Collaborative Research: Hydrogen Atom Transfer Lewis Base Catalysis

在化学部化学合成计划的资助下，德克萨斯大学阿灵顿分校化学系的Junha Jeon和纽约州立大学环境科学与林业学院化学系的Gyu Leem正在开发新的方法，使用廉价和环境友好的硅基试剂来生产高价值的化学品和材料。许多化学过程涉及氢和电子的转移(这个过程被缩写为HAT)。这项研究利用钾存在下的硅络合物来提供氢原子(氢和一个电子)和氢化物(氢和两个电子)转移的通道。如果成功，这些研究可以提供低成本、操作简单、环境可持续的HAT，并为合成关键中间体和有用的聚合物材料开辟新的途径。这项研究的更广泛影响包括招募和培训下一代科学家，特别强调鼓励妇女和代表不足的少数群体参与化学科学。这个多学科项目的主要研究人员是Junha Jeon博士(德克萨斯大学阿灵顿分校合成硅化学)和Gyu Leem博士(纽约州立大学环境科学与林业学院聚合物化学)。此外，还有另外两个合作项目，涉及明尼苏达大学计算科学的高嘉丽博士和阿拉巴马大学的电子顺磁共振波谱研究人员布拉德·皮尔斯。通过理论和实验方法，确定了与钾化的超配位氢化硅物种有关的“氢氢转移二元性”的机理。氢氢转移二元性是指超配位氢硅体系中竞争单电子或双电子转移反应的一种方式，称为碱金属Lewis碱催化络合诱导氢原子转移。除了机理研究外，(1)通过LBCI-HAT进行对映体选择性氧化还原中性、支链选择性烯烃硅氢化反应，以及(2)将该工艺扩展到碱金属-Lewis碱催化、氢原子转移自由基聚合(HATRP)和HATRP扩链合成多嵌段共聚物。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，认为值得支持。

With funding from the Chemical Synthesis Program in the Chemistry Division, Junha Jeon at the Department of Chemistry at the University of Texas at Arlington and Gyu Leem at the Department of Chemistry of the SUNY College of Environmental Science and Forestry are developing new methods to use inexpensive and environmentally benign silicon-based reagents to produce high-value chemicals and materials. A number of chemical processes involve the transfer of both a hydrogen and an electron (the process is abbreviated HAT). This study utilizes silicon complexes in the presence of potassium to provide access to both hydrogen atom (hydrogen and one electron) and hydride (hydrogen and two electrons) transfer. If successful, these studies could provide low-cost, operationally simple, environmentally sustainable HAT and open up new avenues to the synthesis of key intermediates and useful polymeric materials. The broader impacts of this research include the recruitment and training of the next generation of scientists, with a particular emphasis on encouraging participation from women and underrepresented minority groups in the chemical sciences. This multi-disciplinary project involves Dr. Junha Jeon [synthetic silicon chemistry, University of Texas at Arlington] and Dr. Gyu Leem [polymer chemistry, SUNY College of Environmental Science and Forestry] as the primary investigators. In addition, there are two additional collaborations involving Drs. Jiali Gao [computational, University of Minnesota] and Brad Pierce [EPR spectroscopy, University of Alabama]. Through theoretical and experimental methods, the mechanistic origin of 'hydrogen-hydride transfer duality' associated with a potassiated hypercoordinate hydridosilicon species is determined. The of 'hydrogen-hydride transfer duality' refers to a mode of competing single or two-electron transfer reactions of hypercoordinative hydrosilicon systems and is termed alkali metal Lewis base-catalyzed complexation-induced hydrogen atom transfer. In addition to the mechanistic investigations, (1) enantioselective redox-neutral, branch-selective olefin hydrosilylation via LBCI-HAT and (2) the extension of the process to alkali metal-Lewis base-catalyzed, hydrogen atom transfer radical polymerization (HATRP) and chain extension of HATRP for the synthesis of of multiblock copolymers are developed.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.