Fluorinated Aromatic Amide Helices: Synthesis and Modeling of Helical Handedness

We
present a next-generation helical polyamide synthesized from
5-amino-2,4-difluorobenzoic acid. Polymerization, driven by chloro-tritolylphosphonium
iodide (PHOS3), achieved precise molecular weight control and narrow
dispersity. Introducing (R) and (S) chiral initiators successfully
induced well-defined helical structures, as confirmed by distinct
Cotton effects with opposing signs. Molecular dynamics simulations
provided deeper insight into the self-assembly process of two helices
adopting opposite helicities (P and M). Notably, S–M helices
formed compact, highly cohesive, noncovalent stacks, demonstrating
packing efficiency over their S–P counterparts. These findings
enhance our understanding of polymer chirality, molecular organization,
and self-assembly, paving the way for the rational design of advanced
helical materials with promising applications in materials science.

本研究报道了一种由5-氨基-2,4-二氟苯甲酸合成的下一代螺旋聚酰胺（helical polyamide）。以氯三(甲苯基)碘化鏻（chloro-tritolylphosphonium iodide，PHOS3）为引发剂进行聚合反应，可实现精确的分子量调控与窄分散性。引入(R)型与(S)型手性引发剂可成功诱导出结构规整的螺旋结构，该结果通过符号相反的特征科顿效应（Cotton effect）得以验证。分子动力学模拟（molecular dynamics simulations）为两种具有相反螺旋手性（P型与M型）的螺旋链自组装过程提供了更深入的机制解析。值得注意的是，S-M型螺旋链形成了紧凑且高内聚的非共价堆叠结构，其堆积效率优于S-P型螺旋链。上述研究结果加深了我们对聚合物手性、分子排布与自组装行为的认知，为合理设计先进螺旋材料铺平了道路，这类材料在材料科学领域具有良好的应用前景。