Interaction of Palladium(II) Acetate with Sodium and Lithium Acetate in Acetic Acid

Abstract

Palladium(II) acetate in acetic acid in the absence of acetate ion exists as the trimeric species Pd 3 (OAc) 6 . The reaction of the trimer with NaOAc or LiOAc at 25° was not instantaneous. Spectral studies on fully equilibrated systems indicated the first equilibria involved transformation of trimer to dimer[Formula: see text]with K 32 = 7.77 × 10 4 M −5 and K′ 32 = 1.76 × 10 2 M −5 . The kinetics of the slow transformation of trimer to dimer was studied. The reaction has the rate expression: rate = [Pd 3 (OAc) 6 ] (k + k′[MOAc]) (M = Li or Na). This rate expression is consistent with substitution processes suggesting the slow step of the reaction is the S N 2 attack of solvent or acetate on a Pd(II)–acetate bond to break one of the acetate bridges.In the NaOAc system conversion of trimer to dimer was complete at 0.2 M NaOAc. Further addition of NaOAc caused the dimer to be converted to monomer.[Formula: see text]