The role of metallic palladium in the reductive decomposition of ?-allyl palladium chloride in aqueous alkaline solutions

Abstract

1. The reductive decomposition of π-allyl palladium chloride in aqueous alkaline solutions is characterized by the presence of an induction period, after which the reaction rate increases, passes through a maximum, and decreases. The duration of the induction period and position of the point of inflection depend on the experimental conditions. 2. The complex nature of the dependence of the reaction rate on the π-allyl palladium chloride concentration is associated with the autocatalytic action of its decomposition products: metallic palladium and allyl alcohol. 3. The rates of reductive decomposition of π-allyl palladium chloride in water and deuterium oxide are the same within the limits of the experimental accuracy (∼5%). 4. The results obtainedwere interpreted within the framework of a mechanism including intermediate formation of the hydroxo-complex [C3H5PdCl(OH)]−, its intrasphere conversion, leading to the formation of allyl alcohol, which then reduces a second molecule of the complex on the surface of metallic palladium.