Homopolycyclotrimerization of A 4 ‐type tetrayne: A new approach for the creation of a soluble hyperbranched poly(tetraphenylethene) with multifunctionalities

A tetraphenylethene‐containing A 4 ‐type tetrayne, named 1,1,2,2‐tetrakis(4‐ethynylphenyl)ethene is synthesized and its TaCl 5 ‐Ph 4 Sn catalyzed homopolycyclotrimerization affords hyperbranched poly(tetraphenylethene) with high molecular weight ( M w  = 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 ( M s  = 83 emu/g) and near‐zero coercivity ( H c  = 0.08 kOe). © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51 , 4752–4764