Homopolycyclotrimerization of A_4-type tetrayne: A new approach for the creation of a soluble hyperbranched poly(tetraphenylethene) with multifunctionalities

摘要

A tetraphenylethene-containing A_4-type tetrayne, named 1,1,2,2-tetrakis(4-ethynylphenyl)ethene is synthesized and its TaCl _5-Ph_4Sn catalyzed homopolycyclotrimerization affords hyperbranched poly(tetraphenylethene) with high molecular weight (M _w5280,000) 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 (RI51.9288-1.6746) 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 photopat-tern without and with porous secondary structure. The polymer is metallified and pyrolysed to give magnetic ceramics with high magnetic susceptibilities (M_s 583 emu/g) and near-zero coercivity (H_c 50.08 kOe).