Merging Pincer Motifs and Potential Metal-Metal Cooperativity in Cobalt Dinitrogen Chemistry: Efficient Catalytic Silylation of N₂ to N(SiMe₃ )₃.

ABSTRACT: Using a pyrazolate-bridged dinucleating ligand that provides two proximate pincer-type PNN binding sites ("two-in-one pincer"), different synthetic routes have been developed towards its dicobalt(I) complex 2 that features a twice deprotonated ligand backbone and two weakly activated terminal N₂ substrate ligands directed into the bimetallic pocket. Protonation of 2 is shown to occur at the ligand scaffold and to trigger conversion to a tetracobalt(I) complex 4 with two end-on μ_1,2 -bridging N₂ ; in THF 4 is labile and undergoes temperature-dependent N₂ /triflate ligand exchange. These pyrazolate-based systems combine the potential of exhibiting both metal-metal and metal-ligand cooperativity, viz. two concepts that have emerged as promising design motifs for molecular N₂ fixation catalysts. Complex 2 serves as an efficient (pre)catalyst for the reductive silylation of N₂ into N(SiMe₃ )₃ (using KC₈ and Me₃ SiCl), yielding up to 240 equiv N(SiMe₃ )₃ per catalyst.

SUBMITTER: Li M 

PROVIDER: S-EPMC8251579 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature