Thermal and Photochemical Reactions of Transition Metal Complexes of the Nitrogen Oxides and other Small Molecules

美国国家科学基金会无机、生物无机和有机金属化学项目的这一奖项支持加州大学圣巴巴拉分校的Peter C. Ford教授继续研究涉及过渡金属配合物的氮氧化物化学的两个方面。首先，Ford教授和他的学生正在研究复杂化合物的合成和光化学性质，其中一部分含有一氧化氮（NO）的前体，该前体可以在光激发下将NO释放到目标。该复合物的第二部分是一个强吸收天线，它将用于收集光并将能量传递给NO前体。鉴于NO作为各种生化功能的调节剂的重要性，这种NO供体在哺乳动物生物学中具有潜在的应用。此外，阐明此类材料光化学性质的基本原理可以扩展到其他小分子生物调节剂的潜在递送。沿着这条路线，福特小组已经启动了一个新的项目，研究纳米材料的制备和基本的光物理行为，其中吸光天线是一个直径为2-5纳米的半导体量子点（QD）。量子点具有可调谐的光学特性，我们现在已经证明，激发量子点会导致表面NO前体的反应。正在进行的研究准备了新的材料，并将采用最先进的光物理技术来阐明这些天线将能量传递到反应中心的机制，并探索是否可以利用量子点的非线性光学特性来提高它们作为天线的有效性。该项目的另一个技术方面涉及各种氮氧化物（NOx）与铁和铜等金属在适当的配体环境中与氮氧化物的哺乳动物生物化学相关的反应。正在进行的研究正在使用低温分离和光谱学来阐明在精心控制的反应物输送和温度变化下的NOx-金属键合模式和简单反应。对溶液中反应性的相关研究允许表征反应的动力学，例如氧原子从配位氮氧化物到各种有机分子的转移反应。例如，人们对亚硝酸盐离子在生理学中的作用越来越感兴趣，目前对该物种的生物无机研究旨在更好地理解所涉及的基本化学过程。在这个奖项下进行的研究也可以作为UCSB本科生和研究生培训的模板，以及博士后学者在创造性奖学金的细微差别方面的进一步教育。与苏必利尔湖州立大学Alexei Iretskii教授的持续合作也为Iretskii博士和LSSU本科生提供了研究机会。福特小组的成员与UCBS的其他人员一起积极参与了当地K-12学校的科学推广项目。离开这个群体的本科生进入了研究生和医学院项目，博士和博士后毕业生（包括一些未被充分代表的少数民族）进入了独立的工业、政府和教师岗位，增强了美国的科学人才库。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program of the National Science Foundation supports continuing investigations by Prof. Peter C. Ford at the University of California, Santa Barbara into two aspects of nitrogen oxide chemistry involving transition metal complexes. In the first, Prof. Ford and his students are studying the synthesis and photochemical properties of complex compounds for which one part contains a precursor of nitric oxide (NO) that can release this NO to a target upon excitation with light. The second part of the complex is a strongly absorbing antenna, which will serve to gather light and transfer that energy to the NO precursor. Such NO donors have potential applications in mammalian biology given the importance of NO as a regulator of various biochemical functions. Moreover, the fundamental principles in elucidating the photochemical properties of such materials can be extended to the potential delivery of other small molecule bioregulators. Along these lines, the Ford group has initiated a new project investigating the preparation and fundamental photophysical behavior of nanomaterials in which the light absorbing antenna is a semiconductor quantum dot (QD) with diameter of 2-5 nm. Quantum dots have tunable optical properties, and we have now demonstrated that excitation of QDs leads to reactions from NO precursors at the surface. Ongoing studies prepare new materials and will employ state-of-the-art photophysical techniques to elucidate the mechanisms by which these antennas transfer energy to the reactive center and to probe whether the non-linear optical properties of QDs can be exploited to enhance their effectiveness as antennas. The other technical aspect of this project is concerned with the reactions of various nitrogen oxides (NOx) with metals such as iron and copper in appropriate ligand environments relevant to the mammalian biochemistry of the nitrogen oxides. Ongoing studies are using low temperature isolation and spectroscopy to elucidate the NOx--metal bonding modes and simple reactions under carefully controlled delivery of reactants and variation of temperatures. Related studies of the reactivity in solutions allow characterizing the dynamics of reactions such as oxygen atom transfer reactions from coordinated NOx species to various organic molecules. For example, there is increasing interest in the role of nitrite ion in physiology, and the present bioinorganic studies of this species are directed toward providing a better understanding of the fundamental chemical processes that are involved. The research performed under this award also serves as a template for the training of UCSB undergraduate and graduate students and for the further education of postdoctoral scholars in the nuances of creative scholarship. A continuing collaboration with Prof. Alexei Iretskii at Lake Superior State University (MI) also provides research opportunities for Dr. Iretskii and undergraduate LSSU students. Members of the Ford group have participated actively with other UCBS personnel in scientific outreach programs to local K-12 schools. Undergraduates leaving the group have entered graduate and medical school programs and the Ph.D. and postdoctoral graduates (including several underrepresented minorities) have moved on to independent industrial, government and faculty positions, enhancing the US scientific talent pool.