Synthesis And Characterization Of Polymer Containing Naphthalene Unit With Aggregation-induced Emission Effect

The discovery of aggregation-induced emission?AIE?effect fundamentally solves the problem of fluorescence quenching of traditional fluorescent dyes in aggregate state or solid state,which has a good potential application value and has attracted extensive attention of researchers.So far,fluorescent probes with AIE characteristics have been applied in ion detection,biological detection,drug release,etc..The detection of metal ions is of great significance.In this thesis,two kinds of polymer and one kind of compound containing naphthalene units with AIE effect have designed and synthesized for the detection of Fe³⁺and HgCl₂.The main contents and results of this thesis are as follows:1.Compound M1 was synthesized by acyl chloride reaction with sulfoxide chloride and2,6-naphthalenedicarboxylic acid,and compound M2 was synthesized by Friedel-Crafts acylation reaction with compound M1 and tert-butyl benzene,then compound M3 was synthesized with compound M2 and 1,2-ethanedithiol,finally,conjugated polymer PNTB containing naphthalene unit was prepared by the intermolecular desulfurization reaction with M3.PNTB showed an increasing trend of fluorescence intensity with the increasing of water fraction in THF/H₂O mixed solvent,indicating that PNTB has AIE characteristic.PNTB was compared with that of tetraphenylethylene?TPE?in aggregation induced luminescence characteristics,the fluorescence quantum yield of PNTB and TPE in solution state?THF as solvent?and aggregation state?THF/H₂O,10/90,V/V?was 1.83%,12.74%and 0.26%,0.81%,respectively.So PNTB indicated better aggregation effect and luminescence performance.2.Asymmetric compound B2 was synthesized by Friedel-Crafts acylation reaction with M1,tert-butyl benzene and anisole,then compound B3 was synthesized with compound B2and 1,2-ethanedithiol,polymer P1 was prepared by the intermolecular desulfurization reaction of B3,the side group?methoxyl?of P1 became hydroxyl to produce the polymer P2,and P2reacted with 2-bromoisobutyryl bromide to synthesize macromolecular initiator P3,finally P3initiated N-isopropyl acrylamide by ATRP reaction to obtain water-soluble polymer fluorescent P4.The minimum critical micelle concentration?CMC?of P4 was 14.4 mg·L^-1.Detection of metal ions of P4 showed that Fe³⁺dimmed the fluorescence brightness of P4,indicating that P4 has good selectivity to Fe³⁺.The fluorescence intensity of P4 decreased with the increase of Fe³⁺concentration,and the minimum detection limit was 20 nM,indicating that P4 has a good sensitivity to Fe³⁺.After the interaction between P4 and Fe³⁺,the fluorescence intensity gradually decreased with the extension of time and stabilized after36 min,indicating that the interaction between P4 and Fe³⁺was slow.3.Compound NBMK was synthesized by Friedel-Crafts acylation reaction with2-naphthoyl chloride and anisole;Compound NBM-2Br was synthesized by Corey-Fuchs reaction with carbon tetrabromide;finally,compound NBME-Dpy containing naphthalene unit with AIE effect was synthesized by Suzuki coupling reaction with pyridine-3-boronic acid and NBM-2Br.The fluorescence of NBME-Dpy could be quenched only by Fe³⁺when various metal ions were addded in NBME-Dpy DMSO/H₂O?1/99,V/V?solution,respectively,indicating the good selectivity of NBME-Dpy to Fe³⁺.The fluorescence intensity of NBME-Dpy decreased with the increase of Fe³⁺concentration,and the minimum detection limit was 4.9?M,indicating that NBME-Dpy has a good sensitivity to Fe³⁺.Comparing with other mercury salts,HgCl₂ could enhanced the fluorescence of NBME-Dpy in DMSO/H₂O?10/90,V/V?mixed solvents,indicating that NBME-Dpy has good selectivity for HgCl₂.The fluorescence intensity of NBME-Dpy increased with the increasment of HgCl₂ concentration,and the minimum detection limit was 0.40?M,which indicated that NBME-Dpy has good sensitivity to HgCl₂.Two kinds of polymer PNTB and P4 with high planar rigidity and AIE properties were synthesized successfully.PNTB has a high fluorescence quantum yield.P4 has good selectivity and sensitivity to Fe³⁺,so it is expected to be used for Fe³⁺detection in water environment and biological detection.At the same time,compound NBME-Dpy containing naphthalene unit with AIE effect was successfully synthesized,which realized the detection of“fluorescence-attenuated”for Fe³⁺and“fluorescence-enhanced”for HgCl₂.So it is expected to be applied in the field of ion detection and chemical sensor.