Three Keggin-based complexes modified by an asymmetric ligand: structures,electrochemical, photocatalytic and fluorescence sensing properties

By using an asymmetric ligand with triazole and imidazole groups, three Keggin-based complexes were obtained, [Cu(HMET)₄(H₂O)₂](PMo₁₂O₄₀)₂·2H₂O (1), [Cu₃(HMET)₄Cl₂(H₂O)₂(XM₁₂O₄₀)₂]·4H₂O (X?=?Si, M?=?W 2, X?=?Ge, M?=?Mo 3) (MET?=?4-(2-imidazol-1-yl-ethyl)-4H-[1,3,4]triazole). Complex 1 contains discrete Keggin anions and mono-nuclear [Cu(MET)₄(H₂O)₂]²⁺ clusters. Complexes 2 and 3 are isostructural with tri-nuclear Cu clusters linked by Keggin anions to construct a 1D chain. The 1- to 3-CPEs show electrocatalytic properties and can also act as nitrite amperometric sensors. Complexes 1–3 exhibit photocatalytic activities for degradation of MB. Complexes 1–?3 own fluorescence sensing properties for detecting Hg²⁺ ions.

Graphical abstract

By using an asymmetric ligand three POM-based complexes were constructed. The 1– to 3–CPEs exhibit good electrocatalytic activities and can be used as nitrite amperometric sensors. The title complexes show good photocatalytic activities for degradation of MB. Moreover, complexes 1–3 can act as fluorescence sensors to selectively detect Hg²⁺.

     

Selective synthesis and characterization of single-crystal silver molybdate/tungstate nanowires by a hydrothermal process

Selective synthesis of uniform single crystalline silver molybdate/tungstate nanorods/nanowires in large scale can be easily realized by a facile hydrothermal recrystallization technique. The synthesis is strongly dependent on the pH conditions, temperature, and reaction time. The phase transformation was examined in details. Pure Ag(2)MoO(4) and Ag(6)Mo(10)O(33) can be easily obtained under neutral condition and pH 2, respectively, whereas other mixed phases of Mo(17)O(47), Ag(2)Mo(2)O(7,) Ag(6)Mo(10)O(33) were observed under different pH conditions. Ag(6)Mo(10)O(33) nanowires with uniform diameter 50-60 nm and length up to several hundred micrometers were synthesized in large scale for the first time at 140 degrees C. The melting point of Ag(6)Mo(10)O(33) nanowires were found to be about 238 degrees C. Similarly, Ag(2)WO(4), and Ag(2)W(2)O(7) nanorods/nanowires can be selectively synthesized by controlling pH value. The results demonstrated that this route could be a potential mild way to selectively synthesize various molybdate nanowires with various phases in large scale.     

Synthesis of Highly Porous Organic/Inorganic Hybrids by Ambient Pressure Sol-Gel Processing

This paper reports the synthesis of highly porous organic/inorganic hybrids by a two-step acid-base catalyzed sol-gel process and ambient pressure drying. In the method organic and inorganic precursors are copolymerized so as to incorporate organic ligands into the solid network. The two-step acid-base catalyzed process was used to prevent phase segregation during the hydrolysis and co-condensation of organic and inorganic precursors. The organic ligands incorporated into the solid gel network modify the surface chemistry. Thus, the wetting angle is significantly increased so that the collapse of the gel network is greatly reduced upon the removal of pore fluid during drying. Organic/inorganic hybrids with BET surface areas above 1250 m2/g, porosities above 75% and pore sizes of 8 nm have been synthesized.     

水煤气变换反应的微观动力学分析──Cu基催化剂上H_2S中毒失活原因的 Monte Carlo 模拟研究

用ＢＯＣＭＰ方法及ＭｏｎｔｅＣａｒｌｏ模拟技术，对Ｈ２Ｓ导致Ｃｕ基催化剂失活的原因进行了计算分析。研究结果表明，当原料气中存在Ｈ２Ｓ时，ＷＧＳ反应的活化能明显高于无Ｈ２Ｓ时的活化能，随着表面Ｈ２Ｓ浓度的增大（θ＝０，０．１０，０．２５），反应的活化能也逐渐变大（其大小比为１∶１．３４∶３．３），究其原因可归结为Ｈ２Ｓ的存在使得反应物分子的吸附热减小，从而使Ｈ２Ｏ的解离吸附（ＷＧＳ反应的速控步骤）活化能增大。     

低温低内应力化学镀镍工艺的研究

化学镀广泛应用于非金属的电镀、电铸前的施加导电层。化学镀沉积层质量与其在零件上的附着力有着密切的关系 ,重视对化学镀沉积层内应力的研究 ,开发一个低温、低内应力的化学镀镍工艺 ,对于化学镀沉积层的推广应用有着十分重要的意义。本文采用正交实验方法对低温、低内应力化学镀镍工艺进行了系统研究 ,开发出了一个低温、低内应力的化学镀镍工艺。在实验过程中发现沉积层内应力同其在零件上的结合力具有密切关系并对其进行了初步探讨。1　实验方法1 1　正交实验根据探索性实验结果分析 ,影响化学镀镍层内应力σ和沉积层速率ｒ的主要因…     

Study of the Fluorescence System of Europium–Enoxacin and its Applications

 This paper is the study of the fluorescence enhancement of Eu³⁺-1-ethyl-6-fluoro-4-oxo-7-(1-piperazinyl)-1,8-naphthyridin-3-carbonic acid (enoxacin, EFLX) system by surfactants. It was found that sodium dodecylbenzenesulfonate (SDBS) exhibits great enhancement on the fluorescence of the Eu-EFLX system. The molar ratio is 1:2:1 for Eu:EFLX: SDBS. Under the optimum conditions, the fluorescence intensity is a linear function of europium in the range of 1.0 × 10⁻⁸ ∼ 5.0 × 10⁻⁶ mol/L, the detection limit is 1.0 × 10⁻⁹ mol/L. The application of the Eu-EFLX-SDBS system for the determination of trace europium in rare earth samples gave satisfactory results. Received October 19, 2000. Revision August 10, 2001.     

Adsorption of trinitrotoluene on uncoated silicon microcantilever surfaces

We measured the adsorption characteristics of trinitrotoluene (TNT) on piezoresistive silicon microcantilever surfaces under ambient air using a well-characterized TNT vapor generator. This allowed us to quantify the adsorption parameters and to estimate the sticking coefficient. The sticking coefficient initially increases with TNT exposure time and then levels off around 0.3. Atomic force microscopy images of silicon surfaces exposed to TNT revealed "island" formation of the adsorbate on the silicon surface. At low exposure times, mainly the number density of islands increased with exposure time; at longer exposure times, the size (in particular, height) of the islands grew, corresponding to the higher sticking coefficients. These observations can be qualitatively explained via the difference between TNT-surface and TNT-TNT interactions mediated by water molecules.     

Measurement of the half life of126Sn using a radiochemical method

The half-life of¹²⁶Sn has never been measured accurately. The value quoted in the literature is approximately 10⁵y, which was measured in 1958. In the present work we measured accruately the half life of¹²⁶Sn to be (2.5±0.2)×10⁵y using a radiochemical method.     

石墨炉原子吸收法测定生物样品中镉的几种基体改进剂的比较

本文比较了磷酸二氢铵、氟化铵、硫酸铵、氯化钯、氯铂酸以及氯铂酸与多种有机酸的混合试剂在测定ＧＢＷ猪肝标准物质中镉时基体改进效果，其中，氯铂酸的基体改进能力最强，猪肝标准物质的回收率在９０％     

A facile synthesis of bifunctional phospholipids for biomimetic membrane engineering

We report a facile synthesis of bifunctional phospholipid conjugates by acylation of N-protected lyso-phosphatidylethanolamine with 12-acryloxy-1-dodecanoic acid and followed with deprotection and conjugation with biotin, FITC, Texas Red, or EMC groups. The lipid conjugates can be used to generate a multifunctional substrate-supported phospholipid membrane via bioconjugation reaction to biotin or covalent attachment to EMC at their hydrophilic terminus. In addition, conjugation to fluorophores, FITC or Texas Red, provides a convenient mechanism to monitor lipid membrane formation and stability. Significantly, in situ photopolymerization of the acrylate group at the end of one of two hydrophobic alkyl chains stabilizes the phospholipid membrane.