Syntheses, Structures, and Reactivities of Novel Palladium β-Diiminato−Acetate Complexes

The reaction between (Ar2nacnac)H (Ar = C6H5, ligand a; 2,6-(iPr)2C6H3, ligand b) and [Pd(OAc)2] produces red complexes [Pd(Ar2nacnac)(OAc)] (1a: Ar = C6H5; 1b: Ar = 2,6-(iPr)2C6H3). Complex 1a has a dimeric structure in the solid state with two bridging acetates, while a monomer−dimer equilibrium establishes in solution. Complex 1b is monomeric in both the solid state and solution. Both are air- and moisture-stable compounds, unlike [Pd(Ph2nacnac)2] (2), which easily hydrolyzes in the presence of moisture to give [Pd(Phnacac)2] (3) (Phnacac = {CH3C(NPh)CHC(O)CH3}−). Compound 1a reacts with metal acetates to produce heterotrimetallic complexes of a general formula [Pd(Ph2nacnac)]2-μ-[M(OAc)4] (4, M = Cu; 5, M = Zn). Treating 1a with KOH in THF, or alternatively [Pd(Ph2nacnac)Cl]2 with KOtBu in wet THF, produces [Pd(Ph2nacnac)(OH)]2 (6).