Komplexe von Organoaluminium mit elektronenaffinen Kohlenwasserstoffen

Abstract

This is a continuation of a review on organoaluminum complexes given in 1963.
Trialkylaluminum compounds react with alkalimetals and hydrocarbons of sufficient electron affinity (benzene, naphthalene, styrene, tolan, butadiene etc.) to equimolar mixtures of alkalimetal tetraalkylaluminates and alkalimetal dialkylaluminum-(dihydrohydrocarbons).
The stability of these complexes increases with increasing electron affinity of the hydrocarbon. An attempt has been made to explain the course of reaction and the products on the basis of simple hmo models of the initial hydrocarbons, their anions and of the intermediately formed carbeniate anions.
The dialkylaluminum cation from electrolytic dissociation equilibrium is added in the position of highest charge density in the hydrocarbon anion. This gives a new π-electron system having a higher electron affinity than the hydrocarbon, which therefore rapidly takes over an electron from further alkali metal. The now formed carbeniate anion changes into an aluminate ion by formation of a new Al–C-bond between aluminum and the carbon atom with the highest electron density.