College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China.
Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, Guangdong 518060, China.
J Am Chem Soc. 2022 Sep 14;144(36):16559-16571. doi: 10.1021/jacs.2c06251. Epub 2022 Aug 23.
Molecular geometry represents one of the most important structural features and governs physical properties and functions of materials. Nature creates a wide array of substances with distinct geometries but similar chemical composition with superior efficiency and precision. However, it remains a formidable challenge to construct abiological macromolecules with various geometries based on identical repeating units, owing to the lack of corresponding synthetic approaches for precisely manipulating the connectivity between monomers and feasible techniques for characterizing macromolecules at the single-molecule level. Herein, we design and synthesize a series of tetratopic monomers with chevron stripe shape which serve as the key precursors to produce four distinct types of metallo-macromolecules with well-defined geometries, , the concentric hexagon, helicoid polymer, ladder polymer, and cross-linked polymer, via platinum-acetylide couplings. Concentric hexagon, helicoid, and ladder metallo-polymers are directly visualized by transmission electron microscopy, atomic force microscopy, and ultra-high-vacuum low-temperature scanning tunneling microscopy at the single-molecule level. Finally, single-walled carbon nanotubes (SWCNTs) are selected as the guest to investigate the structure-property relationship based on such macromolecules, among which the helicoid metallo-polymer shows high efficiency in wrapping SWCNTs with geometry-dependent selectivity.
分子几何形状代表了最重要的结构特征之一，它控制着材料的物理性质和功能。大自然创造了大量具有独特几何形状但化学成分相似的物质，其效率和精度都非常高。然而，由于缺乏精确操纵单体之间连接性的相应合成方法，以及在单分子水平上对大分子进行表征的可行技术，因此仍然难以构建具有各种几何形状的非生物大分子。在这里，我们设计并合成了一系列具有雪佛龙条纹形状的四官能团单体，这些单体是通过铂-炔基偶联反应生成具有明确几何形状的四种不同类型的金属大分子的关键前体，包括同心六边形、螺旋聚合物、梯形聚合物和交联聚合物。通过透射电子显微镜、原子力显微镜和超高真空低温扫描隧道显微镜，在单分子水平上直接观察到同心六边形、螺旋和梯形金属聚合物。最后，选择单壁碳纳米管（SWCNTs）作为客体，基于这些大分子研究结构-性能关系，其中螺旋金属聚合物在几何形状依赖性选择性地包裹 SWCNTs 方面表现出高效率。
