Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
ACS Nano. 2021 Mar 23;15(3):5322-5332. doi: 10.1021/acsnano.0c10876. Epub 2021 Mar 8.
Precise control of the emergence of macroscopic helicity with specific handedness is promising in rationally designing chiral nanomaterials, but it is rather challenging. Herein, we present a protocol to address the transmission of helicity at a molecularly resolved level to a macroscopically resolved level, in which process supramolecular chirality undergoes an inversion. A series of -terminal aromatic amino acids could self-assemble in water, enabling the occurrence of helicity at the molecularly resolved scale, evidenced by the single crystal structure and chiroptical responses. While it failed to transmit the helicity to the macroscopic scale for individual self-assembly, the coassembly with small organic binder through hydrogen bonding interactions allows for the emergence of helical structures at the nano/micrometer scale. Experimental and theoretical results demonstrate that the introduction of extra hydrogen bonds enables a moderate crystallinity of coassemblies with remaining one-dimensional orientation to enhance the helical growth. The transmission of helicity to higher levels by coassembly is accompanied by the helicity inversion, resulting from the exchange of hydrogen bonds. This study presents a rational protocol to precisely control the emergence of macroscopic helicity from molecularly resolved helicity with finely tailored handedness, providing a deeper understanding of the chirality origin in the assembled systems in order to facilitate the design and construction of functional chiral nanomaterials.
精确控制具有特定手性的宏观螺旋的出现有望在合理设计手性纳米材料方面取得进展，但这是相当具有挑战性的。在此，我们提出了一种方案，以解决分子水平上的螺旋传递到宏观水平的问题，在此过程中，超分子手性经历了反转。一系列的 -端芳基氨基酸可以在水中自组装，从而在分子水平上产生螺旋，这可以从单晶结构和圆二色性响应中得到证明。虽然单个自组装无法将螺旋传递到宏观尺度，但通过氢键相互作用与小分子结合剂共组装可以在纳米/微米尺度上形成螺旋结构。实验和理论结果表明，引入额外的氢键可以使共组装具有适度的结晶度，并保持一维取向，从而增强螺旋生长。通过共组装将螺旋传递到更高水平伴随着螺旋反转，这是由于氢键的交换。这项研究提出了一种合理的方案，可以精确控制从分子水平上的螺旋到宏观螺旋的出现，并且具有精细调整的手性，为组装体系中的手性起源提供了更深入的理解，从而有助于设计和构建功能性手性纳米材料。
