EXCITED STATE DYNAMICS OF TRANSITION METAL PORPHYRINS

过渡金属卟啉的激发态动力学

• 批准号: 6179695
• 负责人: DEWEY HOLTEN
• 金额: $ 15.62万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-09-26 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6179695
• 关键词: chemical models; chemical structure function; chlorophyll; cofactor; conformation; dimer; dipole moment; electron transport; electronic spectra; emission spectrometry; fluorescence; fluorescence spectrometry; hemoprotein; intermolecular interaction; laser spectrometry; metalloporphyrins; molecular energy level; molecular orbital; optics; photochemistry; photosynthetic reaction centers; tetrapyrroles; time resolved data

DESCRIPTION: The goal of this research is to understand the relationships among molecular structure, electron properties, and ground and excited state reactivity and relaxation dynamics of porphyrins and related ring systems. These relationships are central to the mechanisms of the diverse biological functions of tetrapyrrole chromophores, but are often difficult to investigate in detail in vivo. Therefore, research on the biological systems must be complemented by the study of tetrapyrroles in vitro. Time-resolved and steady state optical studies of model complexes are proposed to delineate functional properties of porphyrinic cofactors in biological systems such as the heme proteins and photosynthetic reaction center. Specific Aim 1 is to elucidate the electronic properties and excited state relaxation and electron transfer mechanisms of closely-spaced porphyrin dimers. Several tetrapyrrole dimers will be studied to probe key characteristics of biological complexes such as the bacteriochlorophyll special pair of the reaction center. The proposed studies will explore the effects of electronic asymmetry on the nature and relaxation kinetics of the lowest excited states, the role of the pi-overlap pattern in defining photophysical properties, and electron transfer involving strongly-coupled porphyrin dimers. Specific Aim 2 is to elucidate how nonplanar macrocycle distortions modulate the static and transient electronic properties of tetrapyrrole. Nonplanar distortions of the tetrapyrrole cofactors are widely observed in the protein complexes. Work from the PI s lab has shown that such distortions have dramatic effects on ground and excited state properties. Studies of electronic relaxation rates and pathways, photoinduced conformational excursions, and transient ligand binding/release and other properties will be extended to porphyrins with varying modes of nonplanar distotion (saddle, ruffle, dome, wave), chlorins (chlorophyll models), and iron porphyrins (heme models). Complementary ultrafast time resolved vibrational studies will give direct structural information. There have been few such studies for planar porphyrins and none for the nonplanar complexes. The combined studies will provide fundamental insights into the functional and spectroscopic properties of tetrapyrrole cofactors in vivo.

描述：这项研究的目的是了解关系 在分子结构，电子特性以及地面和激发态中 卟啉和相关环系统的反应性和松弛动力学。 这些关系对于多样的生物学机制至关重要 四吡俄生色团的功能，但通常很难 在体内详细调查。 因此，对生物学的研究 在体外研究四吡咯的研究必须补充系统。 模型复合物的时间分辨和稳态的光学研究是 提议描述卟啉辅助因子的功能特性 生物系统（例如血红素蛋白和光合反应） 中心。 具体目标1是阐明电子特性，并且 兴奋的状态松弛和紧密间隔的电子转移机制 卟啉二聚体。 将研究几个四吡咯二聚体以探测键 生物络合物（例如细菌氯苯酚）的特征 特殊的反应中心。 拟议的研究将探索 电子不对称对性质和放松动力学的影响 最低激发状态，Pi-Overlap模式在定义中的作用 光物理特性和涉及强耦合的电子转移 卟啉二聚体。 特定目标2是阐明非平面大环的方式 扭曲调节静态和瞬态电子特性 四吡咯。 四吡咯辅因子的非平面畸变是 在蛋白质复合物中广泛观察到。 PI S实验室的工作已显示 这种扭曲对地面和激发状态产生了巨大影响 特性。 电子放松率和途径的研究， 光诱导的构象偏移和瞬态配体结合/释放 和其他特性将扩展到具有不同模式的卟啉 非平面分散（马鞍，荷叶边，圆顶，波），氯蛋白（叶绿素 模型）和铁卟啉（血红素模型）。 互补的超快时间 解决的振动研究将提供直接的结构信息。 那里 对于平面卟啉的研究很少，没有平面的研究 复合物。 合并的研究将为您提供基本见解 四吡咯辅因子在体内的功能和光谱特性。