New ligands for small molecule activation by metal complexes

金属配合物活化小分子是无机化学的一个成熟领域。然而，作为生物圈中最丰富的小分子之一的氮分子，由于其固有的缺乏反应性，继续使无机化学家感到沮丧。这种小分子的强大性质是由于许多因素，包括一个大的键解离能（945 kJ/mol），缺乏偶极矩，以及一个大的添加和/或去除电子的障碍。当然，众所周知，在极端条件下，N2会在活化的铁表面与H2反应生成氨；这种被称为哈伯-博世过程的能源密集型催化转化，满足了全球对nh3衍生肥料的需求。相反，生物系统在环境条件下将分子氮转化为氨；氮酶有许多变体，但最常见的是利用蛋白质稳定的铁和钼的硫簇作为辅助因子（FeMoco）。虽然发现Haber-Bosch过程的同质版本是世界各地许多小组的目标，但另一个有价值的目标是开发分子氮的新反应，从而形成高价值的有机氮材料，如胺和n -杂环。本提案概述了一系列旨在加速二氮功能化领域突破的实验。同样重要的是，其他稳定分子可能通过与配体和金属的适当组合相互作用而被迫形成新的反应模式；例如，二氧化碳（CO2）和烷烃（RH）也是非常强大的分子，将被研究为可能的原料，以产生高价值的材料，使用有目的地设计的均相催化剂。

The activation of small molecules by metal complexes is a mature area of inorganic chemistry. Nevertheless, molecular nitrogen, one of the most abundant small molecules in the biosphere, continues to frustrate inorganic chemists due to its intrinsic lack of reactivity. The robust nature of this small molecule is due to a number of factors including, a large bond dissociation energy (945 kJ/mol), the lack of a dipole moment, and a large barrier to addition and/or removal of electrons. Of course, it is well known that under extreme conditions, N2 will react with H2 over an activated iron surface to generate ammonia; this energy-intensive catalytic transformation, known as the Haber-Bosch process, supplies the global need for NH3-derived fertilizers. In contrast, biological systems convert molecular nitrogen into ammonia under ambient conditions; there are a number of variants of the enzyme Nitrogenase but the most common utilize protein-stabilized sulfido-clusters of iron and molybdenum as the cofactor (FeMoco). While discovery of a homogeneous version of the Haber-Bosch process is the goal of a number of groups around the world, another worthwhile goal is to develop new reactions for molecular nitrogen that result in the formation of high-value organonitrogen materials, such as amines and N-heterocycles. This proposal outlines a series of experiments designed to accelerate breakthroughs in the area of dinitrogen functionalization. Also of importance are other stable molecules that might be coerced into new reactivity patterns by interaction with appropriate combinations of ligands and metals; for example, carbon dioxide (CO2) and alkanes (RH) are also very robust molecules that will be examined as possible feedstocks to generate higher-value materials using purposefully designed homogeneous catalysts.