Redox‐Active Heteroatom‐Functionalized Polyacetylenes

The discovery of metallic conductivity in polyacetylene [‐HC=CH‐]n upon doping represents a landmark achievement. However, the insolubility of polyacetylene and a dearth of methods for its chemical modification have limited its widespread use. Here, we employ a ring‐opening metathesis polymerization (ROMP) protocol to prepare functionalized polyacetylenes (fPAs) bearing: (1) electron‐deficient boryl (‐BR2) and phosphoryl (‐P(O)R2) side chains; (2) electron‐donating amino (‐NR2) groups, and (3) ring‐fused 1,2,3‐triazolium units via strain‐promoted Click chemistry. These functional groups render most of the fPAs soluble and can lead to intense light absorption across the visible to near‐IR region. Also, the presence of redox‐active boryl and amino groups leads to opposing near‐IR optical responses upon (electro)chemical reduction or oxidation. Some of the resulting fPAs show greatly enhanced air stability when compared to known polyacetylenes. Lastly, these fPAs can be cross‐linked to yield network materials with the full retention of optical properties. Redox‐active functionalized polyacetylenes bearing a wide range of electronically distinct heteroatom‐based groups have been prepared by ring‐opening polymerization (ROMP). Hallmarks of this work include enhanced polyacetylene solubility, air stability, and electrochromic switching in the near IR spectral window.