Coordination abilities of difunctional, diaminophosphonic acid and its dipeptides towards Cu(II) ions

Phenylenedi(aminomethylphosphonic) acid (L9) and its peptides with L-Ala and β-Ala residues were synthesized and their ability to bind Cu(II) ions in aqueous solution was studied. L9 forms complexes with metal to ligand ratios of 1:1 and 1:2 which are typical for aminophosphonic acids coordination mode 1x or 2x{NH2,PO32-}. In the case of their dipeptide derivatives (L10–L12), only one peptidyl chain is involved in the binding of metal ion with stoichiometry 1:1 and coordination pattern similar to that found in the simple phosphonic dipeptides. The influence of metal ion chelation on the properties of uncoordinated group in the same ligand molecule was found.

Graphical abstractAminophosphonates and their peptidic analogues are systematically investicated compounds as the receptors for biomolecules. We have synthesized a potential receptor, 1,4-phenylene-di(N-l-alanylaminomethyl-phosphonate) able to form ionic-pairs with lysine and arginine in methanol and aqueous solutions. The binding abilities toward Cu(II) ions of this ligand as well as its analogues are presented in this paper.Figure optionsDownload full-size imageDownload as PowerPoint slide