β—型过渡元素三取代钨锗杂多配合物的合成,表征和催化活性

报道Ａ－β－Ｍ＇ｘＨｙ－［ＧｅＷＯＭ３（Ｈ２Ｏ）３Ｏ３７］．ｎＨ２Ｏ（Ｍ＝Ｃｒ＾３＾＋，Ｃｏ＾２＾＋，Ｎｉ＾２＾＋，Ｃｕ＾２＾＋；Ｍ＇＝Ｂｕ４Ｎ＾＋，Ｋ＾＋）的立体有择合成法制备及红外和远红外光谱，紫外和可见光谱和循环伏安，磁化率和磁矩，ＸＰＳ，ＥＳＲ以及催化活性等研究结果。     

咪唑类配体与双过氧钒配合物相互作用的NMR研究

为探讨咪唑环上取代基团对反应平衡的影响, 在模拟生理条件(0.15 mol·L-1 NaCl溶液)下, 应用多核(1H、13C和51V)、扩散排序谱(DOSY)以及变温NMR等谱学技术研究双过氧钒配合物NH4[OV(O2)2{2-(2’-Pyri-dine)-Imidazole}]·4H2O(简写为bpV(Imi-Py))和咪唑类配体(咪唑、2-甲基鄄咪唑、4-甲基-咪唑和组氨酸)的相互作用, 其从强到弱的顺序为咪唑≈4-甲基-咪唑>2-甲基-咪唑>组氨酸. 研究结果表明, 咪唑环上取代基团空间位阻对反应平衡产生较大影响,同时竞争配位的结果导致新的6 配位过氧物种[OV(O2)2L]-(L 为咪唑类配体)的生成, 当配体为4-甲基-咪唑和组氨酸时, 生成的则是一对异构体.     

钨砷杂多阴离子[KAs4W40O140(M·H2O)2]n-中配位水的取代反应

本文报道了[KAs_4W_(40)O_(140)(M·H_2O_2]~(n-)杂多阴离子中配位水的取代反应.在水溶液中,许多配体,如[Fe(CN)_6]~(4-)、[Fe(CN)_6]~(3-),SO_3~(2-)等都能取代配位水形成具有特征颜色的配离子.在水溶液中不能发生的配体取代配位水的反应,在非极性有机溶剂中却容易发生,这与配位水分子在非极性有机溶剂中易脱去形成配位不饱和态有关.     

Synthesis, Crystal Structure, UV-vis and EPR Studies of（ NH3CH2CH2NH2 ） 2.5 [ Mo0.5^（V）W0.5^（VI）O2 （ OC6H4O ） 2]

Cis-dioxo-metal complex ( NH3CH2CH2NH2 ) 2.5 [ Mo0.5^(V)W0.5^(VI)O2 ( OC6H4O ) 2] 1 was obtained by the reaction of tetra-butyl ammonium hexamolybdotungstate with 1, 2-dihydroxybenzene in the mixed solvent of CH3OH, CH3CN and ethylenediamine,and characterized by X-ray diffraction, UV-vis and EPR analysis. Compared with its analogous complexes (NH3CH2CH2NH2)3[Mo^(V)O2(OC6H40)2] 2 and (NH3CH2CH2NH2)2[W^(VI)O2(OC6H4O)2] 3, the results show that tungsten(VI) is less active in redox than molybdenum (VI) and that the change of the valence induced by substitution of W(VI) for Mo(V) in EMO2(OC6H40)2]n- does not influence the coordination geometry of the complex anion in which the metal center exhibits distorted octahedral coordination with cis-dioxo catechol. The responses to EPR of complexes 1 and 2 are active but complex 3 is silent,and the UV-vis spectra exhibited by the three complexes are obvious different because of the different electronic configuration between the central Mo(V) and W(VI) ions in the complexes.It is noteworthy that complexes 1 and 2 have the similar EPR signal to flavoenzyme, suggesting that the three complexes have the same coordination geometry feature with the co-factor of flavoenzyme.     

有机钼,钨化合物研究I.FISCHER型卡宾络合物的合成和性质

我们合成了六个新的钼、钨季铵盐[(CO)5MC(O)R]N(CH3)4和钨的卡宾络合物,并研究了它们的某些性质。经元素分析、IR和1H NMR的鉴定,确证了它们的结构。由这些络合物组成的催化体系,其中某些能使单取代乙炔聚合,有的还能使双取代己炔聚合。     

CrOx/ SBA-15介孔催化剂上丙烷在二氧化碳气氛中脱氢反应的研究

The structure and catalytic properties based on Chromium Oxide supported on mesoporous SBA-15 for oxidative dehydrogenation of propane by CO₂ have been studied by using X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and propane pulsing experiments in the absence of gas-phase O₂. It has been shown that propane conversion and propene yield increase with Cr loadings. The propane conversion and propene yield on CrO_x(Cr: 10wt%)/SBA-15 catalyst for oxidative dehydrogenation of propane by CO₂ at 550 ℃ reach 24.8% and 21.8%, respectively .The results of ESR, UV-Vis DRS and propane pulsing experiments indicate that Cr^Ⅲ in the CrO_x/ SBA-15 catalyst is the main active species in oxidative dehydrogenation of propane by CO₂ and Cr^Ⅵ, Cr^Ⅴ is inactive in dehydrogenation.     

低初始振动激发van der Waals分子HeI_2振动预离解三维含时波包动力学研究

用含时黄金规则波包法,计算了低初始振动激发HeI_2分子振动预离解总和分衰变宽度,寿命和速率及它们随初始振动态υ的变化.计算结果与实验外推数据符合得相当好.计算所需很短的波包总传播时间(不超过1ps)是由离解碎片在振动去激发绝热势能面(υ-1)上驻留时间决定的.较强的终态相互作用的影响是很重要的.预言并解释了终转动态分布随着υ的移动而改变的动力学规律.     

高效液相色谱-电感耦合等离子体质谱法同时测定化妆品中5种含溴防腐剂

建立了同时测定化妆品中苯扎溴铵、2-溴-2-硝基-1,3-丙二醇、5-溴-5-硝基-1,3-二■烷、甲基二溴戊二腈、溴氯芬5种含溴防腐剂的高效液相色谱-电感耦合等离子体质谱法(HPLC-ICP-MS)。样品经含0.1%甲酸的甲醇溶液超声提取后,采用Agilent Eclipse-C_(18)(150 mm×4.6 mm,5μm)色谱柱分离,以0.1%甲酸-甲醇为流动相进行梯度洗脱,ICP-MS测定组分中的~(79)Br,以保留时间定性,外标法定量。5种含溴防腐剂均在0.5～100 mg/L范围内线性关系良好(r0.999),检出限为1.5～3.0μg/g,不同基质化妆品中的回收率为91.2%～108%,相对标准偏差(n=6)为1.3%～4.2%。该方法快速、准确、灵敏、专属性强,适用于化妆品中5种含溴防腐剂的定性定量分析。     

稀土钨青铜K0.71Nd0.028WO3的制备及其电性能

Tetragonal tungsten bronze K_0.71Nd_0.028WO₃ was synthesized by rare earth co-permeation method using Keggin type POMs of α-K₁₀[SiCu₃(OH₂)W₉O₃₇]·6H₂O (abbreviated as SiW₉Cu₃) as precursor. XRD, XPS, XRF, TG-DTA were used to characterize the resulting material. The XPS results indicate that Nd has permeated and diffused into the body of the sample and exists in tungsten bronze in the form of K_0.71Nd_0.028WO₃. The results of TG-DTA show that K_0.71Nd_0.028WO₃ begins to decompose at 320 ℃. The consequence of DC four-probe shows that the conductivity of the sample permeated by rare earth is 10³ times higher than that of the sample only permeated by methanol at room temperature. The conductivity of the sample only permeated by methanol is only 10^-3 S·cm^-1 but the conductivity of the sample permeated by rare earth is 1.65 S·cm^-1.     

温和条件下新型铜基磷酸盐在氧化反应中的高催化活性

系统综述了以新型铜基磷酸盐(Cu2(OH)PO4)为代表的催化剂在一些典型的氧化反应中的活性.本文涉及的反应类型主要包括以过氧化氢为氧化剂,苯、苯酚、2,3,6-三甲基苯酚的羟化,烯烃的环氧化反应和以氧气为氧化剂,烯烃和醇的氧化反应,结果显示Cu2(OH)PO4的比表面积较小,但是在这一系列的反应中展示了很高的催化活性.同时利用电子自旋共振(ESR)、红外(IR)等表征手段对催化反应的机理和反应路径进行了讨论,羟基自由基和铜的过氧物种被认为是催化反应的重要中间体.