On the reactivity of organometallic compounds towards functional substrates. Part III. The kinetics of the reaction between tri-isobutylaluminium and benzonitrile

Abstract

The first-order rate constants for unimolecular thermal decomposition of Bu₃ⁱAl–PhCN complex to benzylideneamino(di-isobutyl)aluminium are given at several temperatures. The rate of reduction of PhCN is shown to be independent of the presence of toluene as solvent. For this reaction E_a= 25·0 ± 1·0 kcal mol^–1 and A= 10¹² s^–1; all the data obtained are consistent with the hypothesis that the reduction involves a six-centre transition state. In the presence of an excess of Bu₃ⁱAl di-isobutyl-(α-isobutylbenzylideneamino)aluminium is formed. On the basis of the experimental results, possible mechanisms for the addition are discussed.