Synthesis, structures and characterization of two cobalt(II) coordination polymers with 2,5-dichloroterephthalic acid and flexible bis(benzimidazole) ligands

Abstract

Two Co(II) coordination polymers (CPs), namely [Co(L1)(DCTP)]n (1) and [Co(L2)(DCTP)]n (2) [L1 = 1,4-bis(5,6-dimethylbenzimidazol-1-yl)butane, L2 = 1,5-bis(5,6-dimethylbenzimidazol-1-yl)pentane, H2DCTP = 2,5-dichloroterephthalic acid] were synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, powder X-ray diffraction (PXRD) and infrared spectroscopy. CP 1 has a 2D (4,4) corrugated sheet structure, which is further extended into a 2D double layer by C–H···O weak hydrogen bonding interactions, while CP 2 displays a 2D layer with hcb network, which is assembled into a 3D supramolecular framework through C–H···O hydrogen bonding. Both CPs exhibited promising photocatalytic activities for the degradation of methylene blue under UV irradiation. In addition, the thermal stabilities and the luminescence properties of both CPs have been investigated.