organometallic chemistry

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organometallic chemistry,

the reactions and use of a class of compounds (R-M) that contain a covalent bond between carbon and metal. They are prepared either by direct reaction of the metal with an organic compound or by replacement of a metal from another organometallic substance. Their use is based on the polar R-M bond, in which the carbon atom carries a partial negative charge, and on the nature of the metal atom. In synthesis they act as nucleophiles that can bond with relatively positive carbon atoms in compounds such as alkyl halides, aldehydes, and ketones. For example, the Grignard reagent, RMgX (where X equals Br, Cl, or I), and organolithium compounds react with ketones to give secondary alcohols. In industry, butyllithium is used for the polymerization of isoprene in the manufacture of synthetic rubber; metalloorganic compounds serve as catalysts. The semimetals, boron, and silicon are important organometallics; organoboranes are used in synthesis, while organosilicones are polymerized to manufacture plastics and elastomers. Many organometallics are toxic primarily because of the toxicity of the metal. For example tetraethyl leadtetraethyl lead
, (C2H5)4Pb, viscous, colorless, poisonous liquid. It is an organometallic compound prepared by reacting ethyl chloride with a sodium-lead alloy.
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 has been banned as gasoline additive and the conversion of mercury to mercury alkyls by fish has had serious consequences in Japan.
References in periodicals archive ?
The substitution of fluorine with an ethynyl anion can be accomplished by using a lithium organometallic reagent, Scheme 2, or a Grignard reagent, Scheme 3.
The usage of organometallic reagents as catalysts and adhesion promoters in reinforced composites," 2nd Int'l Conf.
The topics include electrophilic aromatic substitution, organometallic reagents, acid halides and anhydrides, aldol reactions, amines, and proton (1H) nuclear magnetic resonance.
Specialist from 12 countries explore the chemistry of organometallic derivatives containing zinc, now among the most useful classes of organometallic reagents used in organic and organometallic synthesis.
Most methods employ a stoichiometric amount of organometallic reagents (such as organolithium or organomagnesium) for forming alkynylmetal reagent from alkynes or alkynyl halides in anhydrous organic solvent.
However, recent developments have led to the stabilisation of these compounds and today heavier group 14 element cations, radicals, anions, carbene analogues, alkene and alkyne analogues and aromatics have all been prepared as highly reactive, stable, fully characterizable and readily available organometallic reagents.
They have independently been investigating the use of ILs as solvents for reactions involving reactive organometallic reagents.
They cover synthetic design, stereochemical considerations in planning synthesis, the concept of protecting functional groups, oxidation and reduction as functional group transformations, the chemistry of carbon-carbon pi-bonds and related reactions, formation of carbon-carbon single bonds through enolate anions and organometallic reagents, formation of carbon-carbon pi-bonds, and synthesis of carbocyclic systems.
FUTURESOL[R] DEM provides an environmentally sound option for commercial production of organometallic reagents while maintaining excellent solvating properties, good water work-up characteristics, and low peroxide formation.
Specific topics covered include the rhodium(I)-catalyzed asymmetric addition of organometallic reagents, rhodium-catalyzed hydroborations and related reactions, and carbon-carbon bond-forming reactions starting from Rh-H or Rh-Si species.
We are interested in the development of green solvents such as Room Temperature Ionic Liquids (RTILs) as solvents for organometallic reagents used in organic synthesis.
In order to overcome this critical problem, alternative organometallic reagents and reactions, compatible with water or other alternative media have recently been developed.