Synthesis of Me BICAAC Supported Si(III) Radicals and a Silylone via Reduction Route From Me BICAAC-Si(IV) Precursors.

Past one decade has witnessed a tremendous growth in the field of carbene stabilized low-valent silicon compounds unravelling very exciting properties of these molecules. Herein, we have employed a bicyclic (alkyl)(amino)carbene, ( ^Me BICAAC) to explore the low-valent chemistry of silicon. The reduction of bicyclic (alkyl)(amino)carbene-SiCl ₄ complex, [( ^Me BICAAC)SiCl ₄ ] (1) with KC ₈ afforded low-valent Si complexes, including Si(III) radical [( ^Me BICAAC)SiCl ₃ ] (2) and a complex with silicon center in a formal zero-valent state, [( ^Me BICAAC) ₂ Si] (3). Similarly, the reduction of in-situ generated ^Me BICAAC adduct of Me ₂ SiCl ₂ with one equivalent of KC ₈ led to the formation of [( ^Me BICAAC)SiMe ₂ Cl] (4) complex having an unpaired electron. These complexes have been characterized by IR, UV-Vis., NMR, HRMS, EPR and their solid-state structures were also elucidated by single crystal X-ray crystallography. Further, DFT calculations revealed the lower energy singlet state for complexes 1, 3 and doublet state for complexes 2, 4.
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