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，或者产生不受欢迎的副产品。许多工业和实验室反应使用催化剂--降低反应所需能量和/或将反应过程引导到特定产品的物质。由于目前的许多催化剂需要加入昂贵和/或有毒的金属，因此开发基于廉价、丰富和无毒替代品的新型催化剂是一个重要的目标。为此，布法罗大学化学系的David Lacy教授得到了化学系化学合成计划的支持，以合成和表征新的锰催化剂。锰(Mn)含量丰富，无毒，但与其他金属相比，研究不足。本课题制备了一系列反应性锰络合物，并对它们的基本反应进行了探索。根据这些结果，设计了适用于各种工艺的新型锰催化剂。该项目还包含一个综合教育部分，强调为当地高中生提供实践经验。这一努力旨在帮助当地学校教师激发学生对科学的热情。目前，锰(I)催化剂用于无受体(脱氢)加氢，其配体平台最初是为Ru设计的，但并不是最适合于Mn(I)的。这个项目的重点是准备一个新的配位体库，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。除了合成具有这些配体的锰(I)配合物外，本研究还通过提供新的锰(I)合成子和/或方法来解决缺乏锰(I)催化剂前体的问题，以廉价的原料制备锰(I)催化剂。探索了锰(I)络合物的电子性质和分解途径以及催化机理，以帮助稳健的锰(I)催化剂设计。这一奖项反映了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。

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.