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 [Cd 2 (oba) 2 (phen) 2 ] n ( 1 ), [Mn 3 (oba) 3 (phen) 2 ] n ( 2 ), [Zn(oba)(phen)] n ( 3 ) and [Mn(oba)(dmphen)] n ( 4 ) (H 2 oba = 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 [Mn 3 (oba) 3 (phen) 2 ] bridged by the oba 2− 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 .