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

化学反应常常是低效的，也就是说，它们需要大量的能量，或者产生不需要的副产品。许多工业和实验室的反应都使用催化剂——一种降低反应所需能量和/或指导反应过程以产生特定产物的物质。由于目前许多催化剂需要加入昂贵和/或有毒的金属，开发基于廉价、丰富和无毒替代品的新型催化剂是一个重要目标。为此，布法罗大学化学系的David Lacy教授在化学系化学合成项目的支持下合成并表征了新型锰催化剂。锰（Mn）含量丰富且无毒，但与其他金属相比，研究不足。本课题制备了一系列活性锰配合物，并对其基本反应进行了探讨。在此基础上，设计了适用于多种工艺的新型锰催化剂。该项目还包含一个综合教育组件，强调当地高中生的实践经验。这项工作旨在协助本地学校教师激发学生对科学的热情。锰(I)催化剂目前用于与最初为钌设计的配体平台进行无受体（脱）氢化，但不适合锰(I)。这个项目的重点是准备一个新的配体库，旨在利用Mn(I)的特殊性质。这些新的配体包括苯酚基膦（POP和PO），新的PNN和PNP钳形配体，氨基酸衍生的手性PN配体，以及基于噻吩的PS和PSP膦。除了用这些配体合成Mn(I)配合物外，本研究还通过提供新的Mn(I)合成子和/或用更便宜的材料制备Mn(I)催化剂的方法来解决Mn(I)催化剂前体缺乏的问题。探讨了锰(I)配合物的电子性质和分解途径以及催化机制，以帮助设计稳健的锰(I)催化剂。该奖项反映了美国国家科学基金会的法定使命，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.