CaO-SiO2-Al2O3-MgO-TiOx-FeOy体系氧化动力学

用电动势和化学分析方法研究了富钛还原熔渣－ＣａＯ－ＳｉＯ２－Ａｌ２Ｏ３－ＭｇＯ－ＴｉＯ２－ＦｅＯｙ体系的氧化动力学,得出了氧在熔渣中的扩散速率常数分别为０．６６＊１０＾－５ｍ．ｓ＾－１和１．９８＊１０＾－５ｍ．ｓ＾－１,研究表明：固体电解质构成的氧浓差电池法得出的结果不仅可靠,且方法快速,简便。     

CH（B~2Σ~－）和卤代甲烷、CS_2、O_2及Ar碰撞过程动力学研究

用四倍频ＹＡＧ激光（２６６ｎｍ）光解ＣＨＢｒ_３产生ＣＨ（Ｂ~２Σ~－）自由基，通过测量自发辐射ＣＨ（Ｂ→Ｘ）的时间分辨信号测得室温下ＣＨ（Ｂ）被卤代甲烷、ＣＳ_２、Ｏ_２及Ａｒ的猝灭速率常数（×１０~（－１０）ｃｍ~３·ｍｏｌｅｃ~（－１）·ｓ~（－１））分别为４．４±０．７（ＣＨ_２Ｃｌ_２）、５．２±０．４（ＣＨＣｌ_３）、５．０±０．７（ＣＣｌ_４）、８．２±０．３（ＣＨＢｒ_３）、７．９±０．７（ＣＳ_２）、０．１９±０．０２（Ｏ_２）及（１．１±０．１）×１０~（－２）（Ａｒ）．结果表明，除Ｏ_２外，其它猝灭剂对ＣＨ（Ｂ）的猝灭速率常数均大于对ＣＨ（Ａ）的。对卤代甲烷分子，猝灭速率常数显示了因Ｃｌ原子数增加而增加的趋势。     

用卡尔曼滤波-分光光度法测定无机铬的形态

利用Ｋａｌｍａｎ滤波技术和二溴苯基荧光酮－溴化十六烷基三甲基铵－Ｃ_２Ｈ_５ＯＨ分光光度测定体系,同时对Ｃｒ（Ⅲ）和Ｃｒ（Ⅳ）进行测定。Ｃｒ（Ⅲ）的表观摩尔吸光系数为１．９６ × １０~５ Ｌ· ｍｏｌ~（－１）·ｃｍ~（－１）,线性范围为０～ ４．０ ｘ１０－６ｍｏｌ／Ｌ;Ｃｒ（Ⅵ）的表观摩尔吸光系数为４．１６ ×１０~５Ｌ· ｍｏｌ~（－１）· ｃｍ~（－１）,线性范围为０～５．２×１０~（－１）ｍｏｌ／Ｌ。     

磷钼杂多酸-L-半胱氨酸自组装超分子膜电极对亚硝酸根电催化还原的研究

制备了磷钼杂多酸－Ｌ－半胱氨酸自组装超分子膜电极（Ｐ２Ｍｏ１８－Ｌ－Ｃｙｓ／Ａｕ）。采用水平衰减全反射（ＡＴＲ－ＦＴＩＲ）光谱表征了膜的组成。研究了该膜电极的电化学性质，发现它在１．０ ｍｏｌ／Ｌ　Ｈ２ＳＯ４溶液中，于０．０～０．７Ｖ（ｖｓ．ＳＣＥ）间ＣＶ扫描出现两对稳定、可逆的氧化还原峰，其中峰电位分别为Ｅｍ１＝０．３３４ Ｖ，Ｅｍ２＝０．１８８Ｖ，对应着Ｐ２Ｍｏ１８Ｏ_(６２)~(６－)的两步２电子－２质子反应；计时库仑法计算了薄膜内的电子传递系数Ｄ为５．０１ × １０~（－８）ｃｍ２·ｓ～（－１）。该膜电极对酸性溶液中的ＮＯ_２~－有明显的电催化还原作用，初步探讨了电催化机理。用差分脉冲伏安法（ＤＰＶ）测定其还原峰电流与ＮＯ_２~－的浓度在２．０ ×１０~（－６）～２．０ × １０~（－４）ｍｏｌ／Ｌ范围内呈良好的线性关系，相关系数为０．９９５３，检测限５．０×１０~（－７）ｍｏｌ／Ｌ。该电极用于模拟水样中ＮＯ_２~－的测定，结果满意。     

H2O2-四丁基溴化铵-醋酸盐体系中肉桂酸的吸附平行催化波研究

在醋酸盐（ＰＨ＝４．０）－四丁基溴化铵（Ｂｕ_４Ｎ·Ｂｒ）－Ｈ_２Ｏ_２缓冲溶液中，用线性扫描示波极谱法、循环伏安法和数字模拟法等方法研究了肉桂酸（Ｃ_６Ｈ_５－ＣＨ＝ＣＨ—ＣＯＯＨ）的 吸附平行催化波产生机理．结果表明，肉桂酸的还原机理为 ＥＣ_ｄｉｍＥ’过程，即内桂酸的Ｃ＝Ｃ双键首先发生ｌｅ，１Ｈ~＋还原（Ｅ）产生一个中间体自由基Ｃ_６Ｈ_５－Ｃ·Ｈ－ＣＨ_２－ＣＯＯＨ，随后该自由基在以ｌｅ，１Ｈ~＋方式进一步还原（Ｅ’）的同时伴随着该自由基间的二聚化反应（Ｃ_ｄｉｍ）．由于Ｂｕ_４Ｎ~＋质点的诱导吸附作用，肉桂酸的极谱电流增加，峰电位正移．Ｈ_２Ｏ_２氧化肉桂酸还原中间体自由基使原Ｃ＝Ｃ双键再生（Ｃ’），同时阻止了该自由基的进一步还原和二聚化反应，产生了平行催化波．该催化波的产生机理为ＥＣ＇过程．Ｈ_２Ｏ_２氧化肉桂酸自由基的表观速率常数Ｋ_ｆ为 １．３５ ×１０~２ｍｏｌ· Ｌ~(－１)· ｓ(－１)．提出了一种有机化合物极谱催 化波的新类型──由表面活性剂和氧化剂双增敏的吸附平行催化波．     

Na_6V_（10）O_（28）·12H_2O的合成与结构

合成并测定了十钒酸盐Ｎａ_６Ｖ_（１０）Ｏ_（２８）·１２Ｈ_２Ｏ的单晶结构。晶体属单斜晶系，Ｐ２_１／ｎ群空间，ａ＝１２．０１９（２），ｂ＝１７．１５４（２），ｃ＝１８．１７８（６），β＝１０６．２９（２）°，Ｖ＝３５７９（１），Ｍ_ｒ＝１２８７．５，Ｆ（０００）＝２５６０，μ＝２５，４４ｃｍ￣（－１），Ｚ＝４，Ｄ_ｃ＝２．３８ｇ·ｃｍ（－３）。结构由重原子法解出，全矩阵最小二乘法修正至Ｒ＝０．０６４，Ｒ_ｗ＝０．０８３。Ｖ_（１０）簇阴离子可以看成由１０个ＶＯ_６变形八面体形成，其中氧原子有４种类型：端氧、二桥氧、三桥氧和六桥氧。结果表明，阳离子相同但结晶水的数目不同时，十钒酸盐的晶系和空间群不同。     

Cu（sahm）_2·4H_2O的合成及晶体结构

标题化合物Ｃｕ（ｓａｈｍ）_２·４Ｈ_２Ｏ，Ｃ_（２２）Ｈ_（３０）Ｎ_８Ｏ_（１０），Ｍ_ｒ＝６２９．５（ｓａｈｍ＝４－（邻羟基苯基亚甲基）－亚胺－３．５－二羟甲基－１，２，４－三唑）被合成并得到单晶。Ｘ－衍射结构分析表明，晶体属单斜晶系，空间群Ｐ２_１／ｃ，晶体学数据：ａ＝８．３１８９（８）Ａ，ｂ＝９．８２７（１）Ａ，ｃ＝１６．１２６（２）Ａ，β＝１０２．５８５（９）°，Ｖ＝１２８６．６（３）Ａ~３，Ｚ＝２，Ｄ_ｘ＝１．４８ｇ／ｃｍ~３，μ＝０．９０７ｍｍ（－１），Ｆ（０００）＝５９８。最终偏离因子Ｒ＝０．０４２，Ｒ_ｗ＝０．０５７。结构分析表明，分子中两个偶氮甲碱的Ｎ原子及两个酚氧原子与中心Ｃｕ原子配位，形成规则的菱形平面结构。     

过氧多酸研究──Ⅱ．K_（12）H_2［W（OH）_5（H_2O）（VO（O_2）2－OH－VO（O_2）_2）_5］·2H_2O的合成及表征

过氧多酸研究──Ⅱ．Ｋ_（１２）Ｈ_２［Ｗ（ＯＨ）_５（Ｈ_２Ｏ）（ＶＯ（Ｏ_２）２－ＯＨ－ＶＯ（Ｏ_２）_２）_５］·２Ｈ_２Ｏ的合成及表征张权，岳斌，朱思三，金松林，谢高阳（复旦大学化学系，上海２００４３３）关键词白钨酸，过氧化氢，μ－氧·二［二过氧根·?..     

流动注射-光度法测定超氧阴离子自由基(O-·2)与超氧化物歧化酶(SOD)活性的研究

合成了４种硫代碳酰腙类化合物双水杨醛硫代碳酰腙（ＢＳＴＺ）、双对羟基苯甲醛硫代碳酰腙（ＢＨＢＴＺ）、双香兰素硫代碳酰腙（ＢＭＨＢＴＺ）和双邻香兰素硫代碳酰腙（ＢＭＳＴＺ）,其中苯环醛基对位具有羟基的ＢＨＢＴＺ和ＢＭＨＢＴＺ能与超氧阴离子自由基（Ｏ－·２）、Ｈ２Ｏ２发生显色反应,而且ＢＭＨＢＴＺ与Ｏ－·２的反应灵敏度为最高,由此建立了流动注射－光度法测定超氧阴离子自由基（Ｏ－·２）的方法．此方法的线性范围为４．５×１０－７～１．５×１０－６ｍｏｌ／Ｌ,线性方程为Ａ６９８＝１．８×１０４ｃ（Ｏ－·２）＋０．００４５,相关系数ｒ＝０．９９８４,检出限为１．０×１０－７ｍｏｌ／Ｌ．相对标准偏差为５．２３％．大多数生物样品中共存物质无干扰     

用8－氨基喹啉高选择性分光光度法测定痕量锇的研究

研究了用８－氨基喹啉在ｐＨ３．６２的ＨＡｃ－ＮａＡｃ缓冲溶液中测定痕量Ｏｓ（Ⅳ）的分光光度法。常见的非贵金属和贵金属离子不干扰测定，并且选择性较好。Ｏｓ（Ⅳ）与８－氨基喹啉的组成比为１：３，表观摩尔吸光系数ε_（６００）＝１．３×１０~５Ｌ／ｍｏｌ·ｃｍ。在０～１０μｇ／１０ｍＬ范围内符合比耳定律。合成样品分析结果良好。     

Selective reductive cleavage of 2-(phenylthio)pyrimidines for efficient synthesis of 2-(H)pyrimidines

A reaction method is described for selective reductive cleavage of 2-(phenylthio)pyrimidines using Pd(OAc)₂ and Et₃SiH to produce 2-(H)pyrimidines. The reaction proceeds efficiently with a wide range of 2-(phenylthio)pyrimidines. Considering the ready availability of 2-(arylthio)pyrimidines derived from oxidative CS cross coupling of 3,4-dihydropyrimidin-1H-2-thiones (DHPMs), this method unambiguously provides a shortcut to the preparation of 2-(H)pyrimidines with unprecedented diversity.     

Solid Phase Extraction and Spectrophotometric Determination of Silver with 2-(2-Quinolylazo)-5-diethylaminoaniline as Chromogenic Reagent

 A new chromogenic reagent, 2-(2-quinolylazo)-5-diethylaminoaniline(QADEAA), was synthesized. A highly sensitive, selective and rapid method for the determination of silver was developed. It is based on the rapid reaction of silver (I) with QADEAA and the solid phase extraction of colored chelate using reversed-phase separation cartridge. At pH 6.5 in the presence of sodium dodecyl sulfonate (SDS), QADEAA reacts with silver to form a violet chelate in a molar ratio of 1:2 (silver to QADEAA). This chelate was enriched by solid phase extraction. The retained chelate can be eluted from the cartridge with ethanol. In ethanol medium, the molar absorptivity of the chelate is 1.36×10⁵ L·mol⁻¹·cm⁻¹ at 590 nm. Beer’s law is obeyed in the range 0.01–0.6 μg L⁻¹. The relative standard deviation for eleven replicate samples of 0.01 μg L⁻¹ level is 1.9%. The detection limit reaches the 0.02 μg L⁻¹ level. This method shows satisfactory results when used for the determination of silver in water. Correspondence: Department of Chemistry, Yuxi Teacher’s College, Yuxi, 653100, P.R. China. e-mail: hugiufena@163.com Received 19 August 2002; accepted 20 October 2002     

Determination of Lead Using a New Chromogenic Reagent 2-(2-Sulfo-4-acetylphenylazo)-7-(2,4,6-trichlorophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic Acid

A novel chromogenic reagent, 2-(2-sulfo-4-acetylphenylazo)-7-(2,4,6-trichlorophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid 1, was prepared by diazo coupling of 4-acetylaniline-2-sulfonic acid and 2,4,6-trichloroaniline to chromotropic acid through –N=N– groups. Based on this reagent, a simple, sensitive and selective spectrophotometric method was developed for the determination of lead. In 0.20M phosphoric acid medium, lead reacts with 1 to form a 1:2 blue complex with an absorption maximum of 654nm. Beers law is obeyed in the range of 0–0.6mgL^–1 of lead. The apparent molar absorptivity is 1.25×10⁵Lmol^–1cm^–1. The detection limit and quantification limit were found to be 0.63µgL^–1 and 2.1µgL^–1, respectively. The relative standard deviation for eleven replicate measurements was of 2.6%. The interference of foreign ions was also investigated. All the other foreign ions studied did not interfere with lead determination except for Ca(II) and Ba(II). The interference caused by Ca(II) and Ba(II) can be eliminated by prior extraction of lead with potassium iodide-methylisobutylketone (KI-MIBK). The proposed method was applied to the determination of lead in certified samples with satisfactory results.     

Nano-SiO2 catalyzed three-component preparations of pyrano[2,3-d]pyrimidines, 4H-chromenes,and dihydropyrano[3,2-c]chromenes

An efficient one-pot three-component procedure has been developed for the preparation of tetrahydrobenzo[b]pyrans, dihydropyrano[3,2-c]chromenes, and pyrano[2,3-d]pyrimidines using nano-SiO₂ as catalyst in H₂O at 70 °C. This methodology has a number of advantages such as: use of reusable catalyst, easy access, short reaction times, high yields, easy work up and use of non-toxic and green solvent.     

Interface-controlled synthesis of CeO2(111) and CeO2(100) and their structural transition on Pt(111)

Ceria-based catalytic materials are known for their crystal-face-dependent catalytic properties. To obtain a molecular-level understanding of their surface chemistry, controlled synthesis of ceria with well-defined surface structures is required. We have thus studied the growth of CeO_x nanostructures (NSs) and thin films on Pt(111). The strong metal-oxide interaction has often been invoked to explain catalytic processes over the Pt/CeO_x catalysts. However, the Pt-CeO_x interaction has not been understood at the atomic level. We show here that the interfacial interaction between Pt and ceria could indeed affect the surface structures of ceria, which could subsequently determine their catalytic chemistry. While ceria on Pt(111) typically exposes the CeO₂(111) surface, we found that the structures of ceria layers with a thickness of three layers or less are highly dynamic and dependent on the annealing temperatures, owing to the electronic interaction between Pt and CeO_x. A two-step kinetically limited growth procedure was used to prepare the ceria film that fully covers the Pt(111) substrate. For a ceria film of ~3–4 monolayer (ML) thickness on Pt(111), annealing in ultrahigh vacuum (UHV) at 1000 K results in a surface of CeO₂ (100), stabilized by a c-Ce₂O₃(100) buffer layer. Further oxidation at 900 K transforms the surface of the CeO₂(100) thin film into a hexagonal CeO₂(111) surface.     

Simultaneous determination of vanadium, niobium and tantalum by high-performance liquid chromatography equipped with on-line enrichment using 2-[2-(5-bromoquinolinylazo)]-5-diethylaminophenol as pre-column derivatization reagent

The chelator 2-[2-(5-bromoquinolinylazo)]-5-diethylaminophenol (5-Br-QADEAP) was synthesized. A method was developed for the simultaneous determination of vanadium, niobium and tantalum as metal–5-Br-QADEAP chelates using rapid column high performance liquid chromatography along with an on-line enrichment technique. Vanadium, niobium and tantalum were pre-column derivatized with 5-Br-QADEAP to form colored chelates. The chelates were separated on a 4.6 × 10 mm, 1.8 μm rapid analytical column with acetonitrile–water (50:50, v/v) containing pH 4.5 phosphate buffer and 0.01 mol L⁻¹ of citrate as the mobile phase. The chelates were separated completely within 2.5 min. The detection limits (S/N = 3) of vanadium, niobium and tantalum are 1.6, 1.6, and 1.8 ng L⁻¹, respectively. This method was applied to the determination of vanadium, niobium and tantalum in alloy steel, water, and geologic samples with good results.     

Investigation of 2-[2-(4-Methoxy-phenylamino)-vinyl]-1,3,3-trimethyl-3H-indolium Chloride as a New Reagent for the Determination of Chromium(VI)

 The complex formation and extraction of chromium(VI) with 2-[2-(4-methoxy-phenylamino)-vinyl]-1,3,3-trimethyl-3H-indolium chloride reagent was studied by means of spectrophotometry. The influence of medium acidity, the concentration of chloride ions and dye reagent, the nature of the extractant and some other factors (time of extraction, stability of color, interference, etc.) on the absorbance of colored extracts were studied. The optimum conditions were found to be 0.02–0.1 M H₂SO₄, 1.0–1.5 M NaCl, (2.0–2.5) × 10⁻⁴ M of reagent. The absorbance of the colored extracts obeys Beer’s Law in the range of 0.26–7.28 mg L⁻¹. The procedure of Cr(VI) extraction and spectrophotometric determination was examined. Author for correspondence. E-mail: andruch@kosice.upjs.sk Received November 19, 2002; accepted March 10, 2003 Published online June 13, 2003     

Infinite Three-Dimensional Coordination Polymers: Synthesis and Structures of [Cd (4,4'-bpy)2 (H2O)2]n (pic)2n, [Zn (4,4'-bpy)2 (H2O)2 ]n-(pic)2n (H2O)2n, and [Zn (4,4'-bpy)2 (H2O)2]n (4,4'-bpy)n (H2O)n (pic)2n

Recently, a new research realm in crystal engineering of supramolecular architecturesassembled by means of coordinate covalent bonding', hydrogen bonding', or other weakintermolecular interactions= has been rapidly expanding in order to rationally developnew classes of functional materials with cavities or pores. These types of compoundsmay exhibit interesting topological structures and the clathrations of the cavity structuresmay have many potential properties such as catalysis', electrical co…     

Ni nanoparticles as electron-transfer mediators and NiSx as interfacial active sites for coordinative enhancement of H2-evolution performance of TiO2

The development of efficient photocatalytic H₂-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H₂ production. In addition to the well-known noble metals, low-cost and earth-abundant non-noble metals can also act as electron-transfer mediators to modify photocatalysts. However, as almost all non-noble metals lack the interfacial catalytic active sites required for the H₂-evolution reaction, the enhancement of the photocatalytic performance is limited. Therefore, the development of new interfacial active sites on metal-modified photocatalysts is of considerable importance. In this study, to enhance the photocatalytic evolution of H₂ by Ni-modified TiO₂, the formation of NiS_x as interfacial active sites was promoted on the surface of Ni nanoparticles. Specifically, the co-modified TiO₂/Ni-NiS_x photocatalysts were prepared via a two-step process involving the photoinduced deposition of Ni on the TiO₂ surface and the subsequent formation of NiS_x on the Ni surface by a hydrothermal reaction method. It was found that the TiO₂/Ni-NiS_x photocatalysts exhibited enhanced photocatalytic H₂-evolution activity. In particular, TiO₂/Ni-NiS_x(30%) showed the highest photocatalytic rate (223.74 μmol h^?1), which was greater than those of TiO₂, TiO₂/Ni, and TiO₂/NiS_x by factors of 22.2, 8.0, and 2.2, respectively. The improved H₂-evolution performance of TiO₂/Ni-NiS_x could be attributed to the excellent synergistic effect of Ni and NiS_x, where Ni nanoparticles function as effective mediators to transfer electrons from the TiO₂ surface and NiS_x serves as interfacial active sites to capture H⁺ ions from solution and promote the interfacial H₂-evolution reaction. The synergistic effect of the non-noble metal cocatalyst and the interfacial active sites may provide new insights for the design of highly efficient photocatalytic materials.     

Synthesis of （S）-2-（3-Arylacrylamido）-3-{4-[2-（5-methyl-2-phenyloxazol-4-yl）ethoxy]phenyl}propanoic Acids

The synthesis of （S）-2-（3-arylacrylamido）-3-{4-[2-（5-methyl-2-phenyloxazol-4-yl）etho- xy]phenyl}propanoic acids is described. Their structures were confirmed by ^1H-NMR.