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 KO^tBu in wet THF, produces [Pd(Ph₂nacnac)(OH)]₂ (6).