Metal-Catalyzed Diradical Reactivity: From Fundamental Thermal- and Photo-Chemistry to Novel Nanomaterials

金属催化的双自由基反应：从基础热化学和光化学到新型纳米材料

• 批准号: 1265703
• 负责人: Jeffrey Zaleski
• 金额: $ 40.3万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1265703&HistoricalAwards=false
• 关键词: Metal; Catalyzed; Diradical; Reactivity; Fundamental

In a project entitled "Metal-Catalyzed Diradical Reactivity: From Fundamental Thermal- and Photo-Chemistry to Novel Nanomaterials," the Chemical Catalysis (CAT) program supports Professor Jeffrey M. Zaleski at Indiana University to probe the geometric and electronic factors that control metal-catalyzed and photochemical diradical generation by the Bergman cyclization. Three primary structure types are investigated: 1) combined sigma/pi complexes where activation is geometrically controlled through the sigma bonds and electronically via the pi-system. Structures in this theme examination of catalytic Bergman vs. Myers-Saito cyclization pathways that are important to radical-mediated chemical transformations; 2) construction of large chromophoric assemblies that use thermal and photochemical Bergman cyclizations to fuse ring systems catalytically to form optically responsive molecules; and 3) incorporation of these reactive ligand sets into large nanoassemblies that can be activated to form all carbon frameworks by template vaporization. These three architectural classes carry both a fundamental research question to be addressed as well as a potential broader impact from the final architectures and reactions. Thermal reaction pathways are evaluated using standard synthetic methodology such as NMR, crystallography, and spectroscopic characterization of reaction intermediates. Optical properties of chromophoric products are examined using nanosecond and ultrafast lifetime and transient absorption methods, while characterization of nanoarchitectures is conducted mainly using electron microscopy.This research impacts chemical catalysis methodology for constructing new molecules using metal/radical mediated reactions, which is a fundamental need in the chemical community. The chromophore assembly component of the work builds new constructs that can be used as chemical sensors, or for light harvesting in solar energy conversion. The nanomaterial aspect of the project generates reactions on nanoscale surfaces to create new, higher-order assemblies that have potential applications in molecular electronics and ultralight pure carbon electronic arrays. From an educational perspective, the research helps to train students in a combined fundamental science/application approach to chemistry that spans synthesis and high-tech measurements. Students at all levels from undergraduate to postdoctoral, including those from underrepresented minorities programs at IU, benefit from exposure to a range of research challenges and diversities of solution. Some of the work is outreached to local schools to entice young minds to pursue degrees in science.

在一个名为“金属催化的双自由基反应：从基本的热化学和光化学到新型纳米材料”的项目中，化学催化（CAT）项目支持印第安纳大学的Jeffrey M. Zaleski教授探索通过Bergman环化控制金属催化和光化学双自由基生成的几何和电子因素。研究了三种主要的结构类型：1)组合的sigma/pi配合物，其激活是通过sigma键和pi系统在几何上控制的。在本主题的结构检查催化伯格曼与迈尔斯-齐藤环化途径是重要的自由基介导的化学转化；2)构建大型发色团，利用热和光化学伯格曼环化催化融合环系统形成光学响应分子；3)将这些反应性配体组合结合到大型纳米组件中，这些纳米组件可以通过模板蒸发激活形成所有的碳框架。这三个架构类既包含要解决的基本研究问题，也包含最终架构和反应的潜在更广泛的影响。热反应途径评估使用标准的合成方法，如核磁共振，晶体学和光谱表征的反应中间体。通过纳秒、超快寿命和瞬态吸收方法检测了致色产物的光学性质，而纳米结构的表征主要通过电子显微镜进行。本研究对金属/自由基介导反应构建新分子的化学催化方法产生了影响，这是化学学界的基本需求。这项工作的发色团组装组件构建了新的结构，可以用作化学传感器，或用于太阳能转换中的光收集。该项目的纳米材料方面在纳米级表面上产生反应，以创建新的高阶组件，这些组件在分子电子学和超轻纯碳电子阵列中具有潜在的应用前景。从教育的角度来看，这项研究有助于培养学生在化学基础科学/应用方法的结合，涵盖合成和高科技测量。从本科生到博士后的各个层次的学生，包括那些来自印第安纳大学代表性不足的少数民族项目的学生，都受益于一系列的研究挑战和多样化的解决方案。其中一些工作延伸到当地学校，以吸引年轻人攻读科学学位。