The Synthesis of Copper(II) Salicylaldiminato Complexes and their Catalytic Activity in the Hydroxylation of Phenol
Journal article, 2007
The synthesis of copper(II) salicylaldiminato complexes and their application in the catalytic hydroxylation
of phenol is reported. Tetracoordinated copper complexes (Cu(Ln)2) were obtained by reacting
the N-phenylsalicylaldimine ligands (HL1 –HL7) with copper acetate in a 2 : 1 mole ratio. The
reaction of N-(2,6-diisopropyl)phenyl-3,5-di-tert-butylsalicylaldimine (HL7) with copper acetate in a
1 : 1 mole ratio afforded a dinuclear complex, which was not obtained with the other ligand systems.
All complexes were characterized using FT-IR and elemental analysis. X-Ray crystal structures of
complexes 2, 5 and 8 have also been obtained. The catalytic activity of these complexes was evaluated
in the hydroxylation of phenol using oxygen and hydrogen peroxide as co-oxidants in aqueous
media in the pH range 3 – 6. All complexes studied were found to be active for the hydroxylation
process over the pH range studied with higher selectivity for catechol formation.
Tetracoordinated Copper(II) Complexes