Synthesis And Applications Of Novel Conjugated Polymers Luminescent Nanomaterials

In the past few decades, luminescent nanomaterials based on novel conjugated polymers have attracted great interest due to their excellent optoelectronic performances. It was demonstrated that the optical properties of conjugated polymers can be finely tuned by smart molecular design and synthetic chemistry. These polymers can be further developed into functional nanomaterials with wide applications in bio/chemo sensing and biomedical imaging, etc.In this dissertation, the studies focused on the design, synthesis of novel conjugated polymers luminescent nanomaterials and their applications in cell fluorescence imaging and bio/chemo sensing.1. Far-red/near-infrared fluorescent conjugated polymer nanoparticles with size-dependent optical properties and cell imaging applicationsA novel chiral three-component conjugated polymer 2-P1 is synthesized by Suzuki reaction. By reprecipitation, the polymer was further used for the preparation of conjugated polymer nanoparticles (CPNs) with particle sizes ranging from 80 to 190 nm. Interestingly, the chiral CPNs showed size-dependent optical properties with increasing diameters. All the nanoparticle suspensions can emit far-red/near-infrared fluorescence when excited at 540 nm. Meanwhile, the obtained CPNs can serve as efficient far-red/near-infrared (FR/NIR) fluorescent probes with low cytotoxicity and high photostability for HeLa cell imaging.2. Synthesis of novel boron hybrid conjugated polymers with tunable AIE/AIEE and cell imaging applicationsA series of AIE/AIEE-active boron ketoiminate-based conjugated polymers was synthesized by Suzuki coupling reaction. Interestingly, the tuning of the emission color of 3-P1-3-P4 nanoparticles (NPs) could be conveniently accomplished by varying the substituent in the phenyl ring, the maximal emission wavelength can reach NIR region. CPNs from these polymers showed low cytotoxicity and high photostability and could be further employed for HeLa cell imaging.3. Study on AIE properties of ?-ketoiminate-based D-A type conjugated polymers and their applications in cell imagingThree new boron ketoiminate-based conjugated polymers 4-P1,4-P2, and 4-P3 were designed and synthesized through Sonogashira coupling reaction. Interestingly, it was found that a great difference in the electron-donating abilities of the D-A type polymer linkers can lead to the unique AIE behaviours of the alternating polymers, which provides us with a practical strategy to design tunable AIE-active conjugated polymers. Most importantly, studies on MCF-7 breast cancer cell imaging revealed that the nanoparticles fabricated from the conjugated polymers could serve as promising fluorescent probes with low cytotoxicity and high photostability.4. Silole-containing polymer nanodot as low-potential electrochemiluminescence emitter for biosensingA novel conjugated polymer containing silole and 9-octyl-9H-carbazole units was synthesized via Sonogashira reaction. This silole-containing polymer (SCP) was further used to prepare SCP dots with particles diameter of?7.5 nm by a nanoprecipitation method, which showed an electrochemiluminescence (ECL) emission at relatively low potential in aqueous solution. The strong anodic ECL emission could be observed with a peak value at+0.78 V (vs. Ag/AgCl) in the presence of tri-n-propylamine (TPrA) as a co-reactant. The ECL emission could be quenched via resonance energy transfer from the excited SCP dots to dopamine. The ECL detection method showed a detection limit of 50 nM and high anti-interference ability. This work demonstrates an example of polymer dots as an ECL emitter and its potential application in ECL detection methodology.5. Novel Eu(III)-containing polymer CD sensor for N-Boc-Proline recognition6-P1 could be synthesized by the polymerization of 3,7-dibromo-2,8-dimethoxy-5,5-dioctyl-5H-dibenzo[b,d]silole and (Z)-1,3-bis(4-ethynylphenyl)-3-hydroxyprop-en-l-one. Coordination reaction of the ?-diketonate unit in the main chain backbone of 6-P1 with 4,4,4-trifluoro-l-(thiophen-2-yl)butane-1,3-dionate (TTA) and Eu(NO3)3 was carried out under a basic condition to afford 6-P2. The resulting achiral polymer complex 6-P2 can exhibit strong circular dichroism (CD) response toward both N-Boc-L and D-proline enantiomers through coordination induction. The detection shows good selectivity. This is the first report on CD sensor based on polymer complex for the detection of amino acids, which lays the foundation for the development of polymer complexes CD sensors.