Department für Chemie and Munich Center for Integrated Protein Science CIPSM, Ludwig-Maximilians-Universität München, 81377, Munich, Germany.
Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany.
Chemistry. 2021 Jul 21;27(41):10758-10765. doi: 10.1002/chem.202100950. Epub 2021 Jun 4.
Tuning the thermal behavior of light driven molecular motors is fundamentally important for their future rational design. In many molecular motors thermal ratcheting steps are comprised of helicity inversions, energetically stabilizing the initial photoproducts. In this work we investigated a series of five hemithioindigo (HTI) based molecular motors to reveal the influence of steric hindrance in close proximity to the rotation axle on this process. Applying a high yielding synthetic procedure, we synthesized constitutional isomeric derivatives to distinguish between substitution effects at the aromatic and aliphatic position on the rotor fragment. The kinetics of thermal helix inversions were elucidated using low temperature H NMR spectroscopy and an in situ irradiation technique. In combination with a detailed theoretical description, a comparative analysis of substituent effects on the thermal helix inversions of the rotation cycle is now possible. Such deeper understanding of the rotational cycle of HTI molecular motors is essential for speed regulation and future applications of visible light triggered nanomachines.
调整光驱动分子马达的热行为对于它们的未来合理设计至关重要。在许多分子马达中，热棘轮步骤由螺旋反转组成，从而稳定初始光产物。在这项工作中，我们研究了一系列基于半硫靛（HTI）的分子马达，以揭示在旋转轴附近的空间位阻对该过程的影响。采用高产率的合成方法，我们合成了结构异构的衍生物，以区分在转子片段的芳基和脂肪族位置的取代效应。使用低温 H NMR 光谱和原位辐照技术阐明了热螺旋反转的动力学。结合详细的理论描述，现在可以对旋转循环中取代效应对 HTI 分子马达热螺旋反转的影响进行比较分析。对 HTI 分子马达旋转循环的这种更深入的理解对于可见光触发纳米机器的速度调节和未来应用至关重要。
