Phosphazene Base-Mediated Azide–Alkyne Click Polymerization toward 1,5-Regioregular Polytriazoles

Cu(I)-catalyzed azide–alkyne click polymerization has become a powerful tool for the construction of 1,4-regioregular polytriazoles (PTAs). However, the polymerization toward the synthesis of 1,5-regioregular PTAs has been rarely reported, and the structure–property relationship between 1,5- and 1,4-regioregular PTAs needs to be studied further. In this work, an efficient superbase of phosphazene base (t-BuP4)-mediated azide–alkyne click polymerization was developed, and soluble and thermally stable 1,5-regioregular PTAs with high molecular weights (Mw up to 26 600) were generated in high yields (up to 99%). The relationship between the regiostructures and the thermal stability, light refractivity, photophysical properties, electrochemical behaviors of PTAs was investigated, and the results indicate that the 1,4-regioregular PTA exhibits better conjugation and planarity than that of the 1,5-regioregular one. Thus, this work not only develops a powerful t-BuP4-mediated azide–alkyne click polymerization for the preparation of 1,5-regioregular PTAs but also provides a platform for investigating the structure–property relationship of PTAs, which will guide the design of new PTAs for diverse applications.