POLYIMIDAZOLE OXO-IRON COMPLEXES

聚咪唑氧合铁络合物

• 批准号: 3305217
• 负责人: ROBERT M BUCHANAN
• 金额: $ 3.67万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-05-01 至 1994-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3305217
• 关键词: X ray crystallography; active sites; chemical models; chemical structure function; electron spin resonance spectroscopy; enzyme model; imidazole; iron oxide; ligands; metal complex; metalloproteins; nuclear magnetic resonance spectroscopy; peptide chemical synthesis; polymers; ribonucleotide reductase

The proposed research involves a systematic study of the synthesis and properties of a class of mu-oxo mu-carboxylato Fe2 complexes containing biologically relevant polyimidazole ligands. These compounds will be used as synthetic analogues of the active sites on oxo-iron proteins such as: hemerythrin (Hr), ribonucleotide reductase (RR), purple acid phosphatase (PAP) and methane monooxygenase (MMO). These proteins are thought to have similar mu-oxo-mu-carboxylato Fe2 core structures, histidine as a ligand, stabilize Fe2II,FeIIFEIII and Fe2III oxidation levels, and perform very different biological functions (which may be dependent on the nature of ancillary ligands present at the active sites). Few studies to date have involved a systematic evaluation of the structure and properties of Fe2 complexes containing imidazole ligands. We have developed rational methods for preparing a wide range of polyimidazole ligand frameworks and will use these ligands to stabilize FE2II, FeIIFeIIIandFe2III complexes. A novel class of bis-tripodal and symmetric and asymmetric cyclic polyimidazole ligands will be prepared. These compounds will be used in anion (N3-,PO43- , CN-etc.) binding studies (as functional models of Hr and PAP). We will evaluate ligand strain effects on the structural and electronic properties of oxo-bridged Fe2 complexes in order to gain a better understanding of how imidazole functions as a ligand. The physical properties of all Fe2II, FeIIFeIII and Fe2III compounds will be assessed by a compliment of physical techniques, such as: X-ray crystallography, magnetic susceptibility, EPR, NMR, IR, UV-visible, Mossbauer spectroscopies as well as magnetic and electrochemical methods. Results from these studies will be compared with data on the proteins and other model complexes. We will evaluate the propensity of the Fe2III complex to function as alkane oxidation catalysts (model of MMO). Finally, we propose to extend our preliminary studies on the dynamic trapping/detrapping process observed in solid samples of a class of FeIIFeIII complexes of the phenol containing polyimidazole ligand Hbimp and explore the origin of the g<2 EPR signals observed for these complexes.

拟议的研究涉及的合成和系统的研究， 一类μ-氧代μ-羧酸铁配合物的性质， 生物学相关的聚咪唑配体。 这些化合物将用于 作为氧代铁蛋白上活性位点的合成类似物，例如： 血红蛋白（Hr）、核苷酸还原酶（RR）、紫色酸性磷酸酶 (PAP)和甲烷单加氧酶（MMO）。 这些蛋白质被认为具有 类似的μ-氧代-μ-羧基化Fe 2核心结构，组氨酸作为配体， 稳定Fe 2 II、FeIIFEIII和Fe 2 III氧化水平， 不同的生物学功能（可能取决于 存在于活性位点的辅助配体）。 到目前为止，很少有研究 对Fe 2+的结构和性能进行了系统的评价， 含有咪唑配体的配合物。 我们已经开发出了合理的方法 用于制备宽范围的聚咪唑配体框架，并将使用 这些配体稳定Fe 2 II、Fe II、Fe III和Fe 2 III络合物。 一种新型 一类双三脚架对称和不对称环状聚咪唑 将制备配体。 这些化合物将用于阴离子（N3-，PO 43- 、CN等）结合研究（作为Hr和PAP的功能模型）。 我们将 评估配体应变对结构和电子性质的影响 为了更好地了解氧桥Fe 2络合物如何 咪唑起配体的作用。 所有Fe 2 II的物理性质， FeIIFeIII和Fe 2 III化合物将通过补充物理测试进行评估。 技术，如：X射线晶体学，磁化率，EPR， NMR、IR、UV-可见光、穆斯堡尔谱以及磁性和 电化学方法 这些研究的结果将与 关于蛋白质和其他模型复合物的数据。 我们将评估 Fe 2 III络合物用作烷烃氧化催化剂的倾向 （MMO模式）。 最后，我们建议扩大我们的初步研究， 在固体样品中观察到的动态捕获/去捕获过程 一类含多咪唑配体的苯酚FeIIFeIII配合物 Hbimp和探索的起源g<2 EPR信号观察这些 配合物