Silylation of N-heterocyclic carbene with aminochlorosilane and -disilane: dehydrohalogenation vs. Si–Si bond cleavage

Abstract

Reactions of the aminochlorosilane RSiHCl(2) and disilane R(2)Si(2)HCl(3) (R = (2,6-iPr(2)C(6)H(3))(SiMe(3))N) with an excess of 1,3-bis(tert-butyl)imidazol-2-ylidene resulted in the silylation of the NHC while reaction with the less hindered 1,3-diisopropyl-4,5-dimethyl-imidazol-2-ylidene yielded an NHC-stabilized aminochlorosilylene.

Silicon(II) Coordination Chemistry: N‐Heterocyclic Carbene Complexes of Si2+ and SiI+

“…[1] The ions have also been employed as implants for waveguide fabrication in lithium niobate crystals, which are of great interest for various photonic applications owing to their physical and electro-optical properties. Remarkable examples include NHC adducts of the dihalosilylenes SiX 2 (X = Cl, Br), [9] which are very valuable precursors in Si II chemistry, [9c, 10] or NHC adducts of the organohalosilylenes RSiCl (R = m-terphenyl, (2,6-diisopropylphenyl)(trimethylsilyl)amino), [11] which paved the way for the preparation of the first complexes featuring metalsilicon triple bonds. However, dicationic silicon(II) complexes are presently unknown, in marked contrast to the few germanium homologues, which were reported some years ago by K. M. Baines et al [3] This difference can be explained by the anomalous low electronegativity of silicon versus germanium, [4] which makes the isolation of silicon(II)-centered dications a highly challenging goal.…”

“…Remarkable examples include NHC adducts of the dihalosilylenes SiX 2 (X = Cl, Br), [9] which are very valuable precursors in Si II chemistry, [9c, 10] or NHC adducts of the organohalosilylenes RSiCl (R = m-terphenyl, (2,6-diisopropylphenyl)(trimethylsilyl)amino), [11] which paved the way for the preparation of the first complexes featuring metalsilicon triple bonds. Remarkable examples include NHC adducts of the dihalosilylenes SiX 2 (X = Cl, Br), [9] which are very valuable precursors in Si II chemistry, [9c, 10] or NHC adducts of the organohalosilylenes RSiCl (R = m-terphenyl, (2,6-diisopropylphenyl)(trimethylsilyl)amino), [11] which paved the way for the preparation of the first complexes featuring metalsilicon triple bonds.…”

Recent Advances in the N-Heterocyclic Carbene-Supported Chemistry of Silicon

“…In a separate study, IPr was reacted with the formal Si(III) halide dimer Cl 3 Si-SiCl 3 , resulting in clean disproportionation chemistry to afford IPr•SiCl 4 and IPr•SiCl 2 [59]. (19) with excess ImMe 2 i Pr 2 (5) [60]. The same research team explored related carbene-induced dehydrohalogenation chemistry to yield stable N-heterocyclic silylenes from parent halohydrides LSiHCl (L ¼ dianionic ligand) [61].…”

Reactivity of an NHC‐Stabilized Silylene towards Lewis Acids and Lewis Bases

“…In 2011, we reported an N‐heterocyclic carbene stabilized (NHC‐stabilized) aminochlorosilylene ArN(SiMe 3 )SiCl(I i Pr) ( 1 , Ar = 2,6‐ i Pr 2 C 6 H 3 , I i Pr = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) synthesized by dehydrochlorination under mild conditions. [6a] Compound 1 proved to be a stereo‐ and regioselective bis(silyl)ation reagent for alkynes, ketones, and nitriles . Phosphinosilylenes, which undergo controlled oxidation with dioxygen, have also been isolated from 1 by a salt‐elimination reaction .…”