Free Radical Chemistry of Phosphasilenes

Area of Science:

• Organosilicon chemistry
• Radical chemistry
• Spectroscopy

Background:

• Silicon-containing compounds are crucial in radical polymerization.
• Substituents on phosphasilenes significantly affect radical properties.

Purpose of the Study:

• Investigate radicals derived from phosphasilenes with various substituents (Mes, Tip, Dur, NMe2).
• Understand how steric and electronic effects influence radical structure and species.

Main Methods:

• Muon spin spectroscopy to detect and characterize radicals.
• Density Functional Theory (DFT) calculations to model radical behavior.

Main Results:

• NMe2 and Tip substituents yield multiple muoniated radicals with varied conformations.
• Dur substituents form both Si- and P-centered radicals.
• Mes substituents predominantly form P-centered radicals.

Conclusions:

• Intramolecular substituent effects dictate the number and type of radicals formed from phosphasilenes.
• These findings are vital for controlling radical polymerization using silicon-heavy analogues.