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

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）计划支持杰弗里·M·Zaleski在印第安纳州大学的研究，以探索几何和电子因素，控制金属催化和光化学双自由基的生成伯格曼环化。研究了三种主要结构类型：1）组合的σ/π复合物，其中活化通过σ键几何控制，并通过π系统电子控制。 结构在这个主题检查的催化Bergman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）建设大型发色团的组件，使用热和光化学Bergman环化融合环系统催化形成光学响应分子;和3）将这些反应性配体组结合到大的纳米组装体中，所述纳米组装体可以通过模板蒸发活化以形成所有的碳骨架。 这三个架构类既包含了一个需要解决的基础研究问题，也包含了最终架构和反应的潜在更广泛的影响。 热反应途径使用标准的合成方法，如NMR，晶体学和反应中间体的光谱表征进行评估。 利用纳秒和超快寿命和瞬态吸收方法研究发色产物的光学性质，而纳米结构的表征主要是利用电子显微镜进行的。这项研究影响了利用金属/自由基介导的反应构建新分子的化学催化方法，这是化学界的基本需求。 这项工作的发色团组装部分构建了新的结构，可用作化学传感器，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。 从教育的角度来看，这项研究有助于培养学生在综合基础科学/应用方法的化学，跨越合成和高科技测量。 从本科到博士后的各个层次的学生，包括来自IU代表性不足的少数民族项目的学生，都受益于一系列研究挑战和解决方案的挑战。 一些工作延伸到当地学校，以吸引年轻人攻读科学学位。

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.