Synthesis, characterization and redox properties of macrocyclic Schiff base by reaction of 2,6-diaminopyridine and 1,3-bis(2-carboxyaldehyde phenoxy)propane and its CuII, NiII, PbII, CoIII and LaIII complexes

摘要

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:,14,15-tribenzo-9,13-dioxacyclohexadeca-1,5-diene (L) was synthesized by reaction of 2,6-diaminopyridine and 1,3-bis(2-carboxyaldehyde phenoxy)propane. Then, its CuII, NiII, PbII, CoIII and LaIII complexes were synthesized by a template effect by reaction of 2,6-diaminopyridine and 1,3-bis (2-carboxyaldehyde phenoxy)propane and Cu ${(hbox{NO}_{3})_{2} cdot 3hbox{H}_{2}}$ O, Ni ${(hbox{NO}_{3})_{2} cdot 6hbox{H}_{2}}$ O, Co ${(hbox{NO}_{3})_{2} cdot 6hbox{H}_{2}}$ O, La ${(hbox{NO}_{3})_{3} cdot 6hbox{H}_{2}}$ O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, 1H- and 13C-NMR-, UV-vis spectra, magnetic susceptibility, conductivity measurements, mass spectra and cyclic voltammetry. All complexes are diamagnetic and the CuII complex is binuclear. The diamagnetic behaviour of the binuclear complex may be explained by a very strong anti-ferromagnetic interaction in the Cu–Cu pair. The CoII was oxidised to CoIII.