Advanced X-ray Spectroscopic Approachesfor the Characterization ofHigh-Valent Iron Intermediates

用于表征高价铁中间体的先进 X 射线光谱方法

• 批准号: 495518557
• 负责人: Professorin Dr. Serena DeBeer
• 金额: --
• 依托单位: Max-Planck-Institut für Chemische Energiekonversion (CEC)
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/495518557?language=en
• 关键词: Advanced; ray; Spectroscopic; Approachesfor; Characterization

This proposal will focus on the development and application of advanced X-ray spectroscopic methods to understand the mechanisms of bioinspired homogenous catalysts which mediate oxygenation reactions. We will develop the full information content of 1s2p resonant inelastic X-ray scattering (RIXS), 1s3p RIXS, 1sValence RIXS and 2p3d RIXS, and the relevance of these methods to high valent iron intermediates. RIXS experiments are effectively two-dimensional spectroscopic measurements that combine a selected XAS edge with a selected X-ray emission energy range to select for a specific combination of ground, intermediate and final states. As such, these experiments enable greater selective enabling higher resolution X-ray absorption spectroscopy XAS (from the 1s2p RIXS), spin and oxidation state selective XAS (1s3p RIXS), ligand and polarization selectivity (1sValence RIXS) and access to low lying d-d excited states (2p3d RIXS). Many of these experiments are still in an early development phase, and hence it will be important to perform a range of parallel experiments on well-characterized Fe(IV)-oxo, Fe(III)-peroxo, and Fe(II) precursor complexes. The information content of these spectra will be established through close correlation to theory. The correlation of experiment and theory will allow us to establish the right combination of methods to maximize insight into the electronic structural changes and ultimately to the mechanism of operating catalysts. Our initial studies will focus on static frozen (or freeze-quenched) samples and will then be extended to in situ studies utilizing microfluidic mixers, which we are currently developing. Static and in-situ/operando spectroscopic studies of catalysts developed within the collaborative research team will provide key insight into the processes of O-O bond cleavage, O-atom transfer and C-H atom abstraction. These findings will form a basis for future knowledge based catalytic design.

本提案将重点发展和应用先进的x射线光谱方法来了解生物激发均相催化剂介导氧化反应的机制。我们将开发出12p共振非弹性x射线散射（RIXS）、1s3p RIXS、1sValence RIXS和2p3d RIXS的完整信息内容，以及这些方法与高价铁中间体的相关性。RIXS实验是有效的二维光谱测量，将选定的XAS边缘与选定的x射线发射能量范围相结合，以选择基态，中间态和最终态的特定组合。因此，这些实验能够实现更高的选择性，实现更高分辨率的x射线吸收光谱XAS（来自1s2p RIXS），自旋和氧化态选择性XAS（来自133p RIXS），配体和极化选择性（来自1ssvalence RIXS）以及低空d-d激发态（来自2p3d RIXS）。许多这些实验仍处于早期发展阶段，因此对表征良好的铁(IV)-氧，铁(III)-过氧和铁（II）前体配合物进行一系列平行实验将是重要的。这些光谱的信息量将通过与理论的密切联系来确定。实验和理论的关联将使我们能够建立正确的方法组合，以最大限度地了解电子结构的变化，并最终了解操作催化剂的机制。我们最初的研究将集中在静态冷冻（或冷冻淬火）样品上，然后将扩展到利用我们目前正在开发的微流体混合器的原位研究。在合作研究团队中开发的催化剂的静态和原位/操作光谱研究将为O-O键裂解，o -原子转移和C-H原子提取过程提供关键见解。这些发现将为未来基于知识的催化设计奠定基础。