Direct (hetero)arylation polymerization: toward defect-free conjugated polymers

Abstract

In a very short time, direct (hetero)arylation polymerization (DHAP) has established itself as a valuable and atom-economical alternative to traditional cross-coupling methods such as the Migita–Stille and Suzuki-Miyaura polymerizations for the synthesis of low cost and efficient conjugated polymers for organic electronics. Because of sustained research efforts combining in-depth theoretical calculations, the development of new ligands and the careful fine-tuning of polymerization conditions, selectivity and reactivity issues should be soon a thing of the past. This focus review highlights the recent advances that lead to defect-free polymeric semiconductors and conductors and the current limitations and challenges of DHAP as it moves toward simultaneously becoming an industrially feasible, environmentally friendly, and synthetically powerful polymerization technique. The implementation of Direct Heteroarylation Polymerization (DHAP) in the synthesis of well-defined and defect-free materials for organic electronics is still in its early stages but giant leaps have been made over the past few years to improve and stir the selectivity of the reaction to avoid unwanted side-reaction such as β-branching or homocoupling. DHAP has proven to be an efficient, cost-effective, green and scalable polymerization method now competing or even surpassing well-established Suzuki-Miyaura or Migita–Stille cross-coupling polymerization methods. This focus review puts emphasis on the synthetic strategies that made DHAP successful.