Carboxylate mixed ligand complexes of copper(II) with some chelating carbonyl and imine ligands and their reactivity

Summary

The reaction of CuL₂ where L is ethylacetoacetate (EAA),o-hydroxyacetophenone (OHAP) ando-hydroxycrotonophenone (OHCP), with trichloroacetic acid (TCA) in chloroform yielded mixed ligand complexes of the type CuL(TCA). They have sub-normal magnetic moments and their ligand field spectra suggest a square-planar configuration. Their i.r. spectra indicate bidentate chelating carboxylate groups. The mixed ligand complexes CuL(OXINE), where LH is salicylaldehyde (SAL) or salicylaldimine (SALIMINE), have been also obtained. The treatment of CuL(OXINE) where L is SAL, SALIMINE, ACAC or salicylaldehydephenylhydrazone (SALPHN) with TCA yielded Cu(OXINE)(TCA). On reacting Cu(OHAP)(SAL) and Cu(SAL)(ACAC) with TCA, Cu(SAL)(TCA) and Cu(ACAC)(TCA), respectively, were produced. The displacement of coordinated L from CuL(TCA) by other bidentate chelating ligands in benzene has been also studied. Thus, EAA in Cu(EAA)(TCA) was replaced by OHAP, and SAL in Cu(SAL)(TCA) by OHCP. The reactions reveal the following orders of Cu-O strength: TCA > OXINE > SALIMINE > ACAC > OHCP > SAL > OHAP > EAA and OXINE > SALPHN.