Study On The Construction And Catalytic/Adsorption Performance Of Porphyrin-based Porous Organic Polymers

Porphyrin derivatives have unique ring-conjugated structures and good photosensitivity.The compounds are important structural monomers in the construction of porous organic polymers.Porphyrin-based porous organic polymers（PPOPs）have been widely used in photocatalysis,electrocatalysis,biomimetic catalysis,storage,adsorption,degradation and other fields because of their structure advantages,such as low density,large surface area,tunable pore size,high stability,and good photosensitivity.In this paper,we have designed and prepared a series of porphyrin-based porous organic polymers,which showed enhanced catalytic performance for the selective dehydrogenation of N-heterocyclic compounds and iodine adsorption capacity.The synthetic strategies of PPOPs were developed and the application fields of the materials were expanded more effectively.The resesrch content are summarized as follows:N-heterocyclic aromatic hydrocarbons are prominent moieties in many drug molecules and natural products.N-heterocyclic dehydrogenation,which features atomic economy,high efficiency and strong functional group compatibility,is the most common synthetic strategy.Efficient selective dehydrogenation is a challenge in this field.In this work,we synthesized porphyrin-based triazine porous covalent organic frameworks（M@PTFs）using5,10,15,20-tetrakis（4-cyanophenyl）porphyrin as monomer by ionothermal method.High temperature synthesis resulted in partial graphitization of the materials,and the degree of graphitization became more obvious with the increase of synthesis temperature.At the same time,layered structure was characterized by SEM and TEM test.Using the oxidative dehydrogenation reaction of tetrahydroquinoline and tetrahydroisoquinoline as a model,the catalytic performance of these materials for light-driven organic transformation was studied.Interestingly,under the same conditions,the tetrahydroquinoline substrates achieved dehydroaromatization,while the tetrahydroisoquinoline substrates achieved semi-dehydrogenation,yielding 3,4-dihydroisoquinoline with high selectivity.It was proved that the dehydrogenation process was a free radical process through control experiments.Radioactive iodine is generated during the treatment of nuclear waste,which threatens human health.Porous materials are usually used to adsorbe and remove the radioactive iodine of nuclear waste.Ionic porous organic polymers（i POPs）adsorbents attract more attention due to their faster adsorption rate.In this work,cationic i PPOPs were innovatively synthesized by adjusting the initial monomer concentration and the species of halide ions.The cationic framework increases the affinity for iodine.The adsorption experiments of iodine vapor were conducted with i PPOPs as solid adsorbents.The experimental results showed that more complete material frameworks were obtained when decreasing the concentration of the monomer.Among them,i PPOP-Cl-10 exbibited the best performance for I₂ adsorption and the maximum adsorption capacity reached 5.2 g/g.In the liquid phase adsorption,the removal rates of different concentrations of I₂/n-hexane solution were all above 90%,and the basic removal for I₂ was achieved.Raman spectroscopy proved that the adsorbed iodine mainly existed in the form of I₃^?and I₅^?.