New Cu(I) square grid-type and Ni(II) triangle-type complexes: synthesis and characterization of effective binders of DNA and serum albumins.

Multivalent molecules are a potential group of bioactive compounds endowed with high affinity and specificity in innovative biomolecule-targeting therapeutic approaches. Herein, we report on a new and versatile N,N,N,N-donor ligand L (1 R ,4 R )-N1,N4-bis(quinolin-2-ylmethylene)cyclohexane-1,4-diamine with two coordinating quinoline moieties connected with trans -1,4-diaminocyclohexane. It coordinates Cu + forming a [2 × 2] square grid-type complex C1 [Cu 4 L 4 ] 4+ and Ni 2+ giving a triangle-type complex C2 [Ni 3 L 3 ] 6+ . We screened their potential as versatile metal-based Serum Albumin (SA), double helical and G-quadruplex DNA binders taking advantage of their shape, size and stability effects using different spectroscopic experiments (UV-Vis, fluorescence, circular dichroism). The findings of our work suggest the potential utility of the metal complexes herein described in the context of the new drug discovery.