Manganese(II): the black sheep of the organometallic family

The organometallic chemistry of manganese in the +2 oxidation state is distinct from the organometallic chemistry of a 'typical' transition metal due to a significant ionic contribution to the manganese(II)-carbon bonds. The reduced influence of covalency and the 18-electron rule result in organomanganese(II) cyclopentadienyl, alkyl and aryl complexes possessing reactivity and structural diversity that is unique in organotransition metal chemistry. Recently, this unusual reactivity has resulted in a range of novel applications in selective organometallic and organic synthesis, and polymerization catalysis. This tutorial review summarizes key milestones in the development of manganese(II) organometallics and discusses how some of their current synthetic applications have evolved from many fascinating fundamental studies in the area.     

Organomanganese (II) reagents XII: An efficient one-pot preparation of unsymmetrical secondary or tertiary alcohols

Various unsymmetrical secondary or tertiary alcohols have been prepared in high yields by an efficient one-pot procedure involving the acylation of an organomanganese reagent by an acyl chloride and addition to the ketone formed of various organometallic compounds (RLi, RmgX, LiAlH₄, NaBH₄. The complexation of the intermediate ketone by the metallic salts present in the reaction mixture allows to perform the 1–2 addition step under exceptionally mild conditions (0 to 20°C).     

The chemistry of (1-azabuta-1,3-diene)tricarbonyliron(0) complexes

In this review, an overview of synthetic and structural aspects of 1-azabuta-1,3-diene complexes of iron is given and the reactivity of these complexes is discussed with regard to inorganic, organometallic, organic and stereochemical aspects of their chemistry. Their application in the synthesis of organic and organometallic target compounds, or as transfer reagents of the tricarbonlyiron(0) moiety is demonstrated.     

Transition Metals in the Synthesis and Functionalization of Indoles [New Synthesis Methods (72)]

The use of transition-metal complexes as reagents for the synthesis of complex organic compounds has been under development for at least several decades, and many extraordinary organic transformations of profound potential have been realized. However, adoption of this chemistry by the practicing synthetic organic chemist has been inordinately slow, and only now are transition-metal reagents beginning to achieve their rightful place in the arsenal of organic synthesis. Several factors contributed to the initial reluctance of synthetic organic chemists to use organometallic reagents. Lacking education and experience in the ways of elements having d electrons, synthetic chemists viewed organometallic processes as something mysterious and unpredictable, and not to be discussed in polite society. Organometallic chemists did not help matters by advertising their latest advances as useful synthetic methodology, but restricting their studies to very simple organic systems lacking any serious functionality (e.g., the “methyl, ethyl, butyl, futile” syndrome). Happily, things have changed. Organometallic chemists have turned their attention to more complex systems, and more recently trained organic chemists have benefited from exposure to the application of transition metals. This combination has set the stage for major advances in the use of transition metals in the synthesis of complex organic compounds. This review deals with one aspect of this area, the use of transition metals in the synthesis of indoles.     

Synthesis of Organometallic Compounds in Flow

Microreactor technology has proved to be an important technique in organic synthesis, especially when organometallic compounds are used, because it allows running rapid reactions with reactive and instable intermediates. This review will highlight the preparation of main‐group organometallic compounds deriving from Lithium, Magnesium, Zinc and Aluminum and their applications in flow conditions.     

若干新型有机光电功能材料的分子设计、合成与性能 研究

介绍本研究组得到国家自然科学基金资助的四个方面工作的进展。研究了金属有机化合物的结构与非线性光学性质的关系,总结了从分子几何构型着手,根据不同用途,对金属有机非线性光学材料进行分子设计的经验规律;提出了利用“组合式共轭桥”进行有机非线性光学发色团分子设计的新思路,所合成的几个有机化合物既有很大的光学非线性,又有紫移的最大吸收峰;通过化学键将有机发色团分子张到各种高分子的侧链上,合成和表征了潜在的电光高分子和光折变高分子材料;采用无机-有机夹层复合的思路对兼有导电性和强磁性的分子材料进行了探索,将一些有机小分子和导电高分子分别插入了层状无机物MPS3的层间,得到了8个新的分子磁体,而另一夹层化合物则表现了较高的电导率。     

From molecules to aggregates

The preparation of organometallic oxides, imides and nitrides is described. The molecular structures of these compounds resemble those found in binary systems. However, due to the organic envelope of the molecular solids, they are soluble in organic solvents, easy to crystallize and unambiguously characterizable by single X-ray structural analysis and NMR investigations. Moreover, inorganic oxides can be incorporated in organometallic phosphonates or organoalumoxanes. Herein we describe the organometallic phosphonates as hosts with a hydrophobic exterior.     

Nickel (Ⅱ) Catalyzed 1, 4- Addition Reactions of Functionalized Orgnaozinc Reagents with Enones

Organozinc reagent is one of the earliest organometallic compounds prepared. Investigation of its application in organic synthesis had been completed before 1880.However, it was replaced at the turn of the century by the more reactive organomagnesiun reagent except Reformatsky reaction because of its low reactivity toward most organic electrophiles. In 1978, Mukaiyama first reported that Et2Zn reacted with benzaldehyde in the presence of aminoalcohol to give 1, 2-addition product in excellent yield. Pursuant to this report, a lot of papers about the reaction of organozinc reagent with organic electrophiles have been appeared. However, most of the researches focused on dialkylzinc regents, few papers on study of organozinc halides had appeared until 1988.     

双核钼/钨金属键有机化合物的反应化学研究

着重总结了我们研究组近几年来对M-M(M=Mo,W)金属单键化合物(η^5-RC5H4)2M2(CO)6,M=M金属双键化合物(η^5-RC5H4)2M2(CO)2(μ-EPh)2(E=S,Se,Te)及M≡M金属三键化合物(η^5-RC5H4)2M2(CO)4的反应化学所取得的系列成果。该系列成果清楚地表明这三类典型的金属键有机化合物可分别同多种无机、有机以及金属有机试剂发生涉及金属键加成、金属键断裂以及金属键上配体的消除和环戊二烯基配体上有机官能团的转化等一系列有趣反应。这些反应不仅有重要理论意义而且被广泛地用在新型金属有机和原子簇化合物的合成上。     

A Robust Microfluidic Device for the Synthesis and Crystal Growth of Organometallic Polymers with Highly Organized Structures

A simple and robust microfluidic device was developed to synthesize organometallic polymers with highly organized structures. The device is compatible with organic solvents. Reactants are loaded into pairs of reservoirs connected by a 15 cm long microchannel prefilled with solvents, thus allowing long‐term counter diffusion for self‐assembly of organometallic polymers. The process can be monitored, and the resulting crystalline polymers are harvested without damage. The device was used to synthesize three insoluble silver acetylides as single crystals of X‐ray diffraction quality. Importantly, for the first time, the single‐crystal structure of silver phenylacetylide was determined. The reported approach may have wide applications, such as crystallization of membrane proteins, synthesis and crystal growth of organic, inorganic, and polymeric coordination compounds, whose single crystals cannot be obtained using traditional methods.     

Design and application of a reflux modification for the synthesis of organometallic compounds using microwave dielectric loss heating effects

A commercially available microwave oven has been modified so that syntheses involving the refluxing of organic solvents can be safely and conveniently undertaken. The applications of this technique for accelerating the rates of reactions leading to the synthesis of some commonly used organometallic and coordination compounds are described.     

Regio- and chemoselective metalation of arenes and heteroarenes using hindered metal amide bases

The preparation of highly functionalized organometallic compounds can be achieved by direct C H activation of a broad range of unsaturated substrates using lithium chloride solubilized 2,2,6,6‐tetramethylpiperidide bases (TMP_nMX_m⋅p LiCl). These are excellent reagents for converting a wide range of aromatic and heterocyclic substrates into valuable organometallic reagents with broad applications in organic synthesis.     

Anhydrous scandium, yttrium, lanthanide and actinide halide complexes with neutral oxygen and nitrogen donor ligands

Studies on lanthanide and actinide halide complexes with neutral O- and/or N-donor ligands have intensified in recent years due to their implications in homogeneous catalysis, magnetic and optical materials, as synthons for the synthesis of novel coordination and organometallic compounds and, for Ln(II) halide complexes, as reducing agents in organic synthesis. Synthetic strategies, structural diversity as well as some important properties and reactivities of these anhydrous metal (including scandium and yttrium) halide complexes are reviewed here. These complexes also hold potential as starting materials for constructing more sophisticated heterometallic assemblies by crystal engineering; the compounds of this class, either discrete ion-pairs or coordination polymers, being discussed separately under the heading heterometallic lanthanide and actinide halide complexes. The aim of this article is to provide a reference text for the researchers working in the lanthanide and actinide coordination chemistry field and to identify and signify the area of future research.     

Organometallic Derivatization of the Nematocidal Drug Monepantel Leads to Promising Antiparasitic Drug Candidates

The discovery of novel drugs against animal parasites is in high demand due to drug‐resistance problems encountered around the world. Herein, the synthesis and characterization of 27 organic and organometallic derivatives of the recently launched nematocidal drug monepantel (Zolvix^®) are described. The compounds were isolated as racemates and were characterized by ¹H, ¹³C, and ¹⁹F NMR spectroscopy, mass spectrometry, and IR spectroscopy, and their purity was verified by microanalysis. The molecular structures of nine compounds were confirmed by X‐ray crystallography. The anthelmintic activity of the newly designed analogues was evaluated in vitro against the economically important parasites Haemonchus contortus and Trichostrongylus colubriformis. Moderate nematocidal activity was observed for nine of the 27 compounds. Three compounds were confirmed as potentiators of a known monepantel target, the ACR‐23 ion channel. Production of reactive oxygen species may confer secondary activity to the organometallic analogues. Two compounds, namely, an organic precursor ( 3 a ) and a cymantrene analogue ( 9 a ), showed activities against microfilariae of Dirofilaria immitis in the low microgram per milliliter range.     

Microwave-Assisted Cross-Coupling Reaction of Sodium Tetraphenylboratewith Carboxylic Anhydrides Catalyzed by Palladium

Cross-coupling processes of aryl or alkenyl halides with organometallic compounds of main group elements cat alyzed by palladium complexes have been found extensive use in organic synthesis. These cross-coupling reactions offer a powerful tool for the formation of carbon-carbon bonds. [1] The Suzuki-Miyaura cross-coupling reaction has been employed for the synthesis of ketone as well.     

Synthesis and Structure of Dimeric β-Diketiminato Co(Ⅱ) Chloride Complex

Introduction Recently, late-transition-metal complexes have been extensively used as both inorganic and organometallic catalysts[1]. Some complexes have been developed as the novel olefin polymerization catalysts[2-4] and copolymerization catalysts for ethylene and polar comonomers[5] due to their lower oxophilicity and presumed greater functional tolerance. Moreover, compounds with imine ligands have received more attention and have been reported for the synthesis method, structure, mechanism and application[6-9]. In this contribution, we report the synthesis of the dimericβ-diketiminato Co(Ⅱ)chloride complex:     

Formation of Ad-Layers and Clusters on Condensation of Metal Vapors on Solid Surfaces

Synthesis of organometallic materials can be accomplished in many cases by cocondensation of metal atoms and organic molecules at low temperatures. The reaction kinetics is determined by the competition between metal cluster growth and formation of the organometallic compound. Interesting compounds may contain one or more metal atoms; the latter type could be obtained by reaction between a cluster containing the desired number of metal atoms and an organic molecule. A precise knowledge of the events occurring on condensation of metal atoms and cluster formation can therefore be of value in the control of chemical synthesis. These phenomena have been investigated in connection with the study of the growth of thin metallic films, both experimentally and theoretically. Direct observation of the formation of very small clusters is difficult. The good agreement between experimental results and recent calculations for the development of large clusters, however, allows reliable theoretical conclusions for the first stages of adsorption and cluster formation. The present contribution describes experimental work on film growth and relevant theoretical concepts, and an attempt is made to develop applications to organometallic synthesis.     

Uncatalyzed Hydroamination of Electrophilic Organometallic Alkynes: Fundamental,Theoretical, and Applied Aspects

Simple reactions of the most used functional groups allowing two molecular fragments to link under mild, sustainable conditions are among the crucial tools of molecular chemistry with multiple applications in materials science, nanomedicine, and organic synthesis as already exemplified by peptide synthesis and “click” chemistry. We are concerned with redox organometallic compounds that can potentially be used as biosensors and redox catalysts and report an uncatalyzed reaction between primary and secondary amines with organometallic electrophilic alkynes that is free of side products and fully “green”. A strategy is first proposed to synthesize alkynyl organometallic precursors upon addition of electrophilic aromatic ligands of cationic complexes followed by endo hydride abstraction. Electrophilic alkynylated cyclopentadienyl or arene ligands of Fe, Ru, and Co complexes subsequently react with amines to yield trans‐enamines that are conjugated with the organometallic group. The difference in reactivities of the various complexes is rationalized from the two‐step reaction mechanism that was elucidated through DFT calculations. Applications are illustrated by the facile reaction of ethynylcobalticenium hexafluorophosphate with aminated silica nanoparticles. Spectroscopic, nonlinear‐optical and electrochemical data, as well as DFT and TDDFT calculations, indicate a strong push–pull conjugation in these cobalticenium– and Fe– and Ru–arene–enamine complexes due to planarity or near‐planarity between the organometallic and trans‐enamine groups involving fulvalene iminium and cyclohexadienylidene iminium mesomeric forms.     

The 2 x 3 toolbox of organometallic methods for regiochemically exhaustive functionalization

This review describes a concept aimed at rational and maximal structure proliferation. To this end, simple aromatic or heterocyclic starting materials, often bulk chemicals, are converted into all regionisomerically possible polar organometallic intermediates (mostly lithiated species), which then may be combined with any of the countless electrophiles to provide attractive new building blocks, particularly functionalized derivatives. The practical implementation relies on a set ("toolbox") of sophisticated recipes developed by mechanistically guided modification of the two most prominent exchange methods used for the generation of polar organometallic compounds: hydrogen-metal and halogen-metal interconversion. These mutant methods ("old methods in a new outfit") amplify the existing options for organic synthesis by ensuring maximum regioflexibility. At the same time they offer new insight into factors that govern organometallic reactivity and provide hints on how to alter or finetune this reactivity judiciously.     

有机锡在不对称合成中的应用研究进展

金属有机化合物是不对称合成中常用的有机试剂。有机锡试剂易于制备，而且碳-锡键又易于断开，因此它们被广泛应用于有机合成中，当然也是不对称合成常用的试剂之一，是制备某些手性天然产物必备的试剂。由于锡的结构特点，它可以形成四配位、五配位甚至六配位的配合物，这些配合物作为路易斯酸可用作不对称合成中的催化剂、助催化剂。从已报道的文献看，大多数反应的产率及对映体选择性都在中等或中等以上水平，某些已达到了优良的水平。本文综述了有机锡作为反应试剂、催化剂、助催化剂在不对称合成中的应用。