Hyperbranched conjugated poly(tetraphenylethene): synthesis, aggregation-induced emission, fluorescent photopatterning, optical limiting and explosive detection

Abstract

Tetraphenylethene-containing diyne (1), named 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene, was synthesized and polymerized by TaBr 5 catalyst, affording the hyperbranched polymer hb-P1 with a high molecular weight (M w up to 157 800) in a nearly quantitative yield. The cyclotrimerization of 1-(4-ethynylphenyl)-1,2,2-triphenylethene was also carried out to give 1,3,5-and 1,2,4-tris[4-(1,2,2triphenylvinyl)phenyl]benzene (1,3,5-2 and 1,2,4-2) that served as model compounds for structural characterization and properties investigation. The structures of hb-P1 and 2 are characterized by MS, IR, and NMR spectroscopies with satisfactory results. All the molecules and polymer are completely soluble in common organic solvents such as chloroform, toluene and THF. They show high thermal stability with degradation temperatures up to 443 and 446 C, respectively, in nitrogen and air. Whereas their solutions are almost non-emissive or weakly fluorescent, their aggregates in poor solvents and solid powders emit intensely with fluorescence quantum yields up to 81%, demonstrating a novel phenomenon of aggregation-induced or enhanced emission. The unreacted triple bonds on the periphery of hb-P1 allow its thin film to cross-link under UV irradiation, generating well-resolved photopatterns. The hyperbranched polymer can limit harsh laser pulses. Its emission can be quenched efficiently by picric acid in solution and aggregated states with large quenching constants, suggesting that it is a promising fluorescent chemosensor for explosives detection.

Aggregation‐Induced Emission of Tetraphenylethene–Hexaphenylbenzene Adducts: Effects of Twisting Amplitude and Steric Hindrance on Light Emission of Nonplanar Fluorogens

“…TPE-containing precursors 4, 5, and 3 a were prepared according to the previously published procedures. [14] Palladium-catalyzed Sonogashira coupling of 4 and 5 afforded 1 a, which was transformed into 1 b by a Diels-Alder reaction with tetraphenylcyclopentadienone 6. On the other hand, diyne 9 was obtained by a coupling reaction of 7 with trimethylsilylacetylene followed by base-catalyzed hydrolysis in THF.…”

Ring‐Shaped Silafluorene Derivatives as Efficient Solid‐State UV‐Fluorophores: Synthesis, Characterization, and Photoluminescent Properties

“…The absolute solid-state fluorescence quantum yields were determined on a calibrated integrating sphere according to the method described by de Mello et al, [29] using a 325 nm CW light from a He-Cd laser for optical pumping, an Ocean Optics USB2000 miniature fiber optics spectrometer and the same procedure reported elsewhere. [30] Suitable single crystals of compounds 1-4 were selected under oil under ambient conditions and attached to the tip of a MiTeGenMi-croMount TM . Single-crystal X-ray diffraction intensity data were collected in a stream of cold nitrogen at 100 or 200 K on a Bruker Quazar SMART APEXII diffractometer with Mo Ka (l = 0.71073 ) radiation, or a Bruker SMART APEXII diffractometer with Cu Ka (l = 1.54178 ) radiation, or a Bruker D8 Venture diffractometer with Cu Ka (l = 1.54178 ) radiation.…”

Luminescent AIE materials for high-performance sensing applications

“…8 In performance contents were than the P1 in for explosiv respectively. 9 pathways in t the Stern-Vo ..-f.…”