Syntheses, crystal structures and visible light driven photocatalytic properties of organic-inorganic hybrid cuprous halides

Abstract By using in situ N-alkylating [(Me)2-2,2-bipy]2+ organic cation as structural-directing agent (SDA), two new types of organic-inorganic hybrid cuprous halides, namely, [(Me)2-2,2-bipy]Cu3I5 (1) and [(Me)2-bipy)]2Cu7Br9I2 (2), have been solvothermally synthesized and structurally characterized. The compound 1 crystallizes in the monoclinic space group P21/n (No. 147) and features one-dimensional (1D) anionic [Cu3I5]2- chains separated by [(Me)2-2,2-bipy]2+ cations. The structure of compound 2 contains a 1D [Cu7Br9I2]2- anionic chain, which belongs to the first hybrid cuprous halide with mixed halogen elements. The UV–vis absorption optical measurement reveals that the compounds possesses narrow band gaps of 1.95–2.14 eV, which leads to stable photocatalytic degradation activity over organic pollutant under visible light irradiation. The possible photocatalytic mechanism and reason of photochemical stability is also proposed based on experimental results and electronic band structural calculation.