New Frontiers in Metal-Organic Frameworks: Chemical, Optical, and Electrochemical Control of Pore Size/Aperture

该研究项目的重点是使用多孔材料来解决可持续化学中的挑战。例如，海绵是多孔材料。海绵的特点是它能吸收多少水。在我的实验室里，我们将研究被称为金属有机框架（mof）的多孔材料。mof是由无机金属（节点）制成的，它们通过有机分子（连接物）相互连接。在mof中，80%的晶体是空的。这80%是可供我作为研究人员调查的。与海绵不同，mof的优点是它们的孔隙非常规则和清晰。定义明确的孔具有内部体积和孔孔径（即进入孔的开口大小）。我的研究团队将专注于调整孔的体积和孔的开口，以改变分子的储存方式或与MOF的相互作用。该研究项目将侧重于两个目标。***研究团队和我将使用称为UiO-66的MOF。UiO-66是一个非常坚固的MOF，使其成为各种工业应用的理想选择。当MOF被加热时，从每个节点中除去两个水分子。虽然这个反应是可逆的，但我们将探讨醇而不是水分子是如何附着在节点上的。在这个目标中，节点将呈现一个碳链进入孔，而不是来自水分子的氢原子。通过改变碳链的长度，可以调整孔径，用于气体储存（如二氧化碳封存）和水净化（如汞吸附）。***物镜的前一部分集中在调整MOF内部的每个毛孔。然而，如果使用的酒精时间足够长，那么只有MOF颗粒的外部会被修饰。根据使用的酒精类型，我们将制作可溶于水的mof，这样它们就可以很容易地加工成薄膜，或者很容易地融入塑料中。***研究团队和我将研究内置开关的mof。当分子暴露在光线下时会改变它们的形状。这种转换是可逆的。开关将放置在MOF的两个位置之一。如果开关被放置在MOF的光圈上，那么开关可以用来打开和关闭，或者，至少，收缩光圈的大小。在这个系统中，分子可以通过简单地照射在MOF上而被捕获。用于气体储存的分子（例如，用于甲烷动力汽车的甲烷）、催化剂，甚至潜在的药物都可以储存在这些mof中。在第二种可切换mof中，开关将指向孔的中间。在该系统中，研究小组将研究可以打开和关闭MOF导电性的导电MOF。开关将发生在孔隙内部，因此孔隙大小本身将发生变化。***该研究项目的影响是将探索并利用两种新工具用于可持续性化学的应用

The research program focuses on using porous materials to address challenges in sustainable chemistry. For example, sponges are porous materials. A sponge can be characterized by how much water it can absorb. In my lab, we will work on porous materials known as Metal-Organic Frameworks (MOFs). MOFs are made from inorganic metals (nodes) which are connected to one another by organic molecules (linkers). In MOFs, 80% of the crystal is empty. This 80 % is available for me as a researcher to investigate. Unlike the sponge example, the advantage of MOFs is that their pores are very regular and well defined. A well-defined pore has an internal volume and a pore aperture (i.e., the size of the opening into the pore). My research team will focus on tuning the volume of the pore and the opening of the pore in order to change how molecules are stored or interact with the MOF.***The research program will focus on 2 objectives.***The research team and I will utilize a MOF known as UiO-66. UiO-66 is a very sturdy MOF, making it ideal for a variety of industrial applications. When the MOF is heated, two water molecules are removed from each node. Although this reaction is reversible, we will explore how alcohols, instead of water molecules, are attached to the node. In this objective, the node will present a carbon chain into the pore instead of a hydrogen atom from the water molecule. By changing the length of the carbon chain, then the pore size can be tuned for applications in gas storage (e.g., CO2 sequestration), and water purification (e.g., mercury adsorption).***The previous portion of the objective focused on adjusting every pore inside the MOF. However, if the alcohol that is being used is long enough, then only the outside of the MOF particle will be modified. Depending on the type of alcohol used, we will make MOFs that are soluble in water so that they can be easily processable into films, or easily incorporated into plastics.***The research team and I will investigate MOFs which have switches built into them. Switching molecules change their shape when they are exposed to light. This switching is reversible. The switch will be placed in one of two places of the MOF. If the switch is placed by the aperture of the MOF, then the switch can be used to open and close, or, at the very least, constrict the size of the aperture. In this system, molecules can be trapped inside the MOF by simply shining light on it. Molecules used for gas-storage (e.g., methane for methane-powered cars), catalysts, and potentially even drugs can be stored in these MOFs. In the second type of switchable MOFs, the switch will point into the middle of the pore. In this system, the research team will tackle conducting MOFs in which the conductivity of the MOF can be turned on and off. The switching will occur inside the pore, and thus the pore size itself will change.***The impact of this research program is that two new tools will be explored and utilized for applications in sustainability chemistry.**