SusChEM: New Reactivity Promoted by Group 5 Metal Systems

在这个由化学系化学合成计划资助的项目中，加州大学伯克利分校的约翰·阿诺德教授和罗伯特·伯格曼教授的研究小组正在致力于开发含有廉价和富含地球的早期过渡金属的新试剂，这些金属能够断裂强键。理想情况下，这项研究将导致开发用于从CFCs等对环境有害的卤化有机废物中去除氟和氯的催化剂，选择性地对化学原料进行官能化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。这项建议中描述的工作的最直接和更广泛的影响涉及到对熟练的合成化学家的培训，以及对发生在过渡金属位置上的基本反应步骤的更全面的了解在广泛的工业上重要的化学转化中是重要的。该项目侧重于开发由亚胺和双酮亚胺及相关配体支持的新的Nb体系。这个项目分为两个主要部分。第一个涉及低价Nb体系的反应性和机理研究，以开发用于C-F、C-Cl和C-O键的活化和功能化的试剂。第二部分合成了一系列跨Nb-N多键反应的双(亚胺)配合物，考察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-加成反应的活性。目标化合物将使用一维和二维1H、13C和其他异核核磁共振技术、X射线结晶学、FT-IR(傅立叶变换红外)光谱、质谱学和其他表征技术进行表征。此外，还将使用密度泛函理论(DFT)计算来获得电子结构和机理方面的见解。

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.