Cooperativity in boron- and carbon-based pincer complexes

在这个项目中，我们计划开发一种新的金属-配体合作键激活模式，这一模式在均相催化中的应用具有重要意义，使用的是过渡金属与硼和碳钳型配体的配合物。我们发现这类基于碳二磷烷(CDP)的Rh(I)络合物通过初始氧化加成和随后第二个C-Cl-键的协同断裂与有机生发二氯发生反应。得到的Rh(III)络合物正式含有CDP稳定的碳苯作为配体。对于一些相关的络合物，将详细研究这些配体中的不寻常的成键情况。生发二卤代的协作键活化将被研究用于其他有机二卤代以及第13和14族元素的二氯化物。在这些实验的基础上，我们打算开发使用(可持续的)还原剂的催化反应，从活化产物中再生一个Rh(I)物种并诱导卡宾转移。相应的硼基配合物的合成是一个主要的挑战，因为它正式地包含一个配体稳定的硼化物作为配体。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位体球体结合来应对这一挑战。与相应的基于CDP的络合物相比，将考察得到的络合物的反应性和催化活性。

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.