Facile activation of inert small molecules using a 1,2-disilylene

Abstract

Reactions of the known amidinate stabilised 1,2-disilylene, [{ArC(NDip)₂}Si]₂1 (Dip = 2,6-diisopropylphenyl, Ar = 4-C₆H₄Bu^t) with a series of inert, unsaturated small molecule substrates have been carried out. Compound 1 reduces Bu^tNC: to give the singlet biradicaloid 1,3-disilacyclobutanediyl [{ArC(NDip)₂}Si(μ-CNBu^t)]₂3, which can be oxidised by 1,2-dibromoethane to give [{ArC(NDip)₂}(Br)Si(μ-CNBu^t)]₂4. Disilylene 1 reduces two molecules of ethylene to give an unprecedented disilabicyclo[2.2.0]hexane, [{ArC(NDip)₂}Si(μ-C₂H₄)]₂5. In contrast, only one molecule of ethylene inserts in the Ge–Ge bond of the digermylene analogue of 1, viz. [{ArC(NDip)₂}Ge]₂6, leading to the formation of the bis(germylene), [{ArC(NDip)₂}Ge]₂(μ-C₂H₄) 7. Compound 1 reduces CO₂, generating CO, and the oxo/carbonate-bridged disilicon(IV) system, {ArC(NDip)₂}Si(μ-CO₃)₂(μ-O)Si{(NDip)₂CAr} 10, while its reaction with N₂O proceeds via generation of N₂, and a hydrogen abstraction process, to give the oxo/hydroxy disilicon(IV) species, [{ArC(NDip)₂}(HO)Si(μ-O)]₂11. This study highlights new small molecule activation chemistry for 1,2-disilylenes, which could lead to further adoption of compound 1 as a potent reducing reagent for the transformation of inert unsaturated molecules into value added products.