Neutral organometallic palladium(II) aquo complexes

The reactions of chlorobridged cyclometalated complexes [Pd(C-N)(mu-Cl)](2) (C-N = orthometalated N,N-dimethylbenzylamine, dmba; 2-(para-tolyl)pyridine, p-tolpy; azobenzene, azb; N,N-dimethyl-1-naphthylamine, dmna; and 2-benzylpyridine, bzpy) with Li(Fmes) (Fimes = 2,4,6-tris(trifluoromethyl)phenyl or nonafluoromesityl) give, after hydrolysis, neutral aquo complexes [Pd(C-N)(Fmes)(OH2)] where the ipso carbon atoms of the Fines and the cyclometalated ligand are coordinated cis, as shown by an X-ray diffraction study of [Pd(dmba)(Fmes)(OH2)]. The aquo ligand is readily displaced by other ligands, giving complexes [Pd(C-N)(Fmes)L] (1, = PPh3, 2,6-lutidine, NH3, (CNBu)-Bu-t, CO) when monodentate ligands are employed or [Pd(dmba-C)(Fmes)(2,2'-bipy)], which contains a chelating 2,2'-bipyridyl and a monodentate C-bonded dmba, Different processes in solution are detected for the complexes containing the bulkier ligands: ligand rotation in the complex with PPh3; inversion of the bipy ligand in [Pd(dmba-C(Fmes)(2,2'-bipy)1; and equilibria with residual water in the solutions of [Pd(C-N)(Fmes)(lut)1 and [Pd(dmba-C)(Fmes)(2,2-bipy)].