Expanding Reduction Chemistry via the f Orbital Metals

威廉·埃文斯，加州大学欧文分校，由无机化学、生物无机化学和有机金属化学项目支持，继续研究f元素金属的特殊还原化学。这些研究将集中于将还原化学扩展到传统的非氧化还原活性稀土金属的络合物，将基于氧化还原活性金属的传统还原方法与基于配体的过程相结合来生成多电子还原剂，并探索还原化学的新选择。该项目的第一部分是开发系统，在该系统中，通过用碱金属还原三价稀土前体来生成二价镧系元素。这一过程将用于未知分子二价态的镧系元素。在三价稀土和氮气存在下，类似碱金属诱导还原形成的二氮二阴离子将被开发用于CO和相关体系的还原同系化。该项目的第二部分涉及开发基于空间诱导还原(通过还原剂中的极端空间拥挤促进还原的过程)和传统金属氧化还原相结合的多电子还原化学。通过结合这两种效应，分子将被开发成提供一系列基于金属和配体的反应，每个分子涉及2、3、4、6和8个电子。活性的第三个领域涉及对这些还原方法的反应化学的详细阐述。将研究氮气、一氧化碳和二氧化碳的转化，并将设计使化学催化的系统。稀土金属的独特性质为开发新型还原反应提供了机会。由于还原是化学反应的基本类型之一，这会对合成化学和催化化学产生广泛的影响。此外，通过这项研究，学生将接受f元素化学方面的培训。

William Evans, University of California-Irvine, is supported by the Inorganic, Bioinorganic and Organometallic Chemistry Program for continuing studies of the special reduction chemistry of the f-element metals. These studies will concentrate on expanding reduction chemistry to complexes of traditionally non-redox active lanthanide metals, to combine traditional reduction methods based on redox active metals with ligand-based processes to generate multi-electron reductants, and to explore new options in reduction chemistry. The first part of this project is to develop systems where a divalent lanthanide is generated through reduction of a trivalent lanthanide precursor with an alkali metal. This process will be utilized with lanthanides that have no known molecular divalent states. Dinitrogen dianions formed by similar alkali metal induced reductions carried out in the presence of a trivalent lanthanide and dinitrogen will be developed for the reductive homologation of CO and related systems. A second part of the project involves the development of multi-electron reduction chemistry based on a combination of sterically induced reduction (a process where reduction is facilitated by extreme steric crowding in the reducing agent) and conventional metal-based redox. By combining these two effects, molecules will be developed to deliver a sequence of metal- and ligand-based reactions involving 2, 3, 4, 6, and 8 electrons per molecule. A third area of activity involves elaboration of the reaction chemistry of these reductive methods. Transformations of N2, CO, and CO2 will be studied and systems will be designed to make the chemistry catalytic. The unique properties of the lanthanide metals offer opportunities to develop new types of reductive reactivity. Since reduction is one of the basic types of chemical reactions, this can broadly impact both synthetic and catalytic chemistry. In addition, through this research, students will be trained in the chemistry of the f-elements.