Visible-light-driven photocatalysts of three nickel(II) coordination polymers with mixed ligands

Abstract

Three ternary mixed-ligand Ni(II) coordination polymers (CPs) including {[Ni(DCTP)(L1)·(H2O)2]·(H2O)}n (1), [Ni(DCTP)(L2)·(H2O)2] (2), and [Ni(DCTP)(L3)] (3) (L1=1,4-bis(benzimidazol-1-yl)-2-butene, L2=1,4-bis(imidazol-1-ylmethyl)benzene, L3=1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H2DCTP=2,5-dichloroterephthalic acid), have been synthesized with a hydrothermal technique and structurally characterized by single-crystal X-ray diffraction, infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. Both CPs 1 and 2 display 2D 4-connected sql sheets, CP 1 exhibits a 2D L3(9)2(4) water layer interconnected by hydrogen bonding interactions, CP 2 is further extended into a 3D supramolecular framework through O–H⋯O hydrogen bonding interactions. CP 3 reveals a 3D 3-fold interpenetrated 4-connected dia framework with the point symbol {66}. Crystal packing analysis well indicates that O–H⋯O and C–H⋯ π are the most intermolecular interactions in CPs 1–2. Furthermore, the electrochemical properties of CPs 1–3 were discussed in detail. Notably, CPs 1–3 represented the rare examples of Ni(II) CPs materials as visible-light-driven photocatalysts and showed high activities for degradation of Methyl Blue.