New Redox Tags For Bioorganometallic Chemistry and Electrode Modification

在化学测量和成像（CMI）项目和化学系化学结构、动力学和机制（CSDM）项目的支持下，佛蒙特大学的William Geiger教授和他的团队正在寻找有机金属氧化还原标签在医学成像和表面科学中的应用的新方向。它利用了通过环戊二烯（Cp）或环丁二烯（Cb）环与分子底物或导电表面结合的强红外活性“钢琴凳子”标签的单电子氧化。在标记之前或之后，一个或多个羰基配体可以通过“氧化还原开关”被供体配体取代，以操纵标签的化学和物理效应，包括E1/2电位、红外频率、亲脂性和拓扑结构。一个关键的目标是为化学和生物群落提供一个分子拓宽的工具箱，有机金属氧化还原标签具有显著的红外光谱特征，甚至可以在细胞水平上进行氧化还原和红外成像。将对化合物进行阳极氧化研究，其中MCp(CO)3 （M = Mn, Re）基团被标记到他莫昔芬上作为模型，首次允许对生物系统中有机金属标签的位置和氧化还原状态进行成像。钢琴凳与电极的共价连接也将进行，目的是提供一组分子多样化的强红外活性有机金属单层的入口。与康奈尔大学能源材料中心合作，将使用先进的表面分析方法来表征通过环附加键附着在碳上的钢琴凳化合物。将开展前所未有的有机金属单层中co取代率、离子配对效应和单体/二聚体平衡的研究，增加我们对表面结合有机金属的反应性的理解。这项研究的成功可能会导致一种新的细胞成像方法的基础，其中分子标签的氧化还原状态可以作为时间和地点的函数来跟踪。提出的创新有机金属电接枝方法将扩大化学修饰导电表面的分子可能性，以及它们可能应用于催化，腐蚀，复合材料，传感器和能源需求的方式。与巴黎高等教育学院以及与南非自由邦大学的Jannie Swarts教授和其他学生和教师的密切合作将为该计划提供国际推广的一个方面。通过在佛蒙特大学（UVM）的SEED项目实习，以及从芝加哥州立大学或新墨西哥大学招募的非裔美国人或西班牙裔暑期研究实习生，将解决代表性不足群体的扩大问题。

With support from the Chemical Measurement and Imaging (CMI) Program the Chemical Structure, Dynamics and Mechanisms (CSDM) Program in the Division of Chemistry, Professor William Geiger and his group at the University of Vermont are seeking to identify new directions in the application of organometallic redox tags to medical imaging and to surface science. It takes advantage of the one-electron oxidation of strongly IR-active "piano-stool" tags bonded to molecular substrates or to conducting surfaces through their cyclopentadienyl (Cp) or cyclobutadiene (Cb) rings. Before or after tagging, one or more carbonyl ligands can be substituted by donor ligands using "redox switching" to manipulate both the chemical and physical effects of the tag, including E1/2 potential, IR frequency, lipophilicity, and topology. A key goal is to provide to the chemical and biological communities a molecularly broadened toolbox of organometallic redox tags having a dramatic IR spectroscopic signature, allowing redox and IR imaging even at the cellular level. Anodic oxidative studies will be carried out for compounds in which MCp(CO)3 (M = Mn, Re) groups are tagged to tamoxifen as a model to allow, for the first time, imaging of both the location and redox state of organometallic tags in biological systems. Covalent attachment of piano-stools to electrodes will also be carried out for the purpose of providing entry to a molecularly diverse set of strongly IR-active organometallic monolayers. Piano-stool compounds anchored via cycloadditon click attachment to carbon will be characterized using advanced surface analysis methods in collaboration with the Energy Materials Center at Cornell University. Unprecedented studies of CO-substitution rates, ion-pairing effects, and monomer/dimer equilibria in organometallic monolayers will be carried out, increasing our understanding of the reactivities of surface-bound organometallics. Success in the proposed research could lead to the basis of a new approach to cell imaging, one in which the redox state of a molecular tag can be followed as a function of time and place. The proposed innovative organometallic electro-grafting methods will broaden the molecular possibilities for chemically-modified conducting surfaces, and the ways in which they may be applied to needs in catalysis, corrosion, composite materials, sensors, and energy. Strong collaborations with ENS Paris and with Prof. Jannie Swarts and other students and faculty at the University of the Free State in South Africa will provide an aspect of international outreach to the program. Expansion of the pool of underrepresented groups will be addressed through Project SEED internships at the University of Vermont (UVM) and by inclusion of African-American or Hispanic summer research interns at UVM recruited from either Chicago State University or the University of New Mexico.