Construction And Properties Research On Coordination Polymers Based On D¹⁰transition Metal And Porphyrin Based Polymers

Coordination polymers?CPs?and porous organic polymers?POPs?are known for their porous properties and diverse structures,attracting many researchers to devote themselves to research.In particular,they show excellent potential application value in the fields of fluorescence sensing,chemical adsorption,heterogeneous catalysis,and new energy materials.It attracts more and more researchers to dedicate to this field.In recent years,there have been more and more studies on CPs based on semi-rigid ligands.However,in the molecular design of CPs,bridged oxygen-containing semi-rigid ligand molecules have a larger molecular twisting distance,which makes the ligands more flexible to form CPs with metal ions.Metal porphyrins and their derivatives have ultra-long conjugated structures and metal sites in the molecular center.Porphyrin-based polymer composed of porphyrin as monomer has porous characteristics and Lewis acid active sites,and porphyrin-based polymers exhibit excellent potential application value in the fields of chemical adsorption,catalysis,and solar cells.In the paper,we designed synthesized a semi-rigid ligand containing bridge oxygen,namely 6-?carboxymethoxy?-2-naphthoic acid.Next,we constructed six coordination polymers by using transition metals and ligands we have synthesized,which are named Zn?CIA?]_n?1?,[Cd?CIA??H₂O?]_n?2?,[Co?CIA?₂?H₂O?₄]?3?,[Ni?CIA?₂?H₂O?₄]?4?,[Cu?CIA??H₂O?]_n,?5?[Ni?CIA??H₂O?]_n?6?respectively.The structures were characterized by single crystal X-ray diffraction,powder X-ray diffraction,infrared spectroscopy,elemental analysis,and thermogravimetric analysis.The metal ion in 1 has a tetrahedral geometry,and the 2D layers of 1 are connected to each other through hydrogen bonding to form a 3D supramolecular network.The metal ion in 2 has a octahedral geometry,and the 2D layers of 2 are connected to each other through hydrogen bonding to form a 3D supramolecular network.The molecular skeletons of 3 and 4 are the same,which is an OD structure formed by metal ions,water molecules and ligands.Each OD structure is connected to each other through a hydrogen bond to form a 3D supramolecular network.Compounds 5 and 6 also have an isomorphic relationship,which is a 2D structure formed by alternately connecting adjacent paddle metal centers and ligands,and each layer of skeleton forms a 3D supramolecular network through hydrogen bonding.Based on its structural characteristics,we further explored the fluorescence properties of 1 and 2,and studied the ultraviolet absorption properties of 4-6.In addition,we used 5,10,15,20-tetra?phenyl?porphyrin copper as the monomer to synthesize two porous polymers PAF-40-Cu and HCP-Cu through the crosslinking reaction of dimethoxymethane and Scholl coupling reaction.After PXRD,SEM and TGA characterization,the two polymers were found to have an amorphous structure,with amorphous multi-level pores and excellent thermal stability.Therefore,we tested the catalytic performance of the two polymers during the oxidation of styrene.We found that the reaction efficiency of HCP-Cu as a catalyst reached 89.5%,the selectivity to styrene oxide reached 80.89%.the reaction efficiency of PAF-40-Cu as a catalyst was 91.2%,and the selectivity to styrene oxide reached 84.32%.PAF-40-Cu can maintain good catalytic performance after four cycles.