Construction Of Metal-Organic Cages Based On Anthraquinone And Research On Photocatalytic Properties

Metal-organic cages(MOCs)are well-designed supramolecular self-assemblies with finite backbones and confined cavities.MOCs can encapsulate guest molecules to shorten the distance between host and guest molecules and improve electron transfer and energy transfer.Because of the special microenvironment,metal-organic cages have become an important model for learning and simulating the enzymatic catalytic process in nature.Derivatives of anthraquinone possess good optical activity and can participate in organic photocatalytic reactions.Their electron-withdrawing properties make them desirable to transfer electrons in the reaction.In this paper anthraquinones are selected as the main body to be incoperated into metal-organic cages to explore their photocatalytic properties.A sub-component self-assembly strategy was used to synthesize a tetrahedral structure Ni-AFP,which imparted electronically deficient anthraquinones within the ligand backbone using nickel as metal nodes.The metal-organic tetrahedral cavity can encapsulate fluorescein molecules and can participate in the photo-driven water cracking hydrogen production process.By adjusting the reaction conditions of the system,the TON value is up to 1200 per mole redox catalyst.The control experiments confirmed that the process of hydrogen production from water has the characteristics of enzymatic reaction.The formation of host-guest complex has increased the local reaction concentration and contributed to the improvement for efficient hydrogen production.In recent years,organic photocatalysis has become the focus in organic reactions.Anthraquinones are photooxidation catalysts with broad application prospects in the field of photocatalysis.Zn-DEP with [2+3] structure was synthesized by introducing anthraquinone into metal-organic cage structure and using amide bond as the connecting group.The Zn-DEP could be applied to the oxidation of benzyl alcohols.The host-guest package can enhance the efficiency of the photocatalytic oxidation by closing the distance between the catalytic center and the substrate and increasing the local reaction concentration.The metal-organic cage compound exhibited unique advantages in the photocatalytic reaction compared with anthraquinone monomer.