Molecular Design,Preparation And Properties Of Conjugated Porous Polymers With Vinylene Bridges

Conjugated porous polymer is a new type of materials with higher specific surface area,better environmental stability and more flexible structure,which is composed of light rigid framework.It has a wide range of applications in gas adsorption and storage,environmental water treatment,energy storage and conversion,catalysis,biomedicine and other fields,which makes it has been developed rapidly in recent years.There are many ways to achieve conjugated porous polymers,but most of them require noble metal-catalyzed coupling to obtain the carbon-carbon single bond structure.And part of them obtain azine ring structure through an unconventional environment,while the imine structure can be obtained through Schiff base reaction.Recently,the all-carbon backbone conjugated porous polymers caused by Knoevenagel condensation reaction attracted researchers’ attention.In this work,a new type of conjugated porous polymers was successfully obtained by molecular design of the monomers which underwent Knoevenagel condensation reaction.And its performance is explored by a certain extent:(1)Preparation of 6,6’-dimethyl-3,3’-bipyridine and the derivant:using 5bromo-2-methylpyridine as a monomer,newly prepared tetrakis(triphenylphosphine)Nickel is a catalyst,and 6,6’-dimethyl-3,3’-bipyridine is obtained through Yamamoto coupling reaction.Then,in the iodomethane/anhydrous acetonitrile system,react at a constant temperature at 80℃ for two weeks to obtain 1,1’,6,6’-tetramethyl-[3,3’bipyridine]-1,1’-diium iodide.The structure of the monomers were confirmed by NMR,IR,MS and other methods.And with 1,3,5-tris(4-formylphenyl)-amine,1,3,5-tris(4formylphenyl)benzene in super-dry N,N-dimethylformamide,the Knoevenagel condensation reaction between monomers was carried out by using piperidine as base catalyst,and the conjugated polymer materials were obtained.(2)Design and preparation of 5-(difluoromethyl)-isoxazole series monomers:using a metal-free strategy to use 1,8-diazabicycloundec-7-ene(DBU)/Triethylamine is a base catalyst,and a series of 5-(difluoromethyl)-isoxazoles are obtained through the denitrogenation and cyclization reaction of azide vinyl compound and difluoroacetic anhydride or chlorodifluoroacetic anhydride in the solvents.5(chlorodifluoromethyl)-isoxazole monomer,the reaction system is suitable for most substituted vinyl azide compounds.The structures of the obtained monomers and isoxazoles were confirmed by NMR,IR,MS and other methods.However,it was reacted with benzaldehyde in N,N-dimethylformamide solvent with the organic base piperidine as a catalyst,and the new product could not be obtained by using solvent nuclear magnetic resonance characterization.(3)Preparation and properties of bipyridine salt-based conjugated porous polymer with vinylene bridges:Knoevenagel condensation reaction between 1,1’,6,6’-tetramethyl-[3,3’-bipyridine]-1,1’-diium iodide and polyaldehyde monomers substituted by different aromatic rings was carried out by using piperidine as base catalyst in super-dry N,N-dimethylformamide,and the conjugated polymers with vinylene bridge were obtained at 150℃.The polymers were characterized by NMR,IR,XPS,UV,N2 isothermal adsorption and desorption,microscopy and other methods to confirm their structures and corresponding morphology.Finally,the antibacterial properties of conjugated porous polymers with olefin linkages were explored,and the results showed that the highest inhibition rate of the polymers could be up to 68%.