CAS: A Rethinking of Borrowing Hydrogen: from Ligand Design to New Reactions and Mechanisms

在化学系化学催化项目的支持下，田纳西州立大学中部的丁克英将研究导致碳-碳或碳-杂原子键形成的催化反应。这些反应将由新的富含地球的金属催化系统介导，这些催化系统利用“借氢(BH)”途径。这种BH途径对环境友好，在生产附加值化学品的同时生产水作为唯一的副产品，具有原子和工艺效率。将研究结构与反应性的相关性，以努力收集关于这些催化剂如何在分子水平上促进这一化学的关键信息。结果将被用于指导催化剂开发新的和具有挑战性的反应。该项目将为学生提供在合成无机化学、有机化学和催化方面的研究经验。教育活动包括努力加强来自服务不足群体和低收入家庭或第一代家庭的本科生的参与，参加暑期研究营，并将资助的研究纳入教学实验室。研究和教育活动的广泛影响将有助于在化学科学领域建立一支更加多样化和受过教育的劳动力队伍。田纳西州立大学中部分校的丁凯英和她的研究团队将研究新的碱过渡金属催化剂，以应对催化反应中新出现的挑战，这种催化反应利用“借氢”机制。将合成和表征一类新的双功能配体，这些配体具有反应性的悬臂，可能通过金属-配体的协作性促进氢转移反应，并且含有刚性配体支架以提供稳定性。碱过渡金属络合物的催化活性将以(I)建立对BH催化过程的深入了解，(Ii)消除在BH反应中对使用过量强碱的依赖，以及(Iii)提高产物选择性来确定。这些研究有望为使用富含地球的金属取代BH中的贵重过渡金属和相关的转化提供新的概念和见解，以帮助指导未来催化剂的开发。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，被认为值得支持。

With the support of the Chemical Catalysis program in the Division of Chemistry, Keying Ding of Middle Tennessee State University will study catalytic reactions that result in the formation of carbon–carbon or carbon–heteroatom bonds. These reactions will be mediated by new earth-abundant metal catalytic systems that utilize the “borrowing hydrogen (BH)” pathway. This BH pathway is environmentally friendly and atom- and process-efficient in producing value-added chemicals while producing water as the sole byproduct. Structure-reactivity correlations will be studied in an effort to glean critical information on how these catalysts facilitate this chemistry at the molecular level. The results will be used to direct catalyst development toward new and challenging reactions. This project will offer research experiences for students at the interface of synthetic inorganic chemistry, organic chemistry, and catalysis. The educational activities include efforts to enhance the participation of undergraduate students from underserved groups and low-income or first-generation families, participation in a summer research camp, and the integration of the funded research into teaching laboratories. The broader impacts of the research and educational activities will assist in the creation of a more diverse and educated workforce in the chemical sciences.Dr. Keying Ding and her research team at Middle Tennessee State University will study new base-transition metal catalysts to address emerging challenges in catalytic reactions that utilize the “borrowing hydrogen” mechanistic pathway. A new family of bifunctional ligands that feature reactive pendant arms that potentially promote hydrogen transfer reactions via metal-ligand cooperativity, and that contain rigid ligand scaffolds to provide stability, will be synthesized and characterized. The catalytic activities of the base transition-metal complexes will be determined with a focus on (i) establishing an in-depth understanding of the BH catalytic process, (ii) eliminating the dependence on the use of excess strong base in the BH reactions, and (iii) improving the product selectivity. New concepts and insights on the use of earth-abundant metals in place of precious transition metals for BH and related transformations are expected to arise from these studies to help guide the development of future catalysts.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.