Schlenk equilibrium

The Schlenk equilibrium describes the behavior of Grignard reagents (magnesium - organic compounds) in dependence on the solvent. This was after its discoverer Wilhelm Schlenk (1879-1943) named, who was one of the pioneers in the field of organometallic chemistry.

Importance

" The structure of the Grignard reagent, the has not yet been clarified in detail, mainly depends on the concentration and solvent is removed. " Are solvents, such as used, for example diethyl ether or tetrahydrofuran. The two lone pairs of these ether molecules are complex bound to the magnesium and provide the stability necessary forth octet of electrons, which is here the example of tetrahydrofuran, as presented in the literature:

A closer examination leads to a detailed image, the Schlenk equilibrium: In the production of a magnesium - organic compound is formed depending on the solvent used, and depending on its capabilities in terms of co-ordination and solubilities of the reaction products, various compounds. The Schlenk equilibrium describes what compounds the solvent in which occur in a simple manner. The Schlenk equilibrium is in the following figure, according to the literature described. There is a balance between the molds 1a and 1b. Depending on the solvent, which stabilizes the Grignard compound in a complex shape is formed 2a or 2b.

At low concentration of the solvent, for example diethyl ether, the die 2a is preferably present. Also in tetrahydrofuran as a solvent form 2a is preferred. In triethylamine form 2b is fully formed. The solvent 1,4- dioxane, the insoluble magnesium precipitates and there is only the dialkyl magnesium.