CAS: Metal-Mediated Nitrate Deoxygenation by Rationally-Designed Organic Reductants and Subsequent Nitrogen-Transfer

通过这一奖项，美国国家科学基金会化学部化学合成计划支持印第安纳大学化学系的Kenneth Caulton教授进行针对氮氧化物活化的研究。该项目正在开发新的方法，将农业废物中的氮转化为有用的有机化合物。这种氮循环需要化学促进剂与硝酸盐相互作用，使其具有反应性。化学促进剂选自通常含有硅的廉价和丰富的前体。发现策略从实验室实验开始，将这些硅促进剂与硝酸盐结合起来。这些实验的结果被数学模拟，这导致了改进的促进剂，然后进行了实验测试。整个过程为回收其他含磷、碳和氯的废物带来了新的见解。该项目还包括一个主要的培训部分；学生同事在化学合成和计算机模拟方面都获得了实践经验。考尔顿教授还领导了各种外展活动，旨在让公众熟悉化学技术的好处。最后，该项目正在培养一批具有可持续发展专业知识的本科生和研究生。该项目旨在通过设计使用机械引导的有机还原剂和过渡金属催化剂的新反应方法来减少硝酸盐。对于后者，使用氧化还原活性配体是因为它们能够促进所需的多电子转化。初步结果表明，硝酸盐还原可以与C-─-N键的形成偶联。作为还原氮的一种形式，过渡金属氮化物与不饱和有机底物相结合，提出了反应性的新概念，即超越亲电性和亲核性。通过设计方法在亚硝基和碳之间建立新的键来寻找具有附加值的化合物。新的氮化物官能化也普遍影响了固氮和N-C键形成的研究领域。这种实现高效氮转移的新的合成方法可能为还原含氧阴离子的N、P和S提供了一种蓝图，为氧原子转移领域提供了一个新的进入领域。方法使用量子计算来预测金属选择、物种电荷和取代基效应以进行性能优化。该计划为同事提供有机金属化学、方法开发以及机械和计算化学方面的有效培训，从而有助于建立一支高技能的技术队伍。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 this award, the Chemical Synthesis Program of the Chemistry Division of the National Science Foundation is supporting Professor Kenneth Caulton in the Department of Chemistry at Indiana University for research directed at the activation of nitrogen oxides. This project is developing new ways to incorporate nitrogen from agricultural waste into useful organic compounds. This nitrogen recycling requires chemical promoters that interact with the nitrate, rendering it reactive. The chemical promotors are chosen from among inexpensive and abundant precursors often containing silicon. The discovery strategy begins with laboratory experiments combining these silicon promotors with the nitrate. The results of these experiments are simulated mathematically, which leads to improved promotors, which are then tested experimentally. The overall process is leading to insights for the recycling of other waste products containing phosphorus, carbon, and chlorine. The project also entails a major training component; student coworkers obtain hands-on experience in both chemical synthesis and computer simulations. Professor Caulton also leads diverse outreach activities aimed toward familiarizing the public with the benefits of chemical technology. Finally, the project is preparing a group of undergraduate and graduate students with expertise in sustainability.This project targets nitrate reduction by devising new reaction methods using mechanistically-guided organic reductants and transition-metal catalysts. For the latter, redox-active ligands are being used due to their ability to promote the requires multi-electron conversions. Preliminary results reveal that nitrate reduction can be coupled to C─N bond formation. As one form of reduced nitrogen, transition metal nitrides are being combined with unsaturated organic substrates to give new concepts of reactivity, i.e., beyond electrophilicity and nucleophilicity. Value-added compounds are sought by devising methods to create new bonds between nitrosyl groups and carbon. New nitride functionalization also impacts the research areas of nitrogen fixation and N-C bond formation generally. The new synthetic methodology accomplishing efficient nitrogen transfer can potentially provide a blueprint to reduce N, P, and S containing oxyanions, providing a new entry into the field of oxygen atom transfer. Methods employ quantum calculations for predicting metal choice, species charge and substituent effects for performance optimization. This program provides effective training for coworkers in organometallic chemistry, methods development and mechanistic and computational chemistry and thus will contribute to building a highly skilled technical workforce.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.