分子筛笼内金属羰基簇合物的热稳定性研究

本实验采用戊马比妥钠诱发豚鼠和家兔急性心力衰竭模型，观察了舒心丸的治疗作用。结果表明，舒心丸ｉｖ能明显升高心衰豚鼠的心脏收缩幅度和心衰家兔的Ｂｐ，ＬＶＰ，ＬＶ±ｄｐ／ｄｔ和ＣＯ。其作用与哇巴因相似。     

NaY超笼内[Pt3(CO)3(μ-CO)3]^2-n(n=3,4)簇合物的合成,表征及其催化CO+NO的反应性能

在ＮａＹ分子筛超笼内合成了桔黄色的［Ｐｔ９（ＣＯ）１６］＾２－和深绿色的［Ｐｔ１２（ＣＯ）２４］＾２－簇合物。前者给出２０５６和１７９８ｃｍ＾－１的线式和桥式羰基特征红外谱带；后者给出２０８０和１８２４ｃｍ＾－１谱带。与在ＴＨＦ溶液中结果相比，ＮａＹ内合成的羰基簇合物的线式ｖｃｏ向高波数位移，而桥式ｖｃｏ向低波数位移。ＥＸＡＦＳ为Ｐｔ羰基簇合物在分子筛内的规整形成提供了证据。ＮａＹ内Ｐｔ９和Ｐｔ１     

NaY超笼内[Pt_3(CO)_3(μ_2-CO)_2]_n~(2-)(n=3,4)簇合物的合成、表征及其催化CO+NO的反应性能

在NaY分子筛超笼内合成了桔黄色的[Pt_9(CO)_(18)]~(2-)和深绿色的[Pt_(12)(CO)_(24)]~(2-)簇合物。前者给出2056和1798cm~(-1)的线式和桥式羰基特征红外谱带;后者给出2080和1824cm~(-1)谱带。与在THF溶液中结果相比,NaY内合成的羰基簇合物的线式v_(CO)向高波数位移,而桥式v_(CO)向低波数位移。EXAFS为Pt羰基簇合物在分子筛内的规整形成提供了证据。NaY内Pt_9和Pt_(12)羰基簇合物在NO+CO反应中显示了较高的催化活性及稳定性。     

分子筛笼内铂羰基簇合物在CO＋NO反应中的催化研究

研究了ＮａＹ分子筛超笼内包容的Ｐｔ羰基簇合物催化剂在ＣＯ＋ＮＯ反应中的催化性能。「Ｐｔ１２（ＣＯ）２４」＾２－／ＮａＹ和「Ｐｔ９（ＣＯ）１３」＾２－／ＮａＹ在此反应中表现出比较高的活性。Ｎ２Ｏ被认为是ＣＯ＋ＮＯ反应的中间产物，同时笼内羰基簇合物还表现了比ＳｉＯ２负载的簇合物好的热稳定性，动力学研究表明，在「Ｐｔ１２（ＣＯ）２４」＾２－／ＮａＹ上，ＮＯ被还原和Ｎ２Ｏ生成的反应级数，相对于ＣＯ分压为小     

由分子筛笼内铂羰基簇合物得到的催化剂的分散度研究

由分子筛笼内包容的铂羰基簇合物[Pt_(12)(CO)_(24)]~(2-)/NaY和[Pt_9(CO)_(18)]~(2-)/NaY经还原得到的样品Pt_(12)/NaY和Pi_9/NaY的分散度用EXAFS和化学吸附进行了表征．对Pt_(12)/NaY和Pi_9/NaY，EXAFS分析分别给出R_(Pt－Pt)＝0.274 nm，配位数C.N.＝0.42和R_(Pt－Pt)＝0.274 nm配位数C.N.＝3.8，而化学吸附结果分别为H/Pt＝1.26，CO/Pt＝0.69和H/Pt＝1.24，CO/Pt＝0.64．与浸渍法制备的Pt/Al_2O_3相比小得多的Pt－Pt配位数及大的化学吸附值说明，由分子筛笼内铂羰基簇合物出发，我们得到了高分散的Pt/NaY催化剂．由于还原后原子堆积形式的变化，Pt_(12)/NaY和Pt_9/NaY的再还原羰基化不能可逆地得到与前驱体相同的铂羰基簇合物．     

四核钴羰基簇合物的合成和晶体结构

用Co₂(CO)₈与有机杂环二硫代次膦酸盐SP(C₆H₄OR)(S)N(C₆H₅)NC(Me)(R=Me,Et)反应,得到两类4个含S,P桥基配体的四核钴羰基簇合物Co₄(CO)₁₀(μ₄-S)[μ₄-P(C₆H₄OR)](1:R=Me;3:R=Et)和Co₄(CO)₁₀(μ₃-S)[μ₂-P(C₆H₄OR)N(C₆H₅)NC(Me)](2:R=Me,4:R=Et).在反应中,前配体中的PS键以及C-S,P-S,P-N键劈开,产生的分子片与金属钴原子配位,组建成新的羰基钴簇.对这4个簇合物进行了元素分析,IR,¹HNMR和MS谱学表征,并测定了簇合物4的晶体结构,该晶体属单斜晶系,P2₁/c空间群,晶胞参数a=1.9065(4)nm,b=1.0081(2)nm,c=1.6663(3)nm,β=97.36(3)°,V=3.1704(11)nm₃,Z=4,D_c=1.743g/cm³.Co1Co3Co4呈三角形分布,其中Co-Co平均键长为0.251nm,而Co₂在该三角平面的一侧,Co2-Co3键为0.269nm.该簇合物分子骨架为三角钉型结构,每个Co原子的立体几何均为变形八面体,但配位环境各不相同.     

一种新型结构的七核钴原子羰基簇合物的合成与结构研究

C₂H₅SPCl₂与Co₂(CO)₈反应的产物经柱层析分离得3条带,第一条为深棕色,经IR谱、¹HNMR、谱、元素分析、X光单晶结构分析,确定该带产物为七核钴原子簇CO₇(μ₇-S)(μ₄-PSC₂H₅)(μ-SC₂H₅)₂(μ-CO)₂(CO)₁₂,是八面体骨架Co₄PS和四面体骨架Co₃S结合的松散原子簇合物。     

含硫磷桥基的两核铁羰基簇合物的合成和晶体结构

Fe3(CO)12与杂环二硫代次膦酸盐SP(C6H4OR)(S)N(C6H5)NC(Me)(R=Me,Et)反应,得到两个新的含硫磷桥基的双核铁羰基簇合物Fe2(CO)6[μ-η2-SC(Me)NN(C6H5)P(C6H4OMe)](Ⅰ)和Fe2(CO)6[μ-η2-SC(Me)NN(C6H5)P(C6H4OEt)](Ⅱ),以及簇合物Fe3(CO)9(μ3-S)2(已知).对它们进行了元素分析,IR,1HNMR和MS等谱学表征,并用X-ray衍射技术测定了(Ⅰ)的晶体结构.该晶体属单斜晶系,P2(1)/n空间群,晶胞参数a=11.192(2)A,b=14.272(3)A,c=16.281(3)A,β=108.22(3).,V=2470.2(8)A3,Z=4.两核簇合物中含有两个桥基Fe-S-Fe和Fe-P-Fe,而且-C(7)-N(2)-N(1)-链连结在S、P原子间,形成了两个六员螯环Fe(1)SCNNP和Fe(2)PNNCS,增强了簇合物的稳定性.     

High-Yield Synthesis of New Ni–Ru Carbido–Carbonyl Clusters

Four new bimetallic Ni–Ru mixed-metal carbido–carbonyl clusters of a general formula [NiRu₅C(CO)₁₄ L₂], where L₂ = dppe (2), dppp (5), (PPh₃)₂ (8) and (PBu₃)₂ (13) were synthesised following the general synthetic strategy using penta- and hexaruthenium carbido carbonyl dianions in the reactions with corresponding dichloro complexes of Ni(II). The molecular and crystal structures of 2, 5, 7, 8, and 13 were determined by single crystal X-ray analysis. The mixed-metal core is octahedral with the P atoms coordinating to the Ru atoms.     

正二十面体Au13和Pt13团簇上肉桂醛的吸附

运用广义梯度近似(GGA)密度泛函理论的Perdew-Burke-Ernzerh (PBE)方法, 研究了肉桂醛在正二十面体Au₁₃和Pt₁₃团簇上的吸附行为. 通过分析不同吸附模式的吸附能和几何构型发现: 同一金属团簇, 顺式肉桂醛的吸附能强于反式肉桂醛的吸附能. 对于Au₁₃团簇, 肉桂醛的稳定吸附构型为C＝C和C＝O共吸附模型; 对于Pt₁₃团簇, 肉桂醛的稳定吸附构型为C＝O吸附. 比较二者发现, 肉桂醛在Pt₁₃团簇的吸附能力强于Au₁₃团簇.分析Au₁₃和Pt₁₃团簇上肉桂醛最稳定吸附构型的电子结构表明, 电子由肉桂醛原子的2s、2p轨道向金属表面转移, 同时金属部分电子反馈到肉桂醛的反键轨道, 最终肉桂醛稳定吸附于金属团簇. 此外, 肉桂醛在团簇模型上的吸附能大于其在平板模型上的吸附能.     

Modeling the Adsorption of CO on Small Pt,Fe and Co Clusters for the Fischer–Tropsch Synthesis

The adsorption of CO on Fe, Pt and Co clusters was modeled by the DFT approach using the B3LYP and the BPW91 functionals together with the LANL2DZ and the 6-31G(d) basis set. These calculations show that although CO adsorbs more strongly on Pt than on either Fe or Co, the dissociation energy on Fe and on Co is lower than the corresponding dissociation energy on Pt. Therefore, the activation energy for dissociation is not determined by the adsorption energy. Additionaly, the CO bond distances also do not show any correlation to the adsorption energy.     

CO oxidation over supported Pt clusters at different CO coverage

CO adsorption and oxidation over supported Pt₁₄ with different CO coverage on TiO₂(110) surface were investigated using density functional theory (DFT) calculations and thermodynamic analysis. According to the phase diagram, Pt₁₄/TiO₂(110) and 11CO@Pt₁₄/TiO₂(110) were chosen to represent the low and high CO coverage of Pt clusters, respectively. Our study shows that the high coverage of CO can induce the structural change of supported Pt clusters and weaken the interaction between Pt clusters and TiO₂ support. The CO adsorption and oxidation mechanism depends on the CO coverage, which is determined by the experimental reactant composition, pressure, and temperature. At low CO coverage, the dissociated oxygen is active specie to form CO₂ by reacting with CO. At high coverage, the molecular oxygen can directly react with CO via the formation of OOCO intermediate. Our proposed mechanisms provide useful information for understanding the CO oxidation over Pt clusters with different CO coverage. © 2016 Wiley Periodicals, Inc.     

Reactions of Bis(Trifluoromethyl)Phosphine and Tetrakis(Trifluoromethyl)Phosphine with Ruthenium Carbonyl Clusters

Abstract

The reaction of (CF₃)₂P-P(CF₃)₂ with [Ru₃(CO)₁₂] yielded compounds : [Ru₁₄(CO)₁₃{μ-P(CF₃)₂)₂] (1), [Ru₄(CO)₁₄{μ-P(CF₃)₂}₂] (2), and [Ru₄(CO)₁₁{μ-P(CF₃)₂}₄] (3); reaction with [μ-H)₄Ru₄(CO)₁₂] yielded (1) and [(μ-H)₃Ru₄(CO)₁₂{μ-P(CF₃)₂}] (4). The reaction of (CF₃)₂PH with [Ru₃(CO)₁₂] yielded compounds (1) and (4) and compounds (1) and (2) using cluster : ligand ratios of 1:1 and 1:2 respectively. All the compounds have been characterised by X-ray crystallography; a schematic diagram of their structures is shown in Figure 1. The fluxional behaviour of the hydrides in (4) was studied using variable temperature ¹H NMR spectroscopy (see Figure 2). The result of this study was used in the assignment of hydride positions of (4) in the solid state.     

Kinetics and catalysis by NaY entrapped Pt carbonyl clusters in the CO+NO reaction

[Pt₁₂(CO)₂₄]^2–/NaY and [Pt₉(CO)₁₈]^2–/NaY exhibited much higher activities in the CO+NO reaction at 473 K compared with Pt/Al₂O₃. Kinetic study andin-situ FTIR results suggest that NO adsorption is the rate-limiting step in the CO+NO reaction on intrazeolite Pt carbonyl clusters.     

一种简单的提高Pt/C电极电催化活性的处理方法

一种简单的提高Pt/C电极电催化活性的处理方法;直接甲醇燃料电池;Pt;乙醇;CO;丙酮;四氢呋喃