Di-pyridyl organic cation directed hybrid cuprous halogenides: syntheses, crystal structures and photochromism and photocatalysis

] tetrahedra. The UV-vis diffuse-reflectance measurements reveal that the compounds 3-4 exhibit semiconducting behaviors with narrow band gaps of 1.48 and 2.21 eV, respectively, which lead to efficient photocatalytic degradation activities over an organic pollutant under visible light irradiation. The possible photocatalytic mechanism is also proposed based on experimental and theoretical studies. Furthermore, compound 1 shows interesting photochromism behavior maybe owing to the photo-induced intermolecular charge transfer.