- Synthesis and characterization of poly(tetramethylsilarylenesiloxane) derivatives with oligothiophene based moiety
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Poly(tetramethylsilarylenesiloxane) derivatives (P1T-P4T, P4TC) that contained thiophene (1T), oligothiophenes such as dithiophene (2T), terthiophene (3T), quaterthiophene (4T), or 2,6-di(2-thienyl)-4,4-diphenylcyclopentadithiophene (4TC) as the main chain components were synthesized via polycondensation reaction of the corresponding disilanol monomers (M1T-M4T, M4TC). The obtained polymers other than P4T that contained quaterthiophene units exhibited the good solubility in common organic solvents, such as toluene, chloroform, tetrahydrofuran and so on. The glass transition temperature (Tg) and melting temperature (Tm) of the obtained polymers regarding P1T-P4T were increased with the extension of the thiophene rings of the monomeric unit as deduced from the results of the differential scanning calorimetry (DSC). On the other hand, the Tm was not observed for P4TC that was composed of 2,6-di(2-thienyl)-4,4-diphenylcyclopentadithiophene units. P2T that was composed of dithiophene units exhibited the highest temperature at 5% weight loss (Td5) of 467 °C in all present polymers. The bathochromic and hyperchromic effects in the absorption spectra as well as the improvement of fluorescence quantum yield were observed by the introduction of dimethylsilyl group onto the present oligothiophene derivatives. These effects became unremarkable accompanying the elongation of the thiophene rings of the monomeric units; however, 4TC exhibited a more significant change by the introduction of the dimethylsilyl group than the other oligothiophenes derivatives, indicating that the introduction of the cardo-structure was effective in the improvement of the optical properties. M4TC and P4TC exhibited the fluorescence wavelength around 500 nm and the highest fluorescence quantum yield of the present series of poly(tetramethylsilarylenesiloxane) derivatives, i.e., 0.40, plausibly because the free rotation between thiophene rings in oligothiophene inhibited by the cardo-structures and the bulky diphenyl groups at 4-position of cyclopentadithiophene moiety suppressed the nonradiative transition.
- Nishizawa, Ibuki,Ajito, Hiroki,Gonmori, Yuzuki,Katoh, Ryuzi,Ichikawa, Tsukasa,Nemoto, Nobukatsu
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- Silole-containing poly(silylenevinylene)s: Synthesis, characterization, aggregation-enhanced emission, and explosive detection
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Hydrosilylation polymerizations of 1,1-dimethyl-2,5-bis(4-ethynylphenyl)-3, 4-diphenylsilole with aromatic silylhydrides including 1,4-bis(dimethylsilyl) benzene, 4,4'-bis(dimethylsilyl)biphenyl, 2,5-bis(dimethylsilyl)thiophene, and 2,7-bis(dimethylsilyl)-9,9-dihexylfluorene in the presence of Rh(PPh 3)3Cl catalyst in refluxed tetrahydrofuran afford a series of silole-containing poly(silylenevinylene)s. Under optimum condition, the alkyne polyhydrosilylation reactions progress efficiently and regioselectively, yielding polymers with high molecular weights (Mw up to 95,300) and good stereoregularity (E content close to 99%) in high yields (up to 92%). The polymers are processable and thermally stable, with high decomposition temperatures in the range of 420-449 °C corresponding to 5% weight loss. They are weakly fluorescent in the solution state but become emissive in the aggregate and film states, demonstrating their aggregation-enhanced emission characteristics. The explosive sensing capabilities of the polymers are examined in both solution and aggregate states. The emissions of the polymers aggregates in aqueous mixture are quenched more efficiently by picric acid in an exponential pattern with high quenching constants (up to 27,949 L mol -1), suggesting that the polymers aggregates are sensitive chemosensors for explosive detection. 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 A series of silole-containing poly(silylenevinylene)s are synthesized regioselectively in high yields. These polymers show aggregation-enhanced emission and sensitive response to explosives in aqueous media. Copyright
- Zhao, Zujin,Jiang, Tao,Guo, Yanju,Ding, Liyuan,He, Bairong,Chang, Zhengfeng,Lam, Jacky W. Y.,Liu, Jianzhao,Chan, Carrie Y. K.,Lu, Ping,Xu, Liwen,Qiu, Huayu,Tang, Ben Zhong
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experimental part
p. 2265 - 2274
(2012/07/14)
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- Polymeric organosilicon systems. XVIII. Synthesis and photochemical properties of poly
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Poly (Ib), poly (IIb) and polythienylene> (IIIb) were synthesized by sodium condensation reaction of the corresponding 2,
- Ohshita, Joji,Kanaya, Daisuke,Ishikawa, Mitsuo
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