Center of Micro and Nanochemistry and Engineering, Organische Chemie I, University of Siegen, Adolf-Reichwein Str. 2, 57068, Siegen, Germany.
Chemistry. 2020 Nov 6;26(62):14095-14099. doi: 10.1002/chem.202002877. Epub 2020 Oct 6.
The dynamics of hydrogen bonding do not only play an important role in many biochemical processes but also in Nature's multicomponent machines. Here, a three-component nanorotor is presented where both the self-assembly and rotational dynamics are guided by hydrogen bonding. In the rate-limiting step of the rotational exchange, two phenolic O-H-N,N hydrogen bonds are cleaved, a process that was followed by variable-temperature H NMR spectroscopy. Activation data (ΔG =46.7 kJ mol at 298 K, ΔH =55.3 kJ mol , and ΔS =28.8 J mol K ) were determined, furnishing a rotational exchange frequency of k =40.0 kHz. Fully reversible disassembly/assembly of the nanorotor was achieved by addition of 5.0 equivalents of trifluoroacetic acid (TFA)/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) over three cycles.
氢键的动态不仅在许多生化过程中起着重要作用，而且在自然界的多组分机器中也起着重要作用。在这里，展示了一种三组分纳米转子，其自组装和旋转动力学都受到氢键的控制。在旋转交换的限速步骤中，两个酚类 O-H-N，N 氢键被切断，这一过程通过变温 H NMR 光谱进行了跟踪。确定了活化数据（在 298 K 时 ΔG =46.7 kJ mol，ΔH =55.3 kJ mol，和 ΔS =28.8 J mol K），得到了旋转交换频率 k =40.0 kHz。通过添加 5.0 当量的三氟乙酸（TFA）/1,8-二氮杂二环[5.4.0]十一碳-7-烯（DBU），纳米转子可以完全可逆地进行拆卸/组装，经过三个循环。
