Hyperbranched polyarylenes from copolycyclotrimerization

High molecular weight hyperbranched polyarylenes were synthesized in high yields by one-pot copolycyclotrimerizations of 2,5-diethynylthiophene (1), 4,4′ -biphenyldiyne (2) and 2,7-diethynylfluorenes (3) with 1-heptyne (4) and 1-dodecyne (5) using TaCl₅ · Ph₄Sn catalysts in toluene. The structures and properties of the polymers were characterized and evaluated by IR, NMR, TGA, UV, fluorescence and optical limiting analyses. All the polymers possess high thermal stability and emit strong blue light upon UV irradiation, whose intensities are higher than that from poly (1-phenyl-1-octyne) (PPO), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the photoluminescence is observed in the thin films of the polymers.