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)·(H 2 O) 2 ]·(H 2 O)} n ( 1 ), [Ni(DCTP)(L2)·(H 2 O) 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, H 2 DCTP = 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 {6 6 }. 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.