Organometallic compounds exchange reactions

Elements, Part D 6, Ion Exchange and Solvent Extraction Reactions, Organometallic Compounds (Springer, Berlin) pp. 1-136. 

The bimetallic mechanism is illustrated in Fig. 7.13b the bimetallic active center is the distinguishing feature of this mechanism. The precise distribution of halides and alkyls is not spelled out because of the exchanges described by reaction (7.Q). An alkyl bridge is assumed based on observations of other organometallic compounds. The pi coordination of the olefin with the titanium is followed by insertion of the monomer into the bridge to propagate the reaction. 

Zirconium tetrachloride is instantly hydrolyzed in water to zirconium oxide dichloride octahydrate [13520-92-8]. Zirconium tetrachloride exchanges chlorine for 0x0 bonds in the reaction with hydroxylic ligands, forming alkoxides from alcohols (see Alkoxides, METAl). Zirconium tetrachloride combines with many Lewis bases such as dimethyl sulfoxide, phosphoms oxychloride and amines including ammonia, ethers, and ketones. The zirconium organometalLic compounds ate all derived from zirconium tetrachloride. 

It seems likely that the mechanism of the Wurtz reaction consists of two basic steps. The first is halogen-metal exchange to give an organometallic compound (RX -(- M —+ RM), which in many cases can be isolated (12-36). Following this, the organometallic compound reacts with a second molecule of alkyl halide (RX + RM —> RR). This reaction and its mechanism are considered in the next section (10-94). 

Reaction of aryl organometallic compounds with halogens Aryl halide exchange halo-denitration halo-dehydroxylation Reaction between diazonium salts and iodide ion Heating of diazonium fluoroborates (Schiemann)... 

These compounds are the most stable of the three classes of organothal-lium(III) derivatives and have been prepared by a wide variety of classical organometallic procedures. Many exchange reactions of TIX3 (X = Cl, carboxylate) with organo derivatives of boron, mercury, tin, lead, etc., have been shown to result in formation of R2TIX compounds 73, 78), but are of relatively little preparative significance. The most frequently used procedure... 

Electronic Effects in Metallocenes and Certain Related Systems, 10, 79 Electronic Structure of Alkali Metal Adducts of Aromatic Hydrocarbons, 2, 115 Fast Exchange Reactions of Group I, II, and III Organometallic Compounds, 8,167 Fluorocarbon Derivatives of Metals, 1, 143 Heterocyclic Organoboranes, 2, 257... 

A discussion of ligand exchange reactions of organometallic compounds associated with oxidation-reduction processes leading to free-radical formation will be found in Volume 14 (Free-radical polymerization). 

Organic compound removal, with ion-exchange resins, 14 423 Organic compounds. See also Organic fluorine compounds Organics Organometallic compounds addition to reaction mixtures, 16 409—411... 

What makes the permutation approach so attractive is the ease of execution and the mild reaction conditions. A possible drawback is its moderate exothermicity which may prevent the interconversion to go to completion but rather to stop as soon as an equilibrium composition is attained. Moreover, to rely on an organometallic exchange reagent merely defers the problem. Ultimately, the genesis of any organometallic compound can be traced back to the elemental metal. 

Another useful method of preparing organolithium reagents involves metal-metal exchange. The reaction between two organometallic compounds proceeds in the direction... 

Reaction between an organometallic compound and an organometallic compound (exchange)... 

In Table 1 are summarized representative examples of self-exchange rate constant data for a variety of different types of redox couples based on metal complexes, organometallic compounds, organics and clusters. Where available the results of temperature dependence studies are also cited. For convenience, data obtained from temperature dependence studies are presented as enthalpies and entropies of activation as calculated from the reaction rate theory expression in equation (14). 

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