Multicomponent Click Polymerization: A Facile Strategy toward Fused Heterocyclic Polymers

We herein report a facile and efficient multicomponent click polymerization route to construct fused heterocyclic polymers with advanced functionalities. Mediated by CuI and trimethylamine at room temperature, diynes, disulfonyl azide, and salicylaldehyde, or o-hydroxylacetophenone undergo polymerizations efficiently and smoothly, affording high-molecular-weight poly(iminocoumarin)s (Mw up to 64 600) in satisfactory yields (up to 99%). This multicomponent click polymerization approach enjoys remarkable merits of both multicomponent reactions and click reactions, such as simple operation, high reaction efficiency and isolation yield, mild reaction conditions, and common substrates. The resulting polymers possess outstanding film-forming ability, high thermal stability, and good morphological stability. With tetraphenylethene luminogens embedded in the polymer chains, their solutions fluoresce weakly, whereas their aggregates emit intensely, demonstrative of a typical feature of aggregation-enhanced emission. Furthermore, the obtained polymers with bright film emission and high photosensitivity can be facilely fabricated into well-resolved 2D and 3D patterns by treatment of their films with UV light. Additionally, thanks to the highly polarized conjugated structures, the polymer films possess outstanding refractive indices (1.9284–1.7734) in the visible and near-IR regions (400–893 nm), which can be further adjusted by UV light.