Functional Organic Nanotubes from Self-Assembled Bis-Urea Macrocycles

美国国家科学基金会的大分子、超分子和纳米化学项目支持南卡罗莱纳大学的Linda Shimizu教授制作定义明确的微小一维通道（纳米管），以回答基本的科学问题。这些纳米管是由简单的甜甜圈形状的分子组成的，这些分子一个一个地堆叠在一起，形成微小的稻草状结构。纳米管可以在不改变通道结构的情况下装载气体和小分子。所获得的先进知识使我们对分子运输有了更深入的了解，并有助于优化工业气体分离的性能和开发环保的方法来进行工业氧化反应。该奖项的教育部分包括三个方面：(1)培养研究生的研究能力，并为他们未来在科学或工程领域的职业生涯做好准备；(2)支持大学生和高中生的首次科研经历；(3)通过将化学家引入南卡罗来纳州的K-12教室，以展示科学方法，并培养对化学和自然科学的兴趣，特别是在少数民族入学率高的中学和高中，广泛促进对科学的兴趣。通过分子自组装设计功能材料的自下而上方法提供了一种高效、高保真的策略，可以制备定义良好的纳米结构，用于回答基本问题。在这个研究项目中，Shimizu小组通过控制简单大环构建块的自组装来制备结构可调的一维纳米通道。这些纳米通道主要用于三个目的：(1)研究通过通道传输气体或客体分子的速率，作为通道尺寸、客体尺寸以及客体与通道壁之间可能发生的相互作用的函数。(2)组织能与光相互作用的分子，并研究这种组织对其性质的影响；(3)产生活性氧，单线态氧，并控制有机底物的氧化。

The Macromolecular, Supramolecular and Nanochemistry Program of the National Science Foundation supports the work of Professor Linda Shimizu of the University of South Carolina to make well-defined, tiny 1-dimensional channels (nanotubes) to answer fundamental scientific questions. These nanotubes are prepared from simple, donut-shaped molecules that stack one on top of each other to make tiny straw-like structures. The nanotubes can be loaded with gases and small molecules without altering the channel structure. The advanced knowledge acquired leads to a greater understanding of molecular transport and could help optimize performance for industrial gas separations and the development of environmentally friendly methods to carry out industrial oxidation reactions. The educational component of this award encompasses three areas: (1) it trains graduate students in research and prepares them for future careers in science or engineering fields; (2) it supports the first research experiences of undergraduates and high school students; and (3) it broadly promotes interest in science by bringing chemists into South Carolina's K-12 classrooms to showcase the scientific method and to foster interest in chemistry and in the natural sciences, especially at high minority enrollment middle schools and high schools.Bottom-up approaches to design functional materials through molecular self-assembly provide an efficient and high fidelity strategy to prepare well-defined nanostructures that can be used to answer fundamental questions. In this research project, the Shimizu group prepares structurally tunable 1-dimensional nanochannels by controlling the self-assembly of simple macrocyclic building blocks. These nanochannels are used for three main purposes: (1) to study the rates of transporting gas or guest molecules through the channels as a function of the channel dimensions, guest dimensions, and the interactions that can occur between the guests and the channel walls. (2) to organize molecules that can interact with light and to study the effect of this organization on their properties, and (3) to generate a reactive form of oxygen, singlet oxygen, and to control the oxidation of organic substrates.