Generation of Bis(ferrocenyl)silylenes from Siliranes

Divalent silicon species, the so-called silylenes, represent attractive organosilicon building blocks. Isolable stable silylenes remain scarce, and in most hitherto reported examples, the silicon center is stabilized by electron-donating substituents (e.g., heteroatoms such as nitrogen), which results in electronic perturbation. In order to avoid such electronic perturbation, we have been interested in the chemistry of reactive silylenes with carbon-based substituents such as ferrocenyl groups. Due to the presence of a divalent silicon center and the redox-active transition metal iron, ferrocenylsilylenes can be expected to exhibit interesting redox behavior. Herein, we report the design and synthesis of a bis(ferrocenyl)silirane as a precursor for a bis(ferrocenyl)silylene, which could potentially be used as a building block for redox-active organosilicon compounds. It was found that the isolated bis(ferrocenyl)siliranes could be a bottleable precursor for the bis(ferrocenyl)silylene under mild conditions.

A Redox-Active Bis(ferrocenyl)germylene and Its Reactivity

Bis(ferrocenyl)germylene Fc*₂ Ge: [2; Fc*=2,5-bis(3,5-di-tert-butylphenyl)-1-ferrocenyl] was isolated in the form of red crystals from the reaction of the sterically demanding ferrocenyl lithium dimer (Fc*Li)₂ and GeI₂ . Bis(ferrocenyl)germylene 2 exhibits extraordinary thermal stability in hydrocarbon solution and the solid state, as well as stable redox behavior. Moreover, it undergoes a ligand-redistribution reaction with GeCl₂ ⋅(dioxane) to afford the corresponding chlorogermylene, which was isolated upon coordination with PBu₃ .