Department of Chemical Engineering and Chemistry, Institute for Complex Molecular Systems and Laboratory of Molecular Science and Technology, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Chair of Organic Chemistry I, Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nürnberg , 91054 Erlangen, Germany.
J Am Chem Soc. 2016 Aug 24;138(33):10539-45. doi: 10.1021/jacs.6b05184. Epub 2016 Aug 10.
Functional supramolecular systems like carbonyl-bridged triarylamine (CBT) trisamides are known for their long-range energy transport at room temperature. Understanding the complex self-assembly processes of this system allows for control over generated structures using controlled supramolecular polymerization. Here, we present two novel CBT trisamides with (S)- or (R)-chiral side chains which show a two-pathway self-assembly behavior in solution. Depending on the thermal profile during the self-assembly process, two different stable states are obtained under otherwise identical conditions. A kinetically trapped state A is reached upon cooling to 7 °C, via a proposed isodesmic process. In addition, there is a thermodynamically stable state B at 7 °C that is induced by first undercooling to -5 °C, via a nucleation-elongation mechanism. In both cases, helical supramolecular aggregates comprising H-aggregated CBTs are formed. Additionally, controlled supramolecular polymerization was achieved by mixing the two different states (A and B) from the same enantiomer, leading to a conversion of the kinetically trapped state to the thermodynamically stable state. This process is highly enantioselective, as no conversion is observed if the two states consist of opposite enantiomers. We thus show the importance and opportunities emerging from understanding the pathway complexity of functional supramolecular systems.
功能超分子体系，如羰基桥联三苯胺（CBT）三酰胺，以其在室温下的长程能量传递而闻名。了解该体系的复杂自组装过程，可以通过控制超分子聚合来控制生成的结构。在这里，我们提出了两种具有（S）-或（R）-手性侧链的新型 CBT 三酰胺，它们在溶液中表现出两种途径的自组装行为。根据自组装过程中的热分布，在其他条件相同的情况下，得到两种不同的稳定状态。通过拟议的等摩尔过程，冷却至 7°C 时可达到动力学捕获的状态 A。此外，在 7°C 下存在热力学稳定的状态 B，这是通过首先过冷至-5°C 并通过成核-延伸机制诱导的。在这两种情况下，均形成了包含 H 聚集 CBT 的螺旋超分子聚集体。此外，通过混合两种不同的状态（A 和 B）（来自相同的对映体）实现了受控的超分子聚合，导致动力学捕获的状态向热力学稳定的状态转化。该过程具有高度的对映选择性，如果两种状态由相反的对映体组成，则不会观察到转化。因此，我们展示了从功能超分子体系的途径复杂性中理解其重要性和机遇。
