Palladium(0)-olefin complexes with potentially terdentate nitrogen-sulfur ligands. The role of the chelate in the olefin exchange path

The synthesis and the reactivity of Pd(0) olefin complexes [Pd(eta (2)-olef in)(SNS)] and [Pd(eta (2)-olefin)(NSN)] containing potentially terdentate n itrogen-sulfur ligands were studied. The presence of a potentially coordina ting atom in the environment of the metal, influences strongly the fluxiona l behavior in solution but not the overall reactivity with respect to olefi n exchange and thermodynamic stability which is very close to that of the c orresponding bidentate nitrogen-sulfur complexes. The intimate mechanism of olefin exchange also involves a path promoted by the third dangling coordi nating atom which induces olefin dissociation and stabilizes the ensuing Pd (0) three-coordinated species. (C) 2001 Elsevier Science B.V. All rights re served.