Site-selective functionalization of Si₆R₆ siliconoids

Area of Science:

• Inorganic Chemistry
• Organosilicon Chemistry
• Materials Science

Background:

• Partially substituted neutral silicon clusters (siliconoids) exhibit unique structures and electronic properties similar to silicon surfaces.
• The global minimum Si₆R₆ siliconoid is thermodynamically stable, analogous to benzene.

Purpose of the Study:

• To report the selective 2-lithiation of the global minimum Si₆R₆ siliconoid.
• To introduce a novel nomenclature for distinguishing vertices in the Si₆R₆ scaffold.
• To synthesize and characterize various 2-functionalized Si₆ clusters.

Main Methods:

• Selective 2-lithiation of the Si₆R₆ siliconoid.
• Reaction of the 2-lithiated cluster with electrophiles: Me₃SiCl, SiCl₄, H₃B·SMe₂, (Me₂N)₂PCl, and RCOCl.
• Characterization of products using solution and solid-state techniques.

Main Results:

• Successful selective 2-lithiation of Si₆R₆ at a different position than the known 4-lithiated isomer.
• Synthesis of various 2-functionalized Si₆ clusters, including silylated, phosphinidene, and acylated derivatives.
• Structural and spectroscopic analysis revealed the influence of the functional group's position.

Conclusions:

• The study demonstrates a new synthetic route for regioselective functionalization of Si₆R₆ siliconoids.
• The proposed nomenclature aids in understanding the structure-property relationships of these silicon clusters.
• This work contributes to the development of novel silicon-based materials with tunable electronic properties.