Mixed ligand complexes of cobalt(II and III) - Molecular structure of bis-(4-acetophenylsalicylaldiminato)acetylacetonato cobalt(III)

The bidentate Schiff bases, HL'(= N-4-acetophenylsalicylal- dimine), H "(=N -3-acetophenylsalicylaldimine) and HL"' (=N-4-acetophenyl-5-bromosalicylald imine do not form complexes with simple cobalt(II)salts, e.g.,Co(CH3COO)(2) . 4H(2)O and CoCl2. 6H(2)O but undergo facile reactions with Co(acac)(2). 2 H(2)O (acac=monoanion of acetylacetone). Mixed ligand complexes of both cob alt(III), [Co(L)(2)(acac)] and cobalt(II), [Co(L)(acac)] (L=L', L ", L"') h ave been isolated and characterised by elemental analyses and magnetic susc eptibility measurements, electronic, IR and mass spectral studies and by si ngle crystal X-ray crystallographic structure analysis. The cobalt atom is octahedrally coordinated in which four ligand oxygen atoms define an equato rial plane; the two nitrogen atoms of the L' ligands are in trans-axial pos itions.