Ruthenium Tris(bipyridine) Encapsulation in Zeolitic Imidazolate Framework-71 and its Photocatalytic Properties

Ruthenium tris(bipyridine) [Ru(bpy)3] acts as a photocatalyst under visible-light irradiation. However, it undergoes dimerization and degradation and has a short photocatalytic life. In this study, we encapsulated Ru(bpy)3 as a guest molecule in a suitable host material, which is a zeolitic imidazolate framework-71 (ZIF-71), using a simple in situ synthesis method. This stabilized its photocatalytic activity. A series of Ru(bpy)3@ZIF-71 composites (������ = Zn2+: Ru ratio = 1, 3, 5, 7, and 10) with different amounts of loaded Ru(bpy)3 were synthesized and characterized by X-ray diffraction, ultraviolet-visible (UV-vis) spectroscopy, and fluorescence spectroscopy. The crystal structure of ZIF-71 was maintained in the Ru(bpy)3@ZIF-71 samples, and their UV-vis absorbance and fluorescence were almost identical to those of pure Ru(bpy)3. Moreover, Ru(bpy)3@ZIF-71 exhibited a high conversion yield (95 %) for the photocatalytic conversion of ������-bromoacetophenone to acetophenone and good recycling stability over three cycles. We believe this strategy can be applied to fabricate other similar host-guest photocatalytic systems.