STM and STS Studies of the Structures and Energetics of Axial Ligand Coordination to Metal Porphyrins at the Liquid-Solid Interface

液固界面金属卟啉轴向配体配位的结构和能量的 STM 和 STS 研究

• 批准号: 1112156
• 负责人: Ursula Mazur
• 金额: $ 41.9万
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1112156&HistoricalAwards=false
• 关键词: STM; STS; Studies; Structures; Energetics

The Chemical Structure, Dynamics and Mechanisms Program of the Chemistry Division supports Professor Ursula Mazur at the Washington State University for studies of axial ligand coordination to metal porphyrins (MPs) at the liquid-solid interface. Systematic studies will be performed on the reactions of MPs with an axially coordinated ligand and the electronic orbital structures and energies in these systems will be mapped using scanning tunneling microscopy (STM). These studies will measure deviations from planarity of the MP induced by ligand attachment, identify and map both the metal and the ligand orbitals in the MP complexes, compare the observed density of states for the MP systems to model electronic calculations, and measure kinetics in cases where MP ligand association/dissociation occurs on the time scale of minutes. This research will contribute information about the structure and electronic state changes associated with the ligation of planar and non-planar metal porphyrins with varying occupation of the metal 3d orbitals. Investigations of the connection between porphyrin conformational flexibility and the structural/electronic characteristics of an axially ligated complex are generally applicable to distorted metallo-tetrapyrroles and therefore, relevant to a variety of biologically and biomimetically important processes.Metalloporphyrins perform many versatile functions including light harvesting, electron and energy transfer, catalysis, and act as receptors in molecular recognition. Many of these functions depend on some species (called an axial ligand) interacting with the MP. The attachment of an axial ligand to the MP induces changes in the electronic structure of both the porphyrin and the ligand. Identifying the structural and electronic behavior of the MP during ligation/de-ligation processes is crucial for the understanding of the catalytic and recognition functions of MPs. This project will diverse graduate and undergraduate students in surface science, surface microscopy and spectroscopy, and the basic concepts of coordination chemistry. The proposed research will be used as an educational vehicle for an outreach effort to underrepresented Native American and Hispanic high school students. Mentoring relationships with off-campus science and engineering leaders will provide training, mentorship, and facilitate the formation of collaborative research efforts.

化学部门的化学结构、动力学和机制项目支持华盛顿州立大学的Ursula Mazur教授在液-固界面上与金属卟啉（MPs）的轴向配位研究。系统地研究了MPs与轴配体的反应，并利用扫描隧道显微镜（STM）绘制了这些系统中的电子轨道结构和能量。这些研究将测量由配体附着引起的MP平面度偏差，识别和绘制MP配合物中的金属轨道和配体轨道，比较观察到的MP系统的状态密度来模拟电子计算，并测量MP配体结合/解离发生在分钟时间尺度上的动力学。本研究将有助于揭示平面和非平面金属卟啉的结构和电子态的变化与金属三维轨道占有的不同有关。卟啉构象柔韧性与轴向连接络合物的结构/电子特性之间的联系的研究通常适用于扭曲的金属四吡啶，因此，与各种重要的生物学和仿生学过程相关。金属卟啉具有多种功能，包括光收集、电子和能量转移、催化以及在分子识别中充当受体。许多这些功能依赖于一些物种（称为轴向配体）与MP相互作用。轴向配体附着在MP上引起卟啉和配体电子结构的变化。在连接/去连接过程中识别MPs的结构和电子行为对于理解MPs的催化和识别功能至关重要。本项目将招收表面科学、表面显微学和光谱学以及配位化学基本概念方面的研究生和本科生。这项拟议的研究将作为一种教育工具，用于向代表性不足的美洲原住民和西班牙裔高中学生推广。与校外科学和工程领导者的指导关系将提供培训、指导，并促进合作研究努力的形成。