HYDROGEN BONDING IN METALLOPORPHYRIN REACTIONS

金属卟啉反应中的氢键

• 批准号: 3152022
• 负责人: DWIGHT A SWEIGART
• 金额: $ 6.62万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-07-01 至 1986-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3152022
• 关键词: catalase; chemical reaction; cobalt; cytochromes; electrochemistry; hemoglobin; hemoprotein; hydrogen bond; imidazole; ligands; metalloporphyrins; myoglobin; oxidation reduction reaction; peroxidases; ruthenium; thermodynamics

The aim of the proposed research is to quantitatively establish the effect of hydrogen bonding on the kinetics, thermodynamics, and redox properties of metalloporphyrin reactions. The hydrogen-bonding is of two types: to an axially coordinated ligand (distal effect) and from an axially coordinated ligand (proximal effect). Preliminary experiments suggest that distal hydrogen-bonding can greatly influence the kinetics and thermodynamics of ligand dissociation and association when the coordinated ligand is anionic. One of the reactions to be investigated is Fe(porphyrin)X + 2 RIm greater than Fe(porphyrin)(RIm)2+, X-, where X is one of a variety of anionic ligands and RIm is an imidazole. This reaction goes through the unstable monoimidazole intermediate Fe(porphyrin)(RIm)X which is a model for a number of hemoproteins. The influence of hydrogen-bonding from RIm and to X- in Fe(porphyrin)(RIm)X will be thoroughly investigated by rapid reaction techniques (low temperature stopped-flow, NMR) and electrochemical techniques (stationary electrode voltammetry, polarography). Several other metalloprophyrins, principally those of cobalt and ruthenium containing coordinated dioxygen, will also be investigated. The hydrogen-bonding to be studied can be from the solvent, nucleophile, or other external source to the distal ligand or from coordinated imidazole to solvent or other basic species. The elucidation of the importance of hydrogen-bonding on the ligand association and dissociation rates, reaction thermodynamics, and metalloporphyrin redox potentials will provide a basis for understanding the importance of these effects in reactions mediated by hemoproteins such as hemoglobin, myoglobin, catalases, peroxidases, and cytochromes.

拟议研究的目的是定量确定效果 氢键对动力学、热力学和氧化还原性质的影响 金属卟啉反应。 氢键有两种类型： 轴向配体（远端效应）和轴向配体 协调配体（近端效应）。 初步实验表明 远端氢键可以极大地影响动力学和 配体解离和缔合的热力学 配体是阴离子的。 要研究的反应之一是 Fe(卟啉)X + 2 RIm 大于 Fe(卟啉)(RIm)2+, X-，其中 X 是 RIm是多种阴离子配体之一，是咪唑。 这个反应 经过不稳定的单咪唑中间体 Fe(卟啉)(RIm)X 这是许多血红素蛋白的模型。 的影响 从 RIm 到 Fe(卟啉)(RIm)X 中的 X- 的氢键为 通过快速反应技术（低温 停流、核磁共振）和电化学技术（固定电极 伏安法、极谱法）。 几种其他金属卟啉，主要是 那些含有配位双氧的钴和钌也将被 调查了。 要研究的氢键可以来自溶剂， 亲核试剂，或远端配体的其他外部来源或来自 咪唑与溶剂或其他碱性物质配位。 澄清 氢键对配体缔合的重要性和 解离速率、反应热力学和金属卟啉氧化还原 潜力将为理解这些的重要性提供基础 对血红蛋白等血红蛋白介导的反应的影响， 肌红蛋白、过氧化氢酶、过氧化物酶和细胞色素。