A nucleophilic reaction of acetylacetonatocobalt(III) complexes with nitriles in Lewis acidic conditions

Under Lewis acidic conditions, tris(acetylacetonato)cobalt(double bond; length as m-dashCo(acac)3) reacted with ethoxymethylenemalononitrile (double bond; length as m-dashETMN), analogous derivatives and general aliphatic nitriles to give a new type of β-imino–cobalt(III) complexes. A possible mechanism for this reaction is proposed. In the case of ethyl acetocyanoacetate, an acylated γ-acetylimino–cobalt(III) complex was isolated. The structure of the complex was explained supporting the proposed mechanism. The crystal structures of several complexes were determined by X-ray diffraction. One of the complexes showed prominent crystal dichroic properties in the first absorption band region. Benzoyl cyanide and phthalonitrile did not react with Co(acac)3 under the same conditions.