Synthesis and structure of a 1-D copper(II) coordination polymer bridged both by oxamido and carboxylate: in vitro anticancer activity and reactivity toward DNA and protein BSA

Abstract

A 1-D copper(II) coordination polymer formulated as {[Cu2(bdpox)(dabt)](NO3)·H2O}n, where H3bdpox and dabt denote N-benzoate-N′-[3-(diethylamino)propyl]oxamide and 2,2′-diamino-4,4′-bithiazole, respectively, was synthesized and characterized by elemental analyses, molar conductance measurement, IR and electronic spectra studies, and single-crystal X-ray diffraction. The crystal structure analysis reveals that copper(II) ions are bridged by both cis-oxamido and carboxylato groups to form a 1-D coordination polymer with corresponding Cu···Cu separations of 5.2420(10) and 5.1551(8) Å. The endo- and exo-copper(II) ions of the cis-oxamido-bridge are located in distorted square-planar and square-pyramidal geometries, respectively. There is a 2-D hydrogen bonding network in the crystal. The in vitro anticancer activities suggest that the copper(II) complex is active against selected tumor cell lines. The reactivities toward herring sperm DNA and bovine serum albumin (BSA) reveal that the copper(II) complex can interact with DNA by intercalation and effectively quench the intrinsic fluorescence of BSA via a static mechanism. The influence of hydrophobicity of the substituents in bridging ligands on DNA and protein binding properties and the in vitro anticancer activities of such copper(II) polymers is discussed.