Synthesis and characterization of hexacoordinate cobalt(III) complexes bearing three C,O-bidentate ligands

Hexacoordinated Co(III) complexes bearing three C,O-bidentate ligands (9a and 9b) were prepared from 1-bromo-2-(p-tolyloxymethyl)benzene (8a) and 1-bromo-2,6-bis(p-tolyloxymethyl)benzene (8b), respectively. Both complexes were stable in air at room temperature. X-ray analyses revealed that the structures of both complexes were essentially the same. According to variable temperature ¹H NMR study, it was found that the two oxygen ligands on the same aromatic ring of 9b interchanged with each other.