Organometallic exchange reactions

Seitz, L. M., and Brown, T. L., Organometallic exchange reactions. I. Lithium-7 and proton nuclear magnetic resonance spectra of methyllithium and ethyllithium in ether, J. Am. Chem. Soc., 88, 2174 (1966). 

IV. Early Investigations into Organometallic Exchange Reactions... 

EARLY INVESTIGATIONS INTO ORGANOMETALLIC EXCHANGE REACTIONS... 

Ham, N. S., Mole, T., The Application of NMR to Organometallic Exchange Reactions, Progr. Nucl. Magn. Resonance Spectry. 4 [1969] 91/192. 

The pre.sent account follows a Journey in this arena from solution calorimetric studies dealing with nucleophilic carbene ligands in an organometallic system to the use of these thermodynamic data in predicting the feasibility of exchange reactions to applications in homogeneous catalysis. 

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). 

The articles by J. R. Anderson, J. H. Sinfelt, and R. B. Moyes and P. B. Wells, on the other hand, deal with a classical field, namely hydrocarbons on metals. The pattern of modem wTork here still very much reflects the important role in the academic studies of deuterium exchange reactions and the mechanisms advanced by pioneers like Horiuti and Polanyi, the Farkas brothers, Rideal, Tw igg, H. S. Taylor, and Turkevich. Using this method, Anderson takes ultrathin metal films with their separated crystallites as idealized models for supported metal catalysts. Sinfelt is concerned with hydrogcnolysis on supported metals and relates the activity to the percentage d character of the metallic bond. Moyes and Wells deal with the modes of chemisorption of benzene, drawing on the results of physical techniques and the ideas of the organometallic chemists in their discussions. 

The metalation, particularly lithiation, and halogen-to-metal exchange reactions of 1,3,4-oxadiazoles as well as further reactions of organometallic derivatives were reviewed by Grimmett and Iddon (Equation 8) <1995H(41)1525>. 

Photo-oxidation reactions, 32 118 Photoreduction, metal oxides, 31 123 Phthalic acid, esterification, 17 340 Phthalocyanines EDA complexes of, 20 328-330 catalytic activity for hydrogen exchange reaction, 20 329,330 electronic configuration of, 20 330 organometallic complexes, 30 276-277 Phyllosilicates, see Layer lattice silicates, catalysts... 

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. 

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