CAREER: Development of metal-organic nanotubes with unique water transport and storage properties

技术纳米管材料具有独特的水传输和存储性能，有可能导致分离、催化、药物输送和环境修复方面的技术进步。发展新型杂化材料，如金属-有机纳米管(MON)是特别有兴趣的，因为它们服从于结构工程策略，并可能基于无机成分的存在而显示出独特的性质。这个项目的目标是确定最近被证明促进结构水的形成和有前景的交换性质的U(VI)MON的结构特征。U(VI)MON的独特性质被认为是以下因素的组合：(1)有机连接物的两性离子性质，(2)管的总直径，以及(3)铀酰(UO2)阳离子的存在。这一假说将通过合成具有不同结构特征的MON来验证，表征水的构型，并结合衍射和光谱技术来检查所得到的材料的交换性质。含有不含氨基的有机连接基的材料最初将作为目标(目标1)，以研究两性离子分子对水吸引到纳米管内部的重要性。接下来，将通过改变两性离子连接物的链长和有机螯合剂的选择来研究试管内径的重要性(目标2)。最后，将通过设计含有通过两性离子分子连接的其他金属的MON来审查铀酰离子的重要性(目标3)。这些研究意义重大，因为它们将确定对这些增强的交换性能施加最大控制的结构成分，并开发潜在应用于分离和存储技术的新型纳米分子材料。计划中的研究具有潜在的变革性，因为从实验结果中获得的基本信息可能会导致对水的纳米限制的更好理解，这影响了广泛的生物、地质和物理系统。关于蒙斯地区承压水流动性的实验将支持核磁共振用户设施，使该设施能够更新所有研究小组广泛可用的当前仪器。这项工作还通过开发用于分离和存储介质的先进应用的新材料，以及加强结构和纳米分子化学的本科生和研究生教育，对社会产生更广泛的好处。教育贡献包括指导一名研究生进行与综合MON材料有关的研究，以及制定旨在促进本科生STEM教育的倡议。这些举措包括：(1)为二年级无机化学课程的本科生创建一门关于纳米材料结构性质的引人入胜的课程；(2)招募代表性不足的少数族裔学生加入研究小组，通过麦克奈尔学者计划参与纳米管材料的合成；以及(3)将本科生纳入有关纳米材料在水净化中的作用的非正式科学教育工作。

TECHNICAL Nanotubular materials can have unique water transport and storage properties that have the potential to lead to technological advances in separations, catalysis, drug delivery, and environmental remediation. Development of novel hybrid materials, such as metal-organic nanotubes (MONs) are of particular interest as they are amenable to structural engineering strategies and may exhibit unique properties based upon the presence of inorganic components. The objective of this program is to determine the structural characteristics of the U(VI) MON that has recently been shown to promote the formation of structural water and promising exchange properties. The unique properties of the U(VI) MON are hypothesized to occur from a combination of: (1) the zwitterionic nature of the organic linker, (2) the overall diameter of the tube, and (3) the presence of uranyl (UO2) cation. The hypothesis will be tested by the synthesis of MONs with different structural features, characterization of water configuration, and examination the exchange properties of the resulting material by a combination of diffraction and spectroscopic techniques. Materials that contain organic linkers lacking amino groups will be initially targeted (Objective 1) to investigate the importance of the zwitterionic molecules for the attraction of H2O into the interior of the nanotube. Next, the importance of the internal diameter of the tube will be investigated by varying the chain length of the zwitterionic linker and the choice of organic chelator (Objective 2). Lastly, the importance of the uranyl ion will be examined by designing MONs containing other metals linked through zwitterionic molecules (Objective 3). The studies are significant because they will allow the determination of the structural component that exerts the greatest control over these enhanced exchange properties and develop novel nanomolecular materials for potential application in separations and storage technologies.NON TECHNICALThe planned studies are potentially transformative because fundamental information gained from the experimental results could lead to a greater understanding of nanoconfinement of water, which influences a wide variety of biological, geological, and physical systems. Experiments on the mobility of confined water within the MONs will support the NMR user facility that will enable the facility to update the current instruments that are widely available to all research groups. The work also has more general benefits to society through the development of novel materials for advanced applications in separations and storage media and the enhancement of undergraduate and graduate education in structural and nanomolecular chemistry. Educational contributions include mentoring of a graduate student on research related to the synthesis of MON materials and the development of initiatives aimed at promoting STEM education for undergraduate students. The initiatives include efforts to: (1) create an engaging curriculum on the structural nature of nanomaterials for undergraduate students in a 2nd-year inorganic chemistry course; (2) recruit underrepresented minority students into the research group to participate in the synthesis of nanotubular materials through the McNair Scholar program; and (3) integrate undergraduate students in informal science education efforts regarding the role of nanomaterials in water purification.