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.     

一种基于Lindqvist型多酸阴离子的三维多金属铌酸盐的晶体结构(英文)

利用扩散法合成了K_3 NaH_1Nb_6O_(19)·11H_2O(1),借助IR、UV和X射线单晶衍射分析对这种化合物进行了结构和性质研究.其晶胞参数为:a=1.812 8(6)nm,b=1.790 8(6)nm,c=1.8130(7)nm,V=5.886(4)nm~3,Z=8,R_1[I>2σ(I)]=0.071 0,ωR_2[I>2σ(I)]=0.1857.化合物1由一个Lindqvist型[H_4Nb_6O_(19)]~1聚阴离子,三个K~4离子,一个Na~+离子和十一个H_2O组成.     

A 1-D ladder-like aggregate constructed from Preyssler anion and transition metal linkers

A 1-D ladder-like aggregate, K₂Na₆[Na(H₂O)Fe₂(H₂O)₈(P₅W₃₀O₁₁₀)] · 23.5H₂O (1; K₂Na₆[1a] · 23.5H₂O) has been obtained by conventional aqueous solution reaction. X-ray diffraction analysis reveals that 1 crystallizes in the monoclinic system, space group P 2 ₁ /m, a = 16.938(3) Å, b = 21.396(4) Å, c = 17.520(4) Å, β = 98.14(3)°, V = 6285(2) ų, and Z = 2. Polyoxoanion 1a shows a 1-D ladder-like chain, built up of Preyssler anion and Fe³⁺ linkers, which represents the first extended structure based on Preyssler anion and transition metal linkers. The 1-D chains in 1 are further connected into a 3-D open framework by potassium and sodium cations. Compound 1 displays electrocatalytic activity towards the reduction of nitrite.     

A new fluorescent-colorimetric chemosensor for fluoride anion based on benzimidazolium salt

Two new benzimidazolium salts with the same cationic moiety and different anions 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium bromide and 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium hexafluorophosphate were prepared and characterized. The single crystal structure of 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium bromide was determined by X-ray single crystal diffraction. Particularly, anion recognition using 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium hexafluorophosphate as a chemosensor was carried out via fluorescence and ultraviolet spectroscopy, ¹H NMR titrations, HRMS and IR spectra. The response of this chemosensor to fluoride anion can be observed through both remarkable fluorescence quenching and color change under visible light (from orange to purple). The results indicated that this chemosensor can distinguish fluoride anion from other anions via the instrument and naked eyes, and this is greatly convenient in practical operation.     

A new fluorescent chemosensor for anion based on an artificial cyclic tetrapeptide

A cyclic tetrapeptide composed of alternating glycine and 8-amino-4-iso-butoxyquinoline-2-carboxylic acid was designed and synthesized. Its complexation properties with anions were performed by fluorescence spectroscopy and ¹H NMR method.     

A new organic-inorganic hybrid based on the crescent-shaped polyoxoanion [H6SiNb18O54]8- and copper-organic cations

A new organic-inorganic hybrid, [Cu(en)(2)](3){[Cu(en)(2)][H(6)SiNb(18)O(54)]}·22H(2)O (1, en = ethylenediamine) containing the crescent-shaped polyoxoanion [H(6)SiNb(18)O(54)](8-) and copper-organic cations has been successfully synthesized, and elemental analyses, IR spectra, thermogravimetric analyses and single-crystal X-ray diffraction were investigated.     

A new ratiometric and colorimetric chemosensor for cyanide anion based on coumarin-hemicyanine hybrid

A hybrid coumarin-hemicyanine dye, Cou-BT, was developed as a new ratiometric and colorimetric sensor for cyanide with a sensing mechanism via nucleophilic addition of cyanide anion to the benzothiolium group. Cou-BT shows high sensitivity and selectivity for cyanide detection over other common anion species in aqueous acetonitrile solution. The calculated pseudo-first-order rate constant for cyanide anion addition was (2.13 ± 0.08) × 10(-2) s(-1) at 298 K, and the detection limit was estimated to be 0.64 μM. The DFT and TDDFT calculation results suggest that the ratiometric and colorimetric sensing behavior of Cou-BT upon its reaction with cyanide was due to the interrupted π-conjugation and blocked ICT progress.     

Synthesis and photocatalytic activity of the Co-containing materials based on amorphous SiO2

Functional materials based on highly dispersed amorphous silica and cobalt compounds have been obtained by solvothermal and mechanochemical methods. The formation of silicate Co₃(Si₂O₅)₂(OH)₂ under hydrothermal conditions has been established. This composition, in comparison with mechano-mixes, provides better photoactivity in the hydroquinone decomposition reaction under ultraviolet irradiation, herewith maintaining the surface characteristics of amorphous SiO₂.     

A novel chainlike As-V-O polymer based on a transition metal complex and a dimeric polyoxoanion

The novel polyoxometalate ([As(8)V(13)NiClO(41)][Ni(en)(2)(H(2)O)][Ni(en)(2)])([Ni(en)(2)(H(2)O)(2)](0.5)).4H(2)O (1), which is the first example of a chainlike inorganic-organic hybrid polymer based on dimeric polyoxoanions linked by nickel complex fragments, has been synthesized in the system of As(2)O(3)-V(2)O(5)-H(2)C(2)O(4)-en-NiCl(2).6H(2)O-H(2)O under hydrothermal conditions and characterized by IR, TGA, elemental analysis, single crystal X-ray diffraction, XPS, and magnetic susceptibility studies, respectively. This compound crystallized in the triclinic space group P with a = 13.358(3) angstroms, b = 14.198(3) angstroms, c = 19.723(4) angstroms, alpha = 83.88(3) degrees, beta = 86.04(3) degrees, gamma = 64.66(3) degrees, V = 3360.2(2) angstroms(3), and Z = 2. Interestingly, the dimeric polyoxoanion contains two ([Ni(en)(2)(H(2)O)][As(8)V(13)NiClO(41)]) cluster units linked by Ni-O-As bonds and is a Ni-substituted [As(8)V(13)NiClO(41)] cluster supported by [Ni(en)(2)(H(2)O)] coordination fragment. The chainlike structure consists of ([Ni(en)(2)(H(2)O)][As(8)V(13)NiClO(41)])(2) dimeric polyoxoanions and [Ni(en)(2)] groups which are linked together through vertexes forming a unique one-dimensional polymer. The study of the magnetic susceptibility of 1 demonstrates the presence of antiferromagnetic interaction in 1.     

A catenated anion receptor based on indolocarbazole

A catenated anion receptor 7 comprising two indolocarbazole units was prepared by olefin ring-closing metathesis using Grubbs’ catalyst. Receptor 7 possesses a cage-like cavity where anions are encapsulated by forming four hydrogen bonds in the order of Cl⁻ > AcO⁻ >  >  > Br⁻ >  > I⁻ ≈  in 1% H₂O/acetone.     

A new preconcentration method for platinum and gold based on a macropore anion resin HHY-10A

The ion exchange behavior of Au and Pt on a new China-made macropore anion resin was studied using radiotracer technique. The conditions for adsorption and desorption, such as acidity, flow-rate and concentration of desorbing agents were studied carefully. Using the established method, the contents of Au and Pt in two Chinese ultrabasic SRMs were determined by ICP-MS and the results found in good agreement with the reference values.     

A unique coordination environment for an ion: EXAFS studies and bond valence model approach of the encapsulated cation in the Preyssler anion

X-Ray absorption spectroscopy was used to probe the coordination of different encrypted cations in the Preyssler anions [M(n+)P5W(30)O(110)]((15-n)-)(M(n+)= Sr2+, Am3+, Eu3+, Sm3+, Y3+, Th4+, U4+ in decreasing order of ionic radius, IR), hereafter abbreviated [M(n+)PA](15-n)-. The increase of the M-W distance and the decrease of the M-P distance with increasing M ionic radius reveal that the M cation is displaced along the C5 axis within the Preyssler cavity. The slight change (0.07 A) of the M-O distance that does not correspond to the IR difference of 0.27 A confirms that the cavity retains its rigidity upon cation substitution. Geometric modeling of the encapsulated cation in the channel was performed for comparison to the EXAFS results. The position of the cation in the cavity was calculated as well as the M-O10, -W5 and -P5 distances. This modeling confirms the cation displacement toward the center of the Preyssler anion as the cation size increases, which is understood in terms of the non-homogenous electrostatic potential present within the cavity. The bond valence model approach was applied to obtain experimental bond valences. Only the bond valence sum (BVS) of Am3+ is close to its actual charge. Sums smaller than the actual valences of the +3 and +4 ions (2.39-2.63 for +3 cations, Y, Sm, Eu; 3.17 and 3.38 for +4 cations, U and Th, respectively) were obtained, and a larger sum (2.89) was obtained for Sr2+. The deviations from the formal M sums of the encapsulated ions are attributed to the rigidity of the Preyssler framework. The tendency toward coordinative unsaturation for electroactive cations, such as Eu3+, is thought to be the driving force for facile reduction. Unlike other inorganic chelating ligands, the Preyssler anion provides a unique redox system to stabilize an electroactive cation in a low oxidation state.     

A new chromo-chemodosimeter selective for sulfide anion

A new chromo-chemodosimeter for the anion sulfide in aqueous environments has been developed. The recognition concept is based on a pyrylium-thiopyrylium transformation that is conveniently drawn toward "color chemistry" concepts by means of the anchoring of an aniline group. This causes the color of the aniline-pyrylium backbone in L1 to change selectively from magenta to blue when transformed to the corresponding aniline-thiopyrylium in the presence of the sulfide anion. The method is simple and easy, suggesting potential applications in a variety of different environments where easy and rapid determination of sulfide might be required.     

Crystal structure of a novel two-dimensional supramolecular network based on polyoxoanion and yttriumIII coordination cation

A novel compound (NH⁴)₂Y(H₂O)₈[PMo₁₀V₂O₄₀]·10H₂O has been prepared in an aqueous solution and characterized by elemental analysis, IR, and TG-DTG analysis. X-ray diffraction analysis was carried out on (NH₄)₂Y(H₂O)₈ [PMo₁₀V₂O₄0]·10H₂O single crystal, which crystallizes in the monoclinic system of a space group P21/c witha=0. 9871 (3) nm,b=1. 5424 (5) nm,c=2.7924(9) nm, β = 94.183(5)° and Z=2. In the compound, a two-dimensional network is constructed by the PMo₁₀V₂O ⁵⁻₄₀ anion and the Y(H₂O) ³⁺₈ cation building blocks via hydrogen bonding exhibiting the porous structure.

     

Dispersive solid–liquid phase microextraction based on nanomagnetic Preyssler heteropolyacid: A novel method for the preconcentration of nortriptyline

In this study, a new, simple, rapid, and efficient method combined with ultraviolet visible spectrophotometry and high‐performance liquid chromatography analysis was developed for the extraction and determination of nortriptyline. The tendency of the Preyssler tungsten heteropolyacid, H₁₄[NaP₅W₃₀O₁₁₀], immobilized on the surface of mesoporous nanomagnetite to adsorb the drug from the solution has been investigated. This method involves the use of an appropriate mixture of nanosorbent that was homogenized in disperser solvent (1.0 mL, ethanol). At first, the mixture containing the nanomagnetic sorbent and disperser solvent was injected into the aqueous sample, and a cloudy solution was formed. Subsequently, separation of the two phases was carried out using a magnet. In the second stage, analyte was desorbed from the sorbent by methanol as the optimal desorption solvent using sonication method. The elution solvent containing enriched analyte was introduced to the instruments for further analysis. Optimization of experimental conditions with respect to the extraction efficiency was investigated. The method was linear in the range of 25–5000, while the detection limit (LOD = 3S_B/m) was 7.9 ng/mL and the limit of quantification (LOQ = 10S_B/m) was 26.4 ng/mL. The relative standard deviation was 4.66%. The method was successfully applied to human hair samples.     

A new anionic exchange stir bar sorptive extraction coating based on monolithic material for the extraction of inorganic anion

A novel anionic exchange stir bar sorptive extraction (SBSE) coating based on poly(2-(methacryloyloxy)ethyltrimethylammonium chloride-co-divinylbenzene) monolithic material for the extraction of inorganic anion was prepared. The effect of preparation conditions such as ratio of functional monomer to cross-linker, content of porogenic solvent on the extraction efficiencies were investigated in detailed. The monolithic material was characterized by elemental analysis, scanning electron microscopy and infrared spectroscopy. In order to investigate the extraction capacity of the new coating for inorganic anion, the new SBSE was combined with ionic chromatography with conductivity detection, Br⁻, NO₃⁻, PO₄³⁻ and SO₄²⁻ were selected as detected solutes. Several extractive parameters, including pH value and ionic strength in sample matrix, desorption solvent, extraction and desorption time were optimized. The results showed that strongly ionic strength did not favor the extraction of anlaytes. Under the optimum experimental conditions, low detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target anions were achieved within the range of 0.92–2.62 and 3.03–9.25 μg/L, respectively. The method also showed good linearity, simplicity, practicality and low cost for the extraction inorganic anions. Finally, the proposed method was successfully used to detect the two different trademarks of commercial purified water with satisfactory recovery in the range of 70.0–92.6%. To the best of our knowledge, this is the first to use SBSE to enrich inorganic anions.     

Effect of the polyoxoanion of phosphotungstic acid on the photoconversion efficiency of dye-sensitized solar cells based on titanium dioxide

A method for fabricating form composite photoanodes based on titanium dioxide and phosphotungstic acid has been developed. The introduction of the polyoxometalate into a porous titanium dioxide layer increases the photoconversion efficiency of dye-sensitized solar cells and affects characteristics such as open-circuit voltage and short-circuit current.     

A new type of bromide anion conducting solid

A new type of bromide anion conducting solid electrolyte was designed with the solid electrolyte based on oxybromide; the oxybromide lends unique characteristics of thermal stability and water insolubility (5.6 mg in 100 g of water at 25 degrees C) to the electrolyte which shows the highest Br- anion conductivity reported above 500 degrees C.     

A new fluorinated anion for room-temperature ionic liquids

A new room-temperature ionic liquid (RTIL) consisting of the fluorinated anion bis(trifluoromethyl)-phosphinate((CF₃)₂PO₂⁻) coupled with the 1-butyl-3-methyl-imidazoliuim (BMIM) cation has been synthesized and characterized by physicochemical and electrochemical means including differential scanning calorimetry (DSC), thermogravimetric analysis, viscosity, conductivity and cyclic voltammetry measurements. Properties are compared with those of the known RTIL consisting of BMIM coupled with the bis(trifluoromethyl)-sulfonylimide (TFSI) anion.