联三吡啶配体组装及其金属络合物性能*

金属-配体间的配位作用是超分子化学中最重要的相互作用之一,寡聚吡啶配体可以与许多过渡金属离子配位,形成具有独特磁、光物理和电化学性质的过渡金属配合物,因此联三吡啶配体过渡金属配合物性能研究引起化学家的广泛关注。本文系统综述了联三吡啶配体及其衍生物的组装策略及其过渡金属配合物的光化学与光物理性能,包括单极、二极及多极配体以及由这类配体组装得到的各种拓扑结构的单核、多核过渡金属配合物,如线型金属寡聚物、金属聚合物、金属大环化合物、有机金属树枝状化合物等,并介绍这些配合物在该领域研究和应用前景。     

二价双烯酮亚胺基稀土金属配合物催化ε-己内酯开环聚合

近年来,以双烯酮亚胺基为辅助配体合成金属有机配合物已经引起了化学工作者的广泛关注,其中部分双烯酮亚胺基金属配合物显示出独特的催化反应性能。最近,我们以双烯酮亚胺基为辅助配体合成了一些金属有机配合物,发现具有较大空间位阻的双烯酮亚胺基是合成混配型稀土金属有机配合物的理想配体。进一步研究发现用Na-K合金还原混配型双烯酮亚胺基稀土金属氯化物,     

四氮唑-1-乙酸及其衍生物金属构筑配合物的研究进展

四氮唑-1-乙酸(Htza)类有机配体具有良好的配位能力和多样的配位形式,在配位化学领域得到了迅速且广泛的研究。本文总结了基于四氮唑-1-乙酸配体构筑的金属配合物的研究进展和这些金属配合物的结构特征,讨论了基于四氮唑-1-乙酸构筑的金属配合物在光学、磁性、催化方面的应用,并对这类配体的发展前景进行了展望。     

相转移催化合成N,N′-二(3,5-二甲基吡唑)烷

近年来,多齿含氮配体在金属有机配合物的合成和研究中日益受到重视,不仅用在高氧化态、缺电子中心的高价过渡金属有机配合物上,而且已开始在低氧化态、富电子中心的低价过渡金属有机配合物上应用,其中一个重要原因是自然界里许多的金属酶普遍含有以氮为配位原子的配体。因此,本文试图研究N,N′-二(3,5-二甲基吡唑)烷的合成。70年代初,Trofimenko 用3,5-二甲基     

非平面分子内电荷转移离子配合物的合成及其光物理性质

以N-乙烯基咔唑三羰基铬为模板化合物, 选用丙烯基阳离子取代其中一个羰基配体, 合成了一种新型非平面分子内电荷转移有机金属配合物. 通过元素分析、红外、核磁共振确定了配合物的组成和结构, 电子吸收和荧光光谱结果表明配合物的光物理行为可通过配体取代调控．运用双光束前向简并四波混频(DFWM)的方法, 测试了配合物及配体的三阶非线性效应, 同时探讨了金属配位和配体取代对其的影响.     

不同配体的稀土金属配合物在烯烃聚合领域的研究进展

催化剂在推动聚烯烃工业发展中有着举足轻重的作用,其中金属催化剂的设计与合成更是金属有机催化化学的关键.稀土金属具有独特的轨道结构、反应活性和配位准则,因此稀土金属配合物通过在金属中心周围引入空间位阻,在聚烯烃材料制备中表现出独特优势.其中配体是决定稀土金属配合物的结构、化学活性及稳定性等方面的关键因素.本综述介绍了茂基配体(烷基取代、芳基取代、茚和芴配体)和非茂基配体(大环四齿配体、三齿配体、双齿配体和单齿配体)的稀土金属配合物的发展及其在聚烯烃制备中的应用.这项工作旨在促进稀土金属催化剂在聚烯烃催化和金属有机催化领域的研究,为高端化、差异化聚烯烃聚合催化剂的制备提供新的设计思路和研究方法.     

一种新型的吡唑衍生物的合成

近年来,多齿含氮的配体在有机配合物的合成和研究中日益受到重视,不仅用在高氧化态、缺电子中心的高价过渡金属有机配合物上,而且已开始在低氧化态、富电子中心的低价过渡金属有机配合物上应用,其中一个重要原因是自然界中许多金属酶普遍含有以氮为配位原子的配体.我们合成了N,N'-二(3,5-二甲基吡唑)烷的衍生物1,同时分离得到了一种新型的环状化合物2.     

小分子铱配合物及其电致发光

由于磷光金属配合物可以同时利用单线态和三线态激子发光,使有机电致发光器件的理论内量子效率达到100%,突破了25%的极限。因而以磷光金属配合物为发光材料制成的器件备受关注。在这些金属配合物中,铱配合物由于具有较强的发光特性、发光波长可调性、较好的热稳定性和电化学稳定性以及能够形成便于蒸镀的中性分子,而成为最有应用潜力的电致磷光材料。本文综述了近几年铱配合物磷光材料在分子设计与合成方法、发光机理及器件构筑等方面的研究进展。特别介绍与讨论了磷光铱配合物的两种发光机理,即基于同配体铱配合物或异配体铱配合物的主配体到中心金属离子的电荷转移三线态(³MLCT)发射和基于异配体铱配合物的辅助配体三线态(³LC)发射。根据反应条件的差异,归纳总结了合成铱配合物常用的4种方法以及合成fac式和mer式的铱配合物的方法。还根据材料的发光颜色及其电致发光的不同,对磷光铱配合物材料进行了分类与讨论。此外,简要介绍了用于器件制作的主体材料。最后,展望了金属有机配合物电致磷光材料的发展前景,并提出了今后磷光材料的发展方向。     

基于四齿配体的蓝光d8金属配合物及其OLED应用的研究进展

用于有机发光二极管(OLED)的红光和绿光磷光金属配合物材料在稳定性和发光效率方面均已达到了目前产业化应用的要求,而蓝光磷光配合物则在稳定性方面无法达到应用条件。高能量的激发态以及d-d态引起的配合物分解是造成蓝光磷光OLED器件稳定性差的原因之一。采用四齿配体开发d~8金属配合物是同时提升配合物发光效率和稳定性的途径之一,有望在蓝光磷光材料和器件应用方面取得突破。本文总结了基于四齿配体的蓝光铂(Ⅱ)和钯(Ⅱ)配合物的研究进展,通过探讨配体结构对配合物光物理性质和稳定性的影响,为继续开发具有应用前景的蓝光金属配合物材料提供了指导性方向。     

手性环戊二烯过渡金属配合物在不对称催化反应中的应用

手性环戊二烯配体作为不对称催化反应中的立体控制元素受到金属有机工作者的关注,尤其是设计合成更多通用的手性环戊二烯基配体成为了不对称催化领域的研究中心之一.综述了近年来发展出的各种手性环戊二烯配体与不同过渡金属的配合物,以及这些配合物在催化不对称反应方面的进展.     

Lipase active-site-directed anchoring of organometallics: metallopincer/protein hybrids

The work described herein presents a strategy for the regioselective introduction of organometallic complexes into the active site of the lipase cutinase. Nitrophenol phosphonate esters, well known for their lipase inhibitory activity, are used as anchor functionalities and were found to be ideal tools to develop a single-site-directed immobilization method. A small series of phosphonate esters, covalently attached to ECE "pincer"-type d8-metal complexes through a propyl tether (ECE=[C6H3(CH2E)(2)-2,6]-; E=NR2 or SR), were designed and synthesized. Cutinase was treated with these organometallic phosphonate esters and the new metal-complex/protein hybrids were identified as containing exactly one organometallic unit per protein. The organometallic proteins were purified by membrane dialysis and analyzed by ESI-mass spectrometry. The major advantages of this strategy are: 1) one transition metal can be introduced regioselectively and, hence, the metal environment can potentially be fine-tuned; 2) purification procedures are facile due to the use of pre-synthesized metal complexes; and, most importantly, 3) the covalent attachment of robust organometallic pincer complexes to an enzyme is achieved, which will prevent metal leaching from these hybrids. The approach presented herein can be regarded as a tool in the development of regio- and enantioselective catalyst as well as analytical probes for studying enzyme properties (e.g., structure) and, hence, is a "proof-of-principle design" study in enzyme chemistry.     

Main-chain organometallic polymers: synthetic strategies, applications, and perspectives

Main-chain organometallic polymers utilize transition metal-organic ligand complexes as primary components of their backbones. These hybrid materials effectively integrate the physical and electronic properties of organic polymers with the physical, electronic, optical, and catalytic properties of organometallic complexes. Combined with the rich and continuously growing array of ligands for transition metals, these materials have outstanding potential for use in a broad range of applications. This tutorial review discusses the major classes of main-chain organometallic polymers, including coordination polymers, poly(metal acetylide)s, and poly(metallocene)s. Emphasis is placed on their synthesis, characterization, physical properties, and applications, as well as ongoing challenges and limitations. These discussions are supplemented with highlights from the recent literature. The review concludes with perspectives on the current status of the field, as well as opportunities that lie just beyond its frontier.     

Surface organometallic chemistry on metals: a novel and effective route to custom-designed bimetallic catalysts

The synthesis, characterization and catalytic properties of new materials obtained by reaction of organometallic complexes of groups IIb, IVa, and VIa with the surface of metallic particles are reviewed. Two types of materials may be obtained by surface organometallic chemistry on metals: metal particles covered with organometallic fragments, and bimetallic particles of predetermined composition. Characterization of the organometallic fragments on the metal particles has demonstrated their thermal stability. These particles covered with surface organometallic fragments are new catalytic materials, highly selective in several reactions such as the hydrogenation of α,β-unsaturated aldehydes, ethyl pyruvate, nitrobenzene, acrylonitrile, and olefins. The bimetallic particles without organometallic fragments are also highly active and selective for a variety of reactions such as hydrogenolysis of various alkanes and hydrogenolysis of esters. For these systems, the concept of “site isolation” has been advanced to account for the high selectivity of the reactions.     

Deprotonative metalation using ate compounds: synergy, synthesis, and structure building

Historically, single-metal organometallic species such as organolithium compounds have been the reagents of choice in synthetic organic chemistry for performing deprotonation reactions. Over the past few years, a complementary new class of metalating agents has started to emerge. Owing to a variable central metal (magnesium, zinc, or aluminum), variable ligands (both in their nature and number), and a variable second metallic center (an alkali metal such as lithium or sodium), "ate" complexes are highly versatile bases that exhibit a synergic chemistry which cannot be replicated by the homometallic magnesium, zinc, or aluminum compounds on their own. Deprotonation accomplished by using these organometallic ate complexes has opened up new perspectives in organic chemistry with unprecedented reactivities and sometimes unusual and unpredictable regioselectivities.     

Stoichiometric and catalytic reactivity of organometallic fragments supported on inorganic oxides

The reaction of some organometallic complexes with the surfaces of inorganic oxides leads to the formation of surface organometallic complexes, chemically bound to the surface yet retaining many features of their molecular structure. These surface organometallic complexes can therefore be considered to belong to both the molecular and solid states. In cases where such complexes have been structurally characterised, their reactivity can be interpreted with molecular concepts. In this review article, the stoichiometric and catalytic reactivity of some relatively well-defined surface organometallic fragments is surveyed. Many elementary steps which have precedent in molecular organometallic chemistry and homogeneous catalysis have now been demonstrated with surface organometallic fragments, including reversible ligand binding, oxidative addition, reductive elimination, protonation, heterolytic metal—carbon bond cleavage, electrophilic CH bond activation and insertion into metal—carbon bonds. In some cases, the supported organometallic complexes are highly effective low temperature catalysts, a phenomenon which is not always observed with molecular analogues nor with conventionally prepared heterogeneous catalysts. Applications of surface organometallic chemistry to catalytic alkane hydrogenolysis, olefin isomerisation and hydrogenation, the Fischer—Tropsch synthesis and the water—gas shift reaction are discussed. Proposed mechanisms for several representative catalytic cycles are presented.     

Organotransition-metal chemistry: past development and future outlook

The course of the development of organometallic chemistry is reviewed from the author's personal viewpoint. The impact of the discoveries of ferrocene and the Ziegler catalyst on the later development of organotransition-metal chemistry is discussed. Through evolution of fundamental concepts, such as the insertion of olefins and carbon monoxide into metal—carbon bonds, oxidative addition and reductive elimination, and attack of nucleophiles on coordinated ligands, together with reactivities of carbene and metallacyclic complexes, various important processes have been developed. The diversity of transition-metal complexes and their unique reactivities not found in usual organic compounds warrant further developments in the various forefronts related to organometallic chemistry with almost limitless possibilities in applications as well as in fundamental studies.     

Planar chiral (η5-cyclohexadienyl)- and (η6-arene)-tricarbonylmanganese complexes: synthetic routes and application

Planar chiral arenetricarbonylchromium complexes have been intensively investigated and they have been applied as valuable building blocks for asymmetric synthesis and as ligands for asymmetric catalysis. In contrast, in the field of the isoelectronic cationic [(η(6)-arene)Mn(CO)(3)](+) complexes, until these last 10 years, very few studies were published involving nonracemic planar chiral cationic complexes and their potential applications, certainly because of the difficult access to enantiopure starting material. In 2009, however, the discovery of the first resolution of such compounds opened a new area for their application in the field of organic as well as of organometallic enantioselective syntheses. We felt it important to write a review on this subject to give an up-to-date summary of the methodologies used to prepare enantiomerically pure planar chiral neutral [(η(5)-cyclohexadienyl)Mn(CO)(3)] and cationic [(η(6)-arene)Mn(CO)(3)](+) complexes as well as their potential in enantioselective synthesis.     

Optically active organometallic compounds (a personal account from the inside)

Results of a long experience of our group in Moscow in the area of chiral organometallic stereochemistry are described. They embrace optically active organometallic derivatives of mercury, palladium, platinum, functionalized ferrocenes, ruthenocenes, and cymantrenes as well as less common objects such as organometallic fullerenes and the cyclodextrin-metallocenes inclusion complexes.     

Benzodiazepines: Drugs with Chemical Skeletons Suitable for the Preparation of Metallacycles with Potential Pharmacological Activity

The synthesis of organometallic compounds with potential pharmacological activity has attracted the attention of many research groups, aiming to take advantage of aspects that the presence of the metal-carbon bond can bring to the design of new pharmaceutical drugs. In this context, we have gathered studies reported in the literature in which psychoactive benzodiazepine drugs were used as ligands in the preparation of organometallic and metal complexes and provide details on some of their biological effects. We also highlight that most commonly known benzodiazepine-based drugs display molecular features that allow the preparation of metallacycles via C-H activation. These organometallic compounds merit further attention regarding their potential biological effects, not only in terms of psychoactive drugs but also in the search for drug replacements, for example, for cancer treatments.     

Ligand acyle et ligand alkoxycarbonyle: couplage carbone-carbone ou isomérie cycle-chaîne sur l’exemple des complexes octaédriques du fer du type cis-Fe{[C(O)]xR} {[C(O)]yR′}(CO)4; x,y = 0,1; R ou R′ = CH3, OCH3

This paper concerns the analogies and the differences of behaviour between organometallic ligands and their organic homologues. The study of the carbon-carbon coupling process inducing the formation of mono or bis carbonylated organic compounds, as well as the ring-chain isomerization giving rise to five membered metallacyclic complexes, were realized on a homogeneous series of iron octahedral complexes bis substituted by two carbonylated organic ligands.