Synthesis and photocatalytic properties of a new heteropolyoxoniobate compound: K10[Nb2O2(H2O)2][SiNb12O40)·12H2O

The synthesis and photocatalytic properties of a heteropolyoxoniobate, K(10)[Nb(2)O(2)(H(2)O)(2)][SiNb(12)O(40)]·12H(2)O (1), are reported, revealing an important role of Zr(4+) additives in the crystallization. Compound 1 exhibits overall photocatalytic water splitting activity, and its photocatalytic activity is significantly higher than that of Na(10)[Nb(2)O(2)][SiNb(12)O(40)]·xH(2)O (2). Fluorescence lifetime measurements suggest that the enhanced photocatalytic activity of 1 likely results from a larger yield of longer-lived charge trapping states in 1 due to the coordination of one water molecule to the bridging Nb(5+), leading to highly unsymmetrical seven-coordinated Nb(5+) sites.     

Single-molecule magnetism behavior of [Mn12O12(O2CR)16(H2O)4]2− salts

(PPh₄)₂[Mn₁₂O₁₂(O₂CCHCl₂)₁₆(H₂O)₄] (3) has been prepared by the two-electron reduction of [Mn₁₂O₁₂(O₂CCHCl₂)₁₆(H₂O)₄] (2) using iodide. Crystallization from CH₂Cl₂/hexanes yields a mixture of two crystal forms, 3·4CH₂Cl₂·H₂O (3a) and 36CH₂Cl₂ (3b), which are triclinic and monoclinic, respectively. They are both trapped valence 2Mn(II), 6Mn(III), 4Mn(IV). DC magnetization data for dried, unsolvated 3 in 1.80–4.00 K and 10–70 kG ranges were fit to give S=10, D=−0.28 cm⁻¹, g=2.00. Frequency-dependent out-of-phase (χ″_M) signals in AC susceptibility studies on crystalline sample of 3a and 3b combined with DC relaxation decay data were fit to the Arrhenius equation to give an effective energy barrier of U_eff=18.5 and 30.3 K, respectively. Magnetization vs. DC field sweeps on single crystals of 3a and 3b gave hysteresis loops containing steps due to quantum tunneling of magnetization (QTM). The step separations yielded ∣D∣/g values of 0.087 and 0.14 cm⁻¹, and consequently U=20 and 39 K (for g=2) for 3a and 3b, respectively, suggesting that the differences in U_eff are primarily caused by changes to D. This work demonstrates the sensitivity of the magnetic properties of [Mn₁₂]²⁻ single-molecule magnets to subtle differences in their environment.     

α-Keggin tungstogermanate-supported transition metal complexes: hydrothermal synthesis,characterization, and magnetism of Cu2(phen)4(GeW12O40) and [Ni2(bpy)4(H2O)2(GeW12O40)]⋅2H2O

Two new α-Keggin polyoxometalates, [Cu₂(phen)₄(GeW₁₂O₄₀)] (1) and [Ni₂(bpy)₄(H₂O)₂(GeW₁₂O₄₀)]·2H₂O (2) (phen?=?1,10-phenanthroline, bpy?=?2,2′-bipyridine), have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, single-crystal X-ray diffraction, and magnetic properties. Compound 1 crystallizes in the monoclinic system, space group P2(1)/c, and 1 is assembled into two-dimensional (2-D) layers parallel to (1?0?1) based on the adjacent phen π···π stacking interactions (3.788(8)?Å). Variable temperature magnetic measurements show ferromagnetic behavior from 300 to 2?K. Compound 2 crystallizes in the triclinic system, space group P-1, and 2 is assembled into 2-D layers parallel to (1?0?1) based on the adjacent bpy π···π stacking interactions (3.07?Å). Variable temperature magnetic measurements show a weak ferromagnetic behavior from 300 to 26?K followed by antiferromagnetic behavior below 26?K.     

Hydrothermal Synthesis and Crystal Structure of a Keggin Polyoxometalate [CoⅡ(2,2'-bipy)2(H2O)]2[SiWVI12O40]·2H2O

A Keggin-type tungstosilicate compound [CoII(2,2'-bipy)2(H2O)]2[SiWVI12O40]·2H2O1 (bipy = bipyridine) was prepared by a hydrothermal method for the first time. Single-crystal X-ray diffraction revealed that 1 (C4H40Co2N8O44SiW12) crystallizes in the triclinic system, space group P1 with a = 10.4979(6), b = 13.3946(7), c = 13.5756(8) (A°), α= 70.0769(18), β= 68.910(3), y = 74.186(4)°,V =1649.84(16) (A°)3, M, = 3688.95, Z =1, Dc= 3.713 mg.m-3,μ= 21.432 mm-1, F(000) = 1644, S =1.058, the final R = 0.0511 and wR = 0.1023 for 6523 observed reflections (I> 2σ(I)). Compound 1 consists of two coordinated cation fragments [CoII(2,2'-bipy)2(H2O)]2+, one normal Keggin polyanion unit [SiWVI12O40]4- and two lattice water molecules. To be noted, each polyanion unit is linked to two cation fragments by its two surface terminal oxygen atoms and two cobalt atoms of two cation fragments forming an organic-inorganic hybrid unit in 1. Furthermore, the compound shows strong photo-luminescence property in the solid state at room temperature.     

K3[Fe3.26V0.74(OH)O(PO4)4(H2O)2]·2H2O: a synthetic leucophosphite

A new iron(III)/vanadium(III) phosphate, K₃[Fe_3.26V_0.74(OH)O(PO₄)₄(H₂O)₂]·2H₂O (1), has been obtained by hydrothermal synthesis and characterized by single crystal X-ray diffraction, Scanning electron microscopy–energy dispersive X-ray spectroscopy, Inductively coupled plasma atomic emission spectroscopy (ICP), thermogravimetric analysis, and FTIR spectroscopy. Single crystal X-ray diffraction reveals a 3D open framework (monoclinic, space group P2₁/n, a?=?9.6391(7)?Å, b?=?9.8063(7)?Å, c?=?9.7268(7)?Å, β?=?100.71(1)°, and V?=?903.38(11)?ų). This structure presents Fe^III and V^III in a 4.4?:?1?M ratio with the metal ions in two different crystallographic sites. Both metallic centers have distorted octahedral environments, linked by PO₄ tetrahedra, forming channels along the a-axis. The asymmetric unit of K₃[Fe_3.26V_0.74(OH)O(PO₄)₄(H₂O)₂]·2H₂O presents a {M₄(OH)O(PO₄)₄(H₂O)₂}^3? anionic entity, charge balanced by three K⁺, which are located within the channels. It is also possible to distinguish M₄O₂ units whose M^III polyhedra are linked by vertex and edges.     

Hydrothermal synthesis and structure characterization of a new organic–inorganic composite (4,4′-H2bipy)2(4,4′-hbipy)2(ZnW12O40)·6H2O

A new organic–inorganic composite (4,4′-H₂bipy)₂(4,4′-Hbipy)₂(ZnW₁₂O₄₀)·6H₂O has been prepared by hydrothermal reaction and characterized by elemental analysis, IR and UV spectra, thermal analysis and single-crystal X-ray structural analysis. It belongs to the monoclinic system, space group P2₁/c, with a?=?18.637(4), b?=?14.003(3), c?=?26.470(5)?Å, β?=?104.78(3)°, V?=?6680(2)?ų, Z?=?4. Structural analysis indicates that the title complex consists of a Keggin anion [ZnW₁₂O₄₀]^6?, 4,4′-bipyridine and water of crystallization, constructing a supramolecular system through hydrogen bonding interactions. Thermal analysis shows that the heteropolyanion [ZnW₁₂O₄₀]^6? starts to decompose at 587.0°C.     

新型仲钨酸盐-B化合物[Na_2(H_2O)_(10)][Cu_4(H_2O)_(12)(H_2W_(12)O_(42))]·15H_2O体外抗肿瘤活性研究

对化合物[Na_2(H_2O)_(10)][Cu_4(H_2O)_(12)(H_2W_(12)O_(42))]·15H_2O(简称Na_2Cu_4W_(12))进行了体外抗肿瘤活性研究.应用四甲基偶氮唑盐(3-[4,5-dimethylthiazo-2-y]-2,5-diphenyltetrazolium bromide,MTT)比色法分析Na_2Cu_4W_(12)对人肝癌细胞(Hep G2)、人神经母细胞瘤细胞(SHY5Y)增殖抑制活性.采用光学显微镜观察肿瘤细胞的凋亡形态变化,用流式细胞术分析细胞周期和细胞凋亡,计算各期细胞比例及细胞凋亡率.结果表明,Na_2Cu_4W_(12)对Hep G2和SHY5Y 2种肿瘤细胞增殖半数抑制浓度IC_(50)值分别为5.3和10.2μmol·L~(-1),且呈剂量依赖性.光学显微镜下处理组细胞出现皱缩、变圆、缩小等形态变化,不同浓度Na_2Cu_4W_(12)处理12h早期凋亡细胞所占的百分比显著增加且呈剂量依赖性.综上所述,Na_2Cu_4W_(12)能够抑制胞瘤细胞增殖,诱导细胞凋亡.     

Synthesis of calcium titanate from [Ca(H2O)3]2[Ti2(O2)2O(NC6H6O6)2]·2H2O as a cheap single-source precursor

Calcium titanate (CaTiO₃) was conveniently synthesized by thermal decomposition of a single-source precursor [Ca(H₂O)₃]₂[Ti₂(O₂)₂O(NC₆H₆O₆)₂]·2H₂O at low temperature. This single-source precursor was characterized by elemental analysis, IR spectrum, thermal gravimetric analysis and X-ray single crystal diffraction. The calcined products at different temperature were further characterized by powder X-ray diffractions and IR spectra. The morphology, microstructure, and crystallinity of the resulting CaTiO₃ materials have been characterized by SEM and TEM. The BET measurement revealed that the CaTiO₃ powders had a surface area of 14.0 m²/g. In addition, the microwave dielectric properties of the resulting CaTiO₃ material have been measured.     

Synthesis and Crystal Structure of a Heteropentanuclear Yb(Ⅲ)-Cu (Ⅱ) Complex:[Yb_2Cu_3(O_2CCH_2CI)_(12)(H_2O)_8]·2H_2O

1INTRODUCTIONInterestinpolynuclearcomplexesisstimulatedbytherolestheyplayindifferentfields,e.g.heterogeneouscatalysis,bioinorganicchemistryandthedesignofmagneticmaterials.Since1985ill,considerableattentionshavebeengiventomolecularcomplexest'isimultaneouslycomprisingdandfmetalionsduetotheirspecialmagneticproperties.Coupledpolyr^uclearsystemscontaining3delementshavebeenextensivelyinvestigatedL,3,butonlyafew,derivedfromcarboxylatesL4--63,thatcontainbothtransitionandrare--earthmetalionshavebe…     

Acetate-Functionalized Zirconium-Substituted Tungstogermanate, [Zr4O2(OH)2(CH3COO)2(α-GeW10O37)2]12−

The two acetate-functionalized zirconium(IV)-substituted tungstogermanates, Na₈K₄[Zr₄O₂(OH)₂(CH₃COO)₂(α-GeW₁₀O₃₇)₂] · 33H₂O and Na₈Cs₄[Zr₄O₂(OH)₂(CH₃COO)₂(α-GeW₁₀O₃₇)₂] · 32H₂O, were synthesized by the reaction of ZrOCl₂ with [A-α-GeW₉O₃₄]¹⁰⁻ in pH = 4.8 buffer and their structures were determined by single-crystal X-ray analysis. Both of them contain a centrosymmetric polyanion [Zr₄O₂(OH)₂(CH₃COO)₂(α-GeW₁₀O₃₇)₂]¹²⁻ consisting of two {α-GeW₁₀O₃₇} units sandwiching an inorganic–organic hybrid {Zr₄O₂(OH)₂(CH₃COO)₂} cluster. The polyanion contains a mixing of seven- and eight-coordinate Zr centres. The two compounds were also characterized by elemental analysis, IR spectroscopy, UV–vis and TG–DSC analysis.     

(enH2)5[(VO)12O6B18O36(OH)6]·2(H3O)·6H2O的水热合成和晶体结构

以NH4VO3,H3BO3,乙二胺,MoO3,H2O为原料,按物质的量比2∶20∶9∶3∶222,在180℃条件下晶化,得到黑色棱形晶体(enH2)5[(VO)12O6B18O36(OH)6].2(H3O).6H2O.单晶结构分析结果表明该化合物属三斜晶系,Pī空间群,晶胞参数a=1.336 8(3)nm,b=1.599 8(3)nm,c=1.663 4(3)nm,α=94.040(1)°,β=91.530(1)°,γ=95.830(1)°,V=3.528 1(12)nm3,Z=2,Dc=2.099 g/cm3,μ=1.649 mm-1,F(000)=2 228,15 641个可观察独立衍射点射点(I>2σ(I)),最后结构精修到偏离因子R1=0.047 5,wR2=0.150 4,S=1.039.该化合物的结构主要由阴离子簇[(VO)12O6B18O36(OH)6]12-构成.该阴离子簇由B18O36(OH)6十八元环夹在两个以共边交替相连形成的V6O18簇中间,通过共用氧原子形成三明治式结构新颖的硼-钒-氧离子簇,簇间填充了一些(enH2)2+离子和水分子.     

Synthesis and Crystal Structure of a New Dinuclear Copper(Ⅱ) Polymer: [Cu2(bipy)2(Hbtc)2(H2O)2]·(H2O)1/2

A new dinuclear copper(Ⅱ) polymer [Cu2(bipy)2(Hbtc)2(H2O)2]·(H2O)1/2 1 (bipy=2,2'-bipyridine, H3btc = benzene-1,3,5-tricarboxylic acid) was obtained by the hydrothermal single-crystal X-ray diffraction analysis and identified using elemental analysis and IR spectrum.The title complex crystallizes in monoclinic system, space group P21/c with a = 7.2880(5), b =18.4778(13), c = 13.5465(10)(A), β = 95.9580(10)°, C19H14.50CuN2O7.25, Mr = 450.37, V= 1814.4(2)(A)3, Z=4, Dc = 1.649 g/cm3, μ = 1.253 mm-1, F(000) = 918, Rint = 0.0185, the final R = 0.0271and wR = 0.0710 for 2773 observed reflections (I＞2σ(I)). The study results reveal that a pair of distorted square-pyramidal Cu2+ ions are interlinked by bis-monodentate bridging Hbtc2- ligands to constitute a 16-membered ring.     

Synthesis and Crystal Structure of a Two-dimensional Sil-ver(I)-Iron(III) Heteronuclear Coordination Polymer:{[Ag_4Fe_2(SCN)_(12)(H_2O)_2][(inaH)_2(H_2O)_2]}_n

Introduction Molecules containing different kinds of metal ions play an important role in molecular magnetism.1-3 So considerable attention has been paid to synthesizing heteronuclear complexes.1-4 As a potential bridging ligand, thiocyanate can coordinate to a harder metal center and softer ones with N and S atoms respectively. The complexes of thiocyanate and representative hard acidFe(III) ions usually have a six-coordinate octahe-dral structure such as [Fe(SCN)n]3-n and (Bu4N)4[Ag2-F…     

Synthesis and Structure of a Novel Compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O

A novel compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O was synthesized by the reaction of CuSO4(5H2O with H4EDTA in pyridine/water (V/V = 1/4) solvent, and characterized by elemental analysis, IR spectrum and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 1.26974(6), b = 0.67949(3), c = 1.48548(3) nm, β = 91.454(2)o, V = 1.28122(9) nm3, Z = 2, Dc = 1.673 g/cm3, Mr = 645.56, F(000) = 664, μ(MoKα) = 1.729 mm-1, the final R = 0.0353 and wR = 0.0832 for 1920 observed reflections (I > 2((I)). The compound is a centrosymmetric binuclear molecule with bridged EDTA group. Each Cu(II) atom is linked to two oxygen atoms and one nitrogen atom of EDTA, one oxygen atom of water and one nitrogen atom of pyridine to form a distorted square pyramidal environment. There exist face-to-face π-π stacking interactions between pyridine rings from neighboring molecule with the interplanar distance of 0.3670 nm and hydrogen bonding between EDTA and water molecules.     

Synthesis and crystal structure of a 1D chain polyoxometalate-based complex {[CuI(en)2(H2O)]2{GeW12O40[CuII(en)2]} · 2.5H2O} n

A 1-D infinite chain organic–inorganic hybrid compound, [Cu^I(en)₂(H₂O)]₂{GeW₁₂O₄₀[Cu^II(en)₂]}·2.5H₂O, was synthesized hydrothermally and characterized by IR, UV spectroscopy, TG analyses, and single-crystal X-ray diffraction. Structural analysis indicates that neighboring [GeW₁₂O₄₀]^4? polyanions are interconnected by [Cu(3)(en)₂]²⁺ subunits via W–O_t–Cu(3) bridges, generating a 1D infinite chain structure. Furthermore, the compound shows photoluminescence in the solid state at room temperature.     

CRYSTAL STRUCTURE OF [Tm_4(p-NO_2C_6H_4CO_2)_(12)(H_2O)_(10)·2H_2O

<正> [Tm4 (p-NO2C6H4CO2)12 (H2O)10]·2H2O, Mr = 2885. 28, triclinic, space group P1 with a=14. 109(4) ,b= 14. 594(3) ,c= 13. 638(3) A ,α= 107. 04 (2), β=103. 36(2),γ= 93. 93(2)°, Z=1,V = 2584(1) A3.F(000) = l416,μ = 36. 4cm-1(Moka) ,Dc=1. 85g·cm3. The final R factor is 0. 034. The crystal structure is composed of tetrameric units in which four metal ions are bridged by carboxyl groups in chain form.     

Oxo Peroxo Glycolato Complexesof Vanadium (V). Crystal Structureof (NBu4)2[V2O2(O2)2(C2H2O3)2]ċH2O

Summary.  Oxo peroxo glycolato complexes of vanadium(V) (M ₂[V₂O₂(O₂)₂(C₂H₂O₃)₂]ċnH₂O (n=0, 1; M=NBu₄ ⁺ (1), K⁺ (2), NH₄ ⁺ (3), Cs⁺ (4), NPr₄ ⁺ (5)) as well as (NBu₄)₂[V₂O₄(C₂H₂O₃)₂]ċ H₂O (6) have been prepared and characterized by spectroscopic methods. X-Ray structure analysis of 1 revealed the presence of dinuclear [V₂O₂(O₂)₂(C₂H₂O₃)₂]²⁻ anions with a (chemical structure) bridging core and six coordinated vanadium(V) atoms in a distorted pentagonal pyramidal array. Received July 12, 1999. Accepted (revised) October 28, 1999     

Synthesis and Characterization of a Reduced Molybdenum(Ⅴ) Phosphate, (H3dien)2(H2dien)2[NaMo12O24(OH)6-(H2PO4)(HPO4)5(PO4)2]·nH2O(n= 10.92)

A new reduced molybdenum(Ⅴ) phosphate (H3dien)2(H2dien)2[NaMo12O24 (OH)6 (H2PO4)(HPO4)5(PO4)2]·nH2O(n= 10.92,dien = diethylenetriamine) has been synthesized under hydrothermal conditions and characterized by elemental analyses, IR and X-ray diffraction. C16H96.84MO12N12NaO72.92P8 (Mr = 3046.73) crystallizes in the monoclinic system, space group P21/c with a = 13.3575(18), b = 21.907(3), c = 15.654(2) A, β= 110.22(2)°, V= 4298.4(10) (A)3, Dc = 2.354 g/cm3, Z = 2, μ(MoKα) = 1.966 mm-1, F(000) = 2990.4, the final R = 0.0357 and wR = 0.1086 for 8739 observed reflections with Ⅰ> 2σ(Ⅰ). It consists of sandwich-shaped cluster anions [Na{Mo6P4}2]10- held together into a three-dimensional supramolecular framework through intermolecular hydrogen-bonding contacts. A probe reaction of the oxidation of acetaldehyde with H2O2 showed that this compound has high catalytic activity in the reaction.     

Synthesis,Structure and Characterization of a New Complex: [Mn(C_6H_(12)N_4)_2(H_2O)_4][Mn(H_2O)_6][SO_4]_2·6H_2O

A novel complex,[Mn(C_6H_(12)N_4)_2(H_2O)_4][Mn(H_2O)_6][SO_4]_2·6H_2O,was synthesized and hexagonal single crystals with centimeter-scale sizes were obtained by the method of solvent evaporation.It was characterized by elemental analysis,infrared spectrum,thermogravimetric analysis and X-ray single-crystal diffraction.The complex belongs to triclinic crystal system,space group P■ with a=9.3390(8),b=13.3520(13),c=16.3207(13)?,α=100.7160(3)°,β=90.1020(10)°,γ=109.9490(5)°,V=1874.9(3)?~3,Z=2,D_c=1.542 g/cm~3,M_r=870.64,μ=0.876 mm~(-1),T=293(2) K,F(000)=916 and S=0.990.The crystal structure determination displayed a distorted octahedral geometry around the manganese atom,which is bound to two nitrogen atoms from hexamethylenetetramine,acting as monodentate ligands,and to four aqua ligands.Variable-temperature magnetic measurements of the complex indicate the presence of weak antiferromagnetic interaction between manganese centers.