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

Three polyamine ligands of N1-(2-nitrobenzyl)-N1-(2-aniinoethyl)ethane-1,2-diamine (L-1), N1-(2-nitrobenzyl)-N1-(2-aniinoethyl)propane-1,3-diamine (L-2) and N1-(2-nitrobenzyl)-N1-(3-aniinopropyl)propane-1,3-diamine (L-3) were synthesized and their cyclocondensation with 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde (L-4) 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, H-1 NMR, C-13 NMR, DEPT, COSY, HMQC and microanalysis. The crystal structures of [Cd(NO3)(L-5)(mu-NO3)Cd(NO3)(L-5)]0.5Cd(NO3)(4) (1) and [CdL5(NO3)(CH3OH)]ClO4 (2) have been also determined. (c) 2007 Elsevier Ltd. All rights reserved.