A Two-Coordinate Cyclic (Alkyl)(amino)silylene: Balancing Thermal Stability and Reactivity

Area of Science:

• Organosilicon Chemistry
• Main Group Chemistry
• Reactive Intermediates

Background:

• Silylenes are silicon analogs of carbenes with diverse reactivity.
• Cyclic silylenes offer unique electronic and steric properties.
• Understanding silylene electronic structure is key to predicting reactivity.

Purpose of the Study:

• Synthesize and characterize a novel two-coordinate cyclic (alkyl)(amino)silylene.
• Investigate its electronic properties and structural behavior.
• Explore its reactivity profile, including thermal and photochemical reactions.

Main Methods:

• Crystalline synthesis and isolation of the silylene.
• Spectroscopic analysis (²⁹Si NMR, UV/Vis).
• Density Functional Theory (DFT) calculations.
• Reactivity studies (cycloadditions, insertions, dehydrogenation).

Main Results:

• Successful synthesis of a crystalline cyclic (alkyl)(amino)silylene.
• Electronic properties intermediate between dialkylsilylenes and diaminosilylenes.
• Formation of head-to-head dimers (disilenes) at low temperatures.
• Demonstrated thermal stability and reactivity including cycloadditions, Si-H insertions, and C-H insertions.
• Observed unprecedented dehydrogenation reactions with specific substrates.

Conclusions:

• The synthesized silylene possesses unique electronic characteristics.
• Low-temperature dimerization provides insight into silylene aggregation.
• The compound exhibits a rich reactivity comparable to dialkylsilylenes but with novel dehydrogenation capabilities.
• This study expands the scope of silylene chemistry and reactivity.