Zinc Complexes of Cyclodextrin-bearing 8-Hydroxyquinoline Ligands: A Comparative Study.

The mounting evidence supporting the role of metal ions in several diseases has turned metal-ion chelation therapy into a promising treatment strategy. The design of efficient metal-binding ligands requires in-depth knowledge of molecular structure and stability constants of the complexes formed. This paper presents an extensive overview on the stability of zinc(II) and copper(II) complexes of a series of cyclodextrin-8-hydroxyquinoline conjugates. In order to explain the differences observed in the stability constants between the metal complexes of the 6-functionalized and 3-functionalized cyclodextrin isomers, conformational analysis and DFT simulations were also performed. Molecular simulations allowed us to clarify the binding mode and to explain the differences in the stability constants of the metal complexes of these derivatives.