CAREER: Synthesis and characterization of manganese complexes toward earth-abundant green catalysts

化学反应通常是低效的，也就是说，它们需要相当大的能量，或者产生不期望的副产物。许多工业和实验室反应使用催化剂-降低反应所需能量和/或引导反应过程生成特定产物的物质。 由于许多现有催化剂需要掺入昂贵和/或有毒的金属，因此开发基于廉价、丰富和无毒替代物的新催化剂是一个重要目标。为此，布法罗大学化学系的大卫莱西教授得到化学系化学合成项目的支持，合成和表征新的锰催化剂。锰（Mn）含量丰富且无毒，但与其他金属相比研究不足。本项目制备了一系列活性锰配合物，并对其基本反应进行了探索。基于这些结果，设计了用于各种过程的新的锰催化剂。该项目还包含一个综合教育部分，强调当地高中生的实践经验。这项工作的目的是协助当地学校教师激发学生对科学的热情。锰（I）催化剂目前用于无受体氢化（脱氢），配体平台最初设计用于钌，但不最适合Mn（I）。该项目的重点是制备一个新的配体库，旨在利用Mn（I）的特殊性质。这些新的配体包括基于苯酚的膦（POP和PO）、新的PNN和PNP钳形配体、氨基酸衍生的手性PN配体以及基于硫酚的PS和PSP膦。除了用这些配体合成Mn（I）络合物之外，本研究还通过提供新的Mn（I）配体和/或由更便宜的材料制备Mn（I）催化剂的方法来解决Mn（I）催化剂前体的缺乏。Mn（I）络合物的电子性质和分解途径以及催化机理的探索有助于Mn（I）催化剂的稳健设计。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Chemical reactions are often inefficient, that is, they require considerable energy, or produce undesirable byproducts. Many industrial and laboratory reactions utilize catalysts - substances that lower the energy required for a reaction and/or guide the course of the reaction to specific products. As many current catalysts require the incorporation of expensive and/or toxic metals, the development of new catalysts based on inexpensive, abundant, and non-toxic replacements is an important goal. To this end, Professor David Lacy in the Chemistry Department at the University at Buffalo is supported by the Chemical Synthesis Program of the Chemistry Division to synthesize and characterize new manganese catalysts. Manganese (Mn) is abundant and non-toxic, but is understudied compared to other metals. In this project a series of of reactive maganese complexes are prepared and their basic reactions explored. Based on these results new manganese catalysts for a variety of processes are designed. The project also contains an integrated educational component that emphasizes hands-on experiences for high school students in the local area. This effort aims to assist local schoolteachers in stimulating student enthusiasm in science. Manganese(I) catalysts are currently used in acceptorless (de)hydrogenations with ligand platforms initially designed for ruthenium, but not optimally suited for Mn(I). This project focuses on the preparation of a new library of ligands designed to leverage the special properties of Mn(I). These new ligands include phenol-based phosphines (POP and PO), new PNN and PNP pincer ligands, amino acid-derived chiral PN ligands, and thiophenol-based PS and PSP phosphines. In addition to the synthesis of Mn(I) complexes with these ligands, this research also addresses the lack of Mn(I) catalyst precursors by providing new Mn(I) synthons and/or methods to prepare Mn(I) catalysts from cheaper materials. The electronic properties and decomposition pathways of the Mn(I) complexes and the mechanisms of catalysis are explored to assist robust Mn(I) catalyst design.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.