Three Cd(II) coordination polymers containing phenylenediacetate isomers: Luminescence sensing and adsorption antibiotics performance in water

Abstract

Three new Cd(II) coordination polymers (CPs) [Cd(opda) (tib)]·H2O (1), [Cd4(mpda)4(tib)2(dib)2]·7H2O (2), [Cd(ppda) (tib)]·4H2O (3), have been synthesized by using isomeric phenylenediacetates (H2pda) and 1,3,5-tris(1-imidazolyl)benzene (tib) ligand under hydrothermal condition. Single crystal X-ray structures showed that CP 1 constitutes 3,5-connected 2-nodal net with a three-dimensional (3D) structure, while CP 2 forms an ring 1D chain, CP 3 has a interpenetrated 2D structure. The structural diversity of these CPs is mainly attributed to the different coordination modes and isomer conformations of the flexible phenylenediacetic acids. Three CPs are highly selective and sensitive luminescent sensors toward tetracycline (TEC). Compared with CPs 2 and 3, CP 1 has higher quenching percentage and adsorption capacities (64.493 mg g−1) for TEC due to its large specific surface area (171.72 m2 g−1) and pore volume (0.31 cm3 g−1). The main adsorption mechanisms are physisorption and chemisorption, including pore filling effect and π-π interaction. This study provides new insights into the design of 3D CPs for removing pollutants from industrial wastewaters, with the potential to mitigate health risks to humans and natural ecosystems.