Integrated Paramagnetic Resonance of High-Spin Cobalt(II) Systems

这个无机、生物无机和有机金属化学项目的奖项支持新墨西哥大学的David L. Tierney教授通过x射线吸收光谱和顺磁共振（PMR）的结合来研究一个模型化合物库，包括4-、5-和6-配位。同时应用多频电子顺磁共振（EPR）、电子-核双共振（ENDOR）和核磁共振（NMR）对PMR进行综合分析。PMR将用于定义各种Co（II）系统中电子-核超精细相互作用的场依赖性和温度依赖性。电子弛豫将通过场和温度相关的核磁共振弛豫和核磁共振色散（NMRD）来检验。模型系统的行为将指导未知结构系统的光谱研究，其中x射线吸收光谱（XAS）将提供额外的关键结构约束。初始聚焦系统模拟了钴金属生物化学中的两个关键结构元素- co - nhitidine和Co-Scysteine。为了模拟金属-组氨酸的相互作用，我们将研究一系列双- (Bp)和三- (Tp)吡唑酸酯配合物。模拟Co-Scys相互作用的努力将涉及普通烷基和芳基硫酸盐小分子化学。为了弥合小分子和金属蛋白研究之间的差距，将研究一组全新的金属结合肽，旨在呈现四种半胱氨酸或青霉胺硫代酸盐作为潜在的配体。ENDOR光谱技术在Co（II）体系中的应用将为Co（II）作为Zn（II）金属酶的光谱探针的全面开发奠定基础。Tierney教授重新开发了一个高级本科生“合成与表征”实验室，并在他目前的研究基础上开发了实验。新墨西哥大学（University of New Mexico）的学生群体中有大量少数族裔，其中很大一部分本科化学专业的学生来自传统上代表性不足的群体。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports Professor David L. Tierney at the University of New Mexico to investigate a library of model compounds, encompassing 4-, 5- and 6-coordination, by a combination of x-ray absorption spectroscopy and paramagnetic resonance (PMR). An integrated approach to PMR would be used simultaneously applying mutli-frequency electron paramagnetic resonance (EPR), electron-nuclear double resonance (ENDOR) and nuclear magnetic resonance (NMR). PMR would be used to define the field- and temperature-dependence of electron-nuclear hyperfine interactions in a broad array of hs Co(II) systems. Electronic relaxation will be examined by field- and temperature-dependent NMR relaxation and by NMR dispersion (NMRD). The behavior of the model systems will guide spectroscopic studies of systems of unknown structure, where x-ray absorption spectroscopy (XAS) will provide additional, critical structural constraints. The systems for initial focus mimic two key structural elements in the metallobiochemistry of cobalt - Co-Nhistidine and Co-Scysteine. To emulate metal-histidine interactions, we will study a series of bis- (Bp) and tris- (Tp) pyrazolylborate complexes. Efforts to model Co-Scys interactions will involve common alkyl- and arylthiolate small-molecule chemistry. To bridge the gap between small-molecule and metalloprotein studies, a set of de novo metal-binding peptides, designed to present four cysteine or penicillamine thiolates as potential ligands, will be examined. The application of ENDOR spectroscopy to hs Co(II) systems will help lay the foundation for the full development of Co(II) as a spectroscopic probe of Zn(II) metalloenzymes. Professor Tierney has re-developed a senior-level, undergraduate "Synthesis and Characterization" laboratory, with experiments developed from his current research. The student body of The University of New Mexico has a large minority enrollment with a high fraction of undergraduate chemistry majors coming from traditionally under-represented groups.