Synthesis and characterization of three Cd(II) Schiff-base macrocyclic N3O2 complexes

Three polyamine ligands of N1-(2-nitrobenzyl)-N1-(2-aminoethyl)ethane-1,2-diamine (L1), N1-(2-nitrobenzyl)-N1-(2-aminoethyl)propane-1,3-diamine (L2) and N1-(2-nitrobenzyl)-N1-(3-aminopropyl)propane-1,3-diamine (L3) were synthesized and their cyclocondensation with 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde (L4) in the presence of various metal(II) ions was examined. These reactions only in the presence of a stoichiometric amount of cadmium(II) nitrate gave the related cadmium(II) macrocyclic Schiff-base complexes. In all the other cases no cyclic complexes have been obtained and metal(II) polyamines were the only products. The complexes have been studied with IR, 1H NMR, 13C NMR, DEPT, COSY, HMQC and microanalysis. The crystal structures of [Cd(NO3)(L5)(μ-NO3)Cd(NO3)(L5)]0.5Cd(NO3)4 (1) and [CdL5(NO3)(CH3OH)]ClO4 (2) have been also determined.

Three polyamine ligands of N1-(2-nitrobenzyl)-N1-(2-aminoethyl)ethane-1,2-diamine (L1), N1-(2-nitrobenzyl)-N1-(2-aminoethyl)propane-1,3-diamine (L2) and N1-(2-nitrobenzyl)-N1-(3-aminopropyl)propane-1,3-diamine (L3) were synthesized and their cyclocondensation with 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde (L4) in the presence of various metal(II) ions was examined. These reactions only in the presence of a stoichiometric amount of cadmium(II) nitrate gave the related cadmium(II) macrocyclic Schiff-base complexes. In all the other cases no cyclic complexes have been obtained and metal(II) polyamines were the only products. The complexes have been studied with IR, 1H NMR, 13C NMR, DEPT, COSY, HMQC and microanalysis. The crystal structures of [Cd(NO3)(L5)(μ-NO3)Cd(NO3)(L5)]0.5Cd(NO3)4 (1) and [CdL5(NO3)(CH3OH)]ClO4 (2) have been also determined.Figure optionsDownload as PowerPoint slide