Syntheses, crystal structures, DNA binding and electrochemical properties of two mixed-ligand cobalt(II) coordination polymers constructed from 5-(carboxymethoxy)isophthalic acid and bis-benzimidazole ligands

Abstract

Two new cobalt(II) coordination polymers, [Co(HL)(bbe)] n (1) and [Co(HL)(bbop)] n (2) (H3L = 5-(carboxymethoxy)isophthalic acid, bbe = 1,2-bis(benzimidazol-2-yl)ethane, bbop = 1,3-bis(benzimidazol-2-yl)-2-oxapropane), were synthesized and characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction and thermogravimetric analyses. Both complexes exhibit 1D chain structures, constructed from HL2− anions bridging metal ions. The 1D chains are further connected by hydrogen bonds and π–π stacking interactions to form the 3D supramolecular architectures. The cobalt centers display different coordination environments, with a tetrahedral geometry in 1 and a distorted tetragonal pyramid in 2. The DNA binding properties of both complexes were investigated by UV absorption spectroscopy. The electrochemical properties of both complexes were studied by cyclic voltammetry.