Base-Metal Complexes for Challenging Organometallic Transformations

本提案描述了使镍和钴等可持续的第一排过渡金属成为催化剂的方法，用于C-H、C-F和C-O键的官能化。这些项目的短期目标包括确定新的方法，使这些金属对传统上的惰性键产生反应。解决这一问题的方法包括使用配体设计或确定新的键激活机制。每个项目的长期目标都是这些催化技术在药物合成和生物质转化等领域的商业应用。在过去的几十年里，许多金属催化体系已经实现了从传统的惰性C-H键到官能团的原子经济相对绿色的转化。昂贵的第三排后过渡金属的络合物，如Ir和铂，通常用于这些转化，因为这些元素与碳和氢形成强键，这有助于裂解强的C-H键。相比之下，在这些反应中，镍的络合物在热力学上处于极端不利的地位，但镍的明显优势是，由于其相对丰富，镍的价格约为镍的10000倍。我们的研究表明，镍配合物不仅可以激活强大的C-H键，它们还可以执行催化的C-H键转换，这是前所未有的，或许是这些体系所独有的。我们目前的目标是充分了解这些反应的机制和范围。与C-H键的激活类似，C-F和C-O键的激活也存在动力学和热力学方面的问题。我们希望对镍配合物激活C-F键进行深入研究，以深入了解辅助配体的选择对这些反应的机理和热力学参数的影响。最终目标是一种合理的方法，既可以激活C-F键，又可以形成用于制药或放射性核素的催化C-F键。C-O键的活化与C-F键的活化有关，在合成和生物质转化为燃料或精细化学品方面都有应用。

This proposal describes approaches to render sustainable 1st-row transition metals, such as nickel and cobalt, as catalysts for applications such as the functionalization of C-H, C-F and C-O bonds. The short term goals of the projects involve identification of new ways to render these metals reactive towards traditionally inert bonds. Approaches to this include using ligand design or identifying new mechanisms for bond activation. The long term goal of each project is the commercial application of these catalytic technologies in fields such as pharmaceutical synthesis and biomass conversion. The atom-economic relatively green conversion of traditionally inert C-H bonds to functional groups has been achieved by a number of metal-catalyzed systems in the past decades. Complexes of the expensive 3rd-row late transition metals, such as iridium and platinum, are commonly used in these conversions, due to the strong bonds these elements form to both carbon and hydrogen, which aids in cleaving strong C-H bonds. Comparatively, complexes of nickel are at an extreme thermodynamic disadvantage in these reactions, but nickel has the distinct advantage of being on the order of 10000 times cheaper, due to its relative abundance. Our research suggests that not only can nickel complexes also activate strong C-H bonds, they can also perform catalytic C-H bond transformations that are unprecedented and perhaps unique to these systems. Our current goals are to fully understand the mechanism and scope of these reactions. Similar to C-H bond activation, the activation of C-F and C-O bonds are also problematic for both kinetic and thermodynamic reasons. We hope to do a thorough study of C-F bond activation by nickel complexes to gain insight into how the mechanism and thermodynamic parameters of these reactions are influenced by ancillary ligand choices. The end goal is a rational approach to both C-F bond activation and catalytic C-F bond formation for pharmaceuticals or radionuclide use. The activation of C-O bonds is related to C-F bond activation, and has application in both synthesis and biomass conversion to fuels or fine chemicals.