Playing with Structural Parameters: Synthesis and Characterization of Two New Maltol-Based Ligands with Binding and Antineoplastic Properties

Two maltol-based ligands, , '-bis((3-hydroxy-4-pyron-2-yl)methyl)-1,4-piperazine ( ) and , ', '-tris((3-hydroxy-4-pyron-2-yl)methyl)- -methylethylendiamine ( ), were synthesized and characterized. and , containing, respectively, two and three maltol units spaced by a diamine fragment, were designed to evaluate how biological and binding features are affected by structural modifications of the parent compound malten. The acid-base behavior and the binding properties towards transition, alkaline-earth (AE) and rare-earth (RE) cations in aqueous solution, studied by potentiometric, UV-Vis and NMR analysis, are reported along with biological studies on DNA and leukemia cells. Both ligands form stable complexes with Cu(II), Zn(II) and Co(II) that were studied as metallo-receptors for AE and RE at neutral pH. complexes are more affected than ones by hard cations, the -Cu(II) system being deeply affected by RE. The structural modifications altered the mechanism of action: partially maintains the ability to induce structural alterations of DNA, while provokes single strand (nicks) and to a lesser extent double strand breaks of DNA.