Laboratory of Macromolecular and Organic Chemistry, Institute for Complex Molecular Systems, Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands.
Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany.
ACS Macro Lett. 2022 May 17;11(5):711-715. doi: 10.1021/acsmacrolett.2c00223. Epub 2022 May 9.
The introduction of stereogenic centers in supramolecular building blocks is used to unveil subtle changes in supramolecular structure and dynamics over time. Three stereogenic centers based on deuterium atoms were introduced in the side chains of a benzene-1,3,5-tricarboxamide (BTA) resulting in a supramolecular polymer in water that at first glance has a structure and dynamics identical to its achiral counterpart. Using three different techniques, the properties of the double helical polymers are compared after 1 day and 4 weeks. An increase in helical preference is observed over time as well as a decrease in the helical pitch and monomer exchange dynamics. It is proposed that the polymer of the chiral monomer needs time to arrive at its maximal preference in helical bias. These results indicate that the order and tight packing increase over time, while the dynamics of this supramolecular polymer decrease over time, an effect that is typically overlooked but unveiled by the isotopic chirality.
在超分子构建块中引入手性中心，可用于揭示超分子结构和动力学随时间的微妙变化。在苯-1,3,5-三羧酸酰胺（BTA）的侧链中引入了三个基于氘原子的手性中心，在水中形成超分子聚合物，乍一看，其结构和动力学与非手性对应物相同。使用三种不同的技术，在 1 天和 4 周后比较了双螺旋聚合物的性质。随着时间的推移，观察到螺旋偏好增加，螺旋螺距和单体交换动力学降低。据推测，手性单体的聚合物需要时间才能达到其在螺旋偏向上的最大偏好。这些结果表明，随着时间的推移，有序性和紧密堆积增加，而超分子聚合物的动力学随时间降低，这种效应通常被忽视，但通过同位素手性揭示出来。
