Kinetics and Mechanism of Iron-Ligand Exchange Reactions in the Presence of Surfactants and/or Crown Ethers

表面活性剂和/或冠醚存在下铁-配体交换反应的动力学和机制

• 批准号: 9113199
• 负责人: Alvin Crumbliss
• 金额: $ 19.9万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9113199&HistoricalAwards=false
• 关键词: Kinetics; Mechanism; Iron; Ligand; Exchange

The principal goal in this project is to elucidate the mechanism in microbes whereby iron is released from its extremely stable carrier at the appropriate time and location. Model experiments which use micelles designed to probe possible effects of the aqueous/cell interface on the labilization of iron from siderophores and other polydentate chelators will be performed. The influence of the aqueous/micelle interface on the kinetics of iron/ligand exchange between, for example, the hydrophilic siderophore ferrioxamine B and a micelle bound hydrophobic chelator, benzohydroxamic acid, will be tested. Phenanthroline will also be incorporated into the micelle in some experiments, as preliminary data show that phenanthroline accelerates iron/ligand exchange into the micellar pseudo-phase via a redox mechanism. Supramolecular assemblies in aqueous solution will be investigated in order to evaluate second coordination shell effects on iron(III)-ligand dissociation kinetics. Hydrophobic crown ethers may permit these supra- molecular assemblies to form on micelle "surfaces". These assemblies may be used as models for cell surface receptor complexes. The kinetics of ligand exchange within these supra- molecular assemblies (e.g., ferrioxamine B-crown ether- surfactant) and the influence that ternary complex formation has on these kinetics will be measured. %%% In this project in the Inorganic, Bioinorganic, and Organo- metallic Program of the Chemistry Division, Dr. Alvin L. Crumbliss of Duke University will model the way in which iron is released in microbes at the appropriate time and location. Bacteria contain molecules which bind and transport iron so efficiently that some are used as drugs in chelation therapy. The results of these bioinorganic experiments will enhance our understanding of microbial iron transport mechanisms and mechanisms related to metal extraction processes.

本项目的主要目标是阐明 微生物的一种机制，即铁从其 在适当的时间和地点非常稳定的载体。 模型实验使用胶束设计来探测可能的 水/细胞界面对不稳定的影响 来自铁载体和其他多齿螯合剂的铁将被 执行。 水/胶束界面的影响 铁/配体交换的动力学，例如， 亲水性铁载体铁氧胺B和胶束结合 将测试疏水螯合剂苯并异羟肟酸。 菲咯啉也将被纳入胶束中， 一些实验，如初步数据显示，菲咯啉， 加速铁/配体交换进入胶束假相 通过氧化还原机制。 水溶液中的超分子组装 将研究解决方案，以评估第二个 配位壳层对铁（III）-配体解离的影响 动力学 疏水性冠醚可以允许这些超疏水冠醚。 在胶束“表面”上形成分子组装体。 这些 组装体可用作细胞表面受体的模型 配合物 在这些超- 分子组件（例如，铁草胺B-冠醚- 表面活性剂）及其对三元复合物形成影响 将测量对这些动力学的影响。 %%% 在这个项目中，无机，生物无机和有机- 化学部金属计划，博士阿尔文L。 杜克大学的Crumbliss将模拟铁 在适当的时间和地点被微生物释放。 细菌含有结合和运输铁的分子， 有效地将一些用作螯合疗法中的药物。 这些生物无机实验的结果将增强我们的 了解微生物铁转运机制， 与金属提取过程有关的机制。