Synthesis and Postpolymerization Functionalization of Poly(5-iodo-1,2,3-triazole)s

The step-growth, click polymerization of complementary azide and alkyne-containing monomers to produce polytriazoles (PTAs) has become a versatile and popular method of preparing structurally diverse high molecular weight polymers with a variety of useful functions. We describe here a new class of PTAs that contain 5-iodotriazole linkages prepared by the iodoalkyne version of the copper-catalyzed azide–alkyne cycloaddition ( i CuAAC) of an α-azido-ω-iodoalkyne (A–B) monomer. We found this monomer to be highly reactive in the i CuAAC polymerization and show that the resulting poly(5-iodo-1,2,3-triazole) (iodo-PTA) can serve as a useful building block for further postpolymerization derivatization using palladium-catalyzed cross-couplings such as Suzuki and Heck reactions. The parent iodo-PTA and functionalized materials were successfully characterized by various spectroscopic techniques and shown to exhibit a wide range of chemical and thermal properties that are determined by the nature of functionalization at the 5-position of the triazole ring. This data suggests a certain tunability of PTA properties and offers potential for the development of a multitude of useful triazole-based materials based on this postpolymerization functionalization strategy.