Helmers Ingo, Ghosh Goutam, Albuquerque Rodrigo Q, Fernández Gustavo
Organisch-Chemisches-Institut, Westfälische-Wilhelms-Universität Münster, Correnstrasse 40, 48149, Münster, Germany.
Lehrstuhl für Systemverfahrenstechnik, Technical University of Munich (TUM), Gregor-Mendel-Strasse 4, 85354, Freising, Germany.
Angew Chem Int Ed Engl. 2021 Feb 19;60(8):4368-4376. doi: 10.1002/anie.202012710. Epub 2020 Dec 22.
Programming the organization of π-conjugated systems into nanostructures of defined dimensions is a requirement for the preparation of functional materials. Herein, we have achieved high-precision control over the self-assembly pathways and fiber length of an amphiphilic BODIPY dye in aqueous media by exploiting a programmable hydrogen bonding lock. The presence of a (2-hydroxyethyl)amide group in the target BODIPY enables different types of intra- vs. intermolecular hydrogen bonding, leading to a competition between kinetically controlled discoidal H-type aggregates and thermodynamically controlled 1D J-type fibers in water. The high stability of the kinetic state, which is dominated by the hydrophobic effect, is reflected in the slow transformation to the thermodynamic product (several weeks at room temperature). However, this lag time can be suppressed by the addition of seeds from the thermodynamic species, enabling us to obtain supramolecular polymers of tuneable length in water for multiple cycles.
将π共轭体系组织编程到特定尺寸的纳米结构中是制备功能材料的必要条件。在此，我们通过利用可编程氢键锁，在水介质中实现了对两亲性硼二吡咯染料自组装途径和纤维长度的高精度控制。目标硼二吡咯中（2-羟乙基）酰胺基团的存在使得分子内与分子间形成不同类型的氢键，导致在水中动力学控制的盘状H型聚集体和热力学控制的一维J型纤维之间产生竞争。由疏水效应主导的动力学状态具有高稳定性，这体现在向热力学产物的缓慢转变上（室温下数周）。然而，通过添加热力学物种的晶种可以抑制这种滞后时间，使我们能够在水中多次循环获得长度可调的超分子聚合物。
