X-RAY AND CHEMICAL STUDIES OF METALLOPORPHYRINS

几种新型金属卟啉的合成与表征 提出了化合物的概念。这项工作将强调，但不会局限 到了，铁衍生物。大多数类别的化合物建议用于 研究与血红素蛋白衍生物有关，它们进行的范围很广 包括氧气利用和运输在内的生物功能， 电子传递、药物代谢等酶过程。另一个 衍生物的种类与光合作用反应的种类有关。 三维X射线晶体结构的测定方法将是 用来定义分子结构和各种细节方面 金属卟啉立体化学。需要应用的其他方法，如 适当的，包括通过块状材料表征磁性 温度相关磁化率与电子顺磁共振 (EPR)测量、穆斯堡尔谱、振动光谱和UV-Vis光谱，以及 电化学性质。研究目标，载于 最广义的说法，是实现结构和物理的综合 金属卟啉的性质，特别是这些关系 涉及到对以血红蛋白为基础的生物过程的理解。在……里面 部分，这将通过建立可能的立体化学来实现 一种金属卟啉基团及其生物环境的特征和 所选血液蛋白的特定假体群体行为模型。是这样的 研究有望提供对蛋白质结构的理解 可以调节金属卟啉的几何构型和如何各种各样的 生物过程可以用相同的基础铁来进行 原卟啉IX单位。将研究的卟啉铁酸盐包括合成的 双组氨酸连接的细胞色素b和c的类似物 轴向配基取向等特征会影响其电子结构 和氧化还原性能。另一个重要的研究目标 是对金属卟啉中电子相互作用的探索； 详细的研究将检查系统中的耦合与潜在的内部 和/或分子间途径。在这类研究中包括具有 氧化或还原的卟啉核心，其中的ETA-自由基自旋耦合是 意义重大。这些物种对于理解催化作用很重要 高价血红蛋白系统的重要中间体，如 过氧化氢酶和过氧化物酶。具有电子耦合的其他系统 有待探索的相互作用包括与耦合金属离子的体系 以明确的方式分离(桥联配体或静电 交互)。

The synthesis and characterization of a variety of new metalloporphyrin compounds is proposed. The work will emphasize, but will not be limited to, iron porphyrinate derivatives. Most classes of compounds proposed for study are related to hemoprotein derivatives, which carry out a wide range of biological functions including oxygen utilization and transport, electron transport, drug metabolism and other enzymatic processes. Another class of derivatives are related to species of photosynthetic reactions. The methods of three-dimensional X-ray crystal structure determination will be applied to define molecular structures and various detailed aspects of metalloporphyrin stereochemistry. Other methodologies to be applied, as appropriate, include characterization of magnetic properties by bulk temperature-dependent susceptibility and electron paramagnetic resonance (EPR) measurements, Mossbauer, vibrational and UV-vis spectroscopy, and electrochemical properties. The research objectives, stated in the broadest terms, are to achieve a synthesis of the structural and physical properties of metalloporphyrins, particularly as these relationships pertain to an understanding of hemoprotein-based biological processes. In part, this will be accomplished by establishing possible stereochemical features of a metalloporphyrin group and its biological environment and to model specific prosthetic group behavior of selected hemoproteins. Such studies are expected to provide understanding of how protein structures could modulate metalloporphyrin geometry and how a wide variety of biological processes can be carried out with the same fundamental iron protoporphyrin IX unit. Iron porphyrinates to be studied include synthetic analogues of bis(histidine)-ligated cytochromes b and c to examine how features such as axial ligand orientation affect their electronic structure and oxidation-reduction properties. Another significant research objective is the exploration of electronic interactions in metalloporphyrins; detailed studies will examine coupling in systems with potential intra- and/or intermolecular pathways. Included in such studies are species with oxidized or reduced porphyrin cores in which eta-radical spin-coupling is significant. These species are important to understanding catalytically important intermediates of high-valent hemoprotein systems such as catalases and peroxidases. Other systems with electronic coupling interactions to be explored include systems with the coupled metal ions separated in well-defined ways (bridging ligands or electrostatic interactions).