(NHC)Si═C═N-R: A Two-Coordinated Si⁰-Isocyanide Compound as Si(NHC) Transfer Reagent

Area of Science:

• Organosilicon Chemistry
• Main Group Chemistry
• Carbene Chemistry

Background:

• Two-coordinated silicon compounds are rare and possess unique electronic properties.
• N-heterocyclic carbenes (NHCs) are versatile ligands for stabilizing reactive species.
• Isocyanide ligands can stabilize low-valent main group elements.

Purpose of the Study:

• To synthesize and characterize the first two-coordinated silicon(0)-isocyanide compound.
• To investigate the structural, bonding, and reactivity of this novel compound.
• To explore its potential as a silicon transfer agent.

Main Methods:

• Two-step synthesis involving reduction of a silyliumylidene salt with KC8.
• Bromide abstraction from SiBr2(SIDipp) using Na[B(ArF)4] and ArMesNC.
• Characterization using experimental (NMR, X-ray crystallography) and theoretical (DFT) methods.

Main Results:

• Successful synthesis of the two-coordinated silicon(0)-isocyanide compound (SIDipp)Si═C═N-ArMes (1).
• Compound 1 exhibits a V-shaped geometry at the Si(0) center and a bent Si═C═N core.
• The compound possesses axial chirality, existing as two rapidly interconverting enantiomers in solution.
• Compound 1 demonstrated utility as a Si(SIDipp) transfer agent, synthesizing a germasilyne.

Conclusions:

• The first stable two-coordinated silicon(0)-isocyanide compound has been synthesized and characterized.
• The compound's unique structure and bonding were elucidated through experimental and theoretical studies.
• Its reactivity as a silicon transfer agent opens new avenues in silicon chemistry.