Design,Synthesis And Catalytic Properties Of Porphyrin-based Porous Organic Polymers

As a new type of porous material,porphyrin-based porous organic polymer?PPOP?not only possesses superior porous properties,and its stable and controllable structure is easy to be functionalized.They have received considerable interests in photoelectrocatalysis,biomimetic catalysis,and other oxidation catalyses.In this project,to develop porphyrin-based porous organic polymer and its catalysis studies,we have synthesized three kinds of novel PPOPs material by smartly choosing building blocks and optimizing the synthesis conditions.Then following by the post-modification methods,we finally synthesized PPOP-1?Fe?,Pd@PPPPs and PPOP-2?Pd?materials with high excellent catalytic activity.The main three parts of this project are as follows:1.The biomimetic catalytic performance study of three-dimensional porphyrin-based porous organic polymer:A highly stable porphyrin-based porous organic polymer PPOP-1?Fe?with three-dimensional diamond structure was synthesized via imine condensation of tetrahedral aldehyde and linear porphyrin diamine.FT-IR spectra and ¹³C CP-MAS NMR spectrum clearly revealed the formation of C=N linkages.The X-ray photoelectron spectroscopy?XPS?survey spectrum of PPOP-1?Fe?clearly showed the presence of iron.The Brunauer-Emmett-Teller surface areas were calculated as 237 m²/g and 182 m²/g for PPOP-1and PPPO-1?Fe?,respectively,suggesting permanent porosities.This material also showed both high thermal stability and high chemical stability.PPOP-1?Fe?exhibits high excellent catalytic activity as a biomimetic catalyst,because the heme-like porphyrin active centers in PPOP-1?Fe?are exposed toward the open channels,thus accelerating the catalytic oxidation reactions.Three-dimensional PPOP platforms with open channels,extraordinary stability and high density of catalytic centres open up new avenues to building enzyme-mimic materials.2.The catalytic performance study of porphyrin-based polyimide polymers/Pd nanoparticles composites:Four porphyrin-based porous polyimide polymers,PPPP-1,PPPP-2,PPPP-3 and PPPP-4 were synthesized via polyimide reactions of extended porphyrin tetraamines and pyromellitic dianhydride,or naphthalene dianhydride.The polyimide structures were unambiguously confirmed by FT-IR and ¹³C CP-MAS solid state NMR.Powder X-ray diffraction and computer modeling analysis confirmed the crystallinity and the layered structures with tetragonal channels.The permanent porosity of PPPPs was measured using the nitrogen absorption isotherms.Highly dispersed Pd nanoparticles with a diameter of3±2 nm were successfully immobilized into PPPPs through coordination of Pd?II?ion with porphyrin units on polymers and in-situ reduction afterwards.Pd@PPPP-3 and Pd@PPPP-4show significantly excellent catalytic activity in Suzuki-Miyaura coupling reactions.The performance of Pd@PPPPs is apparently superior to that of the homogeneous palladium catalyst.In addition,Pd@PPPPs have excellent stability and recyclability,and it can be reused without loss of activity in five successive reaction cycles.3.Tandem catalytic performance study of porphyrin-based porous?-diimine organic polymer:A novel porphyrin-based porous organic polymer with bi-functional catalyst was constructed via 4+2 imine condensation of 5,10,15,20-tetrakis?4-aminophenyl?porphyrin and acenaphthequinone.PPOP-2?Pd?was then facilely obtained via divalent palladium ion post-synthetic method.The sciff-base structures were unambiguously confirmed by FT-IR and¹³C CP-MAS solid state NMR.The Brunauer-Emmett-Teller?BET?together with pore size distribution suggested the permanent porosity,whose surface areas were calculated as 223.76m²/g and 151.06 m²/g for PPOP-2 and PPOP-2?Pd?.This material exhibits both superior thermal and excellent chemical stability.In addition,PPOP-2?Pd?possesses two types of catalytic sites:Pd?II?-porphyrin moieties for Suzuki-Miyaura coupling catalysis as well as?-diimine palladium for direct C-H bond arylation of heteroarenes.Good catalytic activity and outstanding reusability make PPOP-2?Pd?material as a promising and efficient heterogeneous catalyst for series catalytic reaction.