(Digital Presentation) Electrochemical Phosphonylation of π-Conjugated Polymers

Abstract

π-Conjugated polymers exhibit attractive optoelectronic properties because of their extended π-conjugation system along with main chains. Therefore, the introduction of functional groups into their main chains is a straightforward strategy to control their optoelectronic properties. In this context, post-functionalization is a practical methodology to install functional units. Among the post-functionalization methods, electrochemical post-functionalization is a promising fashion due to its outstanding abilities to transform aromatic C–H bonds of π-conjugated polymers into various functional units.1) For example, anodic chlorination of poly(3-hexylthiophene) (P3HT) has been reported (Fig. 1 (a)).2) However, functional groups available for this post-functionalization remain limited to those derived from nucleophilic dopants such as a chloride ion.Here, to expand the applicable functional groups for electrochemical post-functionalization, we attempted to develop the electrochemical phosphonylation of P3HT and poly(9,9-dioctylfluorene) (PFO) (Fig. 1 (b)). With the use of non-nucleophilic dopants and triethyl phosphite as neutral nucleophiles, we successfully achieved C–H phosphonylation of the main chains of these polymers. The introduced phosphonyl groups significantly affected the optoelectronic properties of P3HT and PFO. Particularly, phosphonylated PFO was found to show unique emitting properties.References1) S. Inagi, T. Fuchigami, Macromol. Rapid Commun., 2014, 35, 854.2) S. Hayashi, S. Inagi, K. Hosaka, T. Fuchigami, Synth. Met., 2009, 159, 1792. Figure 1