The Synthesis Of Conjugated Micropore Polymers With Distorted Structure And The Study Of Iodine Adsorption And Fluorescence Sensing Properties

Radioactive iodine ¹²⁹I and ¹³¹I have a huge impact on the environment,so how to capture radioactivity and detect iodine has become a top priority.We prepared eight conjugated microporous polymers,TBIM,HBIM,TTTAT,TTDAT,TDP,PCPP,TTPDP and TDTPAP.Our diimidazole based products（TBIM and HBIM）can form liquid complexes with iodide ion.Interestingly,both TBIM and HBIM adsorbed iodine very well.This is the highest adsorption value of all POPs reported so far.In addition,TBIM and HBIM can sense I₂ and nitroaromatic compounds（e.g.picric acid/p-nitrophenol）through fluorescence quenching.In particular,TBIM has a high fluorescence sensing performance for iodine,with a Stern-Volmer quenching constant（Ksv）of1.16×10⁴L mol^-1 and a detection limit of 1.29×10^-10mol L^-1.We selected tetraphenylethylene（TPE）derivatives as the core to construct nitrogen-rich S-triazine rings,which were interlinked with each other through TPA units to construct a three-dimensional porous organic open skeleton.TTTAT and TTDAT were prepared by Friedel-Crafts polymerization catalyzed by CH₃SO₃H with porosity of 564.8 m²g^-1 and 44.1m²g^-1,respectively.Due to the introduction of tetraphenylethylene units,CMPs exhibited excellent fluorescence sensing properties for I₂,with Ksv values of 1.53×10⁵ and 9.07×10⁴ L mol^-1,respectively.The adsorption capacities of I₂ in water vapor reached 3.41 g g^-1 and 2.91g g^-1 by using effective adsorption sites and charge-transfer interaction.Four kinds of 1,6-dibromopyrene based fluorescent conjugated microporous polymers（TDP,PCPP,TTPDP and TDTPAP）were prepared.Their absorption values in iodine vapor were 0.61,3.07,3.49 and 4.19 g g^-1,respectively.Four CMPs showed high sensitivity and selectivity to iodine by fluorescence quenching.PCPP had a very high sensitivity for I₂ detection,with Ksv of 1.40×10⁵L mol^-1 and detection limit of 3.14×10^-13mol L^-1.To our knowledge,it shows the highest Ksv value and the lowest iodine detection limit reported to date.