The facile construction of circularly polarized luminescence (CPL) materials through the clever combination of chirality and fluorescence is of great significance. Herein, we provide a simple and efficient synthesis of CPL-active aggregation-induced emission (AIE) helical polyisocyanides through asymmetric polymerization of commonly used chiral aryl isocyanide monomers featuring a D- or L-methyl-ester pendant group (D/L-IMCIs) catalyzed by a novel AlEt₃/[Ph₃C][B(C₆F₅)₄] binary catalytic system. The typical fluorophore-free chiral D/L-IMCI monomers, silent in circular dichroism (CD), exhibit intriguing AIE properties. After undergoing asymmetric-induced polymerization with remarkable efficiency, the synthesized poly(D/L-IMCI)s have chiral helical structures, manifesting both CD and AIE characteristics. Based on the “matching rule” of the fluorescent moieties and chiral helical polyisocyanides, these poly(D/L-IMCI)s show distinct CPL signals in both the aggregated state and the film state, mirroring each other across the 400–600 nm range in THF, with luminescence dissymmetry factor (|g_lum|) values around 7.6–7.8 × 10⁻⁴ in THF. Moreover, the incorporation of different proportions of an achiral aryl isocyanide bearing an azobenzene pendant (IPPD) into the poly(D/L-IMCI)s through helix-sense-selective copolymerization allows for precise control over the chiroptical properties of the synthesized AIE helical poly(D/L-IMCI-ran-IPPD)s. The nonlinear relationship between the intensity of CD or CPL signals and the D/L-IMCI contents of the synthetic poly(D/L-IMCI-ran-IPPD)s clearly describes strong chiral amplification effects, achieving a maximum |g_lum| value exceeding 1.0 × 10⁻³ in THF, which is superior to those of poly(D/L-IMCI)s. These results demonstrate that the helical (co)polyisocyanide's chirality confers a chiral environment, which in turn effectively induces chirality within both the excited and ground states. This strategy provides new perspectives for the straightforward and simple construction of novel CPL-active AIE polymers through asymmetric polymerization of commonly used functional monomers.

中文翻译：

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AlEt3催化合成圆偏振发光活性聚集诱导发射螺旋多异氰化物


通过手性和荧光的巧妙结合，圆偏振发光 （CPL） 材料的简单构建具有重要意义。在此，我们提供了一种简单高效的 CPL 活性聚集诱导发射 （AIE） 螺旋聚异氰化物合成方法，通过一种新型 AlEt₃/[Ph₃C][B（C₆F₅）₄ 催化的常用手性芳基异氰化物单体的不对称聚合，该单体具有 D 或 L 甲基酯挂基 （D/L-IMCIs）] 二元催化系统。典型的无荧光团手性 D/L-IMCI 单体在圆二色谱 （CD） 中保持沉默，表现出有趣的 AIE 特性。经过非对称诱导聚合后，合成的聚 （D/L-IMCI） 具有手性螺旋结构，同时表现出 CD 和 AIE 特性。基于荧光基团和手性螺旋多异氰化物的“匹配规则”，这些聚 （D/L-IMCI） 在聚集态和薄膜态下都显示出不同的 CPL 信号，在 THF 的 400–600 nm 范围内相互镜像，发光不对称因子 （|g_lum|）THF 值约为 7.6-7.8 × ^10-4。 此外，通过螺旋正义选择性共聚，将不同比例的带有偶氮苯悬垂 （IPPD） 的非手性芳基异氰化物掺入聚 （D/L-IMCI） 中，可以精确控制合成的 AIE 螺旋聚 （D/L-IMCI-RAN-IPPD） 的手性。CD 或 CPL 信号的强度与合成 poly（D/L-IMCI-ran-IPPD）的 D/L-IMCI 含量之间的非线性关系清楚地描述了强手性放大效应，实现了最大 |g_lum|THF 值超过 1.0 × 10⁻³，优于 poly（D/L-IMCI）。这些结果表明，螺旋（共）聚异氰化物的手性赋予了手性环境，这反过来又在激发态和基态中有效地诱导了手性。该策略为通过常用功能单体的不对称聚合直接简单地构建新型 CPL 活性 AIE 聚合物提供了新的视角。