Doping the Backbone of π-Conjugated Polymers with Tricoordinate Boron: Synthetic Strategies and Emerging Applications

The doping of π-conjugated organic compounds with trivalent boron atoms produces materials with intriguing properties and functions that result from the interaction of the π-electron system with the vacant p orbital on boron. This offers unique opportunities in various applications such as organic (opto)electronics, biomedical imaging, and sensors for physiologically relevant anions or amines, as demonstrated by numerous examples on the molecular scale. Recently, the B-doping strategy has been expanded to polymer chemistry with a view to benefit from the best of both worlds. Herein, recent advances in the synthesis of π-conjugated polymers doped with tricoordinate boron in the backbone are reviewed. Selected applications are described where these functional materials have already been successfully implemented.