Functional Organic Nanotubes from Self-Assembled Bis-Urea Macrocycles

University Of South Carolina At Columbia, Columbia SC

Investigators

Abstract

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.