Activation of CO Using a 1,2‐Disilylene: Facile Synthesis of an Abnormal N‐Heterocyclic Silylene

摘要

Abstract Reaction of the 1,2‐disilylene, {ArC(NDip)2}Si2 1 (Dip=2,6‐diisopropylphenyl, Ar=4‐C6H4But), with CO proceeds via insertion of CO into one Si?N bond, and Si?Si bond cleavage, to cleanly give the bis(silylene), {ArC(NDip)2}Si(:)OCSi(:)(NDip)?2C￣ Ar 2, under ambient conditions. The reaction can be partially reversed when solutions of 2 are subjected to UV irradiation. The five‐membered heterocyclic fragment of 2 represents the first silicon analogue of an “abnormal” N‐heterocyclic carbene (aNHC), a view which is substantiated by a computational analysis of the compound. Reaction of 2 with Mo(CO)6 under UV light affords the chelate complex, Mo(CO)4(κ2‐Si,Si‐2) 3, while reaction with Fe(CO)5 gives the unusual silyleneyl bridged complex, {Fe2(CO)6}{μ‐Si(NDip)2CAr}2 4. The same coordination complexes can be accessed by reaction of 1 with Mo(CO)6 or Fe(CO)5 under UV light. As is the case for aNHCs, d‐block metal complexes of bis(silylene) 2 could prove useful as bespoke catalysts for organic transformations.