NCN-Pincer Cobalt Complexes Containing Bis(oxazolinyl)phenylLigands.

We describe the preparation and characterizationof new NCN-pincerCo(III) complexes containing bis(oxazolinyl)phenyl (phebox) ligandsas auxiliary ligands. The reaction of Co2(CO)8with the 2-bromo-substituted ligand precursor (phebox-R)Br (1a, R = Me2; 1b, R = iPr) resulted in the formation of the tricarbonyl Co(I)complex (phebox-R)Co(CO)3(2a, R = Me2; 2b, R = iPr), in which NC-bidentatecoordination of the phebox ligand was observed. Complexes 2underwent oxidative addition of I2to give the Co(III)aqua complex (phebox-R)CoI2(H2O) (4a, R = Me2; 4b, R = iPr) by a change in the coordination geometry to the NCN-tridentatemode. Ligand exchange reactions of H2O or I ligand withCNtBu or AgOAc smoothly proceeded to give the isocyanidecomplex (phebox-dm)CoI2(CNtBu) (5) or the acetate complex (phebox-dm)Co(κ1-OAc)(κ2-OAc) (6), respectively. [ABSTRACT FROM AUTHOR]