正交调控的双定向分子机器

The design, construction and functionalization of molecular machines that can be kinetically controlled and driven in a non-equilibrium way, which involves the efforts to make molecular machines perform work instead of switching functions, has always been a great challenge and is of great significance in the fields of supramolecular organic chemistry, materials science and molecular machines. Inspired by naturally occurring biological molecular motors that can perform important tasks and simulate the protein transport in living substances required for the important processes, the main purpose of this research is to introduce acid/base, oxidation/reduction and/or light responsive units into functional rotaxane and catenane systems for the design and construction of a series of complex functions of multi-input, multi-mode molecular machines that can perform dually unidirectional transport the artificial molecular pumps and molecular rotors. Based on the construction of molecular machines which can realize unidirectional transport of cargoes, more advanced molecular machines that can perform dually unidirectional motion in both clockwise and anticlockwise directions in response to different sequences of stimuli, will be constructed. This will provide a solid theoretical basis for the realization of complex molecular machines based on complicated programming and logic.

如何模拟生命体中分子马达动态的运动过程来构造非平衡、动力学控制的分子机器，是当前分子机器领域的一个非常具有挑战和重大意义的课题。本课题的主要目标是为了模拟自然界中转运蛋白运输生命体中所需物质的过程，将酸/碱、氧化/还原、光响应的功能基团引入到轮烷、索烃体系中，设计并合成一系列具有复杂功能的多输入、多模式、双定向运输的人工“分子泵”、分子转子，在构建新型可单向运输货物的分子机器载体的基础上，创造性地发展双单向运输物质的高级功能，为发展基于复杂编程的单向运动分子机器器件材料提供坚实的理论基础。

在该项目支撑下，项目团队注重功能导向、体系创新，实现动态轮烷分子机器精准创制及其表界面自组装，发展了一系列分子机器智能响应材料：构筑了一系列可刺激响应的动态主体大环体系，通过引入光驱动分子马达设计可多稳态切换的光控主-客体系统，进而控制对不同手性客体的立体可切换的选择性识别，实现了马达化大环与客体的光致切换结合亲和力和立体选择性的动态反转；引入偶氮苯光致异构基团，通过光调控轮烷梭动实现可逆ON/OFF离子跨膜运输，使得该体系在具备高效、离子选择性的基础上，进一步实现了门控的离子传输，该创新成果有助于理解膜蛋白的离子转运机制，有望运用分子机器的穿梭运动，实现轮烷类人工离子转运体系在新药研发领域的应用；创新性地利用Pt-N配位键驱动的定向自组装策略简便高效地实现了若干个分子马达在同一超分子金属大环上的稳定有序组装，并利用分子马达的刺激响应性，成功地将分子尺度的运动放大转化为聚合物形貌的可控调节。将机械互锁分子组装到传统高分子聚氨酯的无溶剂氢键网络中，发现微量的轮烷分子引入即可同时大幅度提高材料的机械强度和拉伸性能，并揭示了机械应力刺激下环状单元在聚氨酯聚合物链上独特的“分子拉链”滑移机理。这种“分子拉链”独特的动态机制提供了一种在聚合物网络中有效放大微量机械互锁分子动态性的策略，该策略对构建兼具高机械强度和拉伸性能的弹性体材料具有潜在应用价值。