Porous Molecular Crystals and Metal-Organic Frameworks Based on Fluorinated Pyrazoles

基于氟化吡唑的多孔分子晶体和金属有机框架

• 批准号: 1507664
• 负责人: Ognjen Miljanic
• 金额: $ 45万
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1507664&HistoricalAwards=false
• 关键词: Porous; Molecular; Crystals; Metal; Organic

Non-technical abstractPorous materials have microscopic voids in their structures. Because these voids are comparable in dimensions to molecules, porous materials find numerous applications related to energy, petrochemical industry, environment, and medicine. With the support of the Solid State and Materials Chemistry program in the Division of Materials Research, this project develops new classes of porous materials in which building blocks are individual molecules. Such materials have superior properties relative to the currently available porous materials: they are lightweight, recyclable, and much more easily processable, as they are soluble and can in principle be "painted" on a surface. Their unusual internal structures make these materials superb water-repellants; they are also capable of capturing Freons and fluorocarbons-which are both powerful greenhouse gases and ozone-depleting substances. In addition, they strongly bind hydrocarbons, which makes them promising in applications in fuel storage and oil spill cleanup. This research project is integrated with a broad education plan that aims to increase student competency in the areas of energy and sustainability, as well as to involve undergraduate and high school students in original research, with a focus on minority and female students.Technical abstractThis collaborative project is focused on the preparation of extensively fluorinated porous materials based on pyrazoles. Fluorinated metal-organic frameworks are formed by deprotonation of pyrazoles into pyrazolates and their coordination to transition metals. Fluorinated pyrazolates have been chosen as ligands since their high basicity should translate into chemically robust frameworks. Fluorinated molecular crystals are formed by the self-assembly of neutral fluorinated pyrazoles into a porous framework held together by a combination of [pi···pi] stacking and hydrogen bonding. These porous molecular crystals were recently discovered by the principal investigators. This research fills a gap in the existing knowledge: extensively fluorinated porous materials have been underexplored because of the paucity of the appropriately fluorinated molecular precursors. This project will dramatically expand the knowledge in this area, through its four goals: (1) creation of a general synthetic strategy to access extensively fluorinated aromatic pyrazoles (and derivatives) through novel copper- and palladium-catalyzed C-H functionalization reactions; (2) reticulation of fluorinated pyrazoles into porous molecular crystals, and understanding of structural elements necessary for the creation of robust porosity that persists above 200 °C; (3) synthesis of extensively fluorinated metal-organic frameworks starting from the precursor pyrazolate ligands prepared in the first part of the proposed work, and (4) exhaustive characterization of both classes of fluorinated materials, with an eye toward future applications. Performance characteristics of interest include: thermal and chemical stability, hydrophobicity, and potential as adsorbents for (a) Freons and fluorocarbons, (b) fluorinated anesthetics, (c) amphiphilic fluorinated pollutants, (d) hydrocarbons, and (e) molecular oxygen. This research generates fundamental new knowledge in the areas of organometallic, inorganic, and supramolecular chemistry.

非技术摘要多孔材料在其结构中具有微观空隙。由于这些空隙的尺寸与分子相当，因此多孔材料在能源、石化工业、环境和医学方面有着广泛的应用。在材料研究部固态和材料化学项目的支持下，该项目开发了新型多孔材料，其中的构建块是单个分子。相对于目前可用的多孔材料，此类材料具有优越的性能：它们重量轻、可回收，并且更容易加工，因为它们是可溶的并且原则上可以“涂漆”在表面上。它们不同寻常的内部结构使这些材料具有极好的防水性；它们还能够捕获氟利昂和碳氟化合物——这两种物质都是强效温室气体和臭氧消耗物质。此外，它们与碳氢化合物的结合力很强，这使得它们在燃料储存和溢油清理方面具有广阔的应用前景。 该研究项目与一项广泛的教育计划相结合，旨在提高学生在能源和可持续发展领域的能力，并让本科生和高中生参与原创性研究，重点是少数族裔和女生。技术摘要该合作项目的重点是制备基于吡唑的广泛氟化多孔材料。氟化金属有机骨架是通过吡唑去质子化成吡唑盐及其与过渡金属的配位而形成的。氟化吡唑盐被选为配体，因为它们的高碱性应转化为化学上坚固的框架。氟化分子晶体是通过中性氟化吡唑自组装成多孔骨架而形成的，该多孔骨架通过π…π堆叠和氢键的组合保持在一起。这些多孔分子晶体是主要研究人员最近发现的。这项研究填补了现有知识的空白：由于缺乏适当氟化的分子前体，广泛氟化的多孔材料尚未得到充分探索。该项目将通过其四个目标极大地扩展该领域的知识：（1）创建通用合成策略，通过新型铜和钯催化的 C-H 官能化反应获得广泛氟化的芳香族吡唑（及其衍生物）； (2) 将氟化吡唑网状化为多孔分子晶体，并了解创建在 200 °C 以上持续存在的强大孔隙度所需的结构元素； （3）从拟议工作第一部分中制备的前体吡唑酯配体开始合成广泛氟化的金属有机框架，以及（4）对两类氟化材料进行详尽的表征，着眼于未来的应用。感兴趣的性能特征包括：热稳定性和化学稳定性、疏水性以及作为 (a) 氟利昂和碳氟化合物、(b) 氟化麻醉剂、(c) 两亲性氟化污染物、(d) 碳氢化合物和 (e) 分子氧吸附剂的潜力。这项研究产生了有机金属、无机和超分子化学领域的基础新知识。