Cobalt(II) Complexes of β-Ketoamines Derived from β-Diketones and Aromatic Amines

Abstract

Abstract Many compounds of the Co(Aca.R)2 and the Co(Bza.R)2 type have been synthesized, in order to examine the stereochemistry of bis(β-ketoaminato) cobalt(II) complexes (bis(acetylacetone and bis(benzoylacetone-aminato)cobalt(II) complexes are abbreviated as Co(Aca.R)2 and Co(Bza.R)2, respectively, R being an aryl group attached to the nitrogen atom.) and compare it with that of bis (salicylideneiminato) cobalt (II) complexes. The configuration of these cobalt (I I) complexes in non-donor solvents is tetrahedral, but the complexes in pyridine take a tetrahedral, a penta-coordinate or an octahedral configuration, depending upon the ligand. The complexes of the Co(Bza.R)2 type in pyridine take an octahedral configuration, except for Co(Bza.2, 6-X2C6H3)2, where X denotes CH3 and C2H5. On the contrary, Co(Aca.CH3C6H4)2, Co(Aca.2, 6-(CH3)2C6H3)2 and Co(Aca.α-naphthyl)2 in pyridine retain a tetrahedral configuration, while the complexes, such as Co(Aca.C6H5)2 and Go(Aca.ClC6H4)2, take an octahedral configuration with two pyridine molecules bound to the cobalt(II) ion.