Polyfluorene-block-poly(phenyl isocyanide) Copolymers: One-Pot Synthesis, Helical Assembly, and Circularly Polarized Luminescence
Polyfluorene-block-poly(phenyl isocyanide) Copolymers: One-Pot Synthesis, Helical Assembly, and Circularly Polarized Luminescence
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DOI：
10.1021/acs.macromol.2c01943
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发表时间：
2023-02
期刊：
影响因子：
5.5
通讯作者：
Hui Zou;Wei Liu;Chaoyue Wang;Li Zhou;Na Liu;Zongquan Wu
中科院分区：
文献类型：
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作者：
Hui Zou;Wei Liu;Chaoyue Wang;Li Zhou;Na Liu;Zongquan Wu
具有光学活性的π共轭嵌段共聚物具有相当大的意义和兴趣，但它们的可控合成和螺旋自组装仍然具有挑战性。本研究通过两步连续聚合，一锅法制备了由聚芴（PF）和聚苯异腈（PPI）组成的π共轭嵌段共聚物。首先，通过使用Pd（0）/t-Bu 3 P体系催化的7-溴-9，9-二己基芴-2-硼酸频哪醇酯的Suzuki交叉偶联聚合来合成Pd（II）封端的PF前体。然后，以Pd（II）封端的PF为催化剂，通过苯异腈单体的可控聚合制备了分子量可控、分散性较窄的PF-b-PPI共聚物。由于PF嵌段的π共轭结构和PPI嵌段的螺旋性，所得PF-b-PPI共聚物可自组装成单手螺旋纳米纤维。在自组装过程中，手性从螺旋PPI块转移到自组装的螺旋纳米纤维，从而赋予它们光学活性和优异的圆偏振发光性能。
Optically active π-conjugated block copolymers are of considerable significance and interest, but their controlled synthesis and helical self-assembly remain challenging. In this study, π-conjugated block copolymers consisting of polyfluorene (PF) and poly(phenyl isocyanide) (PPI) segments were facilely prepared in one pot through two sequential polymerizations. First, a Pd(II)-terminated PF precursor was synthesized via the Suzuki cross-coupling polymerization of 7-bromo-9,9-dihexylfluorene-2-boronic acid pinacol ester, which was catalyzed using a Pd(0)/t-Bu3P system. Then, PF-b-PPI copolymers with controlled molar mass and narrow dispersities were fabricated via controlled polymerization of phenyl isocyanide monomers utilizing Pd(II)-terminated PF as the catalyst. Benefiting from the π-conjugated structure of the PF block and the helicity of the PPI block, the resulting PF-b-PPI copolymers could self-assemble into single-handed helical nanofibers. In the self-assembly process, chirality was transferred from the helical PPI block to the self-assembled helical nanofibers, thereby endowing them with optical activity and excellent circularly polarized luminescence properties.