A family of coordination polymers derived from a flexible dicarboxylic acid and auxiliary N-donor ligands: solvothermal synthesis, crystal structure and dye adsorption properties

Four novel coordination polymers [Cd2(oba)2(phen)2]n (1), [Mn3(oba)3(phen)2]n (2), [Zn(oba)(phen)]n (3) and [Mn(oba)(dmphen)]n (4) (H2oba = 4,4′-oxybis (benzoic acid), phen = 1,10-phenanthroline, dmphen = 2,9-dimethyl-1,10-phenanthroline) have been synthesized by the solvothermal method and then characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectrum, UV–Vis spectroscopy and thermogravimetric analysis. Structural analysis suggests that complex 1 displays a 1D ribbon-like structure, which extends into a 2D supramolecular layer by intermolecular π⋯π stacking. For complex 2, the trinuclear building unit of [Mn3(oba)3(phen)2] bridged by the oba2− ligands leads to the formation of a 3D supramolecular network. Complex 3 adopts a mononuclear and 1D zigzag chain structure and also extends into a 2D supramolecular network by intermolecular π⋯π stacking. Complex 4 shows 1D infinite double-chain structures which are shaped by intermolecular π⋯π stackings. Photoluminescent properties of complexes 1 and 3 in solid state were also studied. In addition, complex 2 exhibits high performance in the selective adsorption of Congo red (CR) with an adsorption capacity of 64.4 mg g−1.