Bond Forming Reactions at High Coordinate and Polynuclear Transition Metal Clusters

无机、生物无机和有机金属化学项目的目标是发现使用过渡金属作为形成化学键模板的新方法。这类研究对于设计化学合成催化剂和模拟金属酶的作用具有重要意义。该项目的重点是在过渡金属配合物中紧密定位的配体之间的还原偶联、氧化偶联和对映体C-C键形成（例如，催化共轭加成）。具有线性配体的高配位早期过渡金属配合物（CO、CNR、-CCR等）为还原偶联化学提供了反应通道。氧化偶联将通过融合两个氧中心三角形金属聚集体（m30， M=Fe, Mn, Cr, Ru）或两个di（mu2）二氧锰单元提供的多金属支架进行探索，后者提供了一种新的方法来模拟光系统II的二氧演化复合体中的四锰中心。在对称（含两对氮供体）或不对称（含一对磷化氢供体和一组三氮供体）双核大环的两极上，与两个相同或不同金属中心结合的配体之间，将进行新的催化和化学计量C-C键形成反应。这些研究的结果将对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提供见解，并将导致具有基本兴趣和合成用途的新分子。

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.