含R_2dtc配体Mo-Cu化合物的动态~(95)Mo NMR

本实验利用动态~(95)Mo NMR监测Mo-Cu系列化合物的形成过程,对反应CuCl+NaR_2dtc+MoO_nS,摩尔比3:3:1,溶剂为DMF;R=Et,n=0(Ⅰ);R=Me,n=0(Ⅱ);R=Et,n=2(Ⅲ)进行了研究,观察到具有不同簇骼的多种中间产物的存在及随反应进程相互转化等现象。     

TA on Mo(W)/Cu(Ag)/S clusters derived with [Cp*MS3]- Kinetics of [PPh4]2[Cp*WS3(CuBr)3]2 and [PPh4]2[Cp*MoS3(CuBr)3]2

Thermal analysis on two new heterometallic sulfide clusters, [PPh4]2[WS3(CuBr)3]2 and [PPh4]2[MoS3(CuBr)3]2 (where PPh4=tetraphenyl phosphonium, =pentamethylcyclopenta- dienyl), was carried out using a simultaneous TG-DTA unit in an atmosphere of flowing nitrogen and at various heating rates. Supplemented using EDS method, their thermal behavior and properties, together with the composition of their intermediate product, were examined and discussed in connection with their distinctive molecular structure as a dianion, which provided some theoretically and practically significant information. Both clusters decomposed in a two-step mode, but without a stable new phase composed of Mo/W-Cu-S formed during their decomposition process as we expected. Based on TG-DTG data, four methods, i.e. Achar-Brindley-Sharp, Coats-Redfern, Kissinger and Flynn- Wall-Ozawa equation, were used to calculate the non-isothermal kinetic parameters and to determine the most probable mechanisms. This revised version was published online in July 2006 with corrections to the Cover Date.     

Trigonal-planare CuX3-Gruppen in Cu2Mo6X14, X = Cl,Br, I

Trigonal Planar CuX₃-Groups in Cu₂Mo₆X₁₄, X = Cl, Br, I Cu₂Mo₆Cl₁₄ (I), Cu₂Mo₆Br₁₄ (II) and Cu₂Mo₆I₁₄ (III) were synthesized by thermal treatment of corresponding mixtures of copper(I) and molybdenum(II) halides. The crystal structures were determined by single crystal X-ray analyses. I and II show isotypism, cubic, Pn3 (no. 201, sec. setting), Z = 4, I: a = 12.772(3) Å, II: a = 13.350(2) Å. III shows a new structural type, orthorhombic, Pbca (No. 61), Z = 4, a = 16.058(3) Å, b = 10.643(2) Å, c = 16.963(3) Å. Trigonal planar CuX₃ units were found in I? III. Structural behaviour relations are discussed, especially with regard to ionic conductivity.     

系列Mo-Cu(Ag,Au)-Se簇合物的95Mo和31P NMR研究

报道了含硬币金属和四硒代钼酸盐的异金属硒簇合物的⁹⁵Mo NMR研究结果和含膦配体Mo(W)-Cu(Ag,Au)-Se配合物的³¹P NMR谱学性能。发现不同硬币金属对⁹⁵Mo核的化学屏蔽效应顺序为Au > Cu > Ag;对系列Mo-Cu-Se化合物的⁹⁵Mo NMR研究结果表明:⁹⁵Mo NMR的化学位移和线宽不仅与配位的Cu原子数目有关,而且对结构的变化特别敏感;[MoSe₄]^2-离子的相对四个方向被Cu⁺配位后,其Mo核的屏蔽基本饱和;外围配体对⁹⁵Mo NMR数据影响甚微。同时还用动态⁹⁵Mo NMR谱技术跟踪配体的取代反应和从MoCu₄到MoCu₁₀核的簇骼转变过程。此外,还讨论了这些化合物在不同构型之间,同一构型不同金属中心和不同配体基团的³¹P NMR化学位移的变化特征。     

超高比表面炭载钼煤气甲烷化催化剂

以沥青中间相为原料，氢氧化钾直接活化，获得了比表面达２３６３ｍ￣２／ｇ的超高比表面炭分子筛（ＣＭＳ）。分别以ＣＭＳ、ＳｉＯ＿２、活性炭和θ－Ａｌ＿２Ｏ＿３为担体，制备了负载钼催化剂，并研究其加压甲烷化反应性能，发现活性依下面顺序增加：θ－Ａｌ＿２Ｏ＿３＜ＳｉＯ＿２＜活性炭（ＡＣ）＜ＣＭＳ。还分别以钼酸铵和磷钼酸（ＨＰＭｏ）为前驱体，制备了ＣＭＳ负载钼催化剂，并考察了其煤气甲烷化活性，发现不同的催化剂前驱体对催化剂反应活性影响很大。根据产物中ＣＨ＿４／ＣＯ＿２的变化，推测ＣＯ在钼催化剂上的甲烷化反应包括如下两个步骤：（１）３Ｈ＿２＋ＣＯ→ＣＨ＿４＋Ｈ＿２Ｏ，（２）ＣＯ＋Ｈ＿２Ｏ→ＣＯ＿２＋Ｈ＿２。     

直流磁控溅射厚度对Cu(Inx,Ga1-x)Se2背接触Mo薄膜性能的影响

采用直流磁控溅射工艺, 在一定条件下通过控制溅射时间, 在钠钙玻璃上制备了不同厚度的用于Cu(In_x, Ga_1-x)Se₂薄膜太阳电池背接触材料的Mo薄膜, 并利用X射线衍射 (XRD)、场发射扫描电子显微镜 (SEM)、四探针测试仪、台阶仪研究了厚度对溅射时间、薄膜微结构、电学性能及力学性能的交互影响. Mo薄膜的厚度与溅射时间呈线性递增关系; 随厚度的增大, Mo薄膜 (110) 和 (211) 面峰强均逐渐增大, 择优生长从(110)方向逐渐向 (211)方向转变, 方块电阻值只随 (110) 方向上的生长而急剧减小直到一特定值约2 Ω/⇑, 电导率随薄膜的 (110) 择优取向程度的降低而线性减小直到一特定值约0.96×10^-4 Ω·cm; Mo薄膜内部是一种多孔的长形簇状颗粒和颗粒间隙交织的结构, 并处于拉应力态, 其内部应变随薄膜厚度的增大而减小. 关键词： Mo薄膜 CIGS背接触 厚度 微结构     

Ni-Mo四近邻作用能对Ni75Al14Mo11合金沉淀行为影响的微观相场

基于微观扩散方程,采用微观离散格点相场法研究Ni-Mo原子间四近邻相互作用能对Ni75Al14Mo11合金沉淀过程微观机制的影响。通过原子尺度的结构演化图、表征浓度和有序度的成分序参数和长程序参数分析沉淀相的有序化、簇聚、镍原子反向析出及粗化行为等。研究结果表明:最近邻、第三近邻原子间作用能增大,可促进沉淀相的簇聚及有序化,但抑制后期镍基原子团簇的反向析出及粗化;次近邻、第四近邻原子间作用能增大的影响则与之相反;在相同条件下,外层作用能对沉淀相的有序化和簇聚影响最大。     

H4SiW6Mo6O40／SiO2在H2O2催化氧化环己酮合成己二酸中的应用

采用溶胶一凝胶法制备了二氧化硅负载硅钨钼酸催化剂．以二氧化硅负载硅钨钼酸（H4SiW6M06040／SiO2）为催化剂,30％H202为氧源,催化氧化环己酮合成己二酸．探讨H4SiW6Mo6O40／SiO2对氧化反应的催化活性,较系统地研究了二氧化硅负载硅钨钼酸用量、反应温度、H。02用量、反应时间等因素对产物收率的影响．实验表明：H4SiW6Mo6O40／SiO2是合成己二酸的良好催化剂;在n（环日酮）：n（H2O2）：n（H4SiW6Mo6O40／SiO2）=100：198：0．124,反应温度为110℃,反应时间3．5h的最佳条件下,己二酸的收率可达86．7％．     

Abnormal positive thermal expansion in Mo substituted ZrW2O8

ZrW₂O₈ displays the unusual property of an isotropic bulk contraction in volume as a function of temperature. We report here on the positive thermal expansion (PTE) property caused by substituting Mo for W sites in ZrW₂O₈ at room temperature. The room temperature crystal structure of ZrW_2−xMo_xO₈ compounds, which were synthesized using a low temperature route, could be divided into ordered phase with α-ZrW₂O₈ structure (0≤x≤0.5) and disordered phase with β-ZrW₂O₈ (0.5<x≤1.5) and c-ZrMo₂O₈ structure (1.5<x≤2). ZrW_2−xMo_xO₈ adopting β-ZrW₂O₈ structure shows abnormal PTE property at room temperature due to the existence of water molecules, while ZrW_2−xMo_xO₈ adopting the other two structures (α-ZrW₂O₈ and c-ZrMo₂O₈) shows negative thermal expansion (NTE) property from room temperature until decomposition for α-ZrW₂O₈ structure or trigonal phase transition for c-ZrMo₂O₈ structure. The reason lies in the fact that the oxygen migration caused by the Mo substitution leads to the re-arrangement of W(Mo)O₄ tetrahedra lying along the 3-fold axis, only particular W/Mo ratio (0.5<x≤1.5) produces a special crystal structure, which allows the entrance of water molecules.     

Ni-Mo氧化物超细粒子催化剂的制备与表征

以柠檬酸为络合剂,采用溶胶凝胶法制备NiMoO4超细粒子催化剂.使用DTA、BET比表面测定、XRD和LRS等表征手段考察了热处理条件和焙烧温度对粒子结构的影响.结果表明,在氩气气氛中于210℃分解干凝胶中的柠檬酸,可以避免柠檬酸分解时燃烧大量放热而引起超细微粒的烧结,脱除柠檬酸后的超细粉末为NiMoO4.经400℃以上的高温处理后,微粒明显晶化.