Simple and Rapid Functionalization of Conjugated Polymers via Thiol-ene 'Click' Chemistry

摘要

Conjugated polymers demonstrate complex properties that are difficult to predict a priori from simple molecular structure considerations. Pendant substituents are critical for solution processing, strongly influence ensemble optoelectronic properties, and dictate the ultimate performance of conjugated polymer-based systems. Arduous bottom-up synthetic approaches have limited available functionalities, forced difficult purification, and results in significant batch-to-batch variability, which also confounds fundamental studies. Recently, we demonstrated that thiol-ene "click" chemistry can be applied toward the rapid and practical synthesis of highly functionalized conjugated polymers. Using a microwave mediated polymerization reaction, we rapidly generated a prototypical (fluorene-co-thiophene) copolymer with pendant alkene functional groups on a multigram scale. This base polymer was subsequently functionalized using thiol-ene chemistry with a library of commercially available thiols including neutral, bulky, cationic, and anionic variants. This top-down approach, carried out under mild reaction conditions, demonstrated complete conversion within hours without the need for laborious purification procedures. We expect this methodology to find widespread utility as it allows for the direct comparison of different functionality with the same polymer backbone for structure-function-property analysis.