Initiating Photocontrolled Atom Transfer Radical Polymerization from a Redox-Activated Functional Group

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Photocatalysis

Background:

• Controlled radical polymerization is crucial for advanced polymer architectures like surface grafts and conjugates.
• Conventional photocontrolled atom transfer radical polymerization (ATRP) is limited by the need for alkyl halide initiators.

Purpose of the Study:

• To develop a method for initiating photo-ATRP directly from primary amines.
• To enable the synthesis of advanced polymer architectures using readily available functional groups.

Main Methods:

• Utilized an iridium photocatalyst to trigger radical deamination of redox-activated primary amines.
• Initiated controlled radical polymerization under visible light irradiation with an exogenous bromide source.

Main Results:

• Achieved controlled radical polymerization with narrow molar mass distributions (Đ ≈ 1.2-1.3).
• Demonstrated high α-chain-end fidelities (>99%) and active bromide ω-chain-ends.
• Showcased good agreement between theoretical and experimental molar masses.

Conclusions:

• Established a novel photo-ATRP initiation method directly from primary amines.
• Paved the way for using non-alkyl halide initiators in well-controlled ATRP polymerizations.
• Enabled the creation of advanced polymer architectures from redox-activated functional groups.