Solvent and temperature effects in the mechanism of allyl amination of the α-diimine complex [Pd(η3-C3H5)-(C5H4N-2-CHNC6H4OMe-4)]+ by piperidine and morpholine

A study is reported of the solvent and temperature effects on the equilibrium of α-diimine displacement from [Pd(η3-C3H5(NN′)]+ (NN′N′C5H4N-2-CHNC6H4OMe-4) by piperidine and morpholine and on the rates of allyl amination by these amines in the presence of activated olefins (ol) leading to [Pd(η2-ol)(NN′)] in either chloroform or methanol. The larger extent of α-diimine displacement in chloroform is essentially governed by entropy factors. ΔH° and ΔS° values for the equilibrium are discussed. The activation parameters for the slow amination reaction indicate that the reactivity differences observed are determined mainly by the entropic factor, as far as the solvent effect is concerned.