Homogeneous hydrocarbon oxidation using nitrous oxide as a sustainable feedstock

一氧化二氮(N2O)是一种强有力的温室气体，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。作为一种丰富和可持续的资源，在化工生产中使用N2O作为氧化剂是一个诱人的前景，可以释放出环境友好的氮素，但这种气体的强健的三原子公式阻碍了它的发展。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，不具有选择性，最终不具有商业可行性。该项目将寻求建立支持均相过渡金属络合物活化N2O的科学基础，最终目标是将这些发现转化为有效的催化应用。利用9族和10族金属络合物，由坚固的多齿“钳形”配体支撑，将利用完整M-N2O加合物的形成和向前反应的活性，从根本上了解如何在化学合成中最有效地利用N2O，并特别严格地研究产生活性末端氧/氧基衍生物的前景。这些研究产生的结构-性质和结构-活性关系将被利用，以实现新催化剂的合理设计，并实现使用N2O作为选择性碳氢化合物氧化剂的转化性能的阶梯变化。甲烷升级为甲醇是一个值得注意和工业梦寐以求的转化，目标是全球每年对甲醇的需求接近1亿吨(MMSA数据)。该提议基于卓别林小组正在进行的实验工作，并将其与早期过渡元素的化学进行比较，这一提议将系统地研究使用第9和10族金属钳形络合物激活N2O的作用，这被认为会导致反应性末端氧/氧衍生物的形成。采用实验(与卓别林)和计算(与Krämer)相结合的协同方法，将研究第9族和第10族金属催化剂靶标，以建立N2O配位和活化的结构-性质和结构-活性关系。这些发现将被用来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.