The Multiple Applications Of Carbazolyl Silsesquioxane-Based Porous Polymers For Adsorption And Chemical Sensing

The design,synthesis,and development of hybrid fluorescent porous polymers have received extensive attention in recent years.More and more hybrid fluorescent porous polymers show good application prospects in gas storage and separation,adsorption of environmental pollutants,detection of harmful compounds and heterogeneous catalysis.Cage silsesquioxane(POSS)offers a three-dimensional rigid structure,good thermal stability,nano-size effect and variable substituents,so it is a good building block for constructing porous polymers;Carbazole is a rigid fluorescent molecule with a planar structure.These characteristics of carbazole are advantageous for the synthesis of hybrid fluorescent polymers.In this thesis,the carbazole was combined with the cage silsesquioxane to construct organic-inorganic hybrid fluorescent porous materials,which were applied to adsorption and fluorescence sensors.1.Fist,we synthesized octa[4-(9-carbazolyl)phenyl]silsesquioxane(OCPS)using carbazole and octaiodophenylsilsesquioxane,and then a hybrid fluorescent porous polymer(HPP-1)was prepared by an anhydrous FeC13-mediated oxidative coupling reaction of OCPS.We validated HPP-1 structures through a series of characterization methods,such as Fourier-Infrared spectroscopy,solid carbon spectroscopy,and solid silicon spectroscopy.HPP-1 possesses good thermal stability,and its Brunauer-Emmett-Teller surface area reach to 1741 m2 g-1.The pore structure consists of micropores and mesopores.In addition,we also use fluorescence spectroscopy,fluorescence lifetime and fluorescence quantum efficiency to evaluate the fluorescence properties of HPP-1.Based on porosity and fluorescent properties,HPP-1 was applied in adsorption and fluorescence sensing.HPP-1 can adsorb CO2,dyes and heavy metal ions,and the adsorption capacity for CO2 is 8.53 wt.%(1.94 mmol g-1);the adsorption capacity is 1715 and 1501 mg g-1 for congo red(CR)and rhodamine B(RB);the adsorption capacity of Pb2+,Hg2+and Ni2+are 227,50 and 34 mg g-1 respectively.Moreover,HPP-1 can be used to detect metal ions and mitroaromatic compounds,which are most sensitive to Fe3+ and 2,4-dinitrophenol with Ksv constants 1.8*104 and 3.2*104 M-1,respectively.2.We used OVS and two different carbazole-derived bromides to prepare two kinds of fluorescent porous polymers HPP-2 and HPP-3 by Heck reaction,and characterized the structures and properties.HPP-2 and HPP-3 both possess hierarchical porous structure,and their specific surface areas can reach 790 m2 g-1 and 396 m2 g-1,respectively.The carbazole units endow HPP-2 and HPP-3 with good fluorescence properties.We use the porous and fluorescent properties of two porous polymers to adsorption and chemical sensing.The adsorption of CO2 by HPP-2 and HPP-3 can reach 5.2 wt%(1.18 mmol g"1)and 5.3 wt%(1.2 mmol g-1),respctively;the adsorption capacity of HPP-2 and HPP-3 for iodine vapor were 1873 mg g-1 and 1552 mg g-1 respectively.Moreover,we studied the kinetics of the adsorption process.Finally,we performed metal ion detection and observed that the two polymers have good responses to Fe3+and Ru3+,especially for Ru3+with Ksv constants 1.57*104.