High-Resolution Crystallographic Studies Using Synchrotron Radiation

化学系的无机、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的 Philip Coppens 教授使用同步加速器辐射进行高分辨率晶体学研究。将使用稳态和时间分辨晶体学来探测光诱导的亚稳态和高反应性瞬态物质的几何形状。这项工作将有助于理解光诱导分子激发态的性质，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绘图，以及根据分子内部和分子之间的化学键对这些数据的解释。阿贡国家实验室先进光子源的高亮度将与区域探测器相结合，以实现对尺寸为 50 微米及以下的小微晶的快速 X 射线数据收集。项目各阶段的数据收集将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、使用该项目可用的超级计算机设施以及对所研究系统的吸收和发射光谱进行光谱测量来补充。X射线衍射被认为是结构确定工具的必要条件，能够测量分子几何形状的极小变化。 然而，该技术仅测量稳定的结构。这项工作利用了创新技术，使 X 射线晶体学能够确定快速时间尺度上发生的分子结构变化。 关于辐射与固态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。这项工作涉及大量合作，并为年轻科学家提供了独特的训练场地。与斯洛伐克理工大学的国际合作将有利于两国推进该领域研究的努力。为了帮助利用本研究中使用的技术，将开发软件并向更广泛的科学界提供。

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.