Understanding the Mechanism of Mn-Promoted H2O Oxidation

在美国国家科学基金会化学部化学催化项目的支持下，华盛顿大学的朱莉·科瓦奇博士正在研究新的锰化合物及其与钙和水的相互作用。长期目标是发现从水中产生氧气的途径。这种转化有望在燃料电池的设计中发挥作用。这种方法的灵感来自于自然界中锰催化剂的作用，锰催化剂可以从水中形成氧气。这个反应在纸上很简单，但是自然界的机制还没有被证明。该研究考察了锰催化剂的结构如何影响它们与钙离子的相互作用，钙离子反过来又影响与水的反应。除了这项研究，这笔拨款还支持科瓦奇博士和一群研究生的工作，他们为K-12学生提供指导，目的是提高他们的科学素养。作为美国化学学会无机化学分会的主席，她以提高年轻化学家的领导技能为目标指导战略规划。总的来说，这些活动通过增加其技术技能和多样性来加强国家的科学劳动力。在美国国家科学基金会化学分部化学催化项目的支持下，华盛顿大学的朱莉·科瓦奇博士致力于开发替代化石燃料的清洁能源。她的研究受到《自然》光合水氧化催化剂（OEC）的启发，需要了解关键的氧气形成步骤。我们对这个步骤知之甚少，因为它发生在速率决定步骤之后。缓慢的水氧化催化剂限制了现有的燃料电池。因此，需要进行基础科学研究。OEC催化剂储存氧化等价物，为形成二氧气体做准备。为此，她正在使用氧化还原活性配体。氧化还原活性钙离子是必不可少的，但其作用仍不清楚。提出了一种氢氧化钙来攻击具有亲电性的氧化锰。Kovacs的研究小组正在用合成的锰-钙、锰-锶和锰-锰化合物来验证这一假设。分子被设计用来快速捕获关键的中间体。瞬态吸收光谱和磁共振实验以及计算补充了合成。除了她的研究，科瓦奇博士还带领一群研究生在西雅图公共图书馆为K-12学生提供指导。作为美国化学学会无机化学分会的主席，她以提高女性化学家的领导能力为目标指导战略规划。总的来说，这些活动通过增加其多样性来加强国家的科学劳动力。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。

With support from the Chemical Catalysis Program of the Chemistry Division of the National Science Foundation, Dr. Julie Kovacs of the University of Washington is studying new manganese compounds and their interactions with calcium and water. The long-range goal is to discover pathways for producing oxygen gas from water. This conversion is expected to be useful in the design of fuel cells. The approach is inspired by the roles of manganese catalysts in nature, which are known to form oxygen gas from water. This reaction is very simple on paper, but Nature's mechanism has not yet been demonstrated. The research examines how the structure of manganese catalysts influences their interaction with calcium ions, which in turn influences the reactions with water. In addition to this research, the grant is supporting work by Dr. Kovacs and a group of graduate students who provide instruction to K-12 students with the goal of enhancing their scientific literacy. As the Chair of the American Chemical Society’s Division of Inorganic Chemistry, she guides strategic planning with the goal of enhancing the leadership skills of younger chemists. Collectively, these activities strengthen the nation's scientific workforce by increasing its technical skills and diversity.With support from the Chemical Catalysis Program of the Chemistry Division of the National Science Foundation, Dr. Julie Kovacs of the University of Washington seeks to develop clean energy alternatives to fossil fuels. Her research, which is inspired by Nature’s photosynthetic water oxidation catalyst (OEC), requires an understanding of the key oxygen forming step. Very little is known about this step because it occurs following the rate-determining step. Sluggish water-oxidation catalysts limit existing fuel cells. Fundamental scientific research is therefore needed. The OEC catalyst stores oxidizing equivalents in preparation for the formation of dioxygen gas. She is using redox active ligands for this purpose. The redox inactive calcium ion is essential, and yet its role is still not understood. A calcium hydroxide has been proposed to attack an electrophilic manganese oxide. Kovacs’ group is testing this hypothesis using synthetic manganese-calcium, manganese-strontium, and manganese-manganese compounds. Molecules are designed to rapidly trap key intermediates. Transient absorption spectroscopy and magnetic resononace experiments as as well as computations complement the synthesis. In addition to her research, Dr. Kovacs leads a group of graduate students who provide instruction to K-12 students at the Seattle Public Library. As the Chair of the American Chemical Society’s Division of Inorganic Chemistry, she guides strategic planning with the goal of enhancing the leadership skills of female chemists. Collectively, these activities strengthen the nation's scientific workforce by increasing its diversity.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.