Deegan Meaghan M, Hannoun Kareem I, Peters Jonas C
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
Angew Chem Int Ed Engl. 2020 Dec 7;59(50):22631-22637. doi: 10.1002/anie.202009814. Epub 2020 Oct 2.
The prototypical reactivity profiles of transition metal dihydrogen complexes (M-H ) are well-characterized with respect to oxidative addition (to afford dihydrides, M(H) ) and as acids, heterolytically delivering H to a base and H to the metal. In the course of this study we explored plausible alternative pathways for H activation, namely direct activation through H-atom or hydride transfer from the σ-H adducts. To this end, we describe herein the reactivity of an isostructural pair of a neutral S= and an anionic S=0 Co-H adduct, both supported by a trisphosphine borane ligand (P ). The thermally stable metalloradical, (P )Co(H ), serves as a competent precursor for hydrogen atom transfer to Bu ArO . What is more, its anionic derivative, the dihydrogen complex [(P )Co(H )] , is a competent precursor for hydride transfer to BEt , establishing its remarkable hydricity. The latter finding is essentially without precedent among the vast number of M-H complexes known.
过渡金属二氢配合物（M-H）的典型反应活性概况在氧化加成（生成二氢化物，M(H)）方面以及作为酸将H异裂地传递给碱和将H传递给金属方面都有很好的表征。在本研究过程中，我们探索了H活化的可能替代途径，即通过H原子或氢化物从σ-H加合物转移进行直接活化。为此，我们在此描述了一对同构的中性S= 和阴离子S=0 Co-H加合物的反应活性，二者均由三膦硼烷配体（P ）支撑。热稳定的金属自由基（P ）Co(H )可作为将氢原子转移至 Bu ArO 的合适前体。此外，其阴离子衍生物二氢配合物[(P )Co(H )] 是将氢化物转移至BEt 的合适前体，证实了其显著的亲水性。后一发现基本上在已知的大量M-H配合物中尚无先例。
