Bond Forming Reactions at High Coordinate and Polynuclear Transition Metal Clusters

无机化学、生物无机化学和金属有机化学项目的目标是发现使用过渡金属作为形成化学键的模板的新方法。这种研究对化学合成催化剂的设计和对金属酶作用的模拟都很重要。该项目的重点是过渡金属络合物中紧密定位的配体之间的还原偶联、氧化偶联和不对称C-C键的形成(例如，催化共轭加成)。具有线性配体(CO、CNR、-CCR等)的高配位早过渡金属配合物为还原偶联化学提供了反应通道。将使用通过熔合两个氧中心三角形金属聚集体(M3O，M=Fe，Mn，Cr，Ru)或两个Di(MU2)二氧锰单元提供的多金属支架来探索氧化偶联，后者提供了一种新的方法来模拟光系统II的氧演化复合体中的四锰中心。新的催化和化学计量比的C-C键形成反应将在连接到两个相同或不同的金属中心的配体之间进行，这些金属中心位于对称的(包含两对氮施主)或不对称的(例如，包含一对膦给电子体和一组三个氮给电子体)双核大环。这些研究的结果将有助于深入了解高配位和多金属过渡金属中心如何促进有机金属和生物无机化学中的成键反应，并将导致新的基本感兴趣的分子和合成用途。

The objective of this project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is to discover new ways to use transition metals as templates for the formation of chemical bonds. Such research is important in the design of catalysts for chemical synthesis and in modelling the action of metalloenzymes. The focus of the project is on reductive coupling, oxidative coupling and enantiospecific C-C bond formation (e.g., catalytic conjugate addition) between closely positioned ligands in transition metal complexes. High coordinate early transition metal complexes with linear ligands (CO, CNR, -CCR, etc.) provide a reaction channel for reductive coupling chemistry. Oxidative coupling will be explored using the polymetallic scaffold provided by fusing two oxo-centered triangular metal aggregates (M3O, M=Fe, Mn, Cr, Ru) or two di(mu2)dioxomanganese units, the latter affording a new approach to modelling the tetramanganese center in the dioxygen evolving complex of photosystem II. New catalytic and stoichiometric C-C bond forming reactions will be carried out between ligands bonded to two identical or disparate metal centers held at the poles of symmetric (containing two pairs of nitrogen donors) or asymmetric (e.g., containing a pair of phosphine donors and a set of three nitrogen donors) binucleating macrocycles. The results of these studies will afford insights into how high coordinate and polymetallic transition metal centers promote bond forming reactions in organometallic and bioinorganic chemistry and should lead to new molecules of fundamental interest as well as synthetic utility.