Ligand displacement reactions. Part III. Kinetics of the reactions between trimethyl phosphite and some tricarbonyl(arene)tungsten complexes

Abstract

The reactions between trimethyl phosphite and tricarbonyl(arene)tungsten complexes are first order in each reactant and occur by S_N2 mechanisms. The study of the effect of substituents in the arenes on the rate of displacement is limited by the difficulty of preparing the complexes, but it is clearly shown that electron releasing substituents do not always stabilize the molecules against nucleophilic attack. The kinetic results are compared with the results of other physical measurements on the analogous chromium complexes, and the greater reactivity of cycloheptatriene complexes compared with arene complexes is also discussed.