The Role of Alkene and Anionic Ligands

1) The rates of oxidative addition starting from complexes [Pdjidbalj dba] or [Pdjidbaij.Sj are probably different, as the excess of dba may retard that reaction. We refer to these complexes as [Pdjidbajj]. 

Anionic ligands play a very significant role in oxidative and transmetallation addition reactions [91, 92]. Thus, for example, Amatore and Jutand [93, 94] concluded that in the presence of acetate, the tricoordinated anionic species [PdL2(OAc)] are the effective complexes in oxidative addition [94], instead of the usually postulated neutral [PdLj] complex. In the presence of halide anions, anionic complexes are also formed [95-97]. In general, the following order of stabilization of the anionic Pd(0) species is observed 1 Br Cl [98]. 

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