双(11-钨锆)镧系元素三元杂多酸钾的合成及表征

本文报道了双（１１－钨锆）镧系元素三元杂多酸钾的合成，并通过ＩＲ，ＵＶ，ＴＧ－ＤＴＡ等物理方法及化学分析，离子交换，摩尔光度实验，电导滴定实验等进行了表征。     

11-钨钛合过渡金属杂多酸钾的合成与性质

11-系列不饱和杂多阴离子可作为配体与过渡金属或希土离子生成混合型杂多阴离子。由于这种无机高分子配合物对某些有机合成反应具有催化活性及抗病毒性能,新型化合物的合成仍吸引着人们的关注。11-钨钛杂多阴离子除与希土离子生成K_(13)[Ln(TiW_(11)O_(39))_2]·xH_2O型化合物外,也可与过渡金属离子生成混合型杂多阴离子。本文报道了K_n[TiW_(11)M(H_2O)O_(39)]·xH_2O(M=Mn~(2+)、Cu~(2+)、Zn~(2+)、Fe~(3+),Co~(3+)和Cr~(3+))型杂多酸盐的合成与性质。     

十一钨锆杂多配合物位置异构体的合成表征及催化性能

过渡元素取代的杂多配合物由于其独特的催化活性和抗病毒性受到人们的重视 ,由于缺位 β位的介稳定性和异构化 ,给合成带来了一定的困难。我们发现 ,某些单取代金属衍生物中 β异构体具有良好的催化活性[1 ,2 ] 。本文报道了通式为α ,βi K6[SiW1 1 ZrO40 ]·XH2 O( βi=β1 ,β2 ,β3)的四种异构体 (简记作α ,β SiW1 1 Zr)的合成、表征及四种异构体对烯烃环氧化反应的催化活性 ,为研究Zr杂多化合物的应用提供选择。1　实验部分1 1　仪器与试剂日本岛津IR 40 8红外光谱仪 (KBr压片 ) ,美国PE公司产λ 35型紫外分光光谱仪 ;384B…     

过渡金属钨硅杂多酸盐合成及酸性研究

钨磷、钨硅杂多酸及其盐是重要的酸催化剂,它们都含有B酸中心,它来源于结构内质子、阳离子电场中结晶水离解出的质子,可在还原金属离子(如Ag~+)过程中释放出H~+。也有杂多酸(盐)含有L酸的报道,认为它来源于易于接受电子对的抗衡金属阳离子,如AlPW_(12)O_(40)中的Al~(3+),以及在高温加热中发生部分Mo=O或Mo—O—Mo键解体后裸露出的Mo表     

第四周期过渡金属钨磷杂多酸盐的合成及表征(C)

合成了Keggin型缺位取代杂多酸盐(Na5PW11Z(H2O)O39,Z=Mn、Fe、Co、Ni、Cu、Zn,以下简称PW11Z)催化剂.通过ICP、IR、UV等表征手段对催化剂进行了表征.元素分析结果表明,各缺位取代杂多酸盐的计量式为Na5PW11Z(H2O)O39.IR光谱表明,取代型杂多化合物仍保持Keggin型骨架结构.而且,除了Na5PW11Ni(H2O)O39以外,其余化合物的P-O键吸收峰发生劈裂,其劈裂强度为PW11Cu>PW11Zn>PW11Mn>PW11Fe>PW11Co.Mo=O键的振动向低波数位移.UV表征结果表明,由于过渡金属的引入,相对于Keggin型杂多酸H3PW12O40,取代产物的紫外可见吸收峰向紫外方向位移,但位移强度不大,基本有与H3PW12O40中Mo=O键的ππ*跃迁大致相同的吸收.还利用以上催化剂对正己醇氧化生成正己醛的反应活性进行了考察.     

十一钨锌杂多配合物位置异构体的合成、表征及催化性能

Keggin结构阴离子 SiW12O404－主要有α和β两种异构体。 SiW12O404－由一个中心原子 Si和四个 W3O13集团构成。当四个 W3O13共角相连,并以四面体方式配位于 Si周围就构成了α 异构体（ Td对称性）,α异构体中的一组 W3O13基团绕 C3轴旋转 60°,则构成了β 异构体（ C3V对称性）。在β SiW12O404－结构中存在 3种不同环境的钨原子,当失去一个 WO4＋后,可衍生出 3种含有缺位的β i SiW11O398－异构体。若空位位于旋转组的对位,称为β 1 SiW11O398－型体,若空位位于旋转组的相邻的钨原子位置,称为β 2 SiW…     

11-钨过渡金属杂多阴离子为配体的配合物的热稳定性研究

The thermal stability of complexes with 11-tungstometalates heteropolyanion as ligands in air was studied by TG-DTA as well as XPS, IR and solubility of different temperatures. It was found that thermal stability of the synthesized heteropolycomplexes was in connection with heteropolycomplexes’ corresponding Keggin units.     

镉的11-钨钛(锆)多元杂多化合物的合成、表征及在金属表面化学处理方面的应用研究

本文报道了镉的 1 1 -钨钛 (锆 )多元杂多酸盐的合成方法 ,用 IR、UV、XRD、化学分析、电导滴定等理化手段进行表征 ,用 TG-DTA测定了其热性质 ,并在钢铁表面化学处理方面进行了应用研究。结果表明 ,这类配合物具有 Keggin结构配合物的结构和性质 ,在铸铁表面能形成稳定的转化膜 ,对钢铁具有良好的缓蚀作用。     

Dawson结构过氧钛、锆-取代钨磷杂多配合物的合成及催化活性

过氧型钨磷杂多酸盐;环氧化作用;Dawson结构过氧钛、锆-取代钨磷杂多配合物的合成及催化活性     

Cyclooligomerization with Transition Metal Catalysts

This report is concerned not only with the syntheses of new ring systems and the preparation of derivatives of known rings but also with new types of catalysts based upon, e. g., nickel, iron, molybdenum, manganese, and palladium. The broad applicability of the methylene insertion reaction as a method for identifying mono- and di-methyl-substituted eight-, ten-, and twelve-membered rings is also demonstrated. A further section is concerned with the possible mechanism of C? C bond formation in transition metal complexes; several earlier suggestions have been revised in the light of new experimental data. In addition, experimental results are discussed which indicate that the reactivity and selectivity of the complexes formed by the nickel-ligand catalyst and olefins or alkynes depend upon the structure of the ligands.     

Methods for the Synthesis of μ-Hydrocarbon Transition Metal Complexes without Metal–Metal Bonds

Transition metal complexes in which hydrocarbons serve as σ,σ-, σ,π- or π,π-bound bridging ligands are currently of great interest. This review presents efficient and directed syntheses for such compounds, which often have very aesthetic structures. These reactions are among the most important reaction types in modern organometallic chemistry. They can be a useful aid for the synthesis of tailor-made compounds, for example, for models of catalytic processes and, specifically, for the construction of heterometallic compounds. We will discuss reactions of electrophilic complexes with nucleophilic ones, numerous transformations of (functionalized) hydrocarbons with metal complexes, the currently very topical complexes with bridging acetylide and carbide ligands, and organometallic polymers, which can be expected to have interesting and novel materials properties. Chisholm

1 M. H. Chisholm, Polyhedron 1988 , 7, 757–1077.

has described the importance of these complexes as follows: “Central to the development of polynuclear and cluster chemistry are bridging ligands and central to organometallic chemistry are metal–carbon bonds. Thus bridging ligands hold a pivotal role ins the development of Binuclear and polynuclear organometallic chemistry”.     

Ambient Temperature Synthesis and Structural Characterization of Six Transition Metal Acetylenedicarboxylate Coordination Polymers

This work reports the ambient temperature synthesis and structural characterization of six new first row transition metal acetylenedicarboxylate coordination polymers. The Co and two Ni compounds adopt structures in which the octahedral metals are connected into 1D chains via the acetylenedicarboxylate ligand. In contrast the Mn and two Zn compounds adopt 3D metal-organic frameworks; while the Mn compound is non-porous the two Zn structures contain dimeric or trimeric clusters connected into frameworks that are potentially porous. These two anionic metal-organic frameworks are, however, charged balanced by cations siting in their pores which greatly reduces the ability to access their porosity.     

Some Recent Developments in the Chemistry of Transition Metal Oxocations

The range of stability of transition metal oxocations in aqueous solution is discussed. Species with a metal-oxygen bond of order higher than unity are particularly interesting. Bond orders can sometimes be determined from bond lengths and angles, but generally only by infrared spectroscopy. – The frequency range of the metal-oxygen stretching vibration, previously assumed as about 900–1100 cm^?1, must according to these investigations be extended at least to 780 cm^?1 if all multiple bonds, particularly those in trans-dioxo complexes, are to be included. Broad bands down to 650 cm^?1 are ascribed to metal-oxygen bridges. — The existence of cations such as ZrO²⁺ and VO, or of the “well-known” titanyl ion, TiO²⁺, has never been proved. In many cases polynuclear, oxygen-bridged oxometal species must be assumed.     

双安息香缩三乙四胺双核过渡金属配合物的合成、表征与载氧性质

合成了双安息香缩三乙四胺及其与草酸共同配位的Co(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)的三元双核金属配合物.经质谱、红外光谱、元素分析、摩尔电导与磁矩测定及热分析等方法表征.用气体吸收装置探讨了配合物在DMF溶剂中的载氧性质和载氧动力学.     

Influence of Ligands on the Activity and Specificity of Soluble Transition Metal Catalysts

The reaction of a covalently σ-bonded ligand (alkyl group, hydrogen) with a molecule (olefin, CO) attached to the transition metal by a coordinate bond is the essence of many catalytic processes. The influence of the other ligands in the complex on this reaction is discussed in the present article. Various ways in which the ligands can act, e.g. by electronic effects via the σ and π electron systems of the complex and by steric effects, are first described separately and then illustrated by examples.     

Asymmetric Syntheses with the Aid of Homogeneous Transition Metal Catalysts

The progress made in the field of homogeneous catalysis during the last five to six years has led, inter alia, to the development of highly selective catalysts for asymmetric syntheses. Homogeneous asymmetric hydrogenation, using well defined transition metal catalysts, may be achieved with optical yields of 85 to 90% or more. Catalytic reactions, in which the chiral centers are generated by C? C bond formation, can result in optical yields of 70 to 80%. The hydrogenation catalysts consist primarily of rhodium(I) complexes containing “Homer phosphanes”, phosphanes with chiral C atoms, or optically active amides. Catalysts which induce optical activity through the formation of C? C bonds have been developed from π-allylnickel halides, Lewis acids, and phosphanes containing chiral C atoms. The results obtained signify a breakthrough in an area of catalysis previously restricted to syntheses involving enzymes.     

Transition Metal Polysulfides: Coordination Compounds with Purely Inorganic Chelate Ligands

It has been long known that certain transition metal sulfides dissolve in aqueous ammonium polysulfide. Although it was assumed that they thereby formed metal polysulfides, attention was first paid to such compounds only a few years ago. In recent years a host of new complexes with polysulfido chelate ligands have been isolated and characterized. The complexes are of interest not only regarding their structure and reactivity but also in view of their potential uses; they can be used for the directed preparation of sulfur rings of a given size, and there are indications that they will find applications in catalysis.