Synthesis,characterization and thermodynamic data of compounds with NZP structure

Data on synthesis, thermal behavior and thermodynamic properties for the NZP phosphates NaMe₂(PO₄)₃ and Na₅Me(PO₄)₃ (Me=Ti, Zr, Hf) are reported. The compounds were synthesized by sol-gel method and solid-state reactions and characterized by X-ray powder diffraction, IR spectroscopy, electron microprobe and chemical analysis. Their thermal behavior was studied by the DTA measurements. The heat capacities of the phosphates were measured between temperatures 7 and 650 K. The fractal dimensions for the phosphates were calculated. The obtained thermodynamic characteristics of these phosphates and also literature data for the compounds of NZP type structure are summarized.     

Thermodynamic data of the NZP compounds family

Summary The thermodynamic data for NZP compounds MZr₂(PO₄)₃ (M=Na, K, Rb, Cs, Zr_0.25) and Na₅D(PO₄)₃ (D=Ti, Zr) are reported. The heat capacities of the phosphates were measured between T=7 and T=640 K. The standard enthalpies entropies, and Gibbs functions of formation at T=298.15 K were derived. The obtained thermodynamic characteristics of phosphates of the NZP type structure and literature data are summarized. Thermodynamic functions of reactions of solid-state synthesis were calculated and the usability of ceramic technology for obtaining NZP compounds was proved.     

Study of exchange processes on framework phosphates of NZP type

Phosphates M _0.5 ^II M ₂ ^IV (PO₄)₃ (M^II = Cd, Sr; MIV = Ti, Zr) with a structure of the NaZr₂(PO₄)₃ (NZP) type were synthesized and their total exchange capacity and chemical stability were studied. The kinetics of exchange processes on strontium-titanium phosphate in acid and alkaline contacting media was examined.     

一个新的具有梯子型链状结构的有机二膦酸铜化合物的合成和结构

０IntroductionThemetalphosphonatechemistryhasbeenofin－creasinginterestinthepastdecadeduetotheirpoten－tialapplicationsinionexchanges，adsorptionsandsensors犤１～４犦．Anumberofphosphonatecompoundshavebeenprepared，amongwhichthecoppercompoundsareuniquebecauseoftheversatilecoordinationcapabilitiesofCuions犤５～７犦．Basedon１－hydroxyethylidenediphosp－honate犤hedp，CH３C（OH）（PO３）２犦，severalcopperph－osphonateshavebeenobtainedinourlaboratoryin－cluding犤NH３（CH２）２NH３犦Cu２（he…     

New Formula Type of Phosphates with Langbeinite Mineral Structure

Phosphates of the new formula type A5/3MgE4/3(PO4)3 (A = K, Rb; E = Ti, Zr) with a langbeinite structure have been synthesized via the sol-gel method followed by heat treatment and studied using X-ray diffraction, IR spectroscopy, and electron microscopy methods.     

Thermal Expansion in the Zr and 1-, 2-valent Complex Phosphates of NaZr2(PO4)3 (NZP) Structure

A_5–4xZr_xZr(PO₄)₃ (A=Na, K;0≤x≤1.25), Na_1-xCd_0.5xZr₂(PO₄)₃ (0≤x≤1), Na_5–xCd_0.5xZr(PO₄)₃ (0≤x≤4) compositions which belong to the NZP structural family were synthesized using the sol-gel method. The lattice thermal expansion of members of these rows were determined up to 600°C by high-temperature X-ray diffractometry. The axial thermal expansion coefficients change from -5.8·10^-6to 7.5·10^-6 °C^-1 (α_a) and from 2.6·10^–6 to 22·10^–6 °C^-1 (α_c). These results, in addition to those for other NZP compounds allow us to explain their low thermal expansion. The mechanism can be attributed to strongly bonded three-dimensional network structure, the existence of structural holes capable to damp some of the thermal vibrations and anisotropyin the thermal expansion of the lattice. This revised version was published online in August 2006 with corrections to the Cover Date.     

Physics and Chemistry of Creating New Titanates with Perovskite Structure

The phase formation, structural features, and dielectric, ferroelectric, and piezoelectric properties of ceramics with compositions from the region of the morphotropic phase boundary in the (Na_0.5Bi_0.5)TiO₃–BaTiO₃–Bi(Mg_0.5Ti_0.5)O₃ system modified by different low-melting additives (Bi₂O₃, V₂O₅, KCl, NaCl–LiF, LiF, CuO, and MnO₂) are studied. First-order phase transitions are detected near 700–800 and 400 K that display relaxor behavior and are indicative of the presence of polar regions in a nonpolar matrix. Prospects for improving the piezoelectric properties of the modified ceramic samples are confirmed.     

Electrochemical de-chlorination/transformation of metal chloride for the preparation of NZP structure product

A new two-step process was investigated to treat LiCl molten salt waste containing volatile radionuclides generated from an electro-metallurgical processing (pyro-processing) of spent oxide fuels. First, the chemical form of the soluble LiCl waste was transformed into a chloride-free and less soluble hydroxide compound by an electrochemical method, where an electrolytic de-chlorination was performed without adding any chemical salt. Then, a gelation process of the chemical form-changed Li compound, named gel-route stabilization/solidification (GRSS) system aimed to reduce the volatility of the radionuclides greatly, was introduced to stabilize/solidify the hydroxide salt wastes. The application of the electrochemical dechlorination/transformation process and the subsequent gel-route stabilization process to treat the soluble LiCl salt wastes was found to be effective.     

Synthesis and Characterization of Niobium-Bearing Members of the NZP and NbOPO 4 Structural Families

Theoretically predicted by us, M 1/3 Nb 5/3 (PO 4 ) 3 (M = Mg, Mn, Co, Ni, Cu or Zn) compounds with the sodium zirconium phosphate (NZP) framework structure having no interstitial ions were synthesized. The rising of temperature above 900;C causes the change of chemical composition of NZP compounds and formation NbOPO 4 -like products. The phase formation regularities stated gave a possibility to choose optimal conditions for preparation of these phosphates.     

溶液结构的X射线衍射研究──一种新的简易恒温技术

报导了针对立式２θ－θ型Ｘ射线衍射仪测量溶液结构的要求，根据热敏电阻器阻值随温度变化的特性，设计制作了液体样品池恒温装置。具有实用性强、携带使用方便等优点。     

Synthesis and Structure of New Substituted Pyrimidinone with Unsaturated Side Chain

Melting of a mixture of 5-substituted 2,4-dimethyl-1,6-dihydropyrimidin-6-ones with cinnamic aldehyde, 1-methylindoline-2,3-dione and 6-methoxy-2-chloroquinoline-3-carbaldehyde in the presence of ZnCl₂ led to the formation of substituted pyrimidines with conjugated bonds in the position 2. The structure of synthesized compounds as 2-isomers was confirmed by 2D ¹H NMR NOESY data.     

Solvothermal Syntheses and Structure of a New Polyoxomolybdate Functionalized with Carboxyphosphonate

A new functionalized polyoxomolybdate [(HOOCC₅H₉NCH₂PO₃)₂Mo₅O₁₅]^4– ( 1 ) was synthesized by solvothermal reaction at 120 °C and structurally characterized by X‐ray single‐crystal diffraction, X‐ray powder diffraction as well as with infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The title polyoxoanion consists of a ring of five distorted MoO₆ octahedra linked through four edge‐sharing and one corner‐sharing junctions. Two pending carboxyphosphonate ligands are attached on opposite sides of the ring by the two PO₃ groups. As a result the two dangling arms with their terminal carboxylate groups protrude away from the {Mo₅O₁₅} framework in diametrically opposed directions. Each Mo₅‐ring is further connected to adjacent Mo₅‐ring through hydrogen bonds, which consist in the protonated nitrogen atoms, the carboxyl oxygen atoms from L^3– ligands and oxygen atoms from {Mo₅O₁₅} cluster to form a 2D framework structure.     

具有新型核心结构的肽类BACE1抑制剂的设计、合成及活性评价

以KMI-008为先导化合物,4-羟基或氨基取代的脯氨酸模拟其Pns,设计并合成了19条肽序列,用时间分辨荧光法测定目标肽体外对BACE1的抑制作用. 所合成化合物对BACE1有一定的抑制作用,其中两个化合物(LK-MX-41、LK-MX-42)与先导化合物活性相近,其核心结构由L-Phe-D-Pro组成,可以模拟BACE1的催化中心与底物相互作用的过渡态;含有该结构的肽序列,有可能成为研究肽类BACE1抑制剂的另一途径. 应用Autodock 4将所合成化合物与BACE1进行对接,结合体外活性测试结果对构效关系进行了初步探讨. 先导化合物及目标肽用固相法合成,经RP-HPLC测定纯度、ESI-MS确定相对分子量.     

Synthesis and Structure of New Aminouracilindolones

Russian Journal of General Chemistry - New derivatives of aminouracilindolone have been prepared and their structure has been studied. The reaction of 2-chloro-1H-indole-3-carbaldehyde and its...     

一种新结构ZnS：Tm^3＋薄膜电致发光器件的研究

采用电子束蒸发法制备了一种新结构（ITO／SiO2/ZnS:TmF3/SiO2/ZnS:TmF3/SiO2/Al)的薄膜电致发光器件,并与传统双绝缘层结构的器件相比较。结果表明,新结构器件的发光蓝红外比和发光亮度要明显高于双绝缘层结构的器件。分析认为这是由于SiO2夹层起到了加速电子和提供界面的作用。     

Crystal Structure and Photoluminescence of a New Cadmium Complex with 6,7-Dicyanodipyridoquinoxalin

The reaction of CdCl2 with 6,7-dicyanodipyridoquinoxaline (DICNQ) by solvothermal reaction gives rise to a coordination polymer [CdCl2(DICNQ)]n 1. Single-crystal X-ray diffraction analysis reveals that the compound in space group Pbcn creates 1-D chloro-bridging chains. Crystal data for 1: a = 6.756(1), b = 35.371(6), c = 7.027(1) , V = 1679.1(5) 3, Z = 4.00, C16H6CdCl2N6, Mr = 465.57, Dc = 1.842 g/cm3, μ = 1.630 mm-1, F(000) = 904, S = 1.005 and T = 293(2) K. The final R = 0.0376 and wR = 0.1029 for 1291 observed reflections with I > 2σ(I), and R = 0.0499 and wR = 0.1125 for all data. The 1-D chloro-bridging chains are parallel-stacked in the a and b directions, and further stabilized through π-stacking interactions, hydrogen-bonding interactions and C≡N···π interactions to generate a 3-D structure. Compound 1 displays intense bluish-green photoluminescence from the intraligand charge-transfer of the DICNQ ligand and the Cl--to-DICNQ charge-transfer mechanism which is probed by the density of states (DOS) calculations.     

Structure Investigation of New Condensation Products of 1,2,3,3-Tetramethylindolenium with Metoxysubstituted Diformylphenols

New spiropyran salts in the row of 1,3,3-trimethylspiro-indoline-2,2'-[2Н]-chromene are prepared and their structures are investigated. Molecular structures of obtained compounds are confirmed by X-ray diffraction and NMR spectroscopy. An open merocyanine isomer is found to be the most stable structure for one of these compounds.