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方面的挑战。例如，海绵是多孔性材料。海绵的特征可以用它能吸收多少水来衡量。在我的实验室里，我们将研究被称为金属有机骨架(MOF)的多孔材料。MOF是由无机金属(节点)制成的，这些金属通过有机分子(连接体)相互连接。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的优势是它们的毛孔非常规则和定义良好。定义明确的孔具有内部体积和孔孔径(即，通向孔的开口的大小)。我的研究团队将专注于调节气孔的体积和气孔的开口，以改变分子的存储方式或与MOF的相互作用。*研究计划将专注于两个目标。*我和研究团队将利用一种名为UIO-66的MOF。UIO-66是一款非常坚固的MOF，非常适合各种工业应用。当MOF被加热时，两个水分子从每个节点上移除。虽然这个反应是可逆的，但我们将探索酒精是如何附着在节点上的，而不是水分子。在这个目标中，节点将向孔中提供碳链，而不是水分子中的氢原子。通过改变碳链的长度，然后可以调整孔大小，用于气体存储(例如，二氧化碳封存)和水净化(例如，汞吸附)。*目标的前一部分侧重于调节MOF内的每个孔。然而，如果正在使用的酒精足够长，则只会对MOF粒子的外部进行修饰。根据使用的酒精类型，我们将制作可溶于水的MOF，以便它们可以很容易地加工成薄膜，或者很容易融入塑料中。*研究团队和我将研究内置开关的MOF。当开关分子暴露在光中时，它们会改变形状。这种转换是可逆的。开关将放置在财政部的两个位置之一。如果开关是通过MOF的光圈放置的，那么开关可以用来打开和闭合，或者至少限制光圈的大小。在这个系统中，只需将光照射到MOF上，分子就可以被困在MOF内。用于储气的分子(例如，用于甲烷动力汽车的甲烷)、催化剂，甚至潜在的药物，都可以存储在这些MOF中。在第二种类型的可切换MOF中，开关将指向孔的中央。在这个系统中，研究小组将解决导电MOF，其中MOF的导电性可以打开和关闭。转换将发生在孔内，因此孔大小本身将改变。*这项研究计划的影响是，将探索和利用两种新工具在可持续发展化学中的应用。**

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.**