Investigation of Palladium-Dioxygen Chemistry

钯双氧化学的研究

• 批准号: 0543585
• 负责人: Shannon Stahl
• 金额: $ 42.6万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-15 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0543585&HistoricalAwards=false
• 关键词: Investigation; Palladium; Dioxygen; Chemistry

This award to Professor Shannon S. Stahl at the University of Wisconsin at Madison will continue work on the selective oxidation of organic chemicals with molecular oxygen using homogeneous palladium catalysts. These reactions proceed by a two-stage mechanism consisting of (1) Pd(II)-mediated oxidation of the organic substrate and (2) reoxidation of the reduced catalyst by molecular oxygen. In order to facilitate palladium-catalyzed oxidation with O2 as the stoichiometric oxidant, the PI will investigate fundamental mechanisms of reactions between dioxygen and well-defined palladium complexes. The viability of three different mechanisms proposed for reoxidation of reduced palladium under catalytic conditions will be assessed, by preparing suitable Pd(0) or Pd(II) precursors and investigating their reactivity under aerobic conditions. Computational studies will elucidate the electronic structural contributions to these reactions. As dioxygen undergoes reversible exchange with electron-deficient alkenes, such as benzoquinone, at diiminecoordinated Pd centers, the kinetic and thermodynamic aspects of these reactions will be investigated in order to gain a better understanding of the relationship between dioxygen and alkene reactions with palladium. These studies, together with the mechanistic characterization of catalytic reactions that employ benzoquinone as the oxidant, should provide insights that will facilitate the replacement of benzoquinone with dioxygen in catalysis. Finally, the ability of benzoquinone and dioxygen to induce oxidative functionalization of Pd(II)-C bonds will be studied. The mechanistic characterization of reaction pathways will assist the development of improved methods for dioxygen-coupled turnover in palladium oxidation catalysis, which has implications for the future development of aerobic C-H oxidation methods. A collaboration with Prof. John Moore, director of the Institute for Chemical Education at the University of Wisconsin, will be undertaken to develop an Internet resource for junior high and high school science students that presents modern academic research in an accessible and educational format. Undergraduate students from traditionally underrepresented groups will be involved in the proposed research activities through the P.I.'s participation in the Undergraduate Research Scholars Program at UW-Madison.

威斯康星大学麦迪逊分校的Shannon S. Stahl教授将继续使用均匀的钯催化剂对有机化学物质的选择性氧化。这些反应是通过由（1）PD（II）介导的有机底物氧化和（2）通过分子氧对还原催化剂的再氧化进行的两阶段机制进行的。为了促进钯催化的O2作为化学计量氧化剂，PI将研究二恶英和定义明确的钯络合物之间反应的基本机制。通过准备合适的PD（0）或PD（II）前体并研究其在有氧条件下的反应性，将评估提出的三种不同机制以在催化条件下再氧化的三种不同机制的生存能力。计算研究将阐明对这些反应的电子结构贡献。由于二氧化烷烯烷基在二iiminecooriented PD中心进行了可逆交换，例如苯二醌PD中心，这些反应的动力学和热力学方面将得到研究，以便更好地了解二氧和烯烃与Palladium之间的关系之间的关系。这些研究以及采用苯喹酮作为氧化剂的催化反应的机械表征，应提供洞察力，以促进在催化中用二恶英替代苯二喹酮。最后，将研究苯喹酮和二恶英诱导PD（II）-c键氧化功能化的能力。反应途径的机械表征将有助于开发改进的钯氧化催化中二氧化偶联方法的转换方法，这对有氧C-H氧化方法的未来发展具有影响。威斯康星大学化学教育研究所主任约翰·摩尔（John Moore）的合作将为初中和高中科学专业的学生开发互联网资源，以可访问和教育的形式为现代学术研究提供了互联网资源。传统上代表性不足的团体的本科生将通过P.I.参加UW-Madison的本科研究学者计划，参与拟议的研究活动。