Bimetallic, Silylene-Mediated Multielectron Reductions of Carbon Dioxide and Ethylene.
Angewandte Chemie (International ed. in English)
A metal/ligand cooperative approach to reduction of small molecules by metal silylene complexes (R2Si=M) is demonstrated, whereby silicon activates the incoming substrate and mediates net two-electron transformations via one-electron redox processes at two metal centers. An appropriately tuned cationic pincer cobalt(I) complex featuring a central silylene donor reacts with CO2 to afford a bimetallic siloxane featuring two Co(II) centers with liberation of CO, and reaction with ethylene yields a similar bimetallic complex with an ethylene bridge. Experimental and computational studies suggest a plausible mechanism proceeding via [2+2]-cycloaddition to the silylene complex that is quite sensitive to steric environment. The Co(II)/Co(II) products are further reactive to oxidation and reduction. Taken together, these findings demonstrate a strategy for metal/ligand cooperative small-molecule activation that is well-suited to 3d metals.
View details for DOI 10.1002/anie.202011489
View details for PubMedID 32991759
- Cooperative CO2 Scission by Anomalous Insertion into a Rh-Si Bond ORGANOMETALLICS 2019; 38 (22): 4420–32
- Synthesis and Reactivity of Pincer-Type Cobalt Silyl and Silylene Complexes ORGANOMETALLICS 2018; 37 (21): 3956–62
Silylene-assisted hydride transfer to CO2 and CS2 at a [P2Si]Ru pincer-type complex
2017; 46 (43): 14757–61
The synthesis and characterization of base-stabilized and base-free pincer-type bis(phosphine)/silylene [P2Si]Ru complexes are reported. The base-free complex readily reduces CO2 and CS2via silylene-assisted hydride transfer, affording structurally distinct products with silicon-to-ruthenium formate and dithioformate bridges.
View details for DOI 10.1039/c7dt03659k
View details for Web of Science ID 000414775000009
View details for PubMedID 29052677