Activation of C-H and B-H bonds through sigma-bonding to Cobalt complexes

通过广泛研究4d和5d金属配合物的C-H活化和氨基硼烷的脱氢偶联，将知识应用于3d金属，特别是钴。一系列新型催化剂将被合成、表征并用于催化，重点是脱氢偶联和碳氢活化过程，特别是西格玛-烷烃配合物的生成。在这些过程中使用3d金属是相对未开发的，并提供了许多科学和技术机会。胺硼烷由于其广泛的潜在用途而受到了广泛的关注：作为储氢和运输载体，作为陶瓷BN薄膜的前驱体，以及作为具有潜在有趣性质的聚合物的前驱体。大多数报道的胺硼烷脱氢偶联催化剂是基于4d和5d金属的，对钴配合物的研究有限。所研究的少数钴样品对聚氨基硼烷目标产物的活性和选择性较低，并且定义不清。通过将先前对铑和铱基催化剂的研究应用于钴基体系，新的、高活性的配合物将被分离、表征并用于催化。在此之后，详细的机理研究将导致深入了解这种以前正在研究的催化剂类别。这些相同的复合物在C-H活化中也应该表现出有趣的行为。由于其在天然气转化为化工原料和天然产物合成中的潜在应用，碳氢化合物活化一直是广泛研究的焦点。同样，大部分工作都是使用4d和5d金属配合物进行的。Weller小组的一个重点是在C-H活化过程中作为中间体的低价西格玛-烷烃络合物的分离。该小组进行了单晶固气反应，分离出了一些铑基西格玛烷烃配合物。将同样的方法应用于钴，可以合成三维西格玛-烷烃配合物，这将是该领域具有里程碑意义的重大发现。该项目属于EPSRC物理科学研究领域，更具体地说，属于催化研究的重点。据估计，催化目前每年为英国经济贡献超过500亿英镑，进一步发展对向可持续社会转型至关重要。

By applying knowledge gained from the extensive research into 4d and 5d metal complexes for C-H activation and dehydrocoupling of amino borane, to 3d metals, especially cobalt. A range of novel catalysts will be synthesised, characterised and used in catalysis with a focus upon dehydrocoupling and C-H activation processes and in particular the generation of sigma-alkane complexes. The use of 3d metals in these processes is relatively unexplored and offers many scientific and technological opportunities. Amine boranes have received considerable recent attention due to the range of their potential uses: as a hydrogen storage and transport vector, as precursors for ceramic BN thin-films, and as precursors to polymers with potentially interesting properties. The majority of reported catalysts for dehydrocoupling of amine boranes are based on 4d and 5d metals, with limited research addressed towards finding examples of cobalt complexes. The few cobalt examples investigated have low activity and selectivity for the polyaminoborane target product and are ill defined. By applying previous research into rhodium and iridium based catalysts to cobalt based systems new, highly active, complexes will be isolated, characterised and used in catalysis. Following this with detailed mechanistic studies will lead to insight into this previously under investigated class of catalyst. These same complexes should also display interesting behaviour in C-H activation. Due to its potential applications in the transformation of natural gas into chemical feedstocks, and in natural product synthesis, C-H activation has been the focus of extensive research. Again, most of this work has been carried out using 4d and 5d metal complexes. A focus within the Weller group has been on the isolation of the low valent sigma-alkane complexes as an intermediate in C-H activation processes. The group has carried out single-crystal solid-gas reactions which have led to the isolation of a number of rhodium based sigma-alkane complexes. Application of this same methodology to cobalt could allow the synthesis of 3d sigma-alkane complexes, which would be a significant landmark discovery in the area. This project falls within the EPSRC Physical Science research area, more specifically within the focus of catalysis. It is estimated that catalysis currently contributes over £50 billion/year to the UK economy, and further development is essential for transformation towards a sustainable society.