Homogeneous hydrocarbon oxidation using nitrous oxide as a sustainable feedstock

一氧化二氮（N2O）是一种强效温室气体，在大气中的半衰期为114年，全球变暖潜力是二氧化碳的300倍，是21世纪排放的主要臭氧消耗物质。作为一种丰富的可持续资源，在化工生产中使用N2O作为氧化剂是一种有吸引力的前景，它可以释放出对环境无害的二氮N2，但受到这种气体强大的三原子配方的阻碍。虽然在极端条件下应用多相催化剂确实允许与N2O进行反应，但这种系统是能源密集型的，无选择性的，最终不具有商业可行性。该项目将寻求建立基于均相过渡金属配合物活化N2O的科学基础，最终目标是将这些发现转化为有影响力的催化应用。利用9和10族金属配合物，由强大的三叉聚合物“钳形”配体支撑，完整的M-N2O加合物的形成和后续反应性将被利用，以获得对N2O如何在化学合成中最有效利用的基本理解，特别是对生成活性末端氧/氧衍生物的前景进行严格检查。从这些研究中产生的结构-性质和结构-活性关系将被利用来合理设计新的催化剂，并在使用N2O作为选择性碳氢化合物氧化剂的转化过程中实现性能的逐步变化。随着全球甲醇年需求量接近1亿吨（MMSA数据），将甲烷转化为甲醇是一个引人注目的、令人垂涎的工业转型目标。基于卓别林小组正在进行的实验工作，并与早期过渡元素的化学相似，本提案将系统地研究使用9族和10族金属螯合物对N2O的活化，假设这将导致活性末端氧/氧衍生物的形成。利用实验（卓别林）和计算（Krämer）方法的协同结合，将研究9和10族金属催化剂目标，以建立N2O配位和活化背后的结构-性质和结构-活性关系。这些发现将用于推动后续的催化剂设计，最有希望的线索将经过严格的实验检验。

Nitrous oxide (N2O) is a potent greenhouse gas, with a half-life of 114 years in the atmosphere and global warming potential 300 times greater than carbon dioxide, and the dominant ozone depleting substance emitted in the 21st century. As an abundant and sustainable resource, the use of N2O as an oxidant in chemical manufacture is an attractive prospect, liberating environmentally benign dinitrogen N2, but encumbered by the robust triatomic formulation of this gas. Whilst application of heterogenous catalysts under extreme conditions does permit reactions with N2O to be performed, such systems are energy intensive, unselective and ultimately not commercially viable. This project will seek to establish the science underpinning the activation of N2O by homogeneous transition-metal complexes with the ultimate objective of translating these findings into impactful catalytic applications. Using group 9 and 10 metal complexes supported by robust mer-tridentate 'pincer' ligands, the formation and onward reactivity of intact M-N2O adducts will be leveraged to gain fundamental understanding of how N2O can be most effectively exploited in chemical synthesis, with the prospect for generating reactive terminal oxo/oxyl derivatives rigorously examined in particular. The resulting structure-property and structure-activity relationships generated from these studies will be harnessed to enable the rational design of new catalysts and achieve step-changes in performance for transformations employing N2O as a selective hydrocarbon oxidant. The upgrading of methane to methanol is one notable and industrially coveted transformation that will be targeted, with world demand for methanol approaching 100 million metric tons annually (MMSA data).Building upon ongoing experimental work in the Chaplin group and drawing parallels with the chemistry of the early transition elements, this proposal will systematically investigate the activation of N2O using group 9 and 10 group metal pincer complexes, that is hypothesised to result in the formation of reactive terminal oxo/oxyl derivatives. Using a synergistic combination of experimental (with Chaplin) and computational (with Krämer) approaches, group 9 and 10 metal catalyst targets will be investigated to establish structure-property and structure-activity relationships underlying the coordination and activation of N2O. These findings will be harnessed to propel subsequent catalyst design, with the most promising leads rigorously examined experimentally.