Luminescence, electrochemical and photocatalytic properties of sub-micron nickel(II) and cobalt(II) coordination polymers synthesized by sonochemical process

Submicron structures of NiII/CoII-based coordination polymers (CPs) [Ni(L1)(mip)·H2O]n (1) and {[Co(L2)(mip)]·0·.5H2O}n(2) (L1 = 1,6-bis(5,6-dimethylbenzimidazole)hexane, L2 = 1,6-bis(benzimidazole)hexane, H2mip = 5-methylisophthalic acid) were obtained by ultrasonic irradiation and structurally characterized by elemental analysis, powder X-ray diffraction and scanning electron microscopy. Structural analysis show that two CPs feature uninodal 3-connected 2D hcb layer, whilst CP 2 is further extended into a 3D complicated supramolecular network by C14-H14⋯O2 hydrogen bonds. Ultrasonic time and power influencing morphology of sub-micron sized CPs, were also discussed. Besides that, thermal stability, luminescence, electrochemical properties and photocatalytic activity of sub-micron sized 1 and 2 were presented in detail. Moreover, sub-micron sized 1 manifests the higher photocatalytic activity than sub-micron sized 2 for decomposition of methylene blue (MB) under UV irradiation.