title: Functionalized Poly(3-hexylthiophene)s via Lithium-Bromine Exchange.
abstract: Poly(3-hexylthiophene) (P3HT) is one of the most extensively investigated conjugated polymers and has been employed as the active material in many devices including field-effect transistors, organic photovoltaics and sensors. As a result, methods to further tune the properties of P3HT are desirable for specific applications. Herein, we report a facile postpolymerization modification strategy to functionalize the 4-position of commercially available P3HT in two simple steps-bromination of the 4-position of P3HT (Br-P3HT) followed by lithium-bromine exchange and quenching with an electrophile. We achieved near quantitative lithium-bromine exchange with Br-P3HT, which requires over 100 thienyl lithiates to be present on a single polymer chain. The lithiated-P3HT is readily combined with functional electrophiles, resulting in P3HT derivatives with ketones, secondary alcohols, trimethylsilyl (TMS) group, fluorine, or an azide at the 4-position. We demonstrated that the azide-modified P3HT could undergo Cu-catalyzed or Cu-free click chemistry, significantly expanding the complexity of the structures that can be appended to P3HT using this method.
authors.affiliation: Department of Chemistry and Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Byungjin
authors.initials: B
authors.lastname: Koo
authors.affiliation: Department of Chemistry and Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Sletten
authors.affiliation: Department of Chemistry and Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Swager