Linear Coordination Polymer Synthesis from Bis-Catechol Functionalized RAFT Polymers.

Area of Science:

• Polymer Chemistry
• Supramolecular Chemistry
• Coordination Chemistry

Background:

• Catechol-Fe(III) complexes possess exceptionally strong metal-chelate bonds.
• These strong bonds have not been previously exploited for linear coordination polymer (LCP) synthesis.
• There is a need for novel methods to create functional polymers with tunable properties.

Purpose of the Study:

• To synthesize a novel bis-catechol functionalized trithiocarbonate agent for reversible addition fragmentation chain transfer (RAFT) polymerization.
• To generate catechol end-functionalized polymers using this new agent.
• To investigate the formation and properties of catechol-Fe(III) linear coordination polymers (LCPs).

Main Methods:

• Synthesis of a symmetrical bis-catechol functionalized trithiocarbonate RAFT agent (CatDMAT).
• Direct photoactivation RAFT polymerization of acrylamide (AM) and dimethylacrylamide (DMA) using CatDMAT.
• Characterization of resulting bis-catechol end-functionalized polymers via UV-vis spectroscopy and GPC.
• Formation of supramolecular LCPs through bis-complexation with Fe(III).

Main Results:

• Successful synthesis of CatDMAT and its use in RAFT polymerization to produce polymers with molecular weights of 10-15 kDa.
• Formation of catechol-Fe(III) LCPs confirmed by UV-vis spectroscopy (λmax = 570 nm) and increased viscosity.
• Evidence of supramolecular polymerization through increased GPC molecular weight (M_n,GPC).
• Demonstrated oxidation and crosslinking of the catechol-LCPs in aqueous solution within 24 hours.

Conclusions:

• A novel bis-catechol functionalized RAFT agent enables the synthesis of catechol end-functional polymers.
• These polymers can effectively form supramolecular linear coordination polymers with Fe(III) via strong coordination bonds.
• The resulting catechol-Fe(III) LCPs exhibit properties indicative of supramolecular assembly and undergo subsequent crosslinking.