The Length of Molecular Tethers Can Be Used to Control the Structure and Electronic Properties of Stapled Supramolecular Polymers
The Length of Molecular Tethers Can Be Used to Control the Structure and Electronic Properties of Stapled Supramolecular Polymers
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DOI：
10.1021/acs.chemmater.2c01353
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发表时间：
2022-07
影响因子：
8.6
通讯作者：
Victor A. Paulino;Danielle M Cadena;Kaixuan Liu;Arindam Mukhopadhyay;S. Roberts;Jean‐Hubert Olivier
中科院分区：
文献类型：
--
作者：
Victor A. Paulino;Danielle M Cadena;Kaixuan Liu;Arindam Mukhopadhyay;S. Roberts;Jean‐Hubert Olivier
通过平衡驱动过程形成的π-共轭超分子聚合物（π-SP）具有主要由重复单元之间的货车范德华相互作用控制的电子结构。因此，这些材料的结构与功能关系对温度、溶剂组成和结构单元浓度的变化极其敏感。这些实验限制不仅使π-SP的加工具有挑战性，而且还限制了分子工具包通过设计来定制它们的基态和激发态电子结构，而不完全改变它们的重复单元的结构设计。在本文中，我们表明，用短分子系链钉合最初形成的π-SP提供电子和结构稳健的纳米级物体，其基态电子结构对温度变化不敏感，从而使系链组分成为通用的合成手柄，以定制π-SP组装后的功能。跟踪钉合结构的激发态动力学的超快瞬态吸收测量进一步突出了它们的结构刚性。钉扎π-SP的光激发产生具有Frenkel激子和电荷转移混合特征的激发态。值得注意的是，我们发现，这些状态的电荷转移贡献可以通过增加π-SP的结构刚度来增强，为捕光应用提供了一种分离电荷的潜在途径。偏离传统的超分子工具，我们报告的组装后修饰策略突出了一组新的设计原则，可以指导具有设计师电子特性的材料的分子工程，用于光捕获，荧光和有机电子学。
Formed through equilibrium-driven processes, π-conjugated supramolecular polymers (π-SPs) are equipped with electronic structures that are primarily governed by van der Waals interactions between repeating units. Consequently, the structure–function relationships of these materials are extremely sensitive to changes in temperature, solvent composition, and building block concentration. These experimental constraints not only render the processing of π-SPs challenging but also restrain the molecular toolkit to tailor, by design, their ground, and excited-state electronic structures without completely overhauling the structural design of their repeating units. Herein, we show that stapling initially formed π-SPs with a short molecular tether delivers electronically and structurally robust nanoscale objects whose ground-state electronic structures are insensitive to changes in temperature, thus making the tethering component a versatile synthetic handle to tailor the functions of π-SPs post assembly. Ultrafast transient absorption measurements that track the excited-state dynamics of stapled structures further highlight their structural rigidity. Photoexcitation of the stapled π-SPs generates excited states with mixed Frenkel exciton and charge-transfer character. Notably, we find that the charge-transfer contributions to these states can be enhanced by increasing the structural rigidity of the π-SPs, providing a potential pathway for separating charges for light-harvesting applications. Deviating from conventional supramolecular tools, our reported post-assembly modification strategy highlights a new set of design principles that can guide the molecular engineering of materials with designer electronic properties for applications in light-harvesting, photocatalysis, and organic electronics.