- Synthesis and nearly monochromatic photoluminescence properties of conjugated copolymers containing fluorene and rare earth complexes
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A series of novel conjugated copolymers containing 9,9-dihexylfluorene and europium complex-chelated benzoate units in the main chain had been synthesized through a three-step process, involving Suzuki coupling copolymerization, hydrolysis of benzoate units, and postchelation. The chemical structures of the copolymers were characterized by FT-IR, 1H NMR, 13C NMR, GPC, and ToF-SIMS. The copolymers exhibited relatively high glass transition temperatures after incorporation of the rare earth complexes. The photoluminescence (PL) properties of the copolymer complexes in solution and in film form were investigated. Intramolecular energy transfer from the fluorene groups to the europium complex occurred in diluted solutions of the copolymer. The efficiency of this process depended strongly on the structure of the ligands for the europium complex and the composition of the copolymers. The PL spectra of the copolymer complexes consisted of two emission bands, one in the 350-550 nm region and another at around 612 nm, corresponding to the π* → π transitions of the fluorene moieties and the f-f transitions of the europium ions, respectively. In the copolymer films cast from solutions, emission from the fluorene groups could be suppressed, and the absorbed excitation energy was transferred effectively to the europium complexes in the copolymer. Nearly monochromatic red emission (with a line width of about 4 nm) was detected under UV excitation at room temperature.
- Ling,Kang,Neoh,Huang, Wei
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- Luminescent organoboron ladder compounds via directed electrophilic aromatic C-H borylation
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Luminescent B-N containing conjugated ladder compounds are prepared by directed electrophilic aromatic substitution. Negishi cross-coupling reaction of 2,7-dibromo-9,9-dihexylfluorene with 6-methylpyridin-2-yl(pivaloyloxy)zinc furnishes the dipyridylfluorene precursor (1) in 44% yield. Compound 1 is then subjected to electrophilic borylation with BBr3 in the presence of iPr2NEt as a bulky base to give the tetra-coordinate ladder-type organoboron species 2-Br. Arylation of 2-Br is accomplished by addition of Ph2Zn or C6F5Cu in toluene furnishing the targeted bis(pentafluorophenyl)borane and diphenylborane species 2-Ar (Ar = Ph, C6F5) in 53 and 44% yield respectively. The products show a strong blue emission and undergo multi-step reversible reduction and oxidation processes. The effect of fluorination of the pendant aryl groups on the electronic structure is further examined by DFT methods.
- Yusuf, Mayyadah,Liu, Kanglei,Guo, Fang,Lalancette, Roger A.,J?kle, Frieder
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- New pyrimidine- and fluorene-containing oligo(arylene)s: Synthesis, crystal structures, optoelectronic properties and a theoretical study
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New pyrimidine containing oligo(arylene)s, notably the pyrimidine-fluorene hybrid systems 13-16, have been synthesised by Suzuki cross-coupling methodology. An efficient synthesis of the key reagent 9,9-dihexylfluorene-2,7-diboronic acid 10 from 2,7-dibro
- Hughes, Gregory,Wang, Changsheng,Batsanov, Andrei S.,Fern, Michael,Frank, Stephen,Bryce, Martin R.,Perepichka, Igor F.,Monkman, Andrew P.,Lyons, Benjamin P.
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- Synthesis and two-photon properties of multi-branched fluorophores composed of ladder-type conjugated cores and functionalized diquinoxalinylamino peripheries
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Two multipolar fluorophores using ladder-type oligo-(p-phenylene) units as the central π-bridges and functionalized diquinoxalinylamino moieties as the peripheral groups have been synthesized and experimentally shown to manifest strong two-photon absorpti
- Lin, Tzu-Chau,Li, Mei-Ling,Liu, Che-Yu,Tsai, Ming-Yu,Lee, Ying-Hsuan,Febriani, Yuyun,Lin, Ja-Hon,Shen, Yu-Kai
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p. 1615 - 1621
(2014/03/21)
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- Synthesis and Two-Photon Properties of Multi-Branched Fluorophores Composed of Ladder-Type Conjugated Cores and Functionalized Diquinoxalinylamino Peripheries
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Two multipolar fluorophores using ladder-type oligo-(p-phenylene) units as the central π-bridges and functionalized diquinoxalinylamino moieties as the peripheral groups have been synthesized and experimentally shown to manifest strong two-photon absorpti
- Lin, Tzu-Chau,Li, Mei-Ling,Liu, Che-Yu,Tsai, Ming-Yu,Lee, Ying-Hsuan,Febriani, Yuyun,Lin, Ja-Hon,Shen, Yu-Kai
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p. 1615 - 1621
(2015/10/05)
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- Synthesis and fluorescent properties of conjugated copolymers containing maleimide and fluorene units at the main chain
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Yamamoto or Suzuki-Miyaura coupling polymerizations of 2,3-diiodo-N- cyclohexylmaleimide with fluorene derivatives (2,7-dibromo-9,9′- dihexylfluorene and 9,9′-dihexylfluorene-2,7-diboronic acid) were carried out. The number-average molecular weights (Mn) of the resulting copolymers were 2600-3500 by gel permeation chromatography analysis. The fluorescence emission of the alternating copolymer showed the emission maxima at 551 nm in THF. On the other hand, the random copolymers showed the bimodal emission peaks at 418-420 and 555-557 nm region, respectively. The fluorescence peaks of the random copolymers on the long wavelength region (555-557 nm) were attributed to the conjugated neighboring N-cyclohexylmaleimide-9,9′- dihexylfluorene units in the polymer main chain. Furthermore, the copolymers exhibited the fluorescence solvatochromism by the difference of the polarity of solvents. The alternating and random copolymers showed the different fluorescence solvatochromism, and the emission colors are distinguishable by the naked eye, respectively. Copyright
- Nakamura, Munetoshi,Yamabuki, Kazuhiro,Oishi, Tsutomu,Onimura, Kenjiro
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p. 4945 - 4956
(2013/11/06)
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- Multi-Functional Copolymers Comprising Rare Earth Metal Complexes and Devices Thereof
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The invention relates to copolymer complexes of the formula (I): wherein [Ax-[B(C)]y-Dz] denotes a single unit of the copolymer complex that is repeated n times, wherein n is an integer greater than one, and wherein the single unit comprises a conjugated backbone coordinated to a complex (C) comprising rare earth metal(s); x, y and z are numbers greater than zero such that x=y+z; A is independently selected from a group consisting of: fluorene, carbazole, oxadiazole, triphenylamine or derivatives thereof; B is a functional ligand selected from the group consisting of: benzoic acid, 1,3-diphenylpropane-1,3-dione, 1,10-phenanthroline, 2,2-bipyridine, or derivatives thereof; and D is independently selected from a group consisting of: fluorene, carbazole, oxadiazole, triphenylamine or derivatives thereof.
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- Dibenzothiophene-S,S-dioxide-fluorene co-oligomers. Stable, highly-efficient blue emitters with improved electron affinity
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Incorporation of dibenzothiophene-S,S-dioxide units into conjugated fluorene oligomers changes the frontier orbital energy levels and presents an effective way to increase the electron affinity of these materials, which are highly fluorescent with bright blue emission in both solution and the solid state. The Royal Society of Chemistry 2005.
- Perepichka, Irene I.,Perepichka, Igor F.,Bryce, Martin R.,Palsson, Lars-Olof
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p. 3397 - 3399
(2007/10/03)
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- Synthesis and characterization of new red-emitting polyfluorene derivatives containing electron-deficient 2-pyran-4-ylidene-malononitrile moieties
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A novel series of red-light-emitting copolymers derived from fluorene and 2-pyran-4-ylidene-malononitrile (PM) have been synthesized through a palladium-catalyzed Suzuki coupling reaction. The polymers were characterized by FT-IR, NMR, and elemental analysis. All these polymers are completely soluble in common organic solvents, such as THF, CH2Cl2, CHCl3, and toluene, and they have good thermal stability with onset decomposition temperature (Td) of 406-407°C and glass-transition temperature (Tg) of 73-186°C. Cyclic voltammetry studies reveal that these copolymers have low-lying LUMO energy levels ranging from -3.53 to -3.57 eV and HOMO energy levels ranging from -5.77 to -5.79 eV, which indicated that they may be promising candidates for electron-transporting or hole-blocking materials in light-emitting diodes. These polymers in thin films can emit strong red photoluminescence (PL) around 641-662 nm with the corresponding additional peaks in the range 704-712 nm upon photoexcitation. Double-layer LEDs fabricated with the configuration of ITO/PEDOT/polymer/Ba/Al can emit red light with external quantum efficiencies of 0.21-0.38%. Preliminary electroluminescent (EL) results show that these polymers are novel promising candidates for red emissive materials in polymer light-emitting diodes.
- Peng, Qiang,Lu, Zhi-Yun,Huang, Yan,Xie, Ming-Gui,Han, Shao-Hu,Peng, Jun-Biao,Cao, Yong
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p. 260 - 266
(2007/10/03)
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- New efficient blue light emitting polymer for light emitting diodes
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The synthesis, by the Suzuki coupling reaction, of a novel soluble blue light emitting polymer, poly{(9,9-dihexyl-2,7-fluorene-alt-co-[2,5-bis(decyloxy)-1,4-phenylene]} (PDHFDDOP) is reported. PDHFDDOP exhibits photoluminescence (PL quantum efficiency of
- Yu, Wang-Lin,Pei, Jian,Cao, Yong,Huang, Wei,Heeger, Alan J.
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p. 1837 - 1838
(2007/10/03)
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