Collaborative Research: Porous Molecules as a Platform for Solid-State Organometallic Chemistry

在化学系化学合成项目的支持下，特拉华大学的埃里克·布洛赫和德克萨斯农工大学的大卫·鲍尔斯将研究制备多孔催化剂的新方法。多孔材料在世界各地被广泛用于各种应用，包括水过滤和/或软化、作为干燥剂以及在医学上的应用。多孔性材料的一个子集被大规模用于催化应用，包括在碳氢化合物的裂解中。然而，使用多孔材料作为催化剂的一个关键挑战是控制和优化它们的反应活性，其中总表面积、结构类型和稳定性可以起到决定其活性的作用。Bloch/Power团队正在有希望的初步结果的基础上，开发一种通过生成活性盐来合成活性多孔催化剂的新方法。在这种方法中，一个带电的非多孔反应性金属有机物种将与一个相反带电的多孔非反应离子结合在一起，得到一类新的多孔固体。可以预见，对于这样构建的多孔材料，催化活性将在一系列有用的转化过程中微调，包括碳氢键功能化和交叉偶联反应。此外，这些研究将有助于利用原位结晶学和光谱学工具来表征催化转化过程中的活性物种。Bloch博士和Power博士将继续致力于增加科学的多样性，通过当地和地区的教育经验将合成化学研究的兴奋带给广大受众，包括为本科生和研究生开发年度X射线粉末衍射在线学校。这个合作项目的目标是开发用于现场隔离和固态金属有机化学的新型多孔材料。尽管沸石和金属-有机骨架等设计型多孔固体作为多相催化剂显示出令人难以置信的前景，但在有限空间内开发固态有机金属化学的一般平台仍然难以捉摸。这项工作试图将带电的、永久多孔的配位笼与互补带电的反应性金属有机片段结合起来，以制备一种新型的反应性催化剂--多孔盐。在此资助期间，Bloch和Power将阐明多孔盐的一般结构-功能特性，其中将利用笼电荷、几何形状和官能团呈现来调节盐的结构和孔隙率。随后，Bloch和Power将使用这些盐作为平台，将设计的反应离子合并到多孔固体中，在那里将研究小分子结合和激活，以评估盐的活性。将研究的反应包括C-H键功能化和交叉偶联催化。最后，Bloch/Power团队将利用简单的逐层生长来制备光学透明、化学可寻址的薄膜，这些薄膜将用于固态光化学转换。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Synthesis program in the Division of Chemistry, Eric Bloch of the University of Delaware and David Powers of Texas A&M University will study new methods for the preparation of porous catalysts. Porous materials are widely used around the world for a wide variety of applications, including water filtration and/or softening, as desiccants, and in medicine. A subset of porous materials is used on a large scale in catalytic applications, including in the cracking of hydrocarbons. A key challenge in using porous materials as catalysts, however, is controlling and optimizing their reactivity where total surface area, structure type, and stability can play a role in determining their activity. The Bloch/Powers team is building on promising preliminary results to develop a new method for the synthesis of active porous catalysts by creating reactive salts. In this method, a charged nonporous reactive organometallic species will be combined with an oppositely-charged porous non-reactive ion to afford a new class of porous solids. It is envisioned that for porous materials so constructed catalytic activity will be finely tunable across a range of useful transformations including carbon-hydrogen bond functionalization and cross-coupling reactions. In addition to this, these studies will aid in the characterization of reactive species during catalytic transformations using the tools of in situ crystallography and spectroscopy. Drs. Bloch and Powers will continue to work to increase diversity in science by bringing excitement of synthetic chemistry research to a broad audience through local and regional educational experiences, including the development of an annual online school on X-ray powder diffraction for undergraduate and graduate students.This collaborative project is targeting the development of new porous materials for site-isolated and solid-state organometallic chemistry. While designer porous solids such as zeolites and metal-organic frameworks have shown incredible promise as heterogeneous catalysts, general platforms for the development of solid-state organometallic chemistry within confined spaces remain elusive. This work seeks to combine charged, permanently porous coordination cages with complementary-charged reactive organometallic fragments for the preparation of a new class of reactive catalysts, porous salts. During this funding period, Bloch and Powers will elucidate the general structure-function properties of porous salts where cage charge, geometry, and functional group presentation will be leveraged to tune salt structure and porosity. Subsequently, Bloch and Powers will use these salts as platforms to incorporate designer reactive ions into porous solids where small molecule binding and activation will be studied to assess salt activity. Reactions to be studied will include C-H bond functionalization and cross-coupling catalysis. Finally, the Bloch/Powers team will utilize straightforward layer-by-layer growth to prepare optically transparent, chemically addressable films which will be used for solid-state photochemical transformations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.