High-Resolution Crystallographic Studies Using Synchrotron Radiation

化学部门的无机、生物无机和有机金属化学项目支持纽约州立大学布法罗分校化学系Philip Coppens教授使用同步辐射进行高分辨率晶体学研究。光诱导亚稳态和高反应瞬态的几何将探索使用稳态和时间分辨晶体学。这项工作将有助于理解光诱导分子激发态的本质，并阐明过渡金属配合物中电子转移过程中发生的几何变化。该研究的第二个组成部分是固体中电荷密度分布的实验映射，并根据分子内部和分子之间的化学键来解释这些数据。阿贡国家实验室的高亮度先进光子源将与区域探测器相结合，允许在尺寸为50微米或更小的小晶体上快速收集x射线数据。项目各阶段的数据采集均采用极低温单晶技术。实验工作将通过对分子和固体进行广泛的理论计算来补充，使用该项目可用的超级计算机设施，并通过对所研究系统的吸收和发射光谱进行光谱测量。x射线衍射是众所周知的结构测定工具的必要条件，能够测量分子几何结构的极小变化。然而，这种技术只能测量稳定的结构。这项工作利用了x射线晶体学的创新来确定在快速时间尺度上发生的分子结构变化。关于固态辐射与物质相互作用的知识将为材料科学和技术的未来应用奠定基础。这项工作涉及许多合作，并为年轻科学家提供了一个独特的训练场所。与斯洛伐克技术大学的国际合作将有利于两国在这一领域推进研究的努力。为了帮助利用本研究中使用的技术，将开发软件并提供给更广泛的科学界。

The Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division supports Professor Philip Coppens, Chemistry Department, State University of New York at Buffalo, for high-resolution crystallographic studies using synchrotron radiation. The geometry of light-induced metastable states and highly reactive transient species will be probed using both steady-state and time-resolved crystallography. The work will contribute to the understanding of the nature of photoinduced molecular excited states and to elucidating geometry changes that occur during electron transfer in transition metal complexes. A second component of the research is the experimental mapping of charge density distribution in solids and the interpretation of these data in terms of chemical bonding within and between molecules. The high-brightness of the Advanced Photon Source at Argonne National Laboratory will be combined with area detectors to allow rapid X-ray data collection on small crystallites of dimensions of 50 micron and less. Very low-temperature single crystal techniques are to be applied for data collection in each stage of the project. The experimental work is to be complemented by extensive theoretical calculations on both molecules and solids, using supercomputer facilities available to the project, and by spectroscopic measurement of the absorption and emission spectra of the systems under investigation.X-ray diffraction is well-known as the sine qua non of structure-determining tools, capable of measuring extremely small changes in molecular geometry. However, this technique only measures stable structures. This work exploits innovations that allow x-ray crystallography to determine structural changes in molecules that occur on fast timescales. Knowledge that is gained about the interaction of radiation with matter in the solid state will underpin future applications in materials science and technology. This work involves much collaboration and provides a unique training ground for young scientists. An international collaboration with the Slovak University of Technology will benefit the efforts of both countries to advance research in this area. To aid in the utilization of the techniques used in this study, software will be developed and made available to the wider scientific community.