XAS DETERMINATION OF THE OXIDATION STATES AND ELECTRONIC STRUCTURES OF GROUP 9 M

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 Ir(III)与5，10，15-三氟苯基冠醚阴离子的配合物是自2008年发现以来表征最彻底的5D金属-冠醚配合物，但其氧化衍生物的电子和分子结构在很大程度上仍然是神秘的。我们从EPR和可见光谱中有强有力的证据表明，与其3D钴类似物不同，Ir(III)腐蚀剂与单一氧化当量反应形成顺磁性M(IV)络合物。事实上，我们发现钴(III)腐蚀似乎在配位体上被氧化，Ir(III)腐蚀在金属上，而Rh(III)腐蚀在某种离域的方式。然而，我们仍然对这些配合物中的共价水平、由Corole配体证明的非无辜量、化合物的配位场结构以及遭受双重氧化的第9族金属配位角色的性质仍有严重的疑问。我们希望利用我们的络合物的边缘位置来确定中心离子的氧化状态和配体上的电子离域水平。我们还建议收集所有氧化络合物的EXAFS数据，以探索金属离子周围的局域结构，因为这些化合物的结晶学数据尚未公布。我们收集了关于我们的Ir络合物的初步数据，表明EXAFS衍生的键长与结晶学参数准确一致，并且LIII-EDGE光谱对金属的氧化状态高度敏感。我们希望通过在传输模式下获取粉末样品的光谱来改进这一数据，因为我们已经开发了一种方法来产生更大数量的Corole。更重要的是，我们将在下一次运行中使用SSRL的已知光谱电化学设置对络合物的氧化状态进行精细控制。这些变化应该使我们能够收集关于金属配位角色结构的高质量数据。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Iridium(III) complexes with the 5,10,15-tris-pentafluorophenylcorrole anion (tpfc) represent the most thoroughly characterized examples of 5d metal-corrole complexes since their discovery in 2008, but the electronic and molecular structures of their oxidized derivatives remain largely mysterious. We have strong evidence from EPR and visible spectroscopy that iridium(III) corroles, unlike their 3d cobalt analogues, form paramagnetic M(IV) complexes upon reaction with a single oxidizing equivalent. In fact, we found that cobalt(III) corroles appear to be oxidized at the ligand, iridium(III) corroles at the metal, and rhodium(III) corroles in some delocalized fashion. However, we still have serious questions about the level of covalency in these complexes, the amount of non-innocence demonstrated by the corrole ligand, the ligand field structure of the compounds, and the nature of Group 9 metallocorroles which have been subjected to double oxidation. We hope to use the edge positions of our complexes to determine the oxidation states of the central ion and the levels of electronic delocalization onto the ligand. We also propose the collection of EXAFS data for all oxidized complexes in order to probe the local structure around the metal ions, since crystallographic data on these compounds has not been forthcoming. We have gathered preliminary data on our iridium complexes showing that EXAFS-derived bond lengths coincide accurately with crystallographic parameters, and that the LIII-edge spectrum is highly sensitive to the oxidation state of the metal. We wish to improve upon this data by taking spectra of powdered samples in transmission mode, now that we have developed a methodology to produce larger amounts of corrole. More importantly, we will execute fine control over the oxidation states of the complexes in our next run using a known spectroelectrochemical setup at SSRL. These changes should allow us to gather high quality data on the structures of metallocorroles.