Copper-catalyzed azide-alkyne cycloaddition oligomerization of 3-azido-1-propyne derivatives

Copper-catalyzed azide-alkyne cycloaddition polymerization of 3-azido-1-propyne derivatives, i.e., 3-azido-1-propyne (APr) and 3-azido-1-butyne (ABu), was investigated using the corresponding bromides as monomer precursors. The APr and ABu oligomers were soluble in strong acids, but insoluble in many organic solvents. IR and solid-state 13C NMR spectra confirmed that the APr and ABu oligomers were composed of 1,2,3-triazole units. Powder X-ray diffraction patterns indicated that the APr oligomer was crystalline whereas the ABu oligomer was almost amorphous. Thermogravimetric analysis data indicated that the residual weights were as large as 54 and 46% for the APr and ABu oligomers, respectively, at 500 °C.