Helix-Induced Asymmetric Self-Assembly of π-Conjugated Block Copolymers: From Controlled Syntheses to Distinct Properties.
Helix-Induced Asymmetric Self-Assembly of π-Conjugated Block Copolymers: From Controlled Syntheses to Distinct Properties.
复制标题
螺旋诱导π共轭嵌段共聚物的不对称自组装：从受控合成到不同性质。
DOI：
10.1021/acs.accounts.3c00425
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发表时间：
2023-10
影响因子：
18.3
通讯作者：
Na Liu;Runpeng Gao;Zongquan Wu
中科院分区：
文献类型：
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作者：
Na Liu;Runpeng Gao;Zongquan Wu
由于π共轭聚合物在光电子学、生物电子学等领域的潜在应用，引起了人们极大的兴趣。π-共轭嵌段聚合物的受控合成优化了它们的性能，并实现了新的性能和功能。然而，精确控制π共轭聚合物的自组装结构仍然是一个艰巨的挑战。受生物大分子精确的螺旋结构的启发，螺旋聚合物和超分子螺旋组装体受到了广泛的关注。具有过量单手螺旋度的螺旋聚合物可以是光学活性的，具有强烈的自组装倾向。将螺旋聚合物转化为π共轭聚合物可以诱导不对称的螺旋组装，从而得到具有独特功能的新型手性材料，为了控制结构的自组装，通常将π共轭聚合物与具有自组装特性的聚合物结合，合成嵌段共聚物。虽然已经生产了各种π-共辄嵌段共聚物，但精确和不对称的自组装仍然具有挑战性，并且很少得到解决。将螺旋聚合物嵌段化到π共轭聚合物中可以诱导精确和不对称的自组装，从而将螺旋聚合物嵌段的手性转移到π共轭聚合物中，形成具有独特手性光学性质和功能的手性超分子结构。然而，合成含有两种不同聚合物嵌段的混合嵌段共聚物是复杂的。一些通用策略，如连接两个预形成的均聚物的链端和用第二单体延长预形成的π-共辄聚合物的链是耗时的，并且需要复杂的合成方案。因此，开发新的策略，易于合成的π-共轭嵌段共聚物具有可预测的摩尔质量，低分散性，和可调的compositions.Recently，我们研究了控制合成的螺旋聚异氰酸酯，螺旋聚联烯，和螺旋聚卡宾通过开发先进的Pd（II）和Ni（II）催化剂。这些螺旋聚合物被成功地纳入到π共轭聚合物，包括聚噻吩，聚芴，和聚（苯乙炔），通过一锅顺序的两个不同的单体的活性嵌段聚合使用Pd（II）或Ni（II）配合物作为催化剂。结果，很容易合成出多种包含螺旋聚合物嵌段的定义明确的π-共轭嵌段共聚物。虽然共聚单体具有不同的结构和聚合机理，但一锅法嵌段共聚遵循活性聚合机理，以高产率获得了分子量可控、粒径分布窄、组成可调的π共轭嵌段共聚物。单手螺旋结构导致独特的光学特性。更有趣的是，通过利用共轭嵌段和单手螺旋嵌段的结晶，结晶驱动和螺旋诱导的精确不对称活性自组装产生了一系列均匀的单手螺旋结构，具有可控的尺寸，窄的分布，和明确的螺旋度。螺旋手性向超分子结构的转移使得非手性π共轭嵌段具有独特的手性光学性质，如在宽光谱范围内发射白色光和圆偏振发光。
Conspectusπ-Conjugated polymers have gained significant interest because of their potential applications in optoelectronics, bioelectronics, and other domains. The controlled synthesis of π-conjugated block polymers optimizes their performance and enables novel properties and functions. However, precise control of the self-assembled architectures of π-conjugated polymers remains a formidable challenge. Inspired by the precise helical architectures of biomacromolecules, the helical polymers and the supramolecular helical assemblies have gained significant attention. Helical polymers with an excess of one-handed helicity can be optically active with a strong tendency toward self-assembly. Incorporating a helical polymer into a π-conjugated polymer can induce asymmetric helical assemblies, leading to novel chiral materials with unique functionalities.To control the self-assembly of architectures, π-conjugated polymers are usually synthesized into block copolymers by incorporating a polymer with self-assembling characteristics. Although various π-conjugated block copolymers have been produced, precise and asymmetric self-assembly is still challenging and has rarely been addressed. Incorporating helical polymers into the π-conjugated polymers can induce a precise and asymmetric self-assembly, which transfers the chirality of the helical polymer block to the π-conjugated polymer, resulting in chiral supramolecular architectures with unique chiroptical properties and functionalities. However, synthesizing hybrid block copolymers containing two distinct polymer blocks is complicated. Some general strategies such as connecting the chain ends of two preformed homopolymers and extending the chain of a prefabricated π-conjugated polymer with a second monomer are time-consuming and require complex synthetic protocols. Therefore, developing novel strategies for the facile synthesis of π-conjugated block copolymers with a predictable molar mass, low dispersity, and tunable composition is of practical importance.Recently, we investigated a controlled synthesis of helical polyisocyanides, helical polyallenes, and helical polycarbenes by developing advanced Pd(II) and Ni(II) catalysts. These helical polymers were successfully incorporated into π-conjugated polymers, including polythiophene, polyfluorene, and poly(phenyleneethynylene), via a one-pot sequential living block polymerization of the two distinct monomers using Pd(II)- or Ni(II)-complexes as catalysts. As a result, a variety of well-defined π-conjugated block copolymers containing helical polymeric blocks were readily synthesized. Although the copolymerized monomers possess different structures and polymerization mechanisms, the one-pot block copolymerization followed a living polymerization mechanism and provided the desired π-conjugated block copolymers in high yields with controlled molar mass, narrow size distribution, and tunable composition.Remarkably, the helical polymeric block induces the π-conjugated block copolymer asymmetric self-assembly into a supramolecular, one-handed helical architecture resulting in distinct optical properties. More interestingly, by utilizing the crystallization of conjugated blocks and one-handed helical blocks, the crystallization-driven and helix-induced precise asymmetric living self-assembly yielded a family of uniform and single-handed helical architectures with controlled dimensions, narrow distribution, and well-defined helicity. The transfer of helical chirality to the supramolecular architectures rendered the achiral π-conjugated blocks with unique chiroptical properties such as the emission of white light over a broad optical spectrum and the circularly polarized luminescence.