A Stable N-Heterocyclic Silylene with a 1,1′-Ferrocenediyl Backbone

The N-heterocyclic silylene [{Fe(η⁵-C₅H4-NDipp)₂}Si] (1DippSi, Dipp=2,6-diisopropylphenyl) shows an excellent combination of pronounced thermal stability and high reactivity towards small molecules. It reacts readily with CO₂ and N₂O, respectively affording (1DippSiO₂)₂C and (1DippSiO)₂ as follow-up products of the silanone 1DippSiO. Its reactions with H₂O, NH₃, and FcPH₂ (Fc=ferrocenyl) furnish the respective oxidative addition products 1DippSi(H)X (X=OH, NH₂, PHFc). Its reaction with H₃BNH₃ unexpectedly results in B−H, instead of N−H, bond activation, affording 1DippSi(H)(BH₂NH₃). DFT results suggest that dramatically different mechanisms are operative for these H−X insertions.