醇对络合物TpRu（PPh3）（CH3CN）H催化氢化二氧化碳生成甲酸的影响

研究了络合物TpRu(PPh3)(CH3CN)H在甲醇溶液中催化氢化CO2生成甲醇的最佳条件，进一步研究了甲醇、乙醇、正丙醇、异丙醇、特丁醇为溶剂时对该络合物催化氢化CO2生成甲酸的影响，提出可能的催化反应机理。     

瑞尼镍催化氢化4-(4-甲氧基苯基)-3-丁烯-2-酮选择性与pH值的关系

4 (4 甲氧基苯基 ) 3 丁烯 2 酮的乙醇溶液在不同的pH值条件下用瑞尼镍催化氢化 ,产物用气相色谱分析 ,研究瑞尼镍的催化选择性与反应介质pH值的关系。实验结果表明 ,在碱性和酸性条件下 ,瑞尼镍的氢化选择性降低 ,在中性条件下 ,瑞尼镍的选择性大于 99%     

添加剂对MoCl3(OC8H17)2-Al(OPhCH3)(i-Bu)2催化丁二烯聚合的影响

研究了3种添加剂对钼系催化丁二烯聚合活性和产物相对分子质量及其分布的影响.结果显示,3种添加剂都能使体系的聚合活性提高;加入方式以Al(OPhCH,3)(i-Bu)2-MoCl3(OC8H17)2-添加剂为好.三者对聚合物的1,2-结构含量均无太大影响.其中α-氯代甲基丙酸酯使产物相对分子质量下降、相对分子质量分布变宽,因此其可在适当范围内用作相对分子质量调节剂.     

Ti对(La2/3Ca1/3)(Mn1-yTiy)O3体系巨磁电阻效应和电特性的影响

通过测量（Ｌａ２／３Ｃａ１／３）（Ｍｎ１－ｈＴｉｙ）Ｏ３体系样品的率－温度关系以及一定温度下磁电阻率与磁场的关系,发现随ｙ的增加其磁电阻率峰和电阻率峰匀向低温位移,磁电阻率峰值增大,并伴生磁电阻率峰展宽效应。     

n(CH3)/n(Si)对甲基硅树脂防水性能的影响

以甲基三乙氧基硅烷和二甲基二乙氧基硅烷或羟基硅油为原料,分别制备了n(CH3)/n(Si)值为1·2、1·4、1·6的甲基硅树脂;考察了n(CH3)/n(Si)值对甲基硅树脂防水性能的影响。结果表明,以甲基三乙氧基硅烷和二甲基二乙氧基硅烷制备的甲基硅树脂,当n(CH3)/n(Si)值为1·2时,具有良好的防水性能;以甲基三乙氧基硅烷和羟基硅油为原料制备的甲基硅树脂,随着n(CH3)/n(Si)值的增大,经其处理的试件的吸水率比减小,与水的接触角增大;综合考虑吸水率比和耐碱性能,n(CH3)/n(Si)值为1·4的硅树脂具有最优的防水性能,并有望具有较持久的防水保护功能。     

磁场对(C4H9NH3)2(CH3NH3)Pb2I7钙钛矿发光特性调控的研究

(C₄H₉NH₃)₂(CH₃NH₃)Pb₂I₇是一种Ruddlesden-Popper相钙钛矿材料,具有层状结构,层间通过van der Waals力结合,因此可以通过机械剥离的方法,获得其二维薄层。二维(C₄H₉NH₃)₂(CH₃NH₃)Pb₂I₇内束缚激子会自发复合从而表现出强的荧光,其圆极化率、峰位均受磁场调控。在外磁场中,荧光圆极化率与磁场呈线性关系,激子中电子和空穴之间的朗德因子差Δg约为0.43。束缚激子在磁场中受抗磁效应影响,致使其发光峰随磁场增加而红移。     

Ru4(μ-CO)(CO)9(η4-μ4-C6H4)(η2-μ1,μ4-PPhCH2CH2PPh2): an unusual pyrolysis product of Ru3(CO)10(dppe) containing a benzyne ligand

The thermal decomposition of Ru₃(CO)₁₀(dppe) in refluxing benzene gives, in contrast to the pyrolysis of the dppm analogue, the tetranuclear cluster Ru₄(μ-CO)(CO)₉(η⁴-μ₄-C₆H₄)(η²-μ₁,μ₄-PCH₂CH₂PPh₂) (1) along with Ru₃(CO)₉(η²-μ₁,μ₂-C₆H₅)(η³-μ₁,μ₂-PPhCH₂CH₂PPh₂) (2). The single-crystal structure analysis of 1 reveals a square-planar tetraruthenium skeleton containing a η⁴-μ₄-benzyne ligand as well as a η²-μ₁,μ₄-phosphinidene–phosphine ligand.     

混合配体配合物[Co3(BTC)2(Lb)2(CH3CH2OH)2·4H2O]n的合成与晶体结构

以1,3,5-均苯三甲酸(H3BTC)、2-[1-(2-吡嗪基)乙缩醛腙(La)、醋酸钴、为原料采用水热法合成了配合物[Co3(BTC)2(Lb)2(CH3CH2OH)2·4H2O]n(1)(Lb=2-乙酰基吡嗪缩水合肼).配合物晶体属单斜晶系,空间群C2/c.X-射线单晶衍射结果表明:两个Co2+离子与氧原子、氮原子...     

配合物[CuL2(ClO4)2]·2CH3CN的晶体结构及表征

以3-乙基-4-对甲氧苯基-5-(2-吡啶基)-1,2,4-三唑为配体合成了配合物[CuL2 (ClO4)2]·2CH3CN,测定了其X-射线单晶结构,并用电子自旋共振谱(ESR)及电子光谱对[CuL2 (ClO4)2]·2CH3CN进行了表征.晶体学数据:P-1空间群,a=0.832 86(11)nm,b=0.912 66(14)nm, c=1.422 5(2)nm, α=100.516(7)°, β=101.067(4)°, γ=98.780(4)°, V=1.023 4(3)nm3, Z=1,s1.163,最终残余因子(I>2σ(I))R1=0.039 1,wR2=0.116 3;对于全部数据R1=0.043 0,wR2=0.120 2.     

Hydrogenation of cis‐1,4‐poly(isoprene) catalyzed by OsHCl(CO)(O2)(PCy3)2

The quantitative hydrogenation of cis‐1,4‐poly(isoprene) (CPIP) provides an easy entry to the alternating copolymer of ethylene–propylene, which is difficult to prepare by conventional polymerization. The homogeneous hydrogenation of CPIP, in the presence of OsHCl(CO)(O₂)(PCy₃)₂ as catalyst, has been studied by monitoring the amount of hydrogen consumed during the reaction. The final degree of olefin conversion measured by computer‐controlled gas uptake apparatus was confirmed by infrared spectroscopy and ¹H nuclear magnetic resonance analysis. Kinetic experiments for CPIP hydrogenation in toluene solvent indicate that the hydrogenation rate is first order with respect to catalyst and carbon–carbon double bond concentration. A second‐order dependence on hydrogen concentration for low values and a zero‐order dependence for higher values of the hydrogen concentration was observed. The apparent activation energy for the hydrogenation of CPIP over the temperature range of 115–140°C was 109.3 kJ/mole. Mechanistic aspects of this catalytic process are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 142–152, 2003     

Hydrogenation of natural rubber in the presence of OsHCL(CO)(O2)(PCY3)2: Kinetics and mechanism

The homogeneous catalyst precursor, OsHCl(CO)(O₂)(PCy₃)₂, was utilized for the hydrogenation of natural rubber to convert the unsaturated structure to a saturated form, providing an alternating ethylene‐propylene copolymer. A detailed kinetic investigation was carried out by monitoring the amount of hydrogen consumption during the reaction using a gas‐uptake apparatus. ¹H NMR spectroscopy was used to determine the final olefin conversion to the hydrogenated product. Kinetic data, collected according to a statistical design framework, defined the influence of catalyst and polymer concentration, hydrogen pressure, and reaction temperature on the catalytic activity. The kinetic results indicated that the hydrogenation rate exhibited a first‐ shifted to zero‐order dependence on hydrogen at lower hydrogen pressure, which then decreased toward an inverse behavior at pressures higher than 41.4 bar. The hydrogenation was also observed to be first‐order with respect to catalyst concentration, and an apparent inverse dependence on rubber concentration was observed due to the impurities in the rubber. The hydrogenation rate was dependent on reaction temperature, and the apparent activation energy over the temperature range of 125–145°C was found to be 122.76 kJ/mol. Mechanistic aspects of the hydrogenation of natural rubber in the presence of OsHCl(CO)(O₂)(PCy₃)₂ were proposed on the basis of the observed kinetic results. The addition of some acids and certain nitrogen containing materials showed an effect on the hydrogenation rate. The thermal properties of hydrogenated natural rubber indicated that the thermal stability increased with increasing % hydrogenation of the rubber. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4499–4514, 2006     

Hydrogenation of cis‐1,4‐polyisoprene catalyzed by Ru(CHCH(Ph))Cl(CO)(PCy3)2

Hydrogenation is a useful method which has been used to improve oxidative and thermal degradation resistance of diene‐based polymers. The quantitative hydrogenation of cis‐1,4‐polyisoprene which leads to an alternating ethylene–propylene copolymer was studied in the present investigation. To examine the influence of key factors on the reaction, such as catalyst concentration, polymer concentration, hydrogen pressure, and temperature, a detailed study of the hydrogenation of cis‐1,4‐polyisoprene catalyzed by the Ru complex, Ru(CH?CH(Ph))Cl(CO)(PCy₃)₂ was carried out by monitoring the amount of hydrogen consumed. Infrared and ¹H‐NMR spectroscopic measurements confirmed the final degree of hydrogenation. The hydrogenation of cis‐1,4‐polyisoprene followed pseudo‐first‐order kinetics in double‐bond concentration up to high conversions of double bond, under all sets of conditions studied. The kinetic results suggested a first‐order behavior with respect to total catalyst concentration as well as with respect to hydrogen pressure. The apparent activation energy for the hydrogenation process, obtained from an Arrhenius plot, was 51.1 kJ mol^?1 over the temperature range of 130 to 180°C. Mechanistic aspects of the catalytic process are discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3259–3273, 2004     

Activated-Carbon-Heterogenized [PdCl2(NH2(CH2)12CH3)2] for the Selective Hydrogenation of 1-Heptyne

The complex [PdCl₂(NH₂(CH₂)₁₂CH₃)₂] has been heterogenized on two different activated carbons and tested as a catalyst for the semihydrogenation of 1-heptyne. The results are compared with those previously reported with the -Al₂O₃-supported complex. An important effect of the support porosity has been found. The location of the complex in the narrow pores induces shape selectivity. The effect of the support in concentrating the substrate close to the active species has been observed. A very active and selective catalyst has been prepared using an essentially microporous carbon.     

Selectivity of the OsHCl(CO)(O2)(PCy3)2 catalyzed hydrogenation of nitrile–butadiene rubber

A new homogeneous catalyst precursor has been discovered for the hydrogenation of carbon–carbon unsaturation resident within acrylonitrile–butadiene copolymers. The hydrido‐phosphine complex OsHCl(CO)(O₂)(PCy₃)₂ (1) selectively and quantitatively saturates olefin, leaving the copolymer's nitrile functionality intact. However, the process suffers from an undesirable crosslinking reaction that is not demonstrated by the established rhodium technology. The extent of this crosslinking is dependent on the process conditions and can be minimized by operating with a low catalyst concentration and high H₂ pressure. Kinetic studies have identified a previously unknown unexpected influence of olefin on the polymer crosslinking process. In light of this new information, the prevailing mechanism for this class of reactions has been reconsidered. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1618–1626, 2001     

Hydrogenation of natural rubber latex in the presence of OsHCl(CO)(O2)(PCy3)2

Hydrogenation is an important method of chemical modification, which improves the physical, chemical, and thermal properties of diene elastomers. Natural rubber latex (NRL) can be quantitatively hydrogenated to provide a strictly alternating ethylene–propylene copolymer using a homogeneous osmium catalyst OsHCl(CO)(O₂)(PCy₃)₂. A detailed kinetic investigation was carried out by monitoring the amount of hydrogen consumption during the reaction using a gas‐uptake apparatus. The kinetic results of NRL hydrogenation indicated that this system had a second‐order dependence of the hydrogenation rate on hydrogen pressure and then decreased toward a zero‐order dependence for hydrogen pressures above 13.8 bar. The hydrogenation was also observed to be first‐order with respect to catalyst concentration and inverse first‐order on rubber concentration due to impurities present in the rubber latex. Additions of a controlled amount of acid demonstrated a beneficial effect on the hydrogenation rate of NRL. The temperature dependence of the hydrogenation rate was investigated and an apparent activation energy (over the range of 120–160°C) was calculated as 57.6 kJ/mol. Mechanistic aspects of this catalytic process are discussed on the basis of kinetic results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 640–655, 2006     

Kinetics of Liquid‐Phase Hydrogenation of Iso‐valeraldehyde to Iso‐amyl Alcohol Over A Ru/Al2O3 Catalyst

The liquid‐phase catalytic hydrogenation of iso‐valeraldehyde to iso‐amyl alcohol was studied in a slurry reactor. The kinetics of liquid‐phase hydrogenation of iso‐valeraldehyde over a 5% Ru/Al₂O₃ catalyst was studied in the range of temperature 373‐393 K and H₂ pressure 0.68‐2.72 MPa using 2‐propanol as the solvent. The selectivity to iso‐amyl alcohol was 100%. The kinetic data were analyzed using a simple power law model. A single site Langmuir‐Hinshelwood type model suggesting dissociative adsorption of hydrogen and surface reaction as the rate‐controlling step provided the best fit of the experimental data. The catalyst could be reused thrice without any loss in activity.     

Hydrogenation of CO2 to formate catalyzed by SBA-15-supported cyclic (alkyl)(amino)carbene-iridium

Recently,cyclic(alkyl)(amino)carbenes(CAACs) have been widely used as ligands to enhance the catalytic reactivity of center metal,but the problem of recycling this expensive ligand remains to be solved.In this work,the heterogeneous SBA-15-CAAC-Ir catalyst was prepared by a covalent attachment method.and using SBA-15 as the carrier.It shows high reactivity for the hydrogenation of CO₂ to formate.After immobilization,the ordered mesoporous structure and the overall rod-like morphology ...     

Stereoselective Alkylations of Enolates Derived from Ligands Attached to the Indenyl Iron Chiral Auxiliary [(η5-C9H7)Fe(CO)(PPh3)]: X-ray Crystal Structure and Conformational Analysis of [(η5-C9H7)Fe(CO)(PPh3)COCH3]

The preparation, X-ray crystal structure, and conformational analysis of the acetyl complex [(η⁵ - C₉H₇)Fe(CO)(PPh₃)COCH₃] ( 5 ) are described. Deprotonation and alkylation of complex 5 generates the corresponding propanoyl ( 6 ) and butanoyl ( 7 ) complexes. Deprotonation and alkylation of complexes 6 and 7 to generate complementary diastereoisomers of the corresponding 2-methylbutanoyl complex occur with high stereoselectivities. The aldol reaction of the diethylaluminium enolate derived from 5 with acetaldehyde also shows a high stereoselectivity (95:5). The reactions of the indenyl complex 5 clearly parallel those for the cyclopentadienyl analogue and this is rationalised in terms of the conformational analysis.     

硅胶固载Ru(Ⅱ)Cl2(PPh3)3催化苯乙酮不对称加氢

通过共价键联的方法将RuCl_2(PPh_3)_3配合物固载于手性二胺修饰的硅胶表面,制备了多相不对称加氢催化剂。采用等离子体发射光谱(ICP)、红外光谱(FTIR)和紫外光谱(UV—Vis)等手段对制备的催化剂进行了表征。结果表明,RuCl_2(PPh_3)_3配合物固载于硅胶表面保持了原有的结构性能。在苯乙酮不对称加氢反应中,不同手性二胺对催化反应具有明显的影响,(1S,2S)-1,2-二苯基乙二胺的手性诱导能力强于其他二胺,优化条件下,苯乙酮转化率达100%,(R)-苯乙醇的对映体过量值达50%,固体催化剂具有良好的稳定性和重复使用性。