Polymer End Group Control through a Decarboxylative Cobalt-Mediated Radical Polymerization: New Avenues for Synthesizing Peptide, Protein, and Nanomaterial Conjugates

Abstract

Cobalt-mediated radical polymerizations (CMRPs) have been initiated by the radical decarboxylation of tetrachlorophthalimide activated esters. This allows for the controlled radical polymerization of activated monomers across a broad temperature range with a single cobalt species, with the incorporation of polymer end groups derived from simple carboxylic acid derivatives and termination with an organozinc reagent. This method has been applied to the synthesis of a polymer/graphene conjugate and a water-soluble protein/polymer conjugate, demonstrating the first examples of CMRP in graphene and protein conjugation.

Radical decarboxylation: an emerging tool in polymer synthesis

“…10). 30 In this work, the decarboxylation of redox active esters was used to initiate cobalt mediated radical polymerisation (CMRP). Based on a previous report by Wang on the cobalt-catalysed decarboxylative Negishi coupling, 31 it was observed that the in situ reduction of Co( ii ) to a Co( i ) species could result in single electron transfer to a redox-active ester and subsequent radical decarboxylation.…”

RAFT polymerization by the radical decarboxylation of carboxylic acids

“…In 2021, our group reported the cobalt-mediated radical polymerization (CMRP) of acrylates and acrylamides initiated by the radical decarboxylation of activated carboxylic acids (Figure 1C). 8 This method allows for the synthesis of polymer conjugates from peptides and other highly functional materials with excellent control of the polymer molecular weight and dispersity. The main disadvantage of this method is that it requires the conversion of carboxylic acids to tetrachlorophthalimide esters ("activated acids") prior to the polymerization reaction.…”

RAFT Polymerisation by the Radical Decarboxylation of Carboxylic Acids**

“…In 2021, our group reported the cobalt‐mediated radical polymerisation (CMRP) of acrylates and acrylamides initiated by the radical decarboxylation of activated carboxylic acids (Figure 1C). [8] This method allows for the synthesis of polymer conjugates from peptides and other highly functional materials with excellent control of the polymer molecular weight and dispersity. The main disadvantage of this method is that it requires the conversion of carboxylic acids to tetrachlorophthalimide esters (“activated acids”) prior to the polymerisation reaction.…”