Self-assembled organic nanotubes from cyclic ureas

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来纳大学的Linda Shimizu教授的工作，该项目研究功能性多孔晶体在吸收、运输和组织客人以及促进他们随后的光反应方面的效用。这些多孔晶体是由双尿素大环自组装成柱状结构制成的。这些柱子紧密堆积在一起，得到直径不超过1 nm的均匀通道的晶体。客体通过圆柱形纳米通道的迁移率是通道的尺寸(大小、形状)和内部属性(极性)的函数。清水小组在这些小空间中研究光反应和氧化。这些反应提供了可控的模型系统来测试限制对反应的影响。对直径小于或等于1 nm的稻草状微通道中的吸收、扩散和储存过程有基本的了解，在分离和催化方面具有实际应用。最终，更好地了解反应机理有助于开发更安全、更环保和更经济的有机合成试剂。本研究为本科生和研究生提供有机化学和材料化学方面的培训。此外，该奖项还支持化学示范计划的继续，该计划将化学家带到南卡罗来纳州的K-12教室，展示科学方法，并培养人们对化学和自然科学的兴趣。

The Macromolecular, Supramolecular and Nanochemistry Program at the National Science Foundation supports the work of Professor Linda Shimizu of the University of South Carolina that investigates the utility of functional porous crystals to absorb, transport and organize guests and to facilitate their subsequent photoreactions. These porous crystals are made by the self-assembly of bis-urea macrocycles into columnar structures. The columns pack close together to give crystals with homogeneous channels with diameters of 1 nm or less. The mobility of the guest through cylinder like nanochannels is a function of the dimensions (size, shape) and interior properties (polarity) of the channel. The Shimizu group studies photoreactions and oxidations in these small spaces. These reactions provide controlled model systems to test the effects of confinement on reactions.Fundamental understanding of the processes of absorption, diffusion, and storage in tiny straw-like channels with diameters of 1 nm or less has practical application in separations and catalysis. Ultimately, a better understanding of a reaction mechanism aids in the development of safer, more environmentally friendly and economical reagents for organic synthesis. This research provides training for undergraduates and graduate students in organic and materials chemistry. In addition, this award supports the continuation of a chemical demonstration program that brings chemists into South Carolina K-12 classrooms to showcase the scientific method and to foster interest in chemistry and in the natural sciences.