Mixed ligand complexes of cobalt(II and III) — Molecular structure of <i>bis-</i>(4-acetophenylsalicylaldiminato)acetylacetonato cobalt(III)

Abstract

The bidentate Schiff bases, HL'(= N-4-acetophenylsalicylal-dimine), H<i>"</i>(=N-3-acetophenylsalicylaidimine) and HL<i>'"</i>(=N-4-acetophenyl-5-bromosalicylaldimine) do not form complexes with simple cobalt(II)salts, e.g.,Co(CH₃COO)₂.4H₂O and CoCl₂.6H₂O but undergo facile reactions with Co(acac)₂.2H₂O (acac=monoanion of acetylacetone). Mixed ligand complexes of both cobalt(III), [Co(L)₂(acac)] and cobalt(II), [Co(L)(acac)] (L=L<i>'</i>, L<i>"</i>, L<i>"'</i>) have been isolated and characterised by elemental analyses and magnetic susceptibility measurements, electronic, IR and mass spectral studies and by single crystal X-ray crystallographic structure analysis. The cobalt atom is octahedrally coordinated in which four ligand oxygen atoms define an equatorial plane; the two nitrogen atoms of the L<i>' </i>ligands are in <i>trans-</i>axial<i> </i>positions.