Novel copper(II) coordination polymer containing the drugs nalidixic acid and 8-hydroxyquinoline: Evaluation of the structural, magnetic, electronic, and antitumor properties

Abstract

Herein we describe the synthesis, structural characterization, physical/spectroscopic studies and evaluation of the antitumoral activity of a new copper(II) coordination polymer, [Cu(ndx)(8-hq)]n, where H(ndx) is nalidixic acid and H(8-hq) is 8-hydroxyquinoline. Single crystal X-ray diffraction shows a zigzag polymeric chain, where the adjacent copper atoms are connected via anti-anti μ-carboxylate bridge of ndx. This structural feature is quite different from those previously proposed for quinolone complexes. Variable-temperature magnetic susceptibility measurements showed weak antiferromagnetic interactions between the paramagnetic copper centers (−0.49 cm−1). In solution, the compound exists as neutral mononuclear species and it can inhibit the growth of a human chronic myelogenous leukemia cell line (K562) in a concentration-dependent manner with IC50 value lower than those of the corresponding free ligands. At similar doses, the compound does not alter the viability of human keratinocytes (HaCaT cell line). Spectroscopic data and viscosity measurements show that the compound binds to DNA (Kb = 2.47 × 105 M−1) interacting with it by a non-intercalative mode.