Expanding Reduction Chemistry via the f Orbital Metals

加州大学欧文分校的威廉·埃文斯（William Evans）得到了无机、生物无机和有机金属化学项目的支持，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镧系金属配合物，将基于氧化还原活性金属的传统还原方法与基于配体的工艺相结合以生成多电子还原剂，并探索还原化学的新选择。该项目的第一部分是开发通过用碱金属还原三价镧系元素前驱体生成二价镧系元素的系统。这一过程将用于没有已知分子二价态的镧系元素。在三价镧系元素和二氮存在的情况下，由类似碱金属诱导还原形成的二氮离子将用于CO和相关体系的还原同源性。该项目的第二部分涉及基于立体诱导还原（一种通过还原剂中的极端立体拥挤促进还原的过程）和传统金属基氧化还原相结合的多电子还原化学的发展。通过结合这两种效应，分子将被开发出一系列基于金属和配体的反应，每个分子包含2、3、4、6和8个电子。第三个活动领域涉及对这些还原方法的反应化学的阐述。将研究N2， CO和CO2的转化，并设计使化学催化的系统。镧系金属的独特性质为开发新型的还原性提供了机会。由于还原是化学反应的基本类型之一，它可以广泛地影响合成化学和催化化学。此外，通过这项研究，学生将在f元素的化学训练。

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.