三维异双金属混合桥氰化物的合成和结构

高Tc分子磁体的研究近年来受到重视，其中尤以双过渡金属氰化物的研究发展异常迅猛．继Verdaguer[1]报道了Tc=90K的CsNi[Cr（CN）6]2·H2O配合物后，Verdaguer[2]和Girlami等[3]又分别报道了一系列TC=240、230、190K的同或异双过渡金属含CN配合物．Fujishima等[4]报道的具有磁光效应的K0.2Co1.4[Fe（CN）6]·6.9H2O配合物使分子磁性应用于分子电子学领域成为可能．但上述化合物均为粉末，未能获得其晶体结构，因此无法阐明其磁交换机理，亦难以发展成为晶须及其它异型磁性材料．为弄清混合金属氰化物成键性质、CN桥中介磁交换机…     

双甲基化大豆苷元磺酸锂的合成及晶体结构

以大豆苷元为先导化合物,合成了水溶性异黄酮化合物4’,7-二甲氧基异黄酮磺酸锂．X射线单晶衍射分析表明：标题化合物属于三斜晶系,空间群Pi,晶胞参数为：a=0．7732（2）nm,b=1．874（5）nm,c=1．920（5）nm,α=111．224（4）°,β=90．21（5）°,γ=100．68（4）°Z=2．标题化合物的分子组成为[Li（H2O）4]2（C17H13O4SO3）2·4H2O,其中两种类型的锂离子均被4分子水所配位．[Li（H2O）4]^＋、C17H13O4SO3^-和H2O之间存在多种氢键作用;氢键作用以及阴阳离子之间的静电引力作用共同将标题化合物组装成具有三维网络结构的超分子．     

两个八氰基W（Ⅳ）-Mn（Ⅱ）双金属配合物的结构及磁性质

合成了两个氰基桥连的异金属配位聚合物[{Mn（dpa）2}2W（CN）8·CH3CN·4H2O]n（1）和[Mn2（H2O）4{W（CN）8}·3H2O]n（2）,并对它们进行了结构和磁性表征．X-射线单晶结构分析表明,在化合物1中,W2（CN）4Mn2四核片段通过公共的[W（CN）8]^4-离子相互连接,形成一个无限延伸的一维链状结构．化合物2的结构较为复杂,是一个含有一维孔道（约13.21A×11．82A）的三维网状结构．磁性研究表明,在两种化合物中,相邻的两个锰离子之间抗磁性的八氰基配离子均传递非常微弱的反铁磁相互作用．     

多钼酸盐[4，4′-H2bipy]2[β-Mo8O26]的水热合成和晶体结构

利用水热合成方法制备了化合物[4，4′-H2bipy]2[β-Mo8O26]，用元素分析、X射线单晶衍射和电子顺磁共振对其结构进行了表征．结构解析表明标题化合物是由／3型[Mo8O26]^4-多阴离子与质子化的4，4’-联吡啶通过氢键作用形成的三维结构超分子化合物．     

由氢键构筑的两个超分子化合物的合成与结构

本文通过质子化内消旋大环配体[meso-H2L]^2＋及其外消旋镍配合物[Ni（rac-L）]^2＋与金属氧酸离子（[VO3]^-/[CrO4]^2）在水溶液中进行超分子组装得到两个氢键连接的超分子化合物[Ni（rac-L）]3[CrO4]2[ClO4]2·4H2O（1）和[meso-H2L][VO3]2·0.33H2O（2）.通过IR、元素分析、X-ray单晶衍射、热重等对其结构进行了表征.化合物1由[Ni（rac-L）]^2＋与CrO4^2-和水分子通过大环中的胺分子与CrO4^2-和水分子形成的氢键组成一维六方棱柱状结构.化合物2则由[VO3]n^n-阴离子螺旋链通过分子间氢键连接[meso-H2L]^2＋构成具有一维疏水通道的三维超分子化合物.研究结果表明氢键在超分子组装中起着重要的作用.     

[Co（phen）3]2[PMo12O40]（OH）的水热合成及晶体结构

利用水热合成法制备了Keggin结构阴离子有机一无机复合物[Co（phen）3]2[PMo12O40]（OH）,通过元素分析,红外光谱和X射线单晶衍射等对其进行了表征．结果表明,该化合物属于单斜晶系,C2／c空间群．=1．97225（18）nm,b=1．81079（16）nm,c=2．5117（2）nm,β=100．5380（10）°,V=8．819O（14）nm^3,Z=4,R1=0．0587,wR2=0．1211．该化合物分子由一个多阴离子[PMo12O40]^3-,两个[Co（phen）3]^2＋及一个羟基组成．     

[4，4＇-bpyH2]5H2[α-P2W18O62]2·4H2O的合成与结构表征

利用水热方法合成了一种基于双Dawson多阴离子和质子化的4,4’-联吡啶阳离子构筑的化合物[4,4’-bpyH2]5H2[α—P2W18O62]2·4H2O,并经IR光谱、元素分析、热重分析和X射线单晶衍射等测试技术进行了表征．标题化合物属于三斜晶系,Pi空间群,晶胞参数：α=1．35373（5）,b=2．24256（13）,c=2．73282（11）nm,α=79．890（13）,β=77．568（8）,γ=80．349（11）°,V=7．9029（6）nm^3,Z=2,Dc=4．031g／cm^3,GOOF=1．049,R1=0．0674,wR2=0．1434．结构分析结果表明,标题化合物分子由5个质子化的4,4’-联吡啶阳离子、2个H^＊离子、2个饱和Dawson结构多阴离子[P2W18O62]^6-和4个结晶水分子组成．     

多钼酸盐[4,4''-H2 bipy]2[β-Mo8O26]的水热合成和晶体结构

利用水热合成方法制备了化合物[4,4'-H2bipy]2[β-Mo8O26],用元素分析、X射线单晶衍射和电子顺磁共振对其结构进行了表征.结构解析表明标题化合物是由β型[Mo8O26]4-多阴离子与质子化的4,4'-联吡啶通过氢键作用形成的三维结构超分子化合物.     

5-[4-（4-吡啶基）苯乙烯基]-1，3-苯二甲酸铜配合物的结构及性质研究

设计合成了一种新型有机配体5-[4-（4-吡啶基）苯乙烯基]-1,3-苯二甲酸（H2L）,并将其与Cu（NO3）2·3H20在不同条件下反应合成了两种不同结构的配位聚合物{[CuL]·H2O}n（1）和{[Cu2L2]·H2O}n（2）．配合物1为utp型有孔道的金属有机框架化合物（MOF）结构,配合物2为含双核铜单元的rtl型拓扑结构．研究发现,1对N2和CO2均未表现出吸附性质,而与其拓扑结构相同的配合物（[Cu（INAIP）]·2H2O}n（H2INAIP=5．异烟酰胺基异酞酸）却有很好的CO2吸附性能．为理解它们的构效关系,从实验和理论计算两方面对这两种化合物进行了比较研究,证实此差异源于配体中连接羧酸和吡啶基的共轭官能团,其中1的共轭官能团为苯乙烯基,而{[Cu（INAIP）]-2H2O}n中的官能团为酰胺基．实验和理论计算的结果表明,酰胺基对CO2吸附起了重要作用．另外,对配合物2的磁性质进行了研究,结果表明,该化合物具有反铁磁性相互作用．     

多钼酸盐[4,4-′H_2bipy]_2 [β-Mo_8O_(26)]的水热合成和晶体结构

利用水热合成方法制备了化合物[4,4′-H2b ipy]2[-βMo8O26],用元素分析、X射线单晶衍射和电子顺磁共振对其结构进行了表征.结构解析表明标题化合物是由β型[Mo8O26]4-多阴离子与质子化的4,4′-联吡啶通过氢键作用形成的三维结构超分子化合物.     

Polarized neutron diffraction and its application to spin density studies

Spin density distributions in molecular compounds containing unpaired electrons have been studied by polarized neutron diffraction (PND). The spin density distributions provide a unique perspective of the magnetic properties of the compounds. The background and fundamentals of polarized neutron diffraction are summarized in this review, followed by examples of applications in inorganic and organic chemistry. Spin densities in several compounds that are obtained by polarized neutron diffraction are highlighted. Spin densities in single molecular magnet [Fe₈O₂(OH)₁₂(tacn)₆]⁸⁺ and cyano-bridged K₂[Mn(H₂O)₂]₃[Mo(CN)₇]₂·6H₂O demonstrate how to obtain magnetic interaction in the complexes by PND. PND studies of Ru(acac)₃, containing one single unpaired electron, show small spin densities in this complex. Finally the use of PND in studying nitronyl nitroxide radicals is given. Our goal in this review is to illustrate how PND functions and how it serves as a sensitive tool in directly probing spin density in molecules.     

Neutron diffraction and theoretical DFT studies of two dimensional molecular-based magnet K2[Mn(H2O)2]3[Mo(CN)7]2.6H2O

Exchange mechanisms and magnetic structure in the two-dimensional cyano-bridged molecule-based magnet K2[Mn(H2O)2]3[Mo(CN)7]2.6H2O have been investigated by a combination of neutron diffraction studies on both single crystal and powder samples and theoretical DFT calculations. The experimental spin density has been deduced from a new refinement of previously obtained polarized neutron diffraction (PND) data which was collected in the ordered magnetic state at 4 K under a saturation field of 3 T performed in the C2/c space group, determined by an accurate re-evaluation of the X-ray structure. Positive spin populations were observed on the two manganese sites, and negative spin populations were observed on the molybdenum site, which provides evidence of antiferromagnetic Mo3+-Mn2+ exchange interactions through the cyano bridge. The experimental data have been compared to the results of DFT calculations. Moreover, theoretical studies reveal the predominance of the spin polarization mechanism in the Mo-C-N-Mn sequence, with the antiferromagnetic nature of the interaction being due to the overlap between the magnetic orbitals relative to manganese and molybdenum in the cyano bridging region. The magnetic structure of K2[Mn(H2O)2]3[Mo(CN)7]2.6H2O has been solved at low temperature in zero field by powder neutron diffraction measurements. The structure was found to be ferrimagnetic where the manganese and molybdenum spins are aligned along the axis in opposite directions.     

Analytical formulas for the magnetic field produced by a spin or a paramagnetic current density in the case of Gaussian basis functions

We present a derivation of simple formulas for the evaluation at any point of space of the magnetic field produced by a spin or a paramagnetic orbital current when Cartesian Gaussian basis functions are used, as is often the case in quantum chemistry. These formulas can be useful to plot the magnetic field vector density obtained from ab initio calculations or from a density operator fitted on experimental data. The magnetic field density is the observable probed in polarized neutron diffraction (PND) experiment, for it is, in fact, with this quantity that the neutron spins interact and not with the spin or magnetization density. The formulas make extensive use of the confluent hypergeometric function. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 81: 11–15, 2001     

Room-temperature synthesis and crystal,magnetic, and electronic structure of the first silver copper oxide

Ag(2)Cu(2)O(3) is the first known silver copper oxide. It was prepared by coprecipitation at room temperature and ambient pressure and shows an increased thermal stability compared with silver oxides. The crystal structure (tetragonal, a = 5.8862(2) A, c = 10.6892(4) A, Z = 4, I4(1)/amd) was refined from neutron and X-ray powder diffraction data, and it is related to that of the mineral paramelaconite (Cu(4)O(3)). In addition to a thorough characterization (chemical and TG analyses, XPS, crystal structure, and electrochemical, magnetic, and transport properties), we have carried out band structure calculations [extended Hückel tight binding (EHTB) and spin polarized density functional (DFT) band calculations] for the title silver copper oxide and for the related paramelaconite structure (Cu(II)-Cu(I) mixed-valence system) with special incidence into the magnetic behavior and coupling constants in these magnetically novel 3-D compounds. This new oxide represents an important precedent in solid state inorganic chemistry but also has potential interest concerning its magnetic, electrochemical, and catalytic properties.     

Electronic interaction in an outer-sphere mixed-valence double salt: a polarized neutron diffraction study of K(3)(MnO(4))(2)

The mixed-valence double salt K(3)(MnO(4))(2) crystallizes in space group P2(1)/m with Z = 2. The manganese centers Mn1 and Mn2 constitute discrete "permanganate", [Mn(VII)O(4)](-), and "manganate", [Mn(VI)O(4)](2-), ions, respectively. There is a spin-ordering transition to an antiferromagnetic state at ca. T = 5 K. The spin-density distribution in the paramagnetic phase at T = 10 K has been determined by polarized neutron diffraction, confirming that unpaired spin is largely confined to the nominal manganate ion Mn2. Through use of both Fourier refinement and maximum entropy methods, the spin on Mn1 is estimated as 1.75 +/- 1% of one unpaired electron with an upper limit of 2.5%.     

两种含大吸电子取代基的SnR_2Cl_2化合物的合成和晶体结构

以SnCl4和2,4,6-(CF3)3C6H2Li、2,6-(CF3)2C6H3Li为原料合成了两种含大吸电子取代基的化合物Sn[2,4,6-(CF3)3C6H2]2Cl2(缩写为SnAr2Cl2)和Sn[2,6-(CF3)2C6H3]2Cl2(缩写为Sn Ar′2Cl2),利用X射线衍射仪和核磁共振谱仪(19F NMR)表征了产物SnAr2Cl2和SnAr′2Cl2的晶体结构.     

Magnetische Wechselwirkungen in Inselstrukturen ternärer Cobaltchalkogenide. Die Spinstrukturen von Na6CoS4 und Na6CoSe4

Magnetic Interactions in Ternary Cobalt Chalcogenides containing Isolated Tetrahedral Cobalt Anionic Groups. The Spin Structures of Na₆CoS₄ and Na₆CoSe₄ The sodium cobalt chalcogenides Na₆CoS₄ and Na₆CoSe₄ are characterized by isolated [CoX₄]-units. Despite the large distances of more than 6 Å between the cobalt ions magnetic inter-actions at low temperatures lead to threedimensionally ordered spin structures, that were determined from neutron diffraction experiments. The magnetic structure can be described in the Shubnicov group P_2abc2₁ with a unit cell that is four times as large as the crystallographic cell. The magnetic moments of both compounds correspond to the value expected for three unpaired electrons per Co²⁺ ion.     

Combined charge and spin density experimental study of the yttrium(III) semiquinonato complex Y(HBPz3)2(DTBSQ) and DFT calculations

High-resolution X-ray diffraction and polarized neutron diffraction experiments have been performed on the Y-semiquinonate complex, Y(HBPz3)2(DTBSQ), in order to determine the charge and spin densities in the paramagnetic ground state, S = (1/2). The aim of these combined studies is to bring new insights to the antiferromagnetic coupling mechanism between the semiquinonate radical and the rare earth ion in the isomorphous Gd(HBPz3)2(DTBSQ) complex. The experimental charge density at 106 K yields detailed information about the bonding between the Y3+ ion and the semiquinonate ligand; the topological charge of the yttrium atom indicates a transfer of about 1.5 electrons from the radical toward the Y3+ ion in the complex, in agreement with DFT calculations. The electron density deformation map reveals well-resolved oxygen lone pairs with one lobe polarized toward the yttrium atom. The determination of the induced spin density at 1.9 K under an applied magnetic field of 9.5 T permits the visualization of the delocalized magnetic orbital of the radical throughout the entire molecule. The spin is mainly distributed on the oxygen atoms [O1 (0.12(1) mu B), O2(0.11(1) mu B)] and the carbon atoms [C21 (0.24(1) mu B), C22(0.20(1) mu B), C24(0.16(1) mu B), C25(0.12(1) mu B)] of the carbonyl ring. A significant spin delocalization on the yttrium site of 0.08(2) mu B is observed, proving that a direct overlap with the radical magnetic orbital can occur at the rare earth site and lead to antiferromagnetic coupling. The DFT calculations are in good quantitative agreement with the experimental charge density results, but they underestimate the spin delocalization of the oxygen toward the yttrium and the carbon atoms of the carbonyl ring.     

Spin-dependent electron momentum densities in Co2FeGa studied by Compton scattering

The spin density of Heusler alloy Co₂FeGa, has been studied using the Compton scattering technique with 274 keV circularly polarized synchrotron radiation in the high energy inelastic scattering beamline (BL08W), at SPring-8, Japan. The magnetic Compton profiles along the two principal directions [1 1 0] and [1 1 1] were measured. The spin profiles shows a good agreement with our FLAPW-GGA results, where the theoretical results were based on the ferromagnetic ground state. The 3d spin moment at the Co and the Fe site was found to be in excellent agreement with the earlier reported neutron diffraction measurements.     

有机-无机复合杂多化合物的合成、结构及表征

利用常规水溶液法制备了三种基于饱和Keggin结构阴离子的有机-无机复合杂多化合物[Pr(pydc)(H2O)6]2H[PMo12O40]·4H2O(1)、[Nd(pydc)(H2O)6]2H[PMo12O40]·4H2O(2)和[Tb(pydc)(H2O)6]2H[PMo12O40]·4H2O(3)(pydc=2,6...