Synthesis And Properties Of Novel Polymer Containing Diazafluorene Moiety

With the development of science and technology,functional polymer materials are widely used in high temperature plastics,adhesives,dielectrics,photoresists,nonlinear optical materials,membrane materials and sensors.Polymers,with tailored functional groups and dendritic structures have allowed researchers to tune the properties and applications.It has been demonstrated that incorporating 4,5-diazafluorene units into the polymer chain is considered as an effective way to increase the thermal stability and solubility.Furthermore,the 4,5-diazafluorene units can form various complexes by coordination to metal ions,and it is a good and alternative approach to develop sensitive and selective polymer metal ions chemosensors.The syntheses of various polymers containing diazafluorene moiety are reported in this paper.Based on the viewpoint of molecular design and combining the characteristics of 4,5-diazafluorene structure,six novel 4,5-diazafluorene-containing aromatic diamines are successfully synthesized.These diamine monomers are employed in reactions with a variety of aromatic dianhydrides to furnish polyimides.The results show that the introduction of 4,5-diazafluorene units can significantly improve the glass transition temperature of the resulting polyimides,and the maximum glass transition temperature is 479 ?.A novel difluoride monomer containing 2,2':6',2"-terpyridines moiety has been successfully designed and synthesized.Then,a new poly(arylene ether)(PAET)has been synthesized by employing a route of the difluoride monomer and 9,9-di-(4-hydroxyphenyl)-4,5-diazafluorene through nucleophilic substitution.To evaluate the selectivity of the poly(arylene ether)towards the analyte,their UV?Vis and fluorescence behavior upon addition of various metal ions have been examined.The polymer(PAET)shows high selectivity and sensitivity to Ni2+,and there is a significant red shift in the UV-Vis spectroscopy.The PAET selectively displays a dramatic quenching fluorescence intensity over other ions.Thus,PAET could be utilized as polymer chemosensor for Ni2+.A novel conjugated polymer(PFDPPZ)containing dipyridophenazine(dppz)groups in the main chain has been designed and synthesized though Suzuki coupling reaction,which shows highly selective 'turn off fluorescence behavior in the presence of Cu2+ ions.The selectivity of PFDPPZ toward metal ions in CHCl3/EtOH(v/v:80/20)has investigated by UV absorption and fluorescence spectroscopy.The results show that this chemosensor exhibits good selectivity toward Cu2+ over other metal ions,and there is a new broad weak low?energy absorption band ranging from 400 to 477 nm.Thus,PAET could be utilized as polymer chemosensor for Cu2+.