Benzyne–azide polycycloaddition: a facile route toward functional polybenzotriazoles†
Benzyne, a highly reactive intermediate, has been used to synthesize various complex and diverse chemical entities, while benzyne-based polymerization has been rarely reported. In this work, three dibenzyne monomers, which were generated in situ from their precursors in the presence of CsF, were used to polymerize with diazides via a Huisgen 1,3-dipolar polycycloaddition, and soluble polybenzotriazoles with weight-average molecular weights (Mw) up to 13 000 were produced in moderate yields (up to 75%). All the resultant polymers show high thermal stability and good light refractivity. The tetraphenylethene-containing polybenzotriazoles exhibit the aggregation-induced emission or aggregation-enhanced emission characteristics. This benzyne–azide polycycloaddition will be a powerful tool for the preparation of functional polybenzotriazoles and be potentially applicable in materials and biological fields.