CAREER: Tuning Photoredox Properties of Carbazolic Porous Organic Frameworks for Visible-Light-Mediated Catalysis

在材料研究部固态和材料化学项目的支持下，该研究小组提议开发一种新型的有机多孔材料-咔唑多孔有机骨架(Cz-POF)。扩展的pi共轭、三维多咔唑网络和可定制的电学和光学性质的独特组合使其在太阳能收集、转换和利用方面具有重要的潜在应用价值。这些基础研究工作与一系列教育活动相结合，包括对研究生和本科生进行材料研究方面的培训和指导，创建可获得的、可适应的和廉价的多孔材料模型套件，以支持多种推广活动，并向不同年龄和知识水平的受众传达对材料化学的基本理解，以及在内布拉斯加-林肯大学建立一个化学大使计划，以提高公众对材料化学在日常生活中作用的认识和欣赏。研究小组证明，与线性聚合物相比，原型Cz-POF具有更大的比表面积、增强的介孔性能和高稳定性，加上强大的还原能力和可回收利用能力，使其非常适合于许多光电子应用。本研究的具体目标是开发合成方法(1)通过理论指导的化学修饰进一步提高Cz-POF的氧化能力，(2)通过调节分子内D-A相互作用来开发具有增强光氧化还原性能的给体-受体Cz-POF，以及(3)提高Cz-POF的光氧化还原催化活性。这项研究有助于更好地了解控制Cz-POF和其他PI共轭聚合物网络的电子和光学性质、光致能量和电子转移以及光氧化还原催化活性的合成因素。这项研究还有助于利用POF从二氧化碳中光化生产清洁的有机燃料，以及太阳能水的分解。此外，多孔性有机框架资源综合在线数据库的建立促进了对多孔性材料的跨学科研究。

Non-technical AbstractWith support from the Solid State and Materials Chemistry program in the Division of Materials Research, the research team proposes to develop a new class of organic porous material?carbazolic porous organic frameworks (Cz-POFs). The unique combination of extended pi-conjugation, three-dimensional polycarbazole networks, and tailorable electronic and optical properties of Cz-POFs enables their significant potential applications in solar energy harvesting, conversion, and utilization. These basic research efforts are integrated with a series of educational activities including the training and mentoring of graduate and undergraduate students in materials research, the creation of accessible, adaptable, and inexpensive model kits of porous materials to support multiple outreach activities and to convey a basic understanding of materials chemistry to audiences of different ages and knowledge levels, and the establishment of a Chemistry Ambassador program at the University of Nebraska-Lincoln to improve awareness of and public appreciation for the role of materials chemistry in everyday lives.Technical AbstractThe proposed research addresses critical knowledge gaps for establishing Cz-POFs as a new generation of photoactive materials for solar-energy harvesting, conversion, and utilization. The research team have demonstrated that, compared to their linear counterparts, prototypic Cz-POFs exhibit large surface area, enhanced mesoporosity, and high stability, which, along with strong reductive ability and recyclability, make them well suited for many optoelectronic applications. The specific aims of this research are centered on developing synthetic approaches (1) to further increase the oxidative ability of Cz-POFs through theory-guided chemical modification, (2) to develop donor-acceptor Cz-POFs with enhanced photoredox properties by adjusting intramolecular D-A interactions, and (3) to enhance photoredox catalytic activities of Cz-POFs. This research provides a better understanding of synthetic factors that control the electronic and optical properties, photoinduced energy and electron transfer, and photoredox catalytic activities associated with Cz-POFs and other pi-conjugated polymer networks in general. This research also contributes to the use of POFs for photochemical production of clean organic fuels from carbon dioxide as well as solar water splitting. Further, the building of a comprehensive online database Porous Organic Framework Resource facilitates interdisciplinary research on porous materials.