Electrical conductivity of fused lead bromide + potassium bromide mixtures

Abstract

Bridge-terminal exchange of methyl groups in trimethylaluminium dimer and the exchange of methyl groups between the dimer and trimethylgallium or dimethylzinc are all interpreted as proceeding by initial rate-determining dissociation of the trimethyl-aluminium dimer to liquid-caged monomer pair. Most exchange occurs before the monomers of the pair become separated. An alternative mechanism in which exchange follows separation is rejected.     The choice of mechanism is based on (a) p.m.r. kinetics of exchange between trimethylgallium and trimethylaluminium in cyclopentane; (b) p.m.r. kinetics of exchange between dimethylzinc and trimethylaluminium in cyclopentane; and (c) estimates of the rate of recombination of trimethylaluminium monomer.