Complex formation of pyridine-azacrown ether amide macrocycles with proton and heavy metal ions in aqueous solution

This research concerns the analysis of the proton and metal ion binding of amide macrocycles of different structures and sizes by potentiometric, H-1 NMR and X-ray diffraction methods. Protonated ligands exist as a 3D network structures. The ligands form 1:1 complexes with heavy metal ions (Cu2+, Cd2+, Pb2+, Zn2+, and Ni2+) in aqueous solutions and demonstrate the high selectivity towards Cu2+ cations. The pyridine-2,6-dicarbamide fragment provides structural rigidity to crown ether, resulting the molecule has an open cavity and faster kinetics of metal complexes formation. Copyright (c) 2015 John Wiley & Sons, Ltd.