Dual Function of β-Hydroxy Dithiocinnamic Esters: RAFT Agent and Ligand for Metal Complexation

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Reversible addition-fragmentation chain-transfer (RAFT) polymerization is a key technique for creating well-defined polymers.
• Existing chain transfer agents (CTAs) primarily focus on polymerization control, with limited exploration of end-group functionality.
• Dithiocinnamic esters are known for metal complexation but underexplored as CTAs.

Purpose of the Study:

• To investigate β-hydroxy dithiocinnamic esters as novel chain transfer agents (CTAs) in RAFT polymerization.
• To evaluate their efficacy in controlling polymerization of various monomers.
• To demonstrate the utility of the resulting polymer end groups for secondary applications, specifically metal complexation.

Main Methods:

• Synthesis of β-hydroxy dithiocinnamic esters with suitable leaving groups.
• Application of these esters as CTAs in RAFT polymerization of acrylates, acrylamides, and styrene.
• Kinetic studies to analyze polymerization control (molar mass vs. conversion).
• Block copolymerization experiments to assess polymer chain livingness.
• Characterization of end-group integrity via platinum complexation.

Main Results:

• β-hydroxy dithiocinnamic esters effectively controlled RAFT polymerization, exhibiting linear molar mass growth with conversion.
• The polymerization process demonstrated living characteristics, confirmed by block extensions.
• The dithiocinnamic ester end groups remained intact and capable of complexing with platinum.
• Variations in aromatic substituents showed minimal impact on polymerization control.

Conclusions:

• β-hydroxy dithiocinnamic esters are a novel and effective class of CTAs for RAFT polymerization.
• These CTAs enable the synthesis of polymers with functional end groups suitable for metal complexation.
• This work presents a new strategy for creating tailor-made polymer-bound metal complexes.