Photoinduced Free Radical Promoted Copper(I)-Catalyzed Click Chemistry for Macromolecular Syntheses

Photoinduced copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC) via photoinduced electron transfer using free radical photoinitiators has been developed as a new platform to serve as orthogonal click system. Photoinitiators acting at near UV and visible range, namely 2, 2-dimethoxy-2-phenyl acetophenone, 2-benzyl-2-dimethylamino-4′-morpholino butyrophenone, 2,4,6-trimethylbenzoyl)diphenylphosphine oxide, dicyclopentadienyl bis[2,6-difluoro-3-(1-pyrrolyl)phenyl] titanium) and camphorquinone/benzyl alcohol were tested with copper(II) chloride/N,N,N′,N″,N″-pentamethyldiethylenetriamine complex to catalyze the CuAAC via photoinduced electron transfer reaction. This strategy has been applied in construction of various macromolecular architectures including telechelic polymers and block copolymers. Spectroscopic and chromatographic investigations revealed that successful macromolecular syntheses have been achieved by this technique.