Hydrothermal Synthesis, Crystal Structures and Electrochemical Properties of Two Phosphatotungstates Containing Keggin Clusters, [Cu(2,2′-bipy)2]5[PW12O40] · 2H2O and (Hpip)3[PW12O40]

Two new phosphatotungstates containing Keggin clusters, [Cu(2,2′-bipy)₂]₅[PW₁₂O₄₀] · 2H₂O (1) (2,2′-bipy = 2,2′-bipyridine) and (Hpip)₃[PW₁₂O₄₀] (2) (pip = piperazine) have been hydrothermally synthesized and characterized by IR, element analysis and cyclic voltammogram. Compound 1 consists of one discrete Keggin polyanion [PW₁₂O₄₀]^5?, five isolated complex cations [Cu(2,2′-bipy)₂]⁺ and two water molecules. The organic moieties exhibit regular packing with offset aromatic–aromatic interactions between the bipys, leading to a compact supramolecular framework structure. Compound 2 is made up of one discrete Keggin polyanion [PW₁₂O₄₀]^3? and three pip cations. Compounds 1 and 2 were employed to fabricate bulk-modified carbon paste electrode to research on their electrochemistry properties. Their electrochemical behaviors and electrocatalysis that 1- and 2-CPEs have electrocatalytic activities toward the oxidation of nitrite. Compound 1 is in the orthorhombic system, space group Pna2₁, with a = 28.1928(9), b = 21.5479(6), c = 19.9088(6) Å, V = 12,094.5(6) Å³ and Z = 4. Compound 2 is in the rhombohedral system, space group R $ \overline{3} Two new phosphatotungstates containing Keggin clusters, [Cu(2,2′-bipy)₂]₅[PW₁₂O₄₀] · 2H₂O (1) (2,2′-bipy = 2,2′-bipyridine) and (Hpip)₃[PW₁₂O₄₀] (2) (pip = piperazine) have been hydrothermally synthesized and characterized by IR, element analysis and cyclic voltammogram. Compound 1 consists of one discrete Keggin polyanion [PW₁₂O₄₀]⁵⁻, five isolated complex cations [Cu(2,2′-bipy)₂]⁺ and two water molecules. The organic moieties exhibit regular packing with offset aromatic–aromatic interactions between the bipys, leading to a compact supramolecular framework structure. Compound 2 is made up of one discrete Keggin polyanion [PW₁₂O₄₀]³⁻ and three pip cations. Compounds 1 and 2 were employed to fabricate bulk-modified carbon paste electrode to research on their electrochemistry properties. Their electrochemical behaviors and electrocatalysis that 1- and 2-CPEs have electrocatalytic activities toward the oxidation of nitrite. Compound 1 is in the orthorhombic system, space group Pna2₁, with a = 28.1928(9), b = 21.5479(6), c = 19.9088(6) ?, V = 12,094.5(6) ?³ and Z = 4. Compound 2 is in the rhombohedral system, space group Rc, with a = 17.9191(5), c = 23.7439(9) ?, V = 6,602.6(4) ?³ and Z = 6. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

hree Inorganic-organic Composite Polyoxotungstates:Syntheses, Characterization and Structures of [Cu(2,2'-bpy)2]5[α-PW11.5Cu0.5O40]·2H2O,[Co(2,2'-bpy)2(N3)2]4H3[α-PW12O40]·3H2O and [Cu(2,2'-bpy)2(4,4'-bpy)]2[α-GeW12O40]·4H2O

Three new inorganic-organic composite polyoxotungstates [Cu(2,2'- bpy)2]5[α- PW11.5Cu0.5O40]·2H2O 1, [Co(2,2'-bp3)2(N3)2]4H3[α-PW12O40]·3H2O 2 and [Cu(2,2'-bpy)2(4,4'- bpy)]2[α-GeW12O40].4H2O 3 (2,2'-bpy = 2,2'-bipyridine, 4,4'-bpy = 4,4'-bipyridine) have been hydrothermally synthesized and structurally characterized. 1 crystallizes in the orthorhombie space group Pna21 with α = 27.847(3), b = 21.597(2), c = 20.1179(19) A, V = 12099(2) A3, Z = 4, GOF= 1.038, R = 0.0427 and wR = 0.1035; 2 belongs to the triclinic space group P1 with a= 12.31150(10), b = 16.1954(4), c = 19.36290(10) A, α = 99.366(11), β=105.168(8),γ = 111.836(8)°, V = 3309.98(9) A3, Z = 1, GOF = 1.024, R = 0.0739 and wR = 0.2216; and 3 crystallizes in the monoclinic space group P21/n with a = 12.858(4), b = 20.943(6), c = 15.598(5) A, β = 102.338(5)°, V = 4103(2) A3, Z = 2, GOF = 1.026, R = 0.0557 and wR = 0.1316. The common structural features of 1～3 are that their molecular structures all consist of a saturated a-Keggin polyoxoanion and several discrete metal-organic moieties. Intriguingly, 2 and 3 are composed of metal-organic coordination moieties with two mixed ligands.     

Crystal structure and properties of H3[PMo12O40] · 3C2H6O

The title compound H₃[PMo₁₂O₄₀]· 3C₂H₆O was prepared and characterized by X-ray crystallography, its i.r. spectrum, cyclic voltammetry and e.s.r. spectra. The anion of the title compound is a Keggin-type heteropoly structure based upon a central PO₄ tetrahedron surrounded by 12 MoO₆ octahedra arranged in four groups of three edge-shared octahedra Mo₃O₁₃. Weak hydrogen bonds exist between the organic solvent molecules and the heteropoly anion. The catalytic activity of the title compound was determined by the synthesis of butyl acetate. The conversion of n-BuOH reached 93.3% and the yield of MeCO₂Bu-n was 92.0% when the ratio of MeCO₂H to n-BuOH, catalyst amount, reaction time, reaction temperature were 2:1, 0.24% of the reactants (50 mg), 2.0 h and 115 120 °C, respectively.     

Synthesis, crystal structure, and thermal analysis of hexahydrogen dodecavanadate of composition [NH3 · H2O]6 · H6[Ca4V12O40] · 6H2O

Dihydrogen dodecavanadate of composition [NH₃ · H₂O]₆ · H₆[Ca₄V₁₂O₄₀] · 6H₂O was synthe-sized and studied by X-ray crystallography and TGA analyses. The crystals are cubic, space group I $\bar 4$ 3m;; unit cell parameters: a = 13.518(2) ?, V = 2470.4(3) ?³, ??_calc = 2.2334 g/cm³, Z = 2.     

Synthesis,Crystal Structure and Spectral Properties of [Ce(NO3)5(H2O)2]·2(Hphen)·(H2O)

A novel complex [Ce(NO3)5(H2O)2]·2(Hphen)·(H2O) (phen =1,10-phenanthroline) with formula C24H24CeN9O18 and Mr = 866.64 has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in triclinic, space group Pī with a = 7.5534(2), b = 8.083(2), c = 25.8377(6) A, α = 86.847(1), β = 89.937(1), γ = 86.981(1)o, V = 1572.94(6) A3, Dc = 1.830 g/cm3, F(000) = 866, β = 1.545 cm-1 and Z = 2. The final refinement gave R = 0.0486 and wR = 0.1278 for 4852 observed reflections with I > 2σ(I). It consists of discrete [Ce(NO3)5(H2O)2]2- anion, two Hphen+ cations and a lattice water molecule. In the compound, all of the five nitrates are bidentate, and the coordination of Ce(III) is 12. The photo-luminescence of this compound was also investigated.     

[Er(nmp)4(H2O)3]H[SiMo12O40]·2nmp·0.5H2O的合成、性质与晶体结构

由Er2O3、H4SiMo12O40和nmp合成了分子组成为[Er(nmp)4(H2O)3]H[SiMo12O40]2nmp0.5H2O(nmp=N-甲基吡咯烷酮)的配合物,并通过单晶X-射线衍射测定了晶体结构。结果表明,该化合物属单斜晶系,P21/c空间群,晶胞参数a=17.4601(7),b=18.1906(5),c=22.9096(8)?b=105.2980(10),Z=4,V=7018.5(4)3,Dc=2.504g/cm3,R=0.0460,wR=0.1114,F(000)=5064.配合物中Er3+以七配位的单加冠三棱柱构型配阳离子形式存在,与之配位的是4个N-甲基吡咯烷酮和3个H2O分子,该配阳离子与[SiMo12O40]4-阴离子通过静电作用相结合。     

Syntheses,crystal structures and antibacterial activities of [Cu2(C11H11NO5S)2(H2O)4] · 5H2O and [Ni2(C11H11NO5S)2(H2O)4] · 2H2O

The binuclear complexes [Cu₂L₂(H₂O)₄] · 5H₂O (1) and [Ni₂L₂(H₂O)₄] · 2H₂O (2) (where L = C₁₁H₁₁NO₅S, H ₂ L = 2-[(3-formyl-5-methyl-2-hydroxy-benzylidene)-amino]ethanesulfonic acid) have been synthesized and characterized by IR, elemental analysis and X-ray diffraction. The crystals belong to the monoclinic system, space group P2₁/c. Complex 1: a = 16.8902(12), b = 11.2829(6), c = 17.4249(11) Å; β = 106.709(4)°; S = 1.131; V = 3180.5(3) ų; Z = 4; D _Calcd = 1.729 g cm^?3; F(000) = 1712; μ = 1.554 mm^?1; R ₁ = 0.0519, wR ₂ = 0.1349; complex 2: a = 11.399(2), b = 19.985(3), c = 7.3694(10) Å; β = 108.664(7)°; S = 1.157; V = 1590.6(4) ų; Z = 2; D _Calcd = 1.604 g cm^?3; F(000) = 800; μ = 1.388 mm^?1; R ₁ = 0.1859, wR ₂ = 0.4346. The geometry around each metal(II) center can be described as slightly distorted octahedral. Water-sulfonic clusters and (H₂O)₄ water clusters can be observed for 1 from the crystal packing diagram, while cavity and offset face-to-face π–π stacking can be observed for 2. The complexes have been tested for the antibacterial activities which show antibacterial activities of 1 for β-hemolytic streptococcus, Staphylococcus aureus and Escherichia coli, and the antibacterial activity of 2 only for β-hemolytic streptococcus.     

Syntheses and Structural Researches of Nine-coordinate K3[TbIII(nta)2(H2O)]·5.5H2O and Eight-coordinate K3[YbIII(nta)2]·5H2O

The crystal and molecular structures of K3[TbIII(nta)2(H2O)](5.5H2O (nta = nitrilotriacetic acid) and K3[YbIII(nta)2](5H2O complexes have been determined by single-crystal Xray structural analyses. Because TbIII and YbIII have different ionic radii and electronic configura- tions, they take nine- and eight-coordinate structures with two nta ligands, respectively. The crystal of K3[TbIII(nta)2(H2O)](5.5H2O belongs to orthorhombic, space group Pccn with a = 1.6374(7), b = 1.9913(8), c = 1.5068(6) nm, V = 4.913(3) nm3, Z = 8, Mr = 769.54, Dc = 2.081 g/cm3, μ= 3.476 mm-1 and F(000) = 3048. The final R and wR are 0.0432 and 0.0916 for 4961 observed reflections (I > 2.0(σI)), and 0.0814 and 0.1042 for all 21921 reflections, respectively. The [TbIII(nta)2(H2O)]3- complex anion has a nine-coordinate pseudo-monocapped square anti-prismatic structure, in which two N and six O coordinated atoms are from two nta ligands and the left ninth O atom from one water molecule. The crystal of K3[YbIII(nta)2]·5H2O is of monoclinic, space group P21/c with a = 1.5579(5), b = 0.9981(3), c = 1.5956(5) nm, β = 109.776(5), V = 2.3348(13) nm3, Z = 4, Mr = 756.62, Dc = 2.153 g/cm3, μ= 4.624 mm-1 and F(000) = 1484. The final R and wR are 0.0253 and 0.0657 for 4123 observed reflections (I > 2.0(σI)), and 0.0320 and 0.0731 for all 9414 reflections, respectively. The [YbIII(nta)2]3- complex anion has an eight-coordination structure with a distorted square antiprismatic prism, in which each nta acts as a tetradentate ligand with one N atom from the amino group and three O atoms from the carboxylic groups.     

Syntheses and structures of nine-coordinate NH4[HoIII(Edta)(H2O)3] · 1.5H2O, (NH4)4[Ho 2 III (Dtpa)2] · 9H2O, and (NH4)3[HoIII(Ttha)] · 5H2O complexes

The three title complexes, NH₄[Ho^III(Edta)(H₂O)₃] · 1.5H₂O (I) (H₄Edta = ethylenedianine-N,N,N′,N′-tetraacetic acid), (NH₄)₄[Ho ₂ ^III (Dtpa)₂] · 9H₂O (II) (H₅Dtpa = diethylenetriamine-N,N,N′,N″,N″-entaacetic acid), and (NH₄)₃[Ho^III(Ttha)] · 5H₂O (III) (H₆ Ttha = triethylenetetramine-N,N,N′,N″,N?,N?-hexaacetic acid), have been prepared and characterized by FT-IR, elemental analyses, and single-crystal X-ray diffraction technique. Complex I has a nine-coordinate mononuclear structure with distorted monocapped square antiprismatic conformation and its crystal structure belongs to orthorhombic system and Fdd2 space group. The crystal data are as follows: a = 19.343(9), b = 35.125(17), c = 12.364(6) Å, V = 8400(7) ų, Z = 16, M = 552.26, ρ_calcd = 1.747 g cm^?3 μ = 3.828 mm^?1, and F(000) = 4368. Complex II has a binuclear nine-coordinate pseudomonocapped square antiprismatic conformation and its crystal structure belongs to triclinic system and space P1 group. The crystal data are as follows: a = 9.7637(16), b = 9.9722(16), c = 12.945(2) Å, α= 85.853(2)°, β = 77. 140(2)°, γ = 77.140(2)°, V = 1198.4(3) ų, Z = 1, M = 1340.80, ρ_calcd = 1.858 g cm^?3, μ = 3.380 mm^?1, and F(000) = 674. As for complex III, it also has nine-coordinate mononuclear structure with distorted tricapped trigonal prism and its crystal structure belongs to monoclinic system andP2₁/c space group. The crystal data are as follows: a = 10.349(3), b = 12.760(4), c = 23.142(7) Å, β = 91.020(6)°, V = 3055.6(16) ų, Z = 2, M = 797.55, ρ_calcd = 1.734 g cm^?3, μ = 2.674 mm^?1, and F(000) = 1624. The results showed that although the ligands are different from one another in the shape and the numbers of coordination atoms, they all have nine-coordinate structures. However, one of them has binuclear structure and the other two have mononuclear structures because of the difference of the ligands.     

Nonisothermal Kinetice of Dehydration Process of [Sm(m-CIBA)3phen]2·2H2O and[Sm(p-CIBA)3phen]2·2H2O

Compounds[Sm(m-CIBA)3phen]2·2H2O and[Sm(p-ClBA)3phen]2·2H2O(m-ClBA=m-chlorobenzoate,PClBA=p-chlorobenzoate,phen=1,10-phenanthroline)were prepared.The dehydration processes and kinetics of these compounds were studied from the analysis of the DSC curves using a method of processing the data of thermal analysis kinetics.The Arrhenius equation for the dehydration process can be expressed as lnk=38.65-243.90x103|RT for and△S≠ of dehydration reaction for the title compounds are determined,respectively.     

Thermal decomposition reaction kinetics of complexes of [Sm(o-MOBA)3bipy]2·H2O and [Sm(m-MOBA)3bipy]2·H2O

The complexes of [Sm(o-MOBA)₃bipy]₂·H₂O and [Sm(m-MOBA)₃bipy]₂·H₂O (o(m)-MOBA = o(m)-methoxybenzoic acid, bipy-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, IR, UV, XRD and molar conductance, respectively. The thermal decomposition processes of the two complexes were studied by means of TG–DTG and IR techniques. The thermal decomposition kinetics of them were investigated from analysis of the TG and DTG curves by jointly using advanced double equal-double steps method and Starink method. The kinetic parameters (activation energy E and pre-exponential factor A) and thermodynamic parameters (ΔH ^≠ , ΔG ^≠ and ΔS ^≠) of the second-step decomposition process for the two complexes were obtained, respectively.     

[Ni(bpy)(mal)(H2O)3]·H2O and [Ni(4,4′-dmbpy)(mal)(H2O)3]·1.5H2O: syntheses,crystal structures,magnetic properties,and computational study of stacking interactions

[Ni(bpy)(mal)(H₂O)₃]·H₂O and [Ni(4,4′-dmbpy)(mal)(H₂O)₃]·1.5H₂O (mal = maleato; bpy = 2,2′-bipyridine; 4,4′-dmbpy = 4,4′-dimethyl-2,2′-bipyridine) exhibit molecular crystal structures. The Ni(II) central ions in both complexes are six-coordinate by one chelate bonded L–L ligand, three aqua ligands, and one position is occupied by a maleato oxygen donor atom. Hydrogen bonded ribbon-like supramolecular structural motifs are present in both studied complexes; these are linked by weaker C–H?O hydrogen bonds in [Ni(bpy)(mal)(H₂O)₃]·H₂O, whereas in [Ni(4,4′-dmbpy)(mal)(H₂O)₃]·1,5H₂O the hydrogen bonded ribbons are linked by O?H-O-H?O hydrogen bonds with the participation of the additional water solvate molecule positioned on the twofold axis. In both structures, π–π stacking interactions with different patterns in respective structures were found. The role of dispersion energy and many-body effects in the stabilization of bpy and 4,4′-dmbpy stacking interactions were investigated using methods of computational chemistry. Those confirm the dispersion-dominated stabilization of the 4,4′-dmbpy supramolecular chain-like structure, with only marginal impact of cooperativity effects. Thermal decompositions of both complexes start with dehydration. Magnetic susceptibility studies performed from 2 to 300 K revealed a dominant effect of the zero-field splitting of the Ni(II) ion, governing the low-temperature magnetic properties of both compounds.     

Synthesis, properties, and thermal decomposition of compounds [Co(En)3][Fe(CN)6] · 2H2O and [Co(En)3]4[Fe(CN)6]3 · 15H2O

Binary complex salts, [Co(En)₃][Fe(CN)6] · 2H₂O and [Co(En)₃]₄[Fe(CN)₆]₃ · 15H₂O, are synthesized. The properties of the salts and their thermolysis in air, dihydrogen, and argon are studied. Oxides of the central ions of the binary complex salts are found to be the thermolysis products in an oxidative atmosphere. Solid solutions (intermetallic compounds) CoFe are the thermolysis products in the reductive atmosphere, whereas intermetallides containing considerable amounts of C and N and an impurity of Co and Fe oxides are the thermolysis products in an inert atmosphere. Gaseous thermolysis products in dihydrogen and argon are NH₃, hydrocarbons, and ethylenediamine.     

Ionic crystals based on Keggin anion and mixed-valent diruthenium tetracetate: [Ru2(CH3COO)4(H2O)2]2[HnXW12O40]·[Ru2(CH3COO)4(H2O)Cl]·12H2O (X = B,Si, Ge)

Three new ionic crystals based on Keggin anion and mixed-valent diruthenium tetracetate, [Ru₂(CH₃CO₂)₄(H₂O)₂]₂[H_nXW₁₂O₄₀]·[Ru₂(CH₃CO₂)₄(H₂O)Cl]·12H₂O {X = B, n = 3 (1); X = Si, n = 2 (2); X = Ge, n = 2 (3)}, have been prepared in acidic aqueous solution at about pH 3.0 by reaction of K₄BW₁₂O₄₀·mH₂O, K₈SiW₁₁O₃₉·mH₂O and K₈GeW₁₁O₃₉·mH₂O with diruthenium tetracetate Ru₂(CH₃COO)₄Cl, respectively, and their structures were determined by X-Ray diffraction analysis. They are isostructural structure with the ratio of heteropolytungstate anion, Ru₂(CH₃CO₂)₄⁺ cation and neutral molecular Ru₂(CH₃CO₂)₄Cl of 1:2:1. The cyclic voltammetry in 0.5 M KNO₃ aqueous solution at pH 3.0 show the respective electrochemical behaviors of the W-centers and Ru₂-centers for these three complexes. Magnetic data analysis shows that diruthenium units display the ground state electronic configuration π*²δ* with large positive D value.     

Study of acid pyridine-3-carboxylic acid dodecatungstenphosphate of the composition (C6NO2H5)2H[PW12O40]·2H2O

Acid pyridine-3-carboxylic acid dodecatungstenphosphate (C₆NO₂H₅)₂H[PW₁₂O₄₀]·2H₂O is synthesized. The compound is studied by chemical analysis, IR spectroscopy, X-ray crystallography, and thermogravimetry. The compound is found to crystallize at 290 K in a hexagonal crystal system (space group \(R\bar 3\) ) (I) with the unit cell parameters: a = 33.015(6) Å, c = 12.010(2) Å, γ = 120°, V = 11337(4) ų, Z = 9. When the temperature decreases to 100 K, a phase transition is observed leading to an increase in symmetry to \(R\bar 3m\) (II), with the unit cell parameters: a = 33.072(1) Å, c = 24.234(1) Å, γ = 120°, V = 22955(2) ų, Z = 18.     

电荷转移盐[C5H10NO]3[PW12O40]·C5H9NO·3H2O的合成和晶体结构

由N-甲基吡咯烷酮和H3PW12O40·nH2O反应得到了标题化合物,并以元素分析,红外光谱,质谱和X射线单晶衍射对其结构进行了表征．结构解析表明,该化合物属于三斜晶系,Pi空间群,晶胞参数为：α=1．335（2）nm,b=1．374（2）nm,c=1．826（2）nm,α=98．92（2）°,β=107．7（2）°,γ=109．9（2）°,V=2．873（1）nm^3,Z=2,Dc=3．840Mg/m^3,μ=24．05mm^-1,F（000）=2926,R1=0．0632,wR2=0．1403．在该化合物中,杂多阴离子仍保持其Keggin结构,通过静电引力与阳离子作用．     

Syntheses, Crystal Structures and Characterization of Two Zeotype Crystals of K4[Cr3O(H2O)3(OOCH)6]2[P2W18O62] ·9.5H2O and K4[Cr3O(H2O)3(OOCH)6[H3P2W17Co(H2O)O61]·20H2O

Two novel zeotype crystals, K4[Cr3O(H2O)3(OOCH)6]2[P2W18O62]·9.5H2O(1) and K4 [Cr3O(H2O)3·X-ray single crystal diffraction. Crystal data: C12H43O103.5K4Cr6P2W18(1), hexagonal P6(3)/m, a=1.5895(2)nm, b=1.5895(2) nm, c=2.1620(4) nm, α=90°, β=90°, γ =120°, V=4.7305(13) nm3, Z=2,R1 =0. 0726, wR2=0. 1542; C6H57O98K4Cr3CoP2W17(2), hexagonal P6(3)/mmc, a=1. 61328 (3) nm, b=1.61328(3) nm, c=2. 06613 (9) nm, α=90°,β=90°, γ=120°, V=4. 6570(2) nm3, Z=2, R1=0. 0377,wR2 =0.1070. These crystals were characterized using elemental analysis, IR, TG-DTA, and XRD. It was found that the polyoxometalate anions maintained Wells-Dawson structure for crystal 1 and lacunary Wells-Dawson structure for crystal 2. Thermal analysis showed that crystal 1 lost the water of crystallization at 132 ℃, whereas crystal 2 lost the water of crystallization at 100 ℃. Crystal 1 could reversibly desorb and adsorb water molecules and its crystal structure could be restored after re-adsorbing the water molecules. It was also found from the XRD patterns that the void size of crystal 2 is smaller compared with that of crystal 1, which is attributed to the higher anion charges.