SusChEM: CAREER: High-Resolution X-ray Spectroscopic Studies of Base Metal Catalysis

凭借这一职业奖，化学系的化学结构、动力学和机理 B 项目正在资助康奈尔大学化学与化学生物学系的 Kyle M. Lancaster 教授使用尖端的 X 射线光谱来探索地球上丰富的过渡金属催化剂的反应性。 这项研究的目的是确定这些催化剂实现显着化学转化的机制，包括将生物质分解为用于生物燃料的单糖以及将天然气转化为可运输的液体形式。了解含有地球丰富金属的催化剂的反应性是可持续化学未来的关键。拟议的工作结合了生物化学、合成、光谱学和理论的元素，为本科生和研究生研究人员提供跨学科培训。光与物质之间的相互作用构成了光谱学的基础，也是该项目外展工作的基础；具体来说，将为K-12学生开发动手“实验室套件”，以探索光的特性。价核X射线发射光谱、高能分辨率荧光检测X射线吸收光谱和共振非弹性X射线散射是表征配位环境和配体电子结构的新兴通用方法。这些方法用于探测铜催化剂，此处定义为酶或配位络合物。一种待研究的催化剂是单核铜酶，它可以氧化裂解生物质中的多糖，例如几丁质和纤维素。停流动力学和快速冷冻淬灭方法被用来捕获活性铜氧物质以进行 X 射线光谱表征。用于将甲烷转化为甲醇的天然铜催化剂是本研究的重点。这种催化剂是一种完整的膜蛋白，其反应性铜氧物质无法通过传统方法进行研究。努力将扩展到非生物系统：铜催化的有氧酒精氧化。这项研究可以证明，所采用的方法不一定需要预催化剂的精确知识来表征反应成分。

With this CAREER award, the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division is funding Professor Kyle M. Lancaster of the Department of Chemistry and Chemical Biology at Cornell University to use cutting-edge X-ray spectroscopies to explore the reactivity of earth-abundant transition metal catalysts. The goal of this research is to determine the mechanisms by which these catalysts effect remarkable chemical transformations including the breakdown of biomass to simple sugars for biofuels and the conversion of natural gas to transportable liquid forms. Understanding the reactivity of catalysts incorporating earth-abundant metals is key to a sustainable chemical future. The proposed work incorporates elements of biochemistry, synthesis, spectroscopy, and theory, affording interdisciplinary training for undergraduate and graduate researchers. The interaction between light and matter that forms the basis of spectroscopy is the foundation for outreach efforts under this project; specifically, hands-on "lab kits" are to be developed for K-12 students to explore properties of light.Valence-to-core X-ray emission spectroscopy, high-energy-resolution fluorescence-detected X-ray absorption spectroscopy and resonant inelastic X-ray scattering are emerging, versatile methods to characterize coordination environments and ligand electronic structures. These methods are being used to probe copper catalysts, defined here as either enzymes or coordination complexes. One such catalyst to be studied is a mononuclear copper enzyme that oxidatively cleaves polysaccharides in biomass such as chitin and cellulose. Stopped-flow kinetics and rapid freeze quench methods are being used to trap reactive copper-oxygen species for X-ray spectroscopic characterization. Nature's copper catalyst for conversion of methane to methanol is a focus of this study. This catalyst is an integral membrane protein whose reactive copper-oxygen species have eluded study by conventional methods. Efforts are to be extended to an abiotic system: copper-catalyzed aerobic alcohol oxidation. This study could demonstrate that the methods to be employed do not necessarily require precise knowledge of precatalysts in order to characterize reaction constituents.