N,N′-Ethylenediaminobis(benzylphosphonic acids) as a potent class of chelators for metal ions

Aminophosphonates were found to be effective metal ion chelators. Ethylenediamine (EN) itself binds strongly to a series of metal ions forming efficient five-membered chelate ring using two nitrogen donors. Combination of EN with phosphonate function results in the family of low molecular chelating agents. Introduction of a pyridine moiety into EN–phosphonate structure results in the very effective ligands involving a four-nitrogen donor set to coordinate the metal ion. In this work, the potentiometric and spectroscopic data for two analogues 2,2′-(ethylenedi-imino)bis(3-pyridylphosphonic-acid) – L2 and 2,2′-(ethylenedi-imino)bis(2-pyridyl-phosphonic-acid) – L3, comprising EN, two phosphonates and two pyridines with Cu(II), Ni(II) and Zn(II) ions are presented showing very high efficacy of one of the ligands studied.

Graphical abstractEthylenediamine (EN) itself binds strongly to a series of metal ions forming efficient five-membered chelate ring using two nitrogen donors. Combination of EN with phosphonate and pirydyl function results in the family of very effective low molecular chelating agents. The potentiometric and spectroscopic data for two analogues L2 and L3 with Cu(II), Ni(II) and Zn(II) are presented.Figure optionsDownload full-size imageDownload as PowerPoint slide