Study On Photoinduced Atom Transfer Radical Polymerization Catalyzed By Perylene-based Metal Coordination Polymer Network

In order to develop a green and efficient photoinduced atom transfer radical polymerization,the key problem is to develop new photocatalysts.Due to the unique advantages of metal coordination polymer network?MCP?,it is widely used in the field of photocatalysis.Based on the molecular structure design of MCP,perylene-based copper coordination polymer network?Cu-PTC?and perylene-based cobalt coordination polymer network?Co-PTC?were synthesized.Cu-PTC was used as a catalyst for atom transfer radical polymerization of conjugated vinyl monomers methyl methacrylate?MMA?under visible light,and co PTC as a catalyst for non conjugated vinyl monomers vinegar under visible light Atom transfer radical polymerization of vinyl acetate?VAc?.The main research contents and important results are as follows:?1?Perylene copper coordination polymer network?Cu-PTC?and perylene cobalt coordination polymer network?Co-PTC?were synthesized by self-assembly at room temperature with 3,4,9,10-perylene tetracarboxylic dianhydride as organic ligand,divalent copper ion and divalent cobalt ion as metal center.The chemical structure,crystal structure,fabric structure,band structure and photoelectric properties of the two materials were compared and analyzed.And the relationship between the structure and photoelectric properties of the two materials was studied.The results show that both Cu-PTC and Co-PTC have 00h crystal structure,larger specific surface area(91.992 m²g^-1 for Cu-PTC and102.876 m²g^-1 for Co-PTC),higher contribution rate of micropore?all around 10%?,stronger photocurrent response?0.07?A/cm² for Cu-PTC and 0.04?A/cm² for Co-PTC?and wider spectral absorption?200-800 nm?.?2?Atom transfer radical polymerization of MMA was carried out by using Cu-PTC with visible light activity as a catalys.The kinetic study shows that the polymerization process is consistent with the living radical polymerization characteristics,and the polymerization behavior can respond quickly to the switching of the light field.By switching the light field,continuous initiation and termination of MMA can be achieved;The results of ¹HNMR show that the microporous structure of Cu-PTC can induce photopolymerization of MMA and improve the stereoregularity of the polymer.UV-spectroscopy?UV?,electron paramagnetic resonance spectroscopy?EPR?and electrochemical studies were carried out to investigate the mechanism of Cu-PTC as a photoinduced catalyst for the polymerization of MMA.The results show that Cu-PTC is excited by photoexcitation to generate photogenerated electrons and holes.Photogenerated electrons activate an alpha-bromophenylacetate?EBP?initiator to achieve living polymerization.After four cycles of experiments,Cu-PTC still has good catalytic activity?the monomer conversion of MMA is about 50%?and good chemical structure stability.?3?The atom transfer radical polymerization of VAc was carried out with Co-PTC as catalyst.The kinetic study shows that the polymerization process accords with the characteristics of"active"radical polymerization,and the polymerization behavior can make a quick response to the switch of light field.Furthermore,the mechanism of Co-PTC as a photocatalyst to catalyze VAc polymerization is studied by ¹HNMR and chain expansion experiments.The results show that:the polymerization of TPO was initiated by the absorption of visible light by Co-PTC,and controlled by the reversible removal of Co???-PTC by PVAc-Co???-PTC?dormant species?.After cycle of experiments,Co-PTC still has good catalytic activity?the monomer conversion of VAc is about 35%?.