Homopolycyclotrimerization of A₄-type tetrayne: A new approach for the creation of a soluble hyperbranched poly(tetraphenylethene) with multifunctionalities

A tetraphenylethene-containing A4-type tetrayne, named 1,1,2,2-tetrakis(4-ethynylphenyl)ethene is synthesized and its TaCl5-Ph4Sn catalyzed homopolycyclotrimerization affords hyperbranched poly(tetraphenylethene) with high molecular weight (Mw = 280,000) in high yield (97%). The polymer shows good solubility and high thermal stability. It is aggregation-enhanced emission (AEE)-active and functions as a fluorescent chemosensor for explosive detection with a superamplification effect and large quenching constants up to 758,000 M−1. The polymer shows high and tunable refractive indices (RI = 1.9288−1.6746) in a wide wavelength region. Porous fluorescent polymer thin film is prepared by breath figure (BF) methods and real-time monitoring of the elusive BF formation process is realized. Photolithography of the thin films readily generates well-resolved fluorescent photopattern without and with porous secondary structure. The polymer is metallified and pyrolysed to give magnetic ceramics with high magnetic susceptibilities (Ms = 83 emu/g) and near-zero coercivity (Hc = 0.08 kOe). © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4752–4764