Lu Wenxin, Mu Tiantian, Ma Yunjin, Gong Lei, Zhao Luyang, Wang Peng, Bian Yongzhong
College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Inorg Chem. 2025 May 12;64(18):9322-9329. doi: 10.1021/acs.inorgchem.5c01188. Epub 2025 Apr 28.
The effective control over the rotary motions of molecular rotors still remains an enormous challenge. Herein, mixed (phthalocyaninato)(porphyrinato) rare-earth triple-decker complexes ()-/()- and ()-/()- have been designed and investigated as a new type of molecular rotors with a phthalocyanine ligand as the rotator and a strapped bisporphyrin ligand as the stator. The rotational rates and thermodynamic parameters of the rotors were determined through variable-temperature H NMR experiments, revealing a higher rotational rate and a reduced rotational barrier for ()-, in comparison to those of ()-. Variable-temperature CD experiments demonstrated that these chiral molecular rotors exhibited temperature-dependent chiroptical properties. Upon elevating the temperature, the reduction of CD intensity is closely related to the conformational perturbation involving the increased rotational rate. The DFT calculation results further elucidate that the increased rotational rate of the phthalocyanine rotator in ()- can be attributed to the reduced steric interaction between the phthalocyanine rotator and the binaphthol linkage of the bisporphyrin stator owing to the diminished radius from Eu(III) to Y(III). Thus, effective control over the rotary motions can be realized by tuning the steric interactions involving adjustment of center metal ions in this new type of molecular rotors.
对分子转子旋转运动的有效控制仍然是一个巨大的挑战。在此，已设计并研究了混合的（酞菁基）（卟啉基）稀土三层配合物（）-/（）-和（）-/（）-，作为一种新型分子转子，其中酞菁配体作为转子，带束缚的双卟啉配体作为定子。通过变温核磁共振实验确定了转子的旋转速率和热力学参数，结果表明，与（）-相比，（）-具有更高的旋转速率和更低的旋转势垒。变温圆二色性实验表明，这些手性分子转子表现出温度依赖性的手性光学性质。升高温度时，圆二色性强度的降低与涉及旋转速率增加的构象扰动密切相关。密度泛函理论计算结果进一步阐明，（）-中酞菁转子旋转速率的增加可归因于由于从铕（III）到钇（III）半径减小，酞菁转子与双卟啉定子的联萘酚连接之间的空间相互作用减弱。因此，通过调节涉及调整中心金属离子的空间相互作用，可以在这种新型分子转子中实现对旋转运动的有效控制。
