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

该研究计划的重点是使用多孔材料来应对可持续化学的挑战。 例如，海绵是多孔材料。 海绵的特征在于它能吸收多少水。 在我的实验室里，我们将研究被称为金属有机框架（MOFs）的多孔材料。 MOFs由无机金属（节点）制成，它们通过有机分子（连接体）彼此连接。在MOF中，80%的晶体是空的。 这80%是我作为研究人员可以调查的。 与海绵的例子不同，MOF的优点是它们的孔非常规则且轮廓分明。 明确限定的孔具有内部体积和孔径（即，孔中开口的尺寸）。 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。研究计划将集中在两个目标上。*研究小组和我将使用一种名为UiO-66的MOF。 UiO-66是一种非常坚固的MOF，使其成为各种工业应用的理想选择。 当MOF被加热时，两个水分子从每个节点被移除。 虽然这个反应是可逆的，但我们将探索醇而不是水分子如何附着在节点上。 在这个目标中，节点将呈现碳链进入孔中，而不是来自水分子的氢原子。 通过改变碳链的长度，可以调整孔径以用于气体储存（例如，CO2封存）和水净化（例如，汞吸附）。目标的前一部分集中于调整MOF内的每个孔。然而，如果所使用的醇足够长，则仅MOF颗粒的外部将被改性。 根据所使用的酒精类型，我们将生产可溶于水的MOFs，以便它们可以容易地加工成薄膜，或容易地掺入塑料中。研究小组和我将研究内置开关的MOF。 开关分子在暴露于光下时会改变其形状。 这种转换是可逆的。交换机将被放置在MOF的两个位置之一。 如果开关被放置在MOF的孔旁，则开关可以用于打开和关闭，或者至少收缩孔的尺寸。 在该系统中，分子可以通过简单地将光照射在MOF上而被捕获在MOF内。用于甲烷动力汽车的甲烷）、催化剂以及甚至潜在的药物可以存储在这些MOF中。 在第二种类型的可切换M0 F中，开关将指向孔的中间。 在这个系统中，研究小组将解决导电的MOF，其中MOF的导电性可以打开和关闭。 开关将发生在孔内，因此孔尺寸本身将改变。这项研究计划的影响是，两个新的工具将被探索和用于可持续发展化学的应用。

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.**