IDENTIFICATION OF TRANSITION METAL ION COMPOUNDS BY ESR SPECTROSCOPY

ESR 光谱法鉴定过渡金属离子化合物

• 批准号: 8363997
• 负责人: PAUL J CHIRIK
• 金额: $ 0.05万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363997
• 关键词: Anisotropy; Cell Nucleus; Complex; Electron Spin Resonance Spectroscopy; Electrons; Funding; Grant; Ions; Isotopes; Methods; National Center for Research Resources; Niobium; Nitrogen; Nitrogen Fixation; Principal Investigator; Reaction; Research; Research Infrastructure; Resources; Services; Source; Spectrum Analysis; Technology; Training; Transition Elements; United States National Institutes of Health; Work; Zirconium; base; cost; graduate student; interest; zirconium oxide

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. Prof Chirik is interested in studying low-valence transition metal ion compounds (Ti, Zr, Hf, Nb) for nitrogen fixation. For this purpose he synthesized and studied a number of compounds, such as bis(cyclopentadienyl)zirconium complexes and used a variety of methods including ESR for their identification. As an important service/training component of the center activity, ACERT staff trained a number of graduate students from Chirik's group to use the Bruker EMX ESR machine and helped them with analyzing the spectra. ESR spectroscopy clearly demonstrated that the reaction products consisted of two nitrogen atoms each bearing a free electron. Synthesis of 13C substituted compounds and analysis of the additional ESR spectral splitting via 13C nuclei provided further structural details. Along with the main product, ESR detects substantial amounts of other products. Based on their g-factors and their anisotropy, isotope satellite lines etc. the products were identified as Zr(III) compounds. ESR was also used to quantify the ratio of reaction products (radical vs. non-radical, Zr(IV) vs. Zr(III)) and helped in choosing conditions favoring the desired reaction path. Similar work is now in progress for niobium organic compounds.

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 子项目的主要研究者可能是由其他来源提供的， 包括其他NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， NCRR赠款不直接向子项目或子项目工作人员提供资金。 Chirik教授有兴趣研究低价过渡金属离子化合物（Ti，Zr，Hf，Nb）用于固氮。为此，他合成并研究了一些化合物，如双（锆）锆配合物，并使用了各种方法，包括ESR对其进行鉴定。作为中心活动的一个重要服务/培训部分，ACERT工作人员培训了Chirik团队的一些研究生使用布鲁克EMX ESR仪器，并帮助他们分析光谱。ESR谱清楚地表明反应产物由两个氮原子组成，每个氮原子带有一个自由电子。13 C取代化合物的合成和通过13 C核的额外ESR谱分裂的分析提供了进一步的结构细节。 沿着主要产品，ESR检测大量的其他产品。根据它们的g因子和各向异性、同位素伴线等特征，确定产物为Zr（III）化合物。ESR还用于定量反应产物的比例（自由基与非自由基，Zr（IV）与Zr（III）），并帮助选择有利于所需反应路径的条件。