Synthesis of Transition Metal Complexes with Aza-Crown Substituted Unsymmetrical Salicylaldimine Bis-Schiff Base Ligands and Metal Schiff Base Complex Catalysed Oxidation of P-Xylene to P-Toluic Acid
Free accessResearch articleFirst published online July, 2012
Synthesis of Transition Metal Complexes with Aza-Crown Substituted Unsymmetrical Salicylaldimine Bis-Schiff Base Ligands and Metal Schiff Base Complex Catalysed Oxidation of P-Xylene to P-Toluic Acid
Four unsymmetrical, salicylaldimine bis-Schiff bases with pendant benzo-10-aza-15-crown-5- or morpholino-groups and their 1:1 (ligand /metal) complexes with cobalt, copper and manganese have been synthesised and studied as catalysts in the aerobic oxidation of p-xylene to p-toluic acid. Significant selectivity (up to −90%) and conversion levels (up to −70%) were obtained. The effects of the pendant aza-crown ether group in Mn(III) Schiff base complexes on the oxidation of p-xylene were also investigated by comparison with analogues having pendant morpholino-groups.
