主成分回归—催化动力学—掩蔽法同时测定钼和钨

利用掩蔽剂与催化同一指示反应的多种催化剂之间的掩蔽反应速率事程度的差异，提出通过一次动力学过程的测量，同时测定多种催化剂的方法。当掩蔽反应为快速反应或可逆反应时，该方法同样适用。以Ｈ２Ｏ２氧化ＫＩ为指示反应，柠檬酸作为掩蔽剂，借助微机直接记录碘离子选择电极在反应过程中的电位变化，以主成分回归作为建模和预报扔多元校正方法，对Ｍｏ和Ｗ进行了同时测定。     

Electrochemical approaches to the generation of (arylphosphinidene)pentacarbonyltungsten

The possibility of formation of arylphosphinidene complexes with tungsten pentacarbonyl ArP=W(CO)₅ upon the nucleophilic substitution of the chlorine atoms in aryldichlorophosphines ArPCl₂ by the electrochemically generated [W(CO)₅]²⁻ anion is demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1356–1359, June, 2005.     

固相配位化学反应研究：LXVII.金属铜表面M—S（M=Mo,W）簇合物的组成

采用ＦＴＩＲ、ＸＰＳ和ＡＥＳ研究了金属铜表面Ｍ－Ｓ（Ｍ＝Ｍｏ，Ｗ）簇合物膜。结果表明，Ｍｏ（Ｗ）Ｓ＾２－４与铜表面的Ｃｕ２Ｏ反应，形成了Ｍｏ（Ｗ）－Ｓ－Ｃｕ键。簇合物膜由Ｍｏ（Ｗ），Ｓ，Ｃｕ，Ｏ元素组成，分别呈＋６、－２、＋１、－２价，膜为多分子层结构并保持，ＭｏＳ４或ＷＳ２单元，膜表面只有Ｃｕ，Ｏ而不存在Ｍｏ（Ｗ），Ｓ，膜层厚度与反应时间有关，时间越长，膜越厚，膜为多组分的复杂体系，其颜色是各组     

Chemistry of heterometallic phenyl imido and phosphinidene clusters

Triruthenium imido cluster Ru₃(CO)₁₀(₃-NPh)⁽¹⁾ reacts with tungsten hydride LW(CO)₃H to afford heterometallic imido clusters LWRu₂(CO)₈(-H) (₃-NPh), L=Cp, (IIa); L=Cp*, (IIb), whereas the respective phosphinidene complexes LWRu₂(CO)₈(-H)(₃-PPh), L=Cp, (IXa); L=Cp*, (IXb), were generated via reaction of Ru₃(CO)₁₀(-H)(-PPh₂) with CpW(CO)₃H and with CP*W(CO)₃H followed by thermolysis in the presence of carbon monoxide. Their molecular structure, solution dynamics, and the subsequent reaction with hexafluoro-2-butyne are presented.     

Effect of Pt,Pd, and Cs<Superscript>+</Superscript> Additives on the Surface State and Catalytic Activity of WO<Subscript>3</Subscript> in Oxidation of Hydrogen

We have shown that additions of Pt(Pd) and Cs⁺ to WO₃ significantly increase its specific surface area and catalytic activity in H₂ oxidation. After reduction, the promoted specimens contain the phases WO₃, WO_2.9, H_xWO₃; and in the case of Cs⁺ additions, Cs_xWO₃. According to X-ray photoelectron spectroscopy (XPS), the Pt and Pd have an oxidation state close to 0, while tungsten has a +5 oxidation state. The W:O ratio indicates the content of oxygen vacancies in the surface layer. The data are explained taking into account hydrogen spillover from Pt(Pd) to the support.__________Translated from Teoreticheskaya i Eksperimental’naya Khimiya, Vol. 41, No. 2, pp. 126–129, March– April, 2005.     

Determination of subnanomolar concentrations of tungsten (VI) by catalytic adsorption polarography

A new differential pulse polarographic method for the determination of W(VI) using a catalytic adsorption wave is described. W(VI) is first chelated by 7-iodo-8-hydroxyquinoline-5-sulfonic acid at pH 0.5. The complex ion formed is strongly adsorbed on the surface of a dropping mercury electrode. At a potential of –0.95 V versus the Ag/AgCl (3M KCl) reference electrode the adsorbed complex is reduced by the polarographic current and oxidized very fast by hydrated hydrogen ions providing the oxidized form of the complex ion for repeated redox cycles. As the redox process taking place in the electric double layer, the diffusion of the complex does not limit the polarographic current. Therefore, high currents occur, and consequently, a very high sensitivity is obtained. The practical detection limit (PDL) is 3.7 ng W/kg solution corresponding to 2 × 10^–11 M. The standard deviation of single values is 1.2 ng/kg at the concentration of 91 ng/kg lying in the middle of the linear part of the calibration curve. Because Mo (VI) gives a very similar catalytic adsorption wave, serious mutual interferences occur in the analysis of mixtures of both species. An effective separation of Mo(VI) was worked out. Using 1% (w/v) solution of trioctylphosphinoxide in kerosene, Mo(VI) can almost completely be extracted from 1.8M HCl with a threefold extraction resulting in a separation factor of 40000.     

Synthesis, Crystal Structures and Characterization of Ba5LiTiNb9O30

A new niobate compound with the chemical composition of Ba5LiTiNb9O30 was synthesized by doping Li^ into the system BaO-TiO2-Nb2O5 in conventional solid state reaction method. The crystalline structure was determined by X-ray diffraction analysis (XRD). The results showed that crystal structure of Ba5LiTiNb9O30 belongs to tetragonal tungsten bronze structure with space group P4bm and its unit cell parameters: a=b=1.2512(2) nm, c=0.4008(5)nm. The microstructure of reaction products was observed by scanning electron microscopy (SEM).     

Interactions with ATP, DNA Cleavage and Anti-tumor Activities of Complexes with Anions [Mo（V）O2（O2CeH4）2]^3-, [Mo（Ⅴ）0.5W（Ⅵ）0.5O2（O2C6H4）2]^2.5- and [W（Ⅵ）O2（O2C6H4）2]^2-

(NH3CH2CH2NH2)3[Mo(Ⅴ)O2(O2C6H4)2] (1), (NH3CH2CH2NH2)2.5[Mo(Ⅴ)o.sW(Ⅵ)o.502(O2C6H4)2] (2) and(NH3CH2CH2NH2)2[VC(Ⅵ)O2(O2C6H4)2] (3) were synthesized, structurally characterized by X-ray diffraction analysis, and studied on their interactions with ATP, their DNA cleavage activities and antitumor properties. The redox state of molybdenum was not changed on going from crystal to aqueous solutions in complexes 1 and 2, while tungsten underwent reduction from W(VI) to W(V) in complexes 2 and 3. ATP promoted the oxidation of both molybdenum and tungsten from M(Ⅴ) to M(Ⅵ) and the hydrolysis of catecholate ligands in solution consisting of ATP and the complexes. Complex 1 possesses fairly good activity to DNA cleavage and against tumor S180 in mice, and is more effective than the control drug cyclophosphamide under the identical conditions. However, complexes 2 and 3 exhibited marginal effectiveness. The effectiveness of anti-tumor of the complexes was related positively to their DNA cleavage activities and their hydrolysis of catecholate ligands.     

Preparation and multicolor electrochromic performance of a WO3/tris(2,2'-bipyridine)ruthenium(II)/polymer hybrid film

A tungsten trioxide (WO(3))/tris(2,2'-bipyridine)ruthenium(II) ([Ru(bpy)(3)](2+); bpy=2,2'-bipyridine)/poly(sodium 4-styrenesulfonate) (PSS) hybrid film was prepared by electrodeposition from a colloidal triad solution containing peroxotungstic acid (PTA), [Ru(bpy)(3)](2+), and PSS. A binary solution of [Ru(bpy)(3)](2+) and PTA (30 vol % ethanol in water) gradually gave an orange precipitate, possibly caused by the electrostatic interaction between the cationic [Ru(bpy)(3)](2+) and the anionic PTA. The addition of PSS to the binary PTA/[Ru(bpy)(3)](2+) solution remarkably suppressed this precipitation and caused a stable, colloidal triad solution to form. The spectrophotometric measurements and lifetime analyses of the photoluminescence from the excited [Ru(bpy)(3)](2+) ion in the colloidal triad solution suggested that the [Ru(bpy)(3)](2+) ion is partially shielded from electrostatic interaction with anionic PTA by the anionic PSS polymer chain. The formation of the colloidal triad made the ternary [Ru(bpy)(3)](2+)/PTA/PSS solution much more redox active. Consequently, the rate of electrodeposition of WO(3) from PTA increased appreciably by the formation of the colloidal triad, and fast electrodeposition is required for the unique preparation of this hybrid film. The absorption spectrum of the [Ru(bpy)(3)](2+) ion in the film was close to its spectrum in water, but the photoexcited state of the [Ru(bpy)(3)](2+) ion was found to be quenched completely by the presence of WO(3) in the hybrid film. The cyclic voltammogram (CV) of the hybrid film suggested that the [Ru(bpy)(3)](2+) ion performs as it is adsorbed onto WO(3) during the electrochemical oxidation. An ohmic contact between the [Ru(bpy)(3)](2+) ion and the WO(3) surface could allow the electrochemical reaction of adsorbed [Ru(bpy)(3)](2+). The composition of the hybrid film, analyzed by electron probe microanalysis (EPMA), suggested that the positive charge of the [Ru(bpy)(3)](2+) ion could be neutralized by partially reduced WO(3)(-) ions, in addition to Cl(-) and PSS units, based on the charge balance in the film. The electrostatic interaction between the WO(3)(-) ion and the [Ru(bpy)(3)](2+) ion might be responsible for forming the electron transfer channel that causes the complete quenching of the photoexcited [Ru(bpy)(3)](2+) ion, as well as the formation of the ohmic contact between the [Ru(bpy)(3)](2+) ion and WO(3). A multicolor electrochromic performance of the WO(3)/[Ru(bpy)(3)](2+)/PSS hybrid film was observed, in which transmittances at 459 and 800 nm could be changed, either individually or at once, by the selection of a potential switch. Fast responses, of within a few seconds, to these potential switches were exhibited by the electrochromic hybrid film.