complex 2 crystallized with the formula Na[CoIII(LC=O:N2(SO)2)(tBuNC)2].urea.2H2O.0.5EtOH. The X-ray structure revealed that the Co(III) complex has an octahedral geometry with Co-S=av. 2.221 A, Co-N=av. 1.998 A, and Co-C=av. 1.87 A. The sulfenyl oxygen and amidate carbonyl oxygen are linked to urea, water, EtOH, and Na+ and participate in a hydrogen-bond and an electrostatic interaction. IR and TG measurements demonstrated that the coordination strength of tBuNC to the Co atom increases as follows: 1<2<3. Complex 2 has almost the same stability as 3 in all solutions tested, although 1 exhibits a release of axial ligands in nonaqueous solutions. DFT calculations for 1, 2, and 3 demonstrated that Milliken atomic charges of the Co(III) centers are +1.466, +1.536, and +1.542, respectively, indicating that the extent of oxidation of the sulfur atoms increases the Lewis acidity of the Co(III) centers. Interestingly, the solution-state IR spectrum of 2 exhibits a solvent-dependent S-O stretching frequency. The frequency decreases with an increase in the electrophilicity (acceptor number) of the solvent. This solvent dependence was not observed for 3, which has a sulfinate (SO2) group, suggesting that the sulfenyl oxygen atom has nucleophilic character and promotes strong binding of the tBuNC molecule to lower the reaction barrier. These findings may suggest that the sulfenate oxygen in native NHase acts as a base (proton acceptor) and contributes to the activation of a water molecule and/or nitrile molecule.     

OL负载Cu催化剂及其催化氧化CO及乙酸乙酯性能

采用氧化还原法合成了层状锰氧化物(OL),并以OL为载体采用离子交换法制备了不同Cu负载量的Cu_x/OL催化剂。利用X射线衍射(XRD)、电子扫描电镜(SEM)、N_2吸附/脱附、H_2~-程序升温还原(H_2-TPR)、TG(热重)、X射线光电子能谱(XPS)、O_2-程序升温脱附(O_2-TPD)等技术对所制催化剂进行结构和织构表征,并对其催化氧化CO及乙酸乙酯活性进行了评价。结果表明,OL具有典型的层状锰氧化物结构,适量掺杂Cu对OL的结构和织构影响不大,但Cu的掺杂明显影响Cu_x/OL的还原性、氧移动性及催化剂表面Cu~(2+)/CuO、(Mn~(2+)+Mn~(3+))/Mn~(4+)和Oads/Olatt的比例。Cu_x/OL的催化性能与以上因素密切相关。在Cu_x/OL样品中,Cu_5/OL催化剂具有最佳的催化活性(CO催化氧化,T_(50)=70°C和T_(90)=100°C;乙酸乙酯催化氧化T50=160°C,T90=200°C)。同时,Cu_5/OL催化剂具有最佳的还原性能、氧移动性能和最多的Cu~(2+)、(Mn~(2+)+Mn~(3+))和表面吸附氧浓度。Cu_x/OL催化性能与铜锰之间相互作用、还原性和氧移动性能密切相关。     

Novel inorganic-organic hybrids constructed from multinuclear copper cluster and Keggin polyanions: from 1D wave-like chain to 2D network

Two novel inorganic-organic hybrids constructed from Keggin-type polyanions and multinuclear copper clusters based on 1-H-1,2,3-benzotriazole (HBTA), [Cu(I)(8)(BTA)(4)(HBTA)(8)(SiMo(12)O(40))]·2H(2)O (1) and [Cu(II)(6)(OH)(4)(BTA)(4)(SiW(12)O(40))(H(2)O)(6)]·6H(2)O (2), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric (TG) analyses. In compound 1, eight Cu(I) ions were linked by twelve HBTA/BTA ligands to form an octanuclear Cu(I) cluster, which is connected by SiMo(12)O(40)(4-) anion with two bridging O atoms and two terminal O atoms to construct a one-dimensional (1D) wave-like chain. The octanuclear copper unit represents the maximum subunit linked just by amine ligands in the POMs system. In 2, four BTA ligands linked five Cu(II) ions constructing a pentanuclear "porphyrin-like" subunit, which is connected by another Cu(II) ion to form a 1D metal-organic band. The SiW(12)O(40)(4-) polyanions as tetradentate inorganic linkages extend the 1D band into a two-dimensional (2D) network with (8(3))(2)(8(5)·10) topology. To the best of our knowledge, compounds 1 and 2 represent the first examples of inorganic-organic hybrids based on metal-HBTA multinuclear subunits and polyoxometalates. The photocatalysis and electrochemical properties have been investigated in this paper.     

Hydrothermal reaction of Cu(II)/pyrazine-2,3,5-tricarboxylic acid and characterization of the copper(II) complexes

Four copper(II) complexes [Cu3(PZHD)2(2,2'-bpy)2(H2O)2].3H2O (1), [Cu3(DHPZA)2(2,2'-bpy)2] (2), [Cu(C2O4)phen(H2O)].H2O (3), and [Cu3(PZTC)2(2,2'-bpy)2].2H2O (4) were synthesized by hydrothermal reactions, in which the complexes 1-3 were obtained by the in situ Cu(II)/H3PZTC reactions (PZHD3- = 2-hydroxypyrazine-3,5-dicarboxylate, 2,2'-bpy = 2,2'-bipyridine, DHPZA3- = 2,3-dihydroxypyrazine-5-carboxylate, C2O42- = oxalate, phen = 1,10-phenanthroline, and H3PZTC = pyrazine-2,3,5-tricarboxylic acid). The Cu(II)/H3PZTC hydrothermal reaction with 2,2'-bpy, without addition of NaOH, results in the formation of complex 4. The complexes 1-4 and transformations from H3PZTC to PZHD3-, DHPZA3-, and C2O4(2-) were characterized by single-crystal X-ray diffraction and theoretical calculations. In the complexes 1, 2, and 4, the ligands PZHD3-, DPHZA3-, and PZTC3- all show pentadentate coordination to Cu(II) ion forming three different trinuclear units. The trinuclear units in 1 are assembled by hydrogen-bonding and pi-pi stacking to form a 3D supramolecular network. The trinuclear units in 2 acting as building blocks are connected by the carboxylate oxygen atoms forming a 2D metal-organic framework (MOF) with (4,4) topology. While the trinuclear units in 4 are linked together by the carboxylate oxygen atoms to form a novel 2D MOF containing right- and left-handed helical chains. The theoretical characterization testifies that electron transfer between OH- and Cu2+ and redox of Cu 2+ and Cu+ are the most important processes involved in the in situ copper Cu(II)/H3PZTC reactions, forming complexes of 1-3.     

二维钨-钒簇聚物[Cu(en)_2]_2·[W_(4.5)~ⅥW_2~ⅤV~ⅤV_(9.5)~ⅣO_(44){Cu(en)_2(H_2O)}_2]·3H_2O的合成与表征

采用水热法合成了一个钨-钒簇聚物[Cu(en)2]2[WⅥ4.5WⅤ2VⅤVⅣ9.5O4 4{Cu(en)2(H2O)}2]·3H2O(1,en=乙二胺),并通过X射线单晶衍射、元素分析、傅里叶变换红外光谱、X射线粉末衍射、热重分析、价键计算、X射线光电子能谱、电子顺磁共振和磁性分析对其结构和性能进行了表征.结果表明,化合物1是以双支撑的四帽Keggin结构[WⅥ4.5WⅤ2VⅣ9.5O4 0(VⅤO4){Cu(en)2(H2O)}2]4-钨-钒簇合物阴离子为基本结构单元,与4个[Cu(en)2]2+配合物阳离子以共价键和弱键相连接形成二维层状结构,相邻层又通过氢键连接成三维超分子网络.研究了化合物1的磁性及光催化降解罗丹明B的活性.     

一个基于[Cu4(μ2-OH)2N12]的10-连接3D配合物的合成、结构和光催化性质

通过扩散法合成了一个新的配位聚合物{[Cu₂（OH）（btre）_1.5（1,2,4-btc）]·13H₂O}_n（1·13H₂O）（btre=1,2-二（4H-1,2,4-三唑）乙烷,1,2,4-btc=1,2,4-苯三甲酸根）。测试了1·13H₂O的晶体结构,并用红外光谱、元素分析、粉末X射线衍射对其进行表征。单晶X射线衍射表明1是基于四核铜簇[Cu₄（μ₂-OH）₂N₁₂]构筑的10-连接的3D框架,其拓扑符号为3¹²·4²⁸·5⁵。研究了1·13H₂O的热稳定性以及对甲基橙的催化降解作用。     

Tl系列超导体中掺F研究

Ｔｌ系列超导体中掺Ｆ研究周鼎元（上海闸北教育学院，上海２０００７０）徐昌华（上海工业大学，上海２０００７２）陈敏（上海市长城电子工业公司，上海）关键词％Ｔｌ系超导体，掺Ｆ在ＲＢａ。Ｃｕ。Ｏｘ中掺加Ｆ的研究已有不少报逍（”．本文研究在ＴＩ系列超导体中掺...     

La1—xMxCoO3（M=Ca,Sr）表面状态的XPS研究

合成了一系列钙钛矿复合氧化物La_(1-x)M_(?)CoO_3(M=Ca,Sr),并用XPS研究了LaCoO_3中的La~(3+)部分被Ca~(2+)或Sr~(2+)取代后表面状态的变化。由XPS的O_(10)谱图拟合得到的吸附氧O(2)百分数与取代量x呈现规律性变化。对Ca_(2p)与Sr_(3d)谱图也进行峰拟合处理,其中结合能较高的Sr(2)、Ca(2)可指认为周围有氧离子缺位物种。Ca(2)或Sr(2)百分数与吸附氧百分数的关系可用取代后表面状态的变化来解释。     

RESr2RuCu2O8(RE=Gd和Eu)的合成与物性研究

报道了磁性超导体RESr2RuCu2O8(RE=Gd和Eu)单相样品的合成以及对其结构和物性的研究。结果表明，这类化合物的结构和YBa2Cu3O7-δ相类似；在这两类化合物中，超导电性与弱铁磁有序共存；两样品铁磁相变温度TM分别为136，130K，超导临界温度TC分别为46，35K；由于Gd^3 和Eu^3 离子磁矩的不同，两样品的磁性质存在一定的差别。     

Three hybrid networks based on octamolybdate: ionothermal synthesis, structure and photocatalytic properties

Three hybrid networks based on octamolybdate building units, Cu(I)(8)BBTZ(6)[(α-Mo(8)O(26))(β-Mo(8)O(26))] (1), (Cu(I)BBTZ)(4)[Mo(7)Cu(II)O(24)(H(2)O)(2)]·6H(2)O (2), and Cu(II)Cu(I)(2)BBTZ(5)[β-Mo(8)O(26)] (3) (BBTZ = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene), have been synthesized under ionothermal conditions and structurally characterized by single-crystal X-ray diffraction. 1 exhibits a rare 3D three-fold self-penetration network (SPN) structure, in which the interpenetrating polymer networks (IPN) formed by α-Mo(8)O(26) units, Cu(I) ions and BBTZ ligands are united by β-Mo(8)O(26) units. 2 shows a classic 10(3)-utp net built by transition-metal monosubstitution octamolybdate β-Mo(7)CuO(26), Cu(I) and BBTZ ligands. 3 displays an interesting interpenetrating network (IPN) structure formed by 2D poly-rings layers and 3D NaCl topology framework. IR, TG, and electrochemical studies were also conducted to further authenticate the identities of these compounds. Photocatalytic investigation indicates that compounds 1-3 are active for photocatalytic H(2) evolution under UV irradiation.     

希土冠醚类配合物的研究--Ⅹ.轻希土硝酸盐与二苯并-24-冠-8固态配合物的合成及性质

在乙腈介质中制得了2:1型固态配合物[Ln(NO_3)_3]_2·DB24C8.2H_2O(Ln=La、Pr)和3:2型固态配合物[Ln(NO_3)_3]_3(DB24C8)_2·3H_2O(Ln=Nd,Sm,Eu)。研究了冠醚及其配合物的红外光谱、紫外光谱、热稳定性及X—射线粉末衍射等性质,观察了它们在常见有机溶剂中的溶解情况,在乙腈中的电导测定结果表明这些配合物均为非电解质。     

Thermal decomposition and kinetic studies on a binuclear copper(II)—Urea complex

A binuclear copper(II)—urea complex was synthesized and its structure was established from elemental analyses, IR, UV and visible spectroscopy and magnetic susceptibility measurements to be [OC(NH₂)₂Cu(OH)₂]₂. The kinetics of the thermal decomposition of the complex were studied by recording thermogravimetric measurements in streams of nitrogen and oxygen. TG analysis showed three main steps of decomposition, leading to Cu₂O formation in the final stage.     

A temperature-dependent relative-rate study of the OH initiated oxidation of n-butane: the kinetics of the reactions of the 1- and 2-butoxy radicals

The kinetics of the reactions of 1-and 2-butoxy radicals have been studied using a slow-flow photochemical reactor with GC-FID detection of reactants and products. Branching ratios between decomposition, CH3CH(O*)CH2CH3 --> CH3CHO + C2H5, reaction (7), and reaction with oxygen, CH3CH(O*)CH2CH3+ O2 --> CH3C(O)C2H5+ HO2, reaction (6), for the 2-butoxy radical and between isomerization, CH3CH2CH2CH2O* --> CH2CH2CH2CH2OH, reaction (9), and reaction with oxygen, CH3CH2CH2CH2O* + O2 --> C3H7CHO + HO2, reaction (8), for the 1-butoxy radical were measured as a function of oxygen concentration at atmospheric pressure over the temperature range 250-318 K. Evidence for the formation of a small fraction of chemically activated alkoxy radicals generated from the photolysis of alkyl nitrite precursors and from the exothermic reaction of 2-butyl peroxy radicals with NO was observed. The temperature dependence of the rate constant ratios for a thermalized system is given by k7/k6= 5.4 x 10(26) exp[(-47.4 +/- 2.8 kJ mol(-1))/RT] molecule cm(-3) and k9/k8= 1.98 x 10(23) exp[(-22.6 +/- 3.9 kJ mol(-1))/RT] molecule cm(-3). The results agree well with the available experimental literature data at ambient temperature but the temperature dependence of the rate constant ratios is weaker than in current recommendations.