Alkyl Triarylstannanecarbodithioates: Synthesis, Crystal Structures, and Efficiency in RAFT Polymerization

Area of Science:

• Organometallic Chemistry
• Polymer Science
• Materials Science

Background:

• Reversible addition-fragmentation chain transfer (RAFT) polymerization is a key technique for controlled polymer synthesis.
• Organotin compounds have been explored for various chemical applications, including catalysis and materials science.

Purpose of the Study:

• To synthesize and characterize novel alkyl triarylstannanecarbodithioates.
• To evaluate the efficacy of these new organotin derivatives as chain-transfer agents in RAFT polymerization.
• To investigate the factors influencing the control and potential limitations of these agents in polymerization processes.

Main Methods:

• Synthesis of eight alkyl triarylstannanecarbodithioates from triarylstannyl chlorides.
• Comprehensive characterization using IR, 1H, 13C, and 119Sn NMR spectroscopy, and mass spectrometry.
• Solid-state structure determination and comparison with related thiocarbonylthio compounds.
• Application as chain-transfer agents in RAFT polymerization of styrene and n-butyl acrylate.

Main Results:

• Successful synthesis and full characterization of eight novel organotin compounds.
• Demonstrated efficiency of these compounds as reversible chain-transfer agents, yielding polymers with controlled molecular weights and narrow dispersities (Đ < 1.3).
• Observed loss of polymerization control in certain instances, linked to the thermal instability of the Sn-RAFT terminal group, evidenced by side products in 119Sn NMR spectroscopy.

Conclusions:

• Alkyl triarylstannanecarbodithioates are effective agents for controlled RAFT polymerization.
• The thermal stability of the organotin moiety is a critical factor for maintaining polymerization control.
• Further research into stabilizing the Sn-RAFT linkage is warranted for broader applications.