Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany.
Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, 9747, Nijenborgh 4, Groningen, AG, The Netherlands.
Angew Chem Int Ed Engl. 2023 Jan 16;62(3):e202214202. doi: 10.1002/anie.202214202. Epub 2022 Dec 20.
Molecular motors are fascinating nanomachines. However, constructing smart materials from such functional molecules presents a severe challenge in material science. Here, we present a bottom-up layer-by-layer assembly of oriented overcrowded-alkene molecular motors forming a crystalline metal-organic framework thin film. While all stator parts of the overcrowded-alkene motors are oriented perpendicular to the substrate, the rotors point into the pores, which are large enough allowing for the light-induced molecular rotation. Taking advantage of the thin film's transparency, the motor rotation and its activation energy are determined by UV/Vis spectroscopy. As shown by gravimetric uptake experiments, molecular motors in crystalline porous materials are used, for the first time, to control the adsorption and diffusion properties of guest molecules in the pores, here, by switching with light between the (meta-)stable states. The work demonstrates the potential of designed materials with molecular motors and indicates a path for the future development of smart materials.
分子马达是令人着迷的纳米机器。然而，将这类功能分子构建成智能材料是材料科学面临的严峻挑战。在这里，我们通过自下而上的层层组装，将取向的过度拥挤烯烃分子马达组装成结晶型金属-有机骨架薄膜。虽然过度拥挤烯烃分子马达的所有定子部分都垂直于基底取向，但转子指向孔内，孔足够大，可以允许光诱导的分子旋转。利用薄膜的透明性，通过紫外/可见光谱确定了马达的旋转及其活化能。通过重量法吸脱附实验表明，首次在结晶多孔材料中使用分子马达来控制孔内客体分子的吸附和扩散性质，这里通过在（间）稳定态之间用光进行切换。这项工作展示了具有分子马达的设计材料的潜力，并为未来智能材料的发展指明了方向。
