Early Metal Bimetallic Platforms for Controlled, Catalytic Dinitrogen Functionalization

在化学系化学合成项目的支持下，加州大学伯克利分校的Polly L Arnold教授将研究f-block和相关正电分子的结构、键合和反应性，这些分子被设计用于将大气中的二氮转化为氨和胺。最重要的工业过程之一是将大气中的氮转化为氨——几乎所有氮肥的基础。这是由Haber Bosch （HB）工艺完成的，该工艺效率高，但需要高温和高压。HB过程使用石油进行，约占全球碳排放量的2%。化学家们花了一百多年的时间，试图开发出可以在室温/常压下操作的HB工艺的替代品。这个项目将使用基于金属的催化剂来促进这些反应，而这些催化剂通常不会应用于这种应用中。在项目期间，学生将在这一重要领域接受培训，并将包括代表性不足的群体的成员。本文将合成s、d和f嵌段的各种正电性和刘易斯酸性金属的金属环酚酸配合物，并对其还原小分子活化化学进行评价。这些配体将被功能化，以分离出可结晶和研究的小而可溶的二镧系配合物。与尺寸，路易斯酸度和单电子氧化还原电位的相关性将被研究。开放面配合物将使复杂的二氮功能化反应性易于研究，并将提供更容易研究s块还原活化化学的机会。在整个研究过程中，将采用一系列光谱学技术来了解电子流从还原电子源到被正电金属中心激活的二氮分子的路径。这些研究将帮助我们理解，通常不能与二氮结合或添加电子的正电性贱金属，是如何支持二氮转化为胺的。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 the support of the Chemical Synthesis program in the Division of Chemistry, Professor Polly L Arnold of the University of California, Berkeley, will study the structure, bonding, and reactivity of f-block and related electropositive molecules that are designed to convert atmospheric dinitrogen to ammonia and amines. One of the most important industrial processes is the conversion of atmospheric nitrogen into ammonia – the basis of nearly all nitrogen fertilizers. This is accomplished by the Haber Bosch (HB) process that is efficient but requires high temperatures and pressures. The HB process is carried out using petroleum and contributes about 2% of the worldwide carbon emissions. Chemists have spent over a hundred years trying to develop alternatives to the HB process that can operate at room temperature/pressure. This project will facilitate these reactions using catalysts based on metals that have not normally been applied to this application. During the project students will be trained in this vital field and will include members of underrepresented groups. Metalacyclic phenolate complexes of a variety of electropositive and Lewis acidic metals from the s, d, and f-block will be synthesized and their reductive small molecule activation chemistry will be evaluated. The ligands will be functionalized to enable the isolation of small and soluble dilanthanide complexes that can be crystallized and studied. Correlations with size, Lewis acidity, and one-electron redox potentials will be investigated. Open-faced complexes will make complicated dinitrogen functionalization reactivity amenable to study and will offer the opportunity to study s-block reductive activation chemistry with greater ease. Throughout the studies, a range of spectroscopic techniques will be employed to understand the path of electron flow from the source of reducing electrons to the dinitrogen molecule that activated by the electropositive metal center(s). The studies will aid our understanding of how electropositive base metals, which would not normally be able to bind or add electrons to dinitrogen, are able to support its conversion to amines.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.