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

2008-12-15T00:00:00Z (GMT) by Alen Hadzovic Datong Song
The reaction between (Ar<sub>2</sub>nacnac)H (Ar = C<sub>6</sub>H<sub>5</sub>, ligand <b>a</b>; 2,6-(<sup><i>i</i></sup>Pr)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>, ligand <b>b</b>) and [Pd(OAc)<sub>2</sub>] produces red complexes [Pd(Ar<sub>2</sub>nacnac)(OAc)] (<b>1a</b>: Ar = C<sub>6</sub>H<sub>5</sub>; <b>1b</b>: Ar = 2,6-(<sup><i>i</i></sup>Pr)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>). Complex <b>1a</b> has a dimeric structure in the solid state with two bridging acetates, while a monomer−dimer equilibrium establishes in solution. Complex <b>1b</b> is monomeric in both the solid state and solution. Both are air- and moisture-stable compounds, unlike [Pd(Ph<sub>2</sub>nacnac)<sub>2</sub>] (<b>2</b>), which easily hydrolyzes in the presence of moisture to give [Pd(Phnacac)<sub>2</sub>] (<b>3</b>) (Phnacac = {CH<sub>3</sub>C(NPh)CHC(O)CH<sub>3</sub>}<sup>−</sup>). Compound <b>1a</b> reacts with metal acetates to produce heterotrimetallic complexes of a general formula [Pd(Ph<sub>2</sub>nacnac)]<sub>2</sub>-μ-[M(OAc)<sub>4</sub>] (<b>4</b>, M = Cu; <b>5</b>, M = Zn). Treating <b>1a</b> with KOH in THF, or alternatively [Pd(Ph<sub>2</sub>nacnac)Cl]<sub>2</sub> with KO<sup><i>t</i></sup>Bu in wet THF, produces [Pd(Ph<sub>2</sub>nacnac)(OH)]<sub>2</sub> (<b>6</b>).