The Design,Synthesis And Applications Of Multi-component AIE-active Functional Conjugated Polymers

Aggregation-induced emission(AIE)-active luminogens exhibit no or weak emission in good solvents,but enhanced emission in aggregate state.This property takes large advantage in overcoming the notorious aggregation-caused quenching(ACQ)property of most traditional chromophores.Among the various AIE-active luminogens,tetraphenylethene(TPE)derivatives have become a class of important members due to their high fluorescence quantum yields and easy synthetic routes.In this dissertation,a variety of TPE based multi-component AIE-active conjugated polymers were designed and synthesized,which had been applied as circularly polarized luminescence(CPL)materials,electrochemiluminescence(ECL)materials and self-indicating drug carriers.The main works include three parts:Part I.Multi-Component AIE-Active Conjugated Polymer Based AI-CPL Materials.1.1 Five three-component conjugated polymers were synthesized via Sonogashira coupling polymerization reaction with chiral BINOL moiety as chiral source,TPE moiety as AIE-active chromophore and fluorene moiety as FRET donor.Both fluorescence and aggregation-induced CPL(AI-CPL)signals of polymers could be tuned by changing fluorene/TPE ratio and gave strongest signals at 2/8(glum = 4×10-3).This work provided a new strategy for designing novel AI-CPL conjugated polymers by adjusting intramolecular FRET pairs.1.2.Based on the conjugated polymers in 1.1,dithiophenebenzothiadiazole(DTBT)moiety was added to give two four-component deep red AI-CPL conjugated polymers with two intramolecular FRET pairs.They were synthesized by one-pot two-step Pd-catalyzed Suzuki and Sonogashira cross reactions.Their AIE behavior could be tuned by changing the excitation wavelength while their AI-CPL signals could be adjusted by tuning TPE/DTBT ratio.This work provided a novel strategy for designing long wavelength AI-CPL materials via two intramolecular FRET pairs mechanism.Part II.Three-Component AIE-Active Conjugated Polymer Nanoparticles Based ECL Materials.2.1 Two three-component donor-acceptor(D-A)type conjugated polymers were designed and synthesized via Suzuki polymerization reaction with fluorene/carbazole moiety as electron donor,BODIPY moiety as electron acceptor and TPE moiety as AIE-active moiety.After stronger electron donor(carbazole)was introduced in,ECL anodic potential decreased for 553 mV while ECL intensity increased for almost 6 times.Developing low potential ECL probes could avoid some backgrounds and achieve high selectivity and sensitivity.This work provided a novel strategy for designing ECL materials with low ECL potential and high ECL intensity.2.2 Three D-A type three-component conjugated polymers were designed and synthesized via Suzuki coupling polymerization reaction basing on TPE moiety.According to them,carbazole moiety acted as electron donor and DFPDB moiety acted as electron acceptor.Due to D-A type structure,the corresponding Pdots exhibited 200 mV decline in ECL potential.The ECL intensity could be amplified for 3 times by increasing the ratio of AIE-active TPE moiety from 0.8 to 0.95.P-10 Pdots with strongest ECL signal could be applied as ECL probe in detecting catechol derivatives with detection limits as 1-7 nM.This work provided a novel strategy for designing high sensitive ECL bioprobes by adjusting AIE-active moiety.Part III.Three-Component AIE-Active Conjugated Polymer Nanoparticles Based Self-Indicating Drug Carriers.Two color-tunable AIE-active conjugated polymers were designed and synthesized via Suzuki coupling polymerization reaction.Among them,the one with only one intramolecular FRET pair(fluorene-TPE)exhibited green-colored emission.As the second intramolecular FRET pair(TPE-DTBT)added,the fluorescence color could be tuned from green to red.After paclitaxel(PTX)was loaded and prepared into conjugated polymer nanoparticles(CPNs),the CPNs could not only indicate their location in cancer cells,but also release PTX to kill cancer cells.This work provided a novel strategy for developing color-tunable self-indicating drug carriers.