生物模板法制备金属氧化物及其催化应用研究进展

自然环境中长期进化形成的多层次、多维和多尺度天然硬模板结构和一些具有多层次多维结构的天然“软”生物分子可为多级结构纳米材料的设计与制备提供了新的思路。金属氧化物通常作为催化剂的重要组成部分,其制备与催化应用得到广泛关注,生物模板法为金属氧化物的制备提供了一条简单、绿色、有效的合成路线。本文从基于生物模板的制备方法、生物模板在氧化物制备过程中的作用和生物模板在金属氧化物催化应用时的作用方面总结近十年来的研究进展。基于硬模板的制备方法简单高效,可完美地复制结构类似的金属氧化物材料,而软模板能够灵活地调控金属氧化物颗粒的尺寸和分散性。基于生物模板制备金属氧化物的过程往往经历“吸附-成核-生长-组装”多步骤,生物模板起着表面吸附、空间限域、导向等重要作用。就所得金属氧化物的催化应用而言,生物模板法的优势在于能够实现氧化物材料元素的自掺杂、有效改善传质以及特殊的表面结构赋予催化剂优异的催化性能。     

多核金属配合物合成及其催化性能研究进展

综述了不同类型多核金属配合物的合成及其催化性能等方面的研究进展。主要从双核、三核及多核金属配合物等方面进行展开。又根据金属种类的不同,分为同核或杂核金属配合物。多核金属配合物在均相催化与材料化学等研究领域表现出优越的性能,为合成不同类型的多核金属配合物及其催化性能研究提供参考。     

多核金属配合物合成及其催化性能研究进展

综述了不同类型多核金属配合物的合成及其催化性能等方面的研究进展。主要从双核、三核及多核金属配合物等方面进行展开。又根据金属种类的不同,分为同核或杂核金属配合物。多核金属配合物在均相催化与材料化学等研究领域表现出优越的性能,为合成不同类型的多核金属配合物及其催化性能研究提供参考。     

异羟肟酸过渡金属络合物在乙苯氧化中的催化性能研究

研究了 N-苯甲酰 -N-苯基羟胺 ( BPHA)类过渡金属络合物在乙苯均相氧化中的催化行为 ,考察了络合物催化剂中心金属离子、配体结构以及添加助剂对络合物催化性能的影响 ,并找到了催化剂、助剂的最佳使用浓度及氧化反应的最适宜温度。结果表明 ,中心金属离子的电子结构对络合物催化性能影响最大 ,其活性顺序为 :Cu( BPHA) 2 >Co( BPHA) 2 >Fe( BPHA) 2>Mn( BPHA) 2 >Ni( BPHA) 2 ,配体结构对催化性能有一定影响 ,配体的芳环上有吸电子基团时 ,催化剂分解氢过氧化物的能力增加 ,主要分解产物为苯乙酮。添加轴配体对氧化反应及催化剂的选择性有较大影响 ,其中含端羟基的非环冠醚类及大环冠醚对氢过氧化物的生成和分解都有加速作用 ,含氮助剂吡啶对氧化反应有抑制作用     

Polystyrene-supported thiosemicarbazone–transition metal complexes: synthesis and application as heterogeneous catalysts

Functionalized polymers are found to be highly efficient in immobilizing transition metal ions. Crosslinked polystyrene supported Schiff's base complexes of metal ions such as Fe(III), Co(II), Ni(II) and Cu(II) are very effective as heterogeneous catalysts. The catalytic activity of these metal complexes has been studied in the decomposition of H₂O₂ and in the epoxidation of cyclohexene and styrene. The reactions show a first order dependence on the concentration of both the substrates and the catalyst. The influence of the degree of crosslinking of the polymer support on the rate of reactions has been studied. The metal complexes show low catalytic activity at low crosslink density (2% and 5%) but 10% crosslinked resins show higher activity. A possible mechanism for the reactions is suggested. © 1999 Society of Chemical Industry     

过渡金属化合物催化合成环氧增塑剂研究进展

从过渡金属元素化合物的元素种类、催化剂类型、反应条件以及反应机理等方面综述了过渡金属化合物催化剂催化制备环氧增塑剂的研究进展。文中提出了催化过程中存在的问题,并对未来的研究方向进行展望。     

过渡金属化合物催化合成环氧增塑剂研究进展

从过渡金属元素化合物的元素种类、催化剂类型、反应条件以及反应机理等方面综述了过渡金属化合物催化剂催化制备环氧增塑剂的研究进展。文中提出了催化过程中存在的问题,并对未来的研究方向进行展望。     

Chemical modification of preceramic polymers: Their reactions with transition metal complexes and transition metal powders

Conclusions This research has demonstrated that a variety of chemistries can be carried out with preceramic polymers that in general are characterized by the presence of an abundance of reactive functional groups. Such chemistries can serve to upgrade a given preceramic polymer by catalytic or stoichiometric processes; they can be used to from new and useful hybrid polymers from the original preceramic polymer, as shown in the present work and also in some of our previously published work; they can, by their pyrolysis in the presence of metal powders, act as chemical reagents that deliver the elements of interest for reaction with the metal to give useful ceramics. Thus the preparation of a preceramic polymer is not the end of the chemistry in the monomer-to-polymer-to-ceramic conversion, but rather it presents many possibilities for further chemistry.     

过渡金属Pd在吲哚及其衍生物合成中的应用

吲哚及其衍生物是一类非常重要的杂环类精细化工中间体。由于Pd催化剂的突出的优越性能,如反应条件温和、活性高、选择性好,在合成吲哚及其衍生物时获得了广泛应用。综述了近几年来的应用发展情况。     

磺胺间甲氧嘧啶过渡金属配合物的制备及其表征

以磺胺间甲氧嘧啶原药为原料合成了Co(Ⅱ),Cd(Ⅱ),Cu(Ⅱ),Mn(Ⅱ),Ag(Ⅰ)的配合物。并通过红外光谱,紫外光谱和元素分析对产物的结构进行了表征。实验中发现磺胺间甲氧嘧啶与Cd(Ⅱ),Cu(Ⅱ)的成键模式相同,而Mn(Ⅱ)与Co(Ⅱ)相同。     

Noble metal nanoparticles supported on MOF nanorods and their catalytic applications

Journal of Porous Materials - Metal nanoparticles (MNPs)/metal–organic frameworks (MOFs) composites have become a research hotspot because the cooperation between MNPs and MOF can effectively...     

电有机合成3,5-二溴水杨醛缩丝氨酸过渡金属配合物的研究

研究了3,5-二溴水杨醛缩丝氨酸过渡金属配合物的绿色电化学合成工艺。以3,5-二溴水杨醛及丝氨酸为原料,无水乙醇为溶剂,合成3,5-二溴水杨醛缩丝氨酸席夫碱。以席夫碱为原料,分别以金属铜、镍、锌片等为阳极,铂片为阴极,乙腈为溶剂,季铵盐为电解质,通入直流电电解,获得了3,5-二溴水杨醛缩丝氨酸席夫碱铜(Ⅱ)、镍(Ⅱ)、锌(Ⅱ)配合物,同时利用正交实验优化了配合物电化学合成工艺条件。利用红外光谱、紫外光谱、热分析等手段对过渡金属配合物进行结构表征,结果表明达到了预期的合成目的。     

Palladium(II) complexes bearing the new pincer ligand 3,5-bis(indazol-2-ylmethyl)toluene; synthesis and catalytic properties

The reaction of 3,5-bis(bromomethyl)toluene with 1H-indazole in toluene, in the presence of triethylamine, yields the ligand 3,5-bis(indazol-2-ylmethyl)toluene (1). Compound 1 reacts with Pd(OAc)₂ in refluxing acetic acid, followed by a metathetic reaction with lithium chloride and with [PdCl₂(cod)] (cod = 1,5-cyclooctadiene) in refluxing acetonitrile to give the complexes [PdCl{3,5-bis(indazol-2-ylmethyl)tolyl-N,C,N}] (2) and [PdCl₂{3,5-bis(indazol-2-ylmethyl)toluene-N,N}] (3), respectively. Compounds 1–3 were characterized by elemental analyses, mass spectra and IR and NMR (¹H, ¹³C) spectroscopies. The molecular structure of 1 was also determined by single-crystal X-ray diffraction. The palladium(II) complexes (2,3) were tested as catalysts in ethylene polymerization and in C–C coupling reactions involving aryl halides substrates.     

Syntheses of group 4 transition metal complexes bearing 2-pyridinethiolate ligands and their catalytic activities for ethylene polymerization

Titanium bis(2-pyridinethiolate) complexes, Ti(6-R-SPy)₂(NMe₂)₂ (6-R-SPy = 6-R-2-pyridinethiolate, 3a: R = H; 3b: R = Me; 3c: R = Ph; 3d: R = C₆H₄-4-Me; 3e: R = C₆H₄-4-t-Bu; 3f: R = C₆H₃-3,5-Me₂), and the titanium bis(2-pyridinolate) complexes, Ti(6-Ph-OPy)₂(NMe₂)₂ (6-Ph-OPy = 6-phenyl-2-pyridinolate, 8) were prepared by treating Ti(NMe₂)₄ with 2 equiv. of 6-R-2-pyridinethiol or 6-Ph-2-pyridinol. The cis-configuration of the diamido moieties in the pseudo octahedral geometry was elucidated by X-ray crystallography for 3a. Reaction of M(NMe₂)₄ (M = Ti, Zr) with 4 equiv. of 2-pyridinethiol cleanly gave tetrakis(pyridinethiolate) complexes, M(6-H-SPy)₄·THF (6: M = Ti; 7: M = Zr). The triangular dodecahedral geometries of 6 and 7 were also revealed by X-ray crystallography. These complexes catalyzed ethylene polymerization upon activation with MAO (methylaluminoxane) or MMAO (modified MAO). The catalytic activities of titanium bis(6-aryl-pyridinethiolate) systems were found to be remarkably higher than that of titanium bis(6-methyl-pyridinethiolate) system. Among the complexes synthesized in this study, Ti[6-(C₆H₃-3,5-Me₂)-SPy]₂(NMe₂)₂ (3f)/MMAO showed the highest activity (1200 kg/Ti-mol h atm) for ethylene polymerization at 60 °C under atmospheric pressure. In contrast, the activity of the corresponding 6-aryl-pyridinolate system 8/MMAO was rather low (9.3 kg/Ti-mol h atm). Both the N-S chelating structure and the bulky aryl substituents are essential for the high activities of the 6-aryl-pyridinethiolate complexes.     

过渡金属氧化物催化氧化甲醛的研究进展

归纳分析了单一金属氧化物、复合金属氧化物、负载贵金属、添加碱金属以及MOFs型的过渡金属氧化物催化剂在甲醛氧化方面的研究进展,指出各类过渡金属氧化物催化剂的优点与不足。对各类过渡金属氧化物催化剂的特点进行总结并展望其未来的发展方向。     

Interaction of polyaniline and transition metal salts: formation of macromolecular complexes

Summary Conditions for complex formation of some transition metal salts and emeraldine base of polyaniline were investigated, and the obtained macromolecular complexes have been characterized by the UV-Vis-IR spectroscopy. It was found that complex formation conditions are dependent on both the cation and anion of the inorganic salt used, as well as on the solvent environment. In some cases, formation of the complex occurred in the form of a precipitate directly in the solution. In other cases, no precipitate was observed in the solution, however, the complex was recognized during film casting from the polyaniline – inorganic salt solution. Electronic absorption spectra for both precipitates and films for the majority of samples possessed features characteristic of the protonated, emeraldine salt form of the polymer. However, IR absorption spectra were different from the protonated polyaniline form. Based on the obtained data, the model of the macromolecular polyaniline – transition metal salt complex is proposed. Received 15 October 2002 / Accepted 5 February 2003 Correspondence to O.P. Dimitriev     

Ruthenium (II) complexes immobilized on swellable polyacrylate matrices: Synthesis and catalytic applications

RuH₂(PPh₃)₄ has been immobilized on swellable polyacrylate matrices to provide heterogenized carboxylate-derivatives. These swellable polymer supported ruthenium (II) complex catalysts have been used in the transfer hydrogenation of aldehydes. Hydrogen donors are formate salt, cyclohexanol, and benzyl alcohol. The catalysts exhibit good activity for hydrogen transfer reduction of aldehydes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008