Chen Zi-Jian, Lu Hsiu-Feng, Chiu Chun-Wei, Liu Yi-Hung, Hsu Chao-Ping, Yang Jye-Shane
Department of Chemistry, National Taiwan University Taipei 10617 Taiwan
Institute of Chemistry, Academia Sinica Taipei 11529 Taiwan
Chem Sci. 2025 Jul 11. doi: 10.1039/d5sc03240g.
Chiral sterically overcrowded alkenes are potential candidates for artificial light-driven rotary molecular motors (LRMMs), which perform a full 360° unidirectional rotation around the C[double bond, length as m-dash]C bond through a series of photochemical and thermal isomerization processes. However, the majority of the reported LRMMs adopt an intrinsic chirality (, an integration of the chirality center with the photoresponsive unit), which hampers the effective gating of their rotary direction through chirality switching. Herein, we report a new sterically overcrowded alkene equipped with a boronic acid receptor for dynamic covalent bonding with chiral vicinal diols, enabling it to function as an extrinsic chirality-based LRMM. The dynamic boronic acid-chiral diol B-O bonding not only implements the extrinsic chirality to induce a helical preference in the alkene backbone but also facilitates chirality switching through diol exchange to reverse the rotation direction. This work demonstrates that dynamic covalent bonding for extrinsic chirality implementation is an effective strategy for designing direction-switchable LRMMs, paving the way for more sophisticated molecular motors with applications in complex (bio)environments.
手性空间位阻过大的烯烃是人工光驱动旋转分子马达（LRMMs）的潜在候选物，这类分子马达通过一系列光化学和热异构化过程围绕碳-碳双键进行360°的单向全旋转。然而，大多数已报道的LRMMs采用固有手性（即手性中心与光响应单元的整合），这阻碍了通过手性切换对其旋转方向进行有效控制。在此，我们报道了一种新型的空间位阻过大的烯烃，它配备了硼酸受体，用于与手性邻二醇进行动态共价键合，使其能够作为基于外在手性的LRMM发挥作用。动态硼酸-手性二醇B-O键不仅实现了外在手性，从而在烯烃主链中诱导螺旋偏好，还通过二醇交换促进手性切换以反转旋转方向。这项工作表明动态共价键用于实现外在手性是设计可切换方向的LRMMs的有效策略，为在复杂（生物）环境中应用的更复杂分子马达铺平了道路。
