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

化学合成（SYN）计划中的这一奖项支持了Jeffrey 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生成的伯格曼环化。 不寻常的二炔-烯化学官能团经历环化以形成高度反应性的双自由基中间体，其可以引发并参与聚合反应，以及与化学底物经历自由基反应。 可以通过选择金属催化剂和结合的烯二炔基序的结构，或者通过用于用光引发反应的发色团的性质来控制反应。 四个化学系统，跨越不同的建筑类的分子，从大卟啉发色团到小无机分子和涂层纳米粒子将准备和他们的反应性检查。 配合物的结构和它们的电子性质将与生成有效的双自由基所需的活化能相关。 最简单的系统的参数将被用来筛选它们对化学底物的反应性。结果可能最终有助于自由基在合成化学中的应用，以及在缺氧环境中用于磁疗或光疗的先进化学试剂。 该项目在合成和光谱学方面也是多方面的，因此在制备和机械化学基础上培养本科生和研究生。

This award in the Chemical Synthesis (SYN) program supports work by Professor Jeffrey M. Zaleski at Indiana University to probe the geometric and electronic factors that control metal-catalyzed and photochemical diradical generation by Bergman cyclization. The unusual diyne-ene chemical functionality undergoes cyclization to form a highly reactive diradical intermediate that can trigger and participate in polymerization reactions, as well as undergo radical reactions with chemical substrates. The reactions can be controlled by choice of metal catalyst and structure of the bound enediyne motif, or by the nature of the chromophore used to trigger the reaction with light. Four chemical systems that span different architectural classes of molecules from large porphyrin chromophores to small inorganic molecules and coated nanoparticles will be prepared and their reactivities examined. The structures of complexes and their electronic properties will be correlated with the activation energy required to generate potent diradicals. Parameters from the most facile systems will then be used to screen their reactivities against chemical substrates.The results may ultimately contribute to applications of radicals in synthetic chemistry as well as advanced chemical reagents for magneto- or phototherapy in hypoxic environments. The project is also multifaceted in synthesis and spectroscopy, and thus develops undergraduate and graduate students on both preparative and mechanistic chemical foundations.