Hydrothermal syntheses, crystal structures, and photocatalytic properties of two Co(II) complexes with the flexible citraconic acid

Two Co(II) coordination polymers, [Co(ca)(bib)]n (I) and {[Co(ca)(bibp)1.5]·1.5H2O} n (II) (H2ca = citraconic acid, bib = 1,4‐bis(1‐imidazoly)benzene, bibp = 1,4‐bis‐[4‐(imidazol‐1‐yl)benzyl]piperazine), were prepared by hydrothermal method and measured structurally by single‐crystal X‐ray diffraction, infrared spectroscopy, and elemental analysis. Complex I shows a 2D layer structure containing Co‐carboxylate chains. Complex II displays a 3D metal–organic framework composed of the binuclear [Co2(CO2)2]2+ cluster nodes through ca2− and bibp as linkers with (412·63) topology. Complexes I and II have high thermal stabilities because their frameworks maintain good integrity before 340°C and 265°C, respectively. Both complexes show well photocatalytic activities for methylene blue degradation under UV irradiation in the presence of H2O2, which may be used as potential materials for photocatalytic dyes degradation.