A facile approach for preparing multicyclic polymers through combining ATRP and photo-induced coupling reaction

Multicyclic polymers including bicyclic and tetracyclic polymers were constructed by combining atom transfer radical polymerization (ATRP) and photo-induced coupling reaction of anthryl groups. First, 4-arm and 8-arm star polystyrenes were synthesized by ATRP using the tetrafunctional and octafunctional initiators, respectively. Subsequently, after two-step modification of Br-terminated 4-arm and 8-arm star polystyrenes, including azidation and copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction with prop-2-yn-1-yl anthracene-9-carboxylate, the precursors with anthryl end groups were obtained. Finally, the photo-induced coupling reaction was conducted upon irradiation at 365 nm in the diluted solution of 4-arm and 8-arm star precursors, to produce bicyclic and tetracyclic polymers, respectively. Besides, the multicyclic polymers can convert back to the original precursors after heating at 150 oC. 1H NMR, FT-IR, GPC and UV-vis analyses were carried out to verify the resultant multicyclic structures and the topological conversion between multicyclic polystyrenes and their precursors.