Syntheses, crystal structures and DNA binding potential of copper(II) carboxylates

Abstract

Copper(II) carboxylate complexes [Cu2{CH3CH(C6H5)CH2COO}4]n (1) and [Cu2{CH3CH(C6H5)CH2COO}4(3-MePy)2] (2) were synthesized and characterized by FT-IR and single crystal X-ray analyses. Bridging bidentate binding modes of the carboxylate ligands were first suggested by FT-IR spectra and later on confirmed by x-ray diffraction. Complexes 1 and 2 exhibited polymeric and discrete molecular units, respectively, with a paddle wheel arrangement of the bridging carboxylate ligands around the copper centers with octahedral coordination geometry. Both the complexes have shown hypochromism with no (complex 2) or a very small red shift of 3 nm (complex 1) on addition of SSDNA suggesting a mixed binding mode consisting of partial intercalation of the complexes into the base pairs of DNA together with groove binding.Molecular docking studies have shown increase in steric descriptors including octanol-water partition coefficient (slogP), molar refractivity (MR), and surface volume (Vsurf) with increasing binding strength of the complexes.