Two 3D Supramolecular Architectures Based on Cobalt(II) Coordination Polymers with Dichloroterephthalate and Semi-rigid Bis(benzimidazole) Ligands

Two Co(II) coordination polymers (CPs) [Co(DCTP)(L1)]n (1) and [Co(DCTP)(L2)·(H2O)2]n (2), were synthesized from hydrothermal reaction of Co2+ ions with the 2,5-dichloroterephthalic acid (H2DCTP) and two semi-rigid bis(benzimidazole) ligands (L1 = 1,3-bis(benzimidazol-1-ylmethyl)benzene, L2 = 1,2-bis(benzimidazol-1-ylmethyl)benzene), and structurally characterized by X-ray single crystal diffraction analysis and FT–IR. The thermal stabilities and luminescence properties of 1–2 were investigated. The two CPs exhibit 2D (4,4)-connected layer structures, which are further extended to 3D supramolecular architectures by π⋯π stacking interactions for 1 and classical O–H⋯O hydrogen-bonding interactions for 2, respectively. In addition, two complexes show promising photocatalytic activities for the degradation of methylene blue under UV irradiation.