SusChEM: New Reactivity Promoted by Group 5 Metal Systems

在这个由化学部化学合成计划资助的项目中，加州大学伯克利分校的John Arnold教授和Robert Bergman教授的研究小组正在致力于开发新的试剂，这些试剂含有廉价且地球上丰富的早期过渡金属，能够切割强键。理想情况下，这项研究将导致开发催化剂，用于从环境危险的卤代有机废物（如CFC）中去除氟和氯，选择性官能化化学原料以生产高价值的有机产品，以及合成新的无机聚合物和材料。本提案中所述工作的最直接的更广泛的影响涉及熟练的合成化学家的培训，以及更完整地理解过渡金属位点上发生的基本反应步骤在广泛的工业上重要的化学转化中是重要的这一事实。该项目分为两个主要部分。第一个涉及的反应性和机制研究的低价铌系统开发试剂的活化和官能化的C-F，C-Cl，和C-O键。第二部分合成了一系列双酰亚胺配合物，并研究了它们对不饱和底物的环加成反应和C-H和E-H（E = H，B，Al，Si，N，P，O，S）键的1，2-加成反应。目标化合物将使用1D和2D 1H、13 C和其他杂波NMR技术、X射线晶体学、FT-IR（傅里叶变换红外）光谱、质谱和其他表征技术进行表征。此外，DFT（密度泛函理论）计算将用于获得电子结构和机理的见解。

In this project funded by the Chemical Synthesis program of the Chemistry Division, the research groups of Professors John Arnold and Robert Bergman of University of California, Berkeley are working toward developing new reagents containing inexpensive and earth-abundant early transition metals that are capable of cleaving strong bonds. Ideally, this research will lead to development of catalysts for removal of fluorine and chlorine from environmentally dangerous halogenated organic wastes, such as CFCs, selective functionalization of chemical feedstocks to produce high-valued organic products, and synthesis of new inorganic polymers and materials. The most immediate broader impacts of the work described in this proposal relate to the training of skilled synthetic chemists and the fact that a more complete understanding of fundamental reaction steps that occur at transition metal sites is important in a wide range of industrially important chemical conversions.This project focuses on the development of new niobium systems supported by imido and β-diketiminate and related ligands. This project is split into two major parts. The first involves reactivity and mechanistic studies of low-valent niobium systems toward developing reagents for activation and functionalization of C-F, C-Cl, and C-O bonds. The second involves synthesis of a series of bis(imido) complexes that are reactive across a niobium-nitrogen multiple bond, and investigation of their reactivity toward cycloaddition of unsaturated substrates and 1,2-addition of C-H and E-H (E = H, B, Al, Si, N, P, O, S) bonds. Target compounds will be characterized using 1D and 2D 1H, 13C, and other heteronuclear NMR techniques, X-ray crystallography, FT-IR (Fourier transform infra-red) spectroscopy, mass spectrometry, and other characterization techniques. Additionally, DFT (Density Functional Theory) calculations will be used to gain electronic structure and mechanistic insights.