非晶态镍硼酸盐结构的EXAFS研究

由摩尔比分别为1:2和1:8的NiCl₂·6H₂O和Na₂B₄O₇·10H₂O作为反应物, 合成两种非晶态镍硼酸盐, 同时通过水热法合成β-Ni(OH)₂. 化学分析和热重-微商热重法(TG-DTG)分析结果确定两种非晶态镍硼酸盐的分子组成分别为NiO·0.8B₂O₃·4.5H₂O和NiO·B₂O₃·3H₂O. 激光拉曼(Raman)实验结果表明镍硼酸盐样品中主要存在的硼氧阴离子为B₃O₃(OH)₅^2-和B₂O(OH)₆^2-. 同步辐射扩展X射线吸收精细结构(EXAFS)方法对样品进行结构解析, 通过数据拟合给出样品中Ni 原子周围近邻配位原子种类、配位数以及原子间距离. 用不同晶体结构作为标准对两种非晶态镍硼酸盐进行拟合的结果表明, 样品中Ni 原子周围局域结构与Ni₃B₂O₆晶体(ICSD No.31387)中的吻合较好. Ni 原子周围配位原子为O、B和Ni, 对于NiO·0.8B₂O₃·4.5H₂O, 配位数分别为5.7、3.8和3.8, 配位距离分别为0.208、0.263 和0.311 nm; 对于NiO·B₂O₃·3H₂O, 配位数分别为6.0、4.0 和4.0, 配位距离分别为0.207、0.262和0.310 nm.     

Ni-Mo-B非晶态合金纳米颗粒的抗氧化性能研究

在水溶液体系中用化学还原法制备Ni-B和Ni-Mo-B非晶态合金纳米颗粒.SEM测试表明,样品的颗粒形貌呈球形或类球形,平均粒径约10nm.XPS分析结果表明,Ni-Mo-B非晶态合金中钼元素主要以氧化态形成于合金的表面,并导致合金表面合金化硼原子浓度显著增加,氧化态硼（B3＋）的原子浓度显著减少,氧的原子浓度明显减少,合金化镍的原子浓度显著增加,氧化态镍（Ni3＋）的原子浓度显著减少.因此,Ni-Mo-B合金的抗氧化性能显著高于Ni-B合金.XPS谱图分析还表明,在Ni-B和Ni-Mo-B非晶态合金中,存在Ni和B的合金化物Ni2B,其中B失去部分电子,而Ni则富余电子.Ni2B的氧化产生副产物Ni2O3和B2O3.     

N-苯甲酰基水杨酰肼为配体的三核镍(Ⅱ)配合物的合成与结构

N-苯甲酰基水杨酰肼配体(简写为H3Bzshz)与Ni(OAc)2·4H2O在不同的溶剂中反应得到2个三核镍配合物[Ni3(Bzshz)2(C5H5N)6](C5H5N)·CH3OH·2H2O(1)和[Ni3(Bzshz)2(OH)2(C2H6O)2]·2(C3H7NO)·0.5C2H6O(2).X射线衍射实验结果表明:化合物1属单斜晶系,空间群为P2(1)/n,晶胞参数a=2.198 9(2) nm,b=1.336 9(1) nm,c=2.503 4 nm,β=107.886(1)°,V=7.004(1) nm3,Z=4,R1=0.081 0,wR=0.215 4.3个Ni原子依次以八面体/八面体/平面正方形配位,其中Ni(1)…Ni(2)…Ni(3)原子间角是169.84(3)°,形成准直线形三核镍配合物;化合物2属三斜晶系,空间群为P-1,晶胞参数a=1.138 9(2) nm,b=1.368 2(2) nm,c=1.563 3(2) nm,α=67.190(2)°,β=83.953(2)°,γ=83.618(2)°,V=2.226 3(4) nm3,Z=2,R1=0.065 2,wR=0.188 0,而3个中心原子Ni(1)…Ni(2)…Ni(3)原子间角是180°,且依次以平面正方形/八面体/平面正方形相交替方式配位,具有中心对称的直线形结构.     

柠檬酸镍前驱体热分解制备镍酸镁复氧化物纯相

以组成和结构确定的柠檬酸配合物Mg2[Ni(Hcit)2]@10H2O和Mg[Ni(Hcit)(H2O)]2@8H2O(H4cit为柠檬酸)为前驱体,热分解得到Ni和Mg摩尔比分别为12和21的镍酸镁纯相Mg2NiO3和MgNi2O3.粉末衍射实验证实,它们是由半径相近、价态相等的Ni2+和Mg2+形成的固溶体.     

十八元环多钒硼酸盐的水热合成及其氧化还原性质研究

在水热条件下合成了[Ni(en)2]6[(VO)12O6B18O39(OH)3].6H2O多钒硼酸盐,X射线衍射分析表明,该晶体属三方晶系,R-3空间群.测试了晶体的IR光谱和TG曲线,用循环伏安法详细研究了合成化合物的氧化还原性质及电子转移机理,结果表明该化合物具有两对氧化还原峰,其电子转移数分别为单电子和三电子.     

过饱和五硼酸钠溶液结构

用快速X射线衍射法测量了298和323K时过饱和五硼酸钠溶液的时间空间平均结构,得到了溶液径向分布函数.通过模型设计及理论计算获得了B-B、B-O、O-O、Na-O、Na-B原子对相互作用的理论偏径向分布函数,并讨论了浓度和温度对五硼酸钠溶液结构的影响.在五硼酸钠过饱和溶液中六水合Na+形成八面体结构,其平均配位数随浓度和温度变化不大,作用距离随温度升高及浓度减小而减小;给出了溶液中主要硼酸盐离子B3O3(OH)4-、B5O6(OH)4-和B(OH)3的水合结构,较高温度及较高浓度有利于更高聚合的多聚硼酸根离子的形成;浓度对硼酸盐离子的第一水合层的水合数影响较大,在较浓的五硼酸钠过饱和溶液中,五硼酸根离子的一个端氧单齿配位到Na+上形成离子对,Na-B特征距离为0.328nm.     

对乙酰氨基苯甲酸和含氮配体构筑铜、锌配合物的合成、结构及性质研究(英文)

利用对乙酰氨基苯甲酸(HPABA)和邻菲咯啉(phen)、硝酸铜在DMF/CH3OH/H2O溶液中合成了单核铜配合物[Cu(PABA)(phen)(H2O)2]·(NO3)·H2O(1),然后又和4,4′-联吡啶(4,4′-bpy)、硝酸锌在DMF/CH3OH/H2O溶液中获得配位聚合物{[Zn(PABA)2(4,4′-bpy)]·4H2O}n(2)。根据X射线衍射分析结果,配合物1中每个铜离子周围有2个氮原子和3个氧原子与之配位形成畸变的四方锥配位构型,然而在配合物2中,六配位八面体构型的锌离子通过配体4,4′-联吡啶扩展为一维Zigzag型链。分别对这两个配合物的热稳定性和电化学性质进行了研究。     

2-(5-甲基-1,3,4-噻二唑)-硫乙酸镍(Ⅱ)配合物的合成和晶体结构

本文合成了2个镍配合物[Ni(mtyaa)2(H2O)4]·4(H2O)(1)和[Ni(4,4′-bipy)2(mtyaa)2(H2O)2]·2H2O(2)(Hmtyaa=2-(5-甲基-1,3,4-噻二唑)-硫乙酸;4,4′-bipy=4,4′-联吡啶),用X-射线单晶衍射仪测定了配合物的单晶结构,并对它进行了元素分析、红外光谱、热重和粉末X-射线衍射等表征。配合物1和2的晶体分别属于三斜晶系和单斜晶系,空间群分别为P1和P21/n。X-射线单晶结构分析表明配合物1和2中镍原子均采取六配位扭曲的八面体配位模式。在配合物1中配位水和游离水分子与羧基氧之间的氢键作用将单分子结构连成三维网状结构。配合物2中配位水和游离水分子与羧基氧以及配体中的氮原子之间的氢键作用将链连接成二维层状结构。     

两个单核镍含氮配体配合物的合成、晶体结构及荧光性质(英文)

采用回流法在水溶剂中合成了2个含氮配体单核镍配合物[Ni(phen)2(H2O)2](1,6-nds)·2H2O(1)和[Ni(phen)3](1,6-nds)·10H2O(2)(1,6-nds=1,6-萘二磺酸根离子,phen=1,10-邻菲罗啉)。配合物1中,镍离子与2个1,10-邻菲罗啉和2个水分子配位,形成[Ni(phen)2(H2O)2]2+阳离子。2个没有配位的水分子通过氢键与[Ni(phen)2(H2O)2]2+和1,6-萘二磺酸根离子相互连接形成二维层状结构。配合物2中,镍离子与3个1,10-邻菲罗啉配位,形成[Ni(phen)3]2+阳离子。大量的氢键将自由的水分子和1,6-萘二磺酸根离子连接形成三维网状结构。2个配合物中1,6-萘二磺酸根离子均没有与镍离子配位,只是起到平衡电荷的作用。室温下,配合物显示了较大的荧光发射峰,其最大发射峰分别在443和438 nm。     

Co(en)3[B4O5(OH)4]Cl·3H2O和[Ni(en)3][B5O6(OH)4]2·2H2O的合成、结构以及热力学性质

利用水热法合成了两种过渡金属配合物为模板剂的含水硼酸盐晶体Co(en)3[B4O5(OH)4]Cl·3H2O(1) 和 [Ni(en)3][B5O6(OH)4]2·2H2O (2),并通过元素分析、X射线单晶衍射、红外光谱及热重分析对其进行了表征。化合物1晶体结构的主要特点是在所有组成Co(en)33+, [B4O5(OH)4]2–, Cl– 和 H2O之间通过O–H…O、O–H…Cl、N–H…Cl和N–H…O四种氢键连接形成网状超分子结构。化合物2晶体结构的特点是[B5O6(OH)4]–阴离子通过O–H…O氢键连接形成沿a方向有较大通道的三维超分子骨架,模板剂[Ni(en)3]2+阳离子和结晶水分子填充在通道中。     

Measurement of Solid-liquid Equilibria in Quaternary System Li+, K+//SO42-, B4O72--H2O at 288 K

In order to utilize the brine resources in China, the solid-liquid equilibria in quaternary system Li⁺, K⁺//SO₄^2-, B₄O₇^2--H₂O at 288 K was studied by the isothermal solution equilibrium method. Solubilities and densities of solutions were determined experimentally. According to the experimental data, the equilibrium phase diagrams, density-composition diagram and corresponding water content diagram of the quaternary system were plotted. Double salt KLiSO₄ was found in the reciprocal quaternary system Li⁺, K⁺//SO₄^2-, B₄O₇^2--H₂O at 288 K. The quaternary system has three invariant points, seven univariant curves and five fields of crystallization. The five crystallization regions correspond to Li₂B₄O₇·3H₂O, Li₂SO₄·H₂O, K₂B₄O₇·4H₂O, K₂SO₄ and KLiSO₄, respectively. The crystallization field of salt Li₂B₄O₇·3H₂O is the largest, whereas that of Li₂SO₄·H₂O is the smallest. The experimental results show that Li₂SO₄·H₂O has a strong salting-out effect on other salts.     

Solid-liquid Equilibria in the Quaternary System Na＋, K＋//Br-, B4O72--H2O at 298 K

According to the compositions of the underground gasfield brines in the west of Sichuan Basin, the solu- bilities and densities of the solid-liquid equilibria in the quaternary system Na＋, K＋//Br-, B4O72--H2O at 298 K were determined by the method of isothermal solution saturation. From the experimental data, the phase diagram, water content diagram and density-composition diagram were obtained. This quaternary system is of simple eutectic type, without double salt and solid solution. There are two invariant points, five univariant curves, four fields of crystalli- zation in the system. The equilibrium solid phases are Na2BaO7·10H20, K2B4O7·4H2O, NaBr·2H2O and KBr. Na2B4O7·10H2O has a larger crystallization field, and NaBr·2H2O has a smaller crystallization field. It is also found that bromide has the salting-out effect on borate in the quaternary system Na＋, K＋//Br-, B4O72--H2Oat 298 K.     

Large heteropolymetalate complexes formed from lanthanide (Y, Ce, Pr, Nd, Sm, Eu, Gd), nickel cations and cryptate [As4W40O140]: synthesis and structure characterization

A new family of heteropolytungstate complexes (NH₄)₂₁[Ln(H₂O)₅{Ni(H₂O)}₂As₄W₄₀O₁₄₀]·xH₂O(Ln=Y, Ce, Pr, Nd, Sm, Eu, Gd) were prepared by the reaction of Na₂₇[NaAs₄W₄₀O₁₄₀]·60H₂O with NiCl₂·6H₂O and Ln(NO₃)₃·xH₂O at pH≈4.5. The crystal structures of (NH₄)₂₁[Gd(H₂O)₅{Ni(H₂O)}₂As₄W₄₀O₁₄₀]·51H₂O was determined by X-ray diffraction analysis and element analysis. The compound crystallizes in the monoclinic space group P2₁/n with a=19.754(3), b=24.298(4), c=39.350(6) Å, β=100.612(3)°, V=18564(5) ų, Z=2, R1(wR₂)=0.0544(0.0691). The central site S1 and two opposite sites S2 of the big cyclic ligand [As₄W₄₀O₁₄₀]²⁸⁻ are occupied by one Ln³⁺and two Ni²⁺, respectively, each site supply four O_d coordinating to metal ion, another one water molecule and other five water molecules coordinate, respectively, to Ni²⁺and Ln³⁺. Polyanion [Ln(H₂O)₅{Ni(H₂O)}₂As₄W₄₀O₁₄₀]²¹⁻ has C_2v symmetry. IR and UV–vis spectra of [NaAs₄W₄₀O₁₄₀]²⁷⁻ of the title compounds are discussed.     

One Dimensional Iron Molybdophosphate Anionic Chains with Different Structural Arrangements Reflecting a Flexibility Character

Structural comparison of a new compound[(bpp)₃H₆]Fe₂^IIIFe₂^IIMo₂₄^V(H₂PO₄)₈(HPO₄)₄(PO₄)₄O₄₈(OH)₁₂· (H₂O)₄·2H₂O(1)[bpp=1,3-di(4-pyridyl)propane] with our previously reported two compounds[(bpy)₃Fe^II]₃· Fe₂^IIIFe₂^IIMo₂₄^V(H₂PO₄)₈(HPO₄)₄(PO₄)₄O₄₈(OH)₁₂(H₂O)₄·12H₂O(2) and[(bpy)₃Fe^II]₂Fe^IIFe^IIIMo₁₂^V(H₂PO₄)₂(H_2-xPO₄)·(H_1+xPO₄)(HPO₄)₂(PO₄)₂O₂₄(OH)₆(H₂O)₂·9H₂O(x=0―1)(3)(bpy=2,2'-bipyridine), which all exhibit one-dimensional mixed-valence iron molybdophosphate anionic chains constructed by alternating connection of Fe^III ions and magic[Fe^II(Mo₆P₄O₃₁)₂] units, reveals that the non-hydrogen atomic ratios of Mo:Fe:P:O within the polymeric anionic chains are the same for all the three compounds, while the polymeric anionic chains of the different compounds bear different numbers of negative charges. And therefore there exist different numbers of counter cations per {Fe₂^III[Fe₂^II(P₁₆Mo₂₄^VO₁₂₄)]} unit found in the titled compounds. It discloses that not only are the spatial assembling of counter cations and polymeric inorganic chains of three compounds quite different, but also the O―Fe^III―O bond angles and Fe^III―O bond lengths of the three different inorganic chains exhibit small differences. What is more important is that such small changes in bond length and bond angle in the assemblage of Fe^III―O bonds lead to the considerable fluctuations of inorganic chains in their structural conformation within the three compounds, reflecting an interesting phenomenon of “flexibility" in the pure inorganic one dimensional mixed-valence iron molybdophosphate chains.     

Two New Alkaline Metal Borates with Supramolecular Framework Constructed from 1D {B5}/{B6} Helical Chains

Two new alkaline metal borates containing 1D{B5}/{B6}oxoboron helical chains,namely Na0.5[B5O8(OH)2]0.5[B5O6(OH)2]0.5·0.5H3O(1)and NaKCs[B6O9(OH)3](2)were synthesized under solvothermal conditions.Compound 1 contains the interesting alternative left-and right-handed helical{[B5O8(OH)2][B5O6(OH)2]}2-({B5}-1 and{B5}-2)1D chains and compound 2 possesses the similar[B6O11(OH)3]7-({B6})chains.Their 1D chains are further assembled into 2D layers and 3D supramolecular frameworks through O-H…O hydrogen bonds.In addition,the UV cutoff edge of compounds 1 and 2 is both below 190 nm.     

Two New Borates Built by Different Types of {B9} Cluster Units

Two new belt-like borates Na₄[B₉O₁₄(OH)₃]·0.5H₂O(1) and Na₅[B₉O₁₄(OH)₄](2) have been synthesized under solvothermal conditions. Both compounds contain unprecedented B₉O₁₆(OH)_n^(n+5)-[n=3(1), 4(2)] clusters, which are constructed from four B₃O₃ rings via three BO₄ tetrahedra. Compound 1 exhibits a rare 1D belt with two types of 8-membered ring(MR) windows based on B₉O₁₆(OH)₃^8- clusters. Compound 2 features two different 1D belts built by different B₉O₁₆(OH)₄^9- units, which is first discovered in borate family. UV-Vis diffuse reflectance spectra reveal that compounds 1 and 2 have the cut-off edges below 190 nm, indicating that they may have potential application in deep UV(DUV) region.     

New Supramolecular Networks Based on Paratungstate with N-Donor Bridging Ligands

Three new supramolecular networks based on paratungstate and N-donor bridging ligands, [H₂bpmp]_2.5H[H₂W₁₂O₄₀]2H₂O(1), [H₂(bpp)]₂[H(py―CH₃)]_0.25[H(py―C₂H₅)]_0.25H_1.5[H₂W₁₂O₄₀]·4H₂O(2) and [H₂pip]₃[H₂W₁₂O₄₀](3)[bpmp=N,N'-bis(4-pyridylmethyl)piperazine; bpp=1,3-bis(4-pyridyl)propane; py=pyridine; pip=piperazine] were prepared by the hydrothermal synthesis and characterized by elemental analysis, infrared(IR), thermogravimetric(TG) analysis and single-crystal X-ray diffraction(XRD). All the compounds show high-dimen- sional supramolecular networks based on [H₂W₁₂O₄₀]^6- and the protonated N-donor ligands via the N―H···O―W hydrogen bonds and/or π···π stacking interactions. Their luminescent properties were investigated.     

新的四帽Keggin结构的金属-氧簇合物[NiMo12O40H10{Ni(H2O)3}4]的水热合成与结构表征

多金属氧酸盐 (也称金属 -氧簇 )由于在催化、材料及医药等领域的应用日益广泛而备受关注 .近年来 ,一些新颖的非经典结构的化合物不断被合成出来 .如带二帽的 Keggin结构化合物 [V15O4 2 ]9- [1] ,[PV14 O4 2 ]9- [2 ] ,[As V14 O4 2 ]9- [3 ] ,[{ Mo8V7O4 2 } 2 ]14 - [4 ] ,     

Multi-component Hydrogen-bonding Organic Salts Formed from 1-Methylpiperazine with Aromatic Carboxylic Acids: Synthons Cooperation and Crystal Structures

1-Methylpiperazine was employed to crystallize with 2,4-dihydroxybenzoic acid and 1,8-naphthalene acid, affording two multi-component hydrogen-bonding salts [(C₅H₁₄N₂)²⁺·(C₇H₅O₄)_2-·H₂O](1) and [(C₅H₁₄N₂)²⁺(C₁₂H₆O₄)²ˉ·2H₂O](2). These two forms of salts are both monoclinic systems with space group P2₁/c(14). The lattice parameters of salts 1 and 2 are a=1.32666(10) nm, b=0.90527(7) nm, c=1.67107(13) nm, β=103.125(1)° and a=1.4950(2) nm, b=0.75242(15) nm, c=1.6563(3) nm, β=92.834(2)°, respectively. Expected classical hydrogen bonds N―H…O and O―H…O appear in the chargetransfer salts, and asymmetric units of these two forms both contain water molecules which play a significant role in building novel supramolecular architectures. Robust hydrogen-bond interactions between 1-methylpiperazine and aromatic acid provide sufficient driving force to direct the two crystals to three-dimensional structures. Weak interactions C―H…O emerging in salts 1 and 2 further enhance their crystal structures. As a consequence, hydrogen-bonding interactions in these compounds afford diverse 3D net supramolecular architectures. Thermal stability of these compounds was investigated by thermogravimetric analysis(TGA).