Nickel-Catalyzed Azide-Alkyne Click Polymerization toward 1,5-Regioregular Polytriazoles

The click polymerization has emerged as a powerful tool for the synthesis of functional polymers. Among the reported click polymerizations, the Cu(I)- and Ru(II)-catalyzed azide-alkyne ones have received considerable attention. To further develop such click polymerization, a new catalyst is desirable. In this work, we used Cp₂Ni/Xantphos/Cs₂CO₃ to catalyze the azide-alkyne click polymerization (NiAACP) under mild conditions, and 1,5-regioregular polytriazoles (PTAs) with weight-average molecular weights as high as 67,900 were produced in high yields (up to 96.7%) in only 30 min. The obtained PTAs process high thermal stability, and their glass-transition temperatures range from 38.9 to 168.0 °C. The relationship between the polymer structures and their refractive indices was also investigated. Moreover, PTAs with aggregation-induced emission (AIE) features and chirality were produced through the incorporation of the AIE moiety of tetraphenylethene and the chiral moiety of 2,2′-substituted 1,1′-binaphthyl into the polymer chains, respectively, indicative of the great potential of the NiAACP in constructing functional polymeric materials.