Nanohoops as Modular Building Blocks to Molecular Cylinders and Machines

俄勒冈大学的Ramesh Jasti教授在化学系大分子、超分子和纳米化学（MSN）项目的支持下，开发了一种通用的方法，利用纳米环分子作为构建块，自组装成具有控制形状和功能的精确纳米级材料。设想了两种结构形式：纳米管和联锁结构。探索新的合成方法来实现这些目标。期望的产品具有结构稳定性和独特的尺寸相关光电性能。产品经过合理设计，在气体吸附、过滤、质量传输、分子开关和传感等方面具有特定的功能。控制几何形状和直径的纳米管被用来从富勒烯（类似足球的）碳基分子中制备一维材料。参与该项目的学生将在跨学科的环境中接受培训，并获得有机合成、超分子化学和纳米科学方面的经验。与俄勒冈大学暑期科学项目合作，为俄勒冈州传统上代表性不足的学生群体提供实践科学经验。将分子构建块组装成具有新功能的精确纳米级材料是材料科学、超分子化学和合成领域的一个巨大挑战。虽然制备纳米环的合成方法在过去十年中得到了发展，但将这些纳米环自组装成具有可控形状和功能的纳米级材料的研究相对较少。在这个项目的第一个目标中，Jasti研究小组正在探索弱芳基氟相互作用，作为引导碳纳米环自组装成非共价纳米管的手段。这些纳米管被用来将富勒烯自组装成一维通道，然后可以进行聚合反应，从而产生一系列新的一维富勒烯纳米材料。该项目的第二个目标是，Jasti小组正在探索氮掺杂纳米环类似物和金属配位策略，以制备链烷结构，这将代表分子机器的简单版本。Jasti小组正在探索这些新的链烷结构的新特性，如通过机械键或纳米尺度上的超低摩擦运动进行光电通信。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Professor Ramesh Jasti at the University of Oregon is supported by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program of the Division of Chemistry to develop general methods to use nanohoop molecules as building blocks to self-assemble into precise nanoscale materials with controlled shape and function. Two forms of structures are envisioned: nanotubes and interlocked structures. Novel synthetic approaches are explored to achieve these objectives. The desired products are expected to have structural stability and unique size-dependent optoelectronic properties. The products are rationally designed to perform specific functions in gas adsorption, filtration, mass transport, and molecular switching and sensing. Nanotubes with controlled geometry and diameter are used to prepare one-dimensional materials from fullerenes (soccer-like) carbon-based molecules. Students involved in the project are trained in an interdisciplinary environment and acquire experience in organic synthesis, supramolecular chemistry, and nanoscience. A partnership with the University of Oregon Summer Science Program provides hands-on science experience to groups of students who are traditionally underrepresented in the state of Oregon. The assembly of molecular building blocks into precise nanoscale materials with novel function is a grand challenge at the interfaces of materials science, supramolecular chemistry, and synthesis. While synthetic approaches for the preparation of nanohoops have been developed in the last decade, the self-assembly of these nanohoops into nanoscale materials with controlled shape and function is relatively unexplored. In the first aim of this project, the Jasti research team is exploring weak aryl fluorine interactions as means to guide the self-assembly of carbon nanohoops into noncovalent nanotubes. The nanotubes are used to self-assemble fullerenes into 1D channels, which can then undergo a polymerization reaction to lead to a host of new 1D fullerene nanomaterials. In the second aim of the project, the Jasti group is exploring nitrogen-doped nanohoop analogues and metal-coordination strategies to prepare catenane structures, which would represent simple versions of molecular machines. The Jasti group is probing these new catenane structures for novel properties such as optoelectronic communication through the mechanical bond or ultra-low friction motion on the nanoscale.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.