Cooperativity in boron- and carbon-based pincer complexes

在这个项目中，我们计划利用过渡金属配合物与硼基和碳基螯合型配体开发一种新的金属-配体协同键激活模式，并在均相催化中应用。我们发现这种类型的碳二磷酸基（CDP）铑配合物通过最初的氧化加成和随后的第二个c - cl键的协同裂解与有机生发二氯化物反应。所得到的铑（III）配合物形式上含有一个cdp稳定的碳作为配体。这些配体的不寻常的结合情况将详细研究一些相关的配合物。生发二卤素的配合键活化将在其他有机二卤素以及13族和14族元素的二氯化物中进行研究。在这些实验的基础上，我们打算使用（可持续的）还原剂开发催化反应，从活化产物中再生铑(I)-物种并诱导二氧化碳转移。相应的硼基配合物的合成，形式上包含一个配体稳定的硼化物作为配体，是一个主要的挑战。我们将通过为中心硼原子开发合适的稳定环境，并将其与合适的金属碎片和配体球体结合来解决这一挑战。所得到的配合物的反应性和催化活性将相对于相应的基于cdp的配合物进行研究。

In this project we plan to develop a new mode of metal-ligand cooperative bond activation with implications for applications in homogeneous catalysis, using transition metal complexes with boron- and carbon-based pincer-type ligands. We found that carbodiphosphorane-based (CDP) rhodium(I) complexes of this type react with organic germinal dichlorides via initial oxidative addition and subsequent cooperative cleavage of the second C–Cl-bond. The resulting rhodium(III) complexes formally contain a CDP-stabilized carben as ligand. The unusual bonding situation in these ligands will be investigated in detail for a number of related complexes.The cooperative bond activation of germinal dihalogenes will be investigated for other organic dihalogenes as well as for dichlorides of group 13 and 14 elements. On the basis of these experiments we intend to develop catalytic reactions using (sustainable) reductants that regenerate a rhodium(I)-species from the activation products and induce a carbene transfer. The synthesis of corresponding boron-based complexes, that formally contain a ligand-stabilized boride as ligand, represents a major challenge. We are going to address this challenge by developing a fitting stabilizing environment for the central boron atoms and combining it with suitable metal fragments and ligand spheres. The reactivity and catalytic activity of the resulting complexes will be investigated with respect to the corresponding CDP-based complexes.