Solving the Loss of Orthogonality During the Polyaddition of α-Azide-ω-Alkyne Monomers Catalyzed by Cu(PPh3)3Br: Application to the Synthesis of High-Molar Mass Polytriazoles

Polyaddition of an alpha-azide-omega-alkyne monomer by Cu(PPh3)(3)Br catalyzed 1,3-dipolar cycloaddition was thoroughly studied as a model system to investigate the orthogonality of this click chemistry process. Indeed, loss of chain-end functionality and occurrence of side reactions have a tremendous impact on the molar mass of polymers obtained by step growth polymerization. Particularly, SEC, H-1, and P-31 NMR experiments have highlighted the occurrence of a Staudinger side-reaction between azide chain-ends and PPh3 from the copper(I) catalyst that dramatically alters M-n of the resulting polytriazoles. A significant enhancement of M-n could be achieved by using an alternative catalyst and optimized experimental conditions, that is, dilution and reaction time. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2470-2476, 2010