Synthesis of two new tripodal ligands and their cyclocondensation with 2-[2-(2-formylphenoxy)ethoxy]benzaldehyde in the presence of manganese(II) and cadmium(II) metal ions

Two new asymmetric tripodal tetraamine ligands, 2-((bis(2-aminoethyl)amino)methyl)benzenamine (L2) and 2-(((2-aminoethyl)(3-aminopropyl)amino)methyl)benzenamine (L3) were synthesized and characterized. [1+1] Macrocyclic Schiff-base complexes containing 1,2-diphenoxyethane head units and a 2-aminobenzyl pendant arm, were synthesized as [MnL4(MeOH)](ClO4)2 (1), [MnL5(MeOH)](ClO4)2 (2), [CdL4(H2O)](NO3)2 (3) and [CdL5(H2O)](NO3)2 (4) from the metal ion templated cyclocondensation reactions of 2-[2-(2-formylphenoxy)ethoxy]benzaldehyde with the (L2) or (L3) tripodal tetraamine ligands. The crystal structure determination of (1) and (4) showed that the complex cations that had formed consisted of pentagonal bipyramidally coordinated Mn(II) and Cd(II) ions, centrally located in a N3O2 macrocycle, with one 2-aminobenzyl pendant arm. Supporting ab initio HF-MO calculations have been undertaken using the standard 3-21G∗ and 6-31G∗ basis sets.

Graphical abstractTwo tetraamine tripodal ligands of 2-((bis(2-aminoethyl)amino)methyl)benzenamine (L2) and 2-((2-amino-ethyl)(3-aminopropyl)amino)methyl)benzenamine were synthesized and their cyclocondensation with 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde (L4) in the presence of Manganes(II) and cadmium(II) ions were examined.Figure optionsDownload full-size imageDownload as PowerPoint slide