Structure–Property Relationships in Donor–Acceptor Systems With Thiophene/Furan π‐Bridges Built by Iterative Oxidation–Decarboxylative Coupling

ABSTRACT

This study investigates six donor–π–acceptor (D–π–A) compounds incorporating various π‐conjugated bridges based on bifuran, bithiophene, terfuran, terthiophene, and mixed furan–thiophene sequences. These bridges were synthesized via a key decarboxylative coupling approach utilizing thiophene‐ or furan‐based carboxylic acid derivatives and their corresponding bromo‐ or carbaldehyde analogs. This synthetic route enabled efficient coupling and reoxidation, facilitating the introduction of up to three consecutive heterocyclic units without a significant loss in yield. A comparative analysis of their optoelectronic properties demonstrates that both the nature and the sequence of the heterocyclic units within the π‐conjugated bridge play a decisive role in governing the electronic structure and overall performance of the resulting materials.