Self-assembled porous materials from cyclic ureas

环状脲自组装多孔材料

• 批准号: 0718171
• 负责人: Linda Shimizu
• 金额: $ 36万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0718171&HistoricalAwards=false
• 关键词: Self; assembled; porous; materials; cyclic

The Organic and Macromolecular Chemistry Program supports the work of Professor Linda Shimizu of the University of South Carolina who will develop homogeneous microporous materials with rationally tunable cavities. These will be used as confined environments for inducing selectivity in reactions, for host/guest chemistry, and for separations. It has been demonstrated that bis-urea macrocycles predictably self-assemble into porous crystals, which contain hollow tubular channels. The assembly is directed by non-covalent interactions, primarily urea-urea hydrogen bonds, and aryl stacking interactions. The initial structure, phenylether bis-urea, proves that this approach is valid, as it assembles as designed into crystals containing into tubular channels filled with acetic acid guests. The guests can be removed from these crystals forming a porous host that display a type 1 gas adsorption isotherm consistent with an open framework microporous material. Recently it has been shown that crystalline phenylether bis-urea binds guest molecules and that these guests can be removed and rebound reversibly, much like zeolites. In fact, crystalline phenylether bis-urea can be used as a container for reactions, promoting highly stereoselective head-to-tail [2+2] photodimerizations of 2-cyclohexenone in high conversion. Focus will be on the synthesis of bis-urea macrocycles from rigid spacers and ureas that upon self-assembly will display a greater range of cavity sizes and interior properties by modulating the size and shape of the spacers. Functional groups can then be added on the interior to tune the reaction environment and will lead to 'tunable' cavities, designed to bind specific guests and catalyze reactions. Also, these porous materials will be investigated as environments for selective photochemical reactions and as catalysts for alcohol dehydration.The funding of this work by the Organic and Macromolecular Chemistry Program will result in new molecular building blocks that predictably self-assemble into tubular supramolecular assemblies and porous solids that have been sought for applications as sensors, templates for directed reactions, as separation and catalyst supports, and for metal sequestering agents. Graduate students trained in this program will receive a broad multidisciplinary background that will empower them to pursue a wide range of scientific careers. This award will support the first research experiences of undergraduates and high school students. This award will also support the enhancement and continuation of a chemistry outreach program that fosters interactions between K-12 students and teachers and skilled scientific researchers. New experiments to meet teacher requests and to relate to science standards will be incorporated.

有机和高分子化学计划支持南卡罗来纳州大学的琳达清水教授的工作，他将开发具有合理可调腔的均匀微孔材料。这些将被用作封闭的环境，用于诱导反应的选择性，用于主体/客体化学和分离。已经证明，双脲大环可预测地自组装成含有中空管状通道的多孔晶体。组装是由非共价相互作用，主要是脲-脲氢键，和芳基堆积相互作用。最初的结构，苯基醚双脲，证明这种方法是有效的，因为它组装成晶体的设计包含到管状通道充满乙酸客人。客体可以从这些晶体中除去，形成多孔主体，其显示与开放骨架微孔材料一致的1型气体吸附等温线。最近，它已被证明，结晶苯基醚双脲结合客体分子，这些客人可以被删除和反弹可逆，很像沸石。事实上，结晶苯基醚双脲可用作反应容器，以高转化率促进2-环己烯酮的高度立体选择性头-尾[2+2]光二聚。重点将放在从刚性间隔物和脲合成双脲大环上，所述脲在自组装后将通过调节间隔物的尺寸和形状显示更大范围的腔尺寸和内部性质。然后可以在内部添加官能团来调节反应环境，并将导致“可调”腔，旨在结合特定的客人并催化反应。此外，这些多孔材料将作为选择性光化学反应的环境和醇脱水的催化剂进行研究。有机和大分子化学计划对这项工作的资助将导致新的分子结构单元，可预测地自组装成管状超分子组装体和多孔固体，这些固体已被用作传感器，定向反应的模板，作为分离和催化剂载体，和金属螯合剂。在该计划中培训的研究生将获得广泛的多学科背景，使他们能够从事广泛的科学事业。该奖项将支持本科生和高中生的第一次研究经验。该奖项还将支持化学推广计划的增强和延续，该计划旨在促进K-12学生和教师以及熟练的科学研究人员之间的互动。新的实验，以满足教师的要求，并与科学标准将被纳入。