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Excited-State Dynamics of Pyrene Incorporated into Poly(substituted methylene)s: Effects of Dense Packing of Pyrenes on Excimer Formation
Macromolecules ( IF 5.5 ) Pub Date : 2018-07-13 00:00:00 , DOI: 10.1021/acs.macromol.8b01060
Tomohisa Takaya 1 , Tatsuya Oda 2 , Yuki Shibazaki 2 , Yumiko Hayashi 2 , Hiroaki Shimomoto 2 , Eiji Ihara 2 , Yukihide Ishibashi 2 , Tsuyoshi Asahi 2 , Koichi Iwata 1
Affiliation  

The excited-state dynamics of pyrene incorporated into poly(substituted methylene)s is investigated by picosecond time-resolved fluorescence spectroscopy and femtosecond time-resolved near-IR absorption spectroscopy in the 900–1400 nm region. The pyrene rings in poly(substituted methylene)s are photoexcited to the monomer excited state immediately after UV irradiation, followed by prompt excimer formation with time constants of a few picoseconds to a few hundred picoseconds. The excimer formation in poly(substituted methylene)s proceeds with much shorter time constants than that in pyrene-incorporated polyacrylates, vinyl polymer counterparts with the same side-chain structures, indicating the presence of stronger electronic interaction between the pyrene rings in poly(substituted methylene)s. The effects of every methylene substitution hold when each pyrene ring is connected to the polymer backbone with a monomethylene linker, while the effects are observed only weakly when a tetramethylene linker is employed. The results demonstrate the effectiveness of every methylene substitution in the prompt excimer formation of pyrene connected to the polymer backbone either directly or with the monomethylene linker.

中文翻译:

掺入聚(取代亚甲基)s中的P的激发态动力学:密集堆积的on对准分子形成的影响

通过皮秒时间分辨荧光光谱和飞秒时间分辨近红外吸收光谱在900-1400 nm范围内研究掺入聚(取代亚甲基)中的pyr的激发态动力学。紫外线照射后,聚(取代的亚甲基)中的pyr环立即被光激发到单体激发态,随后迅速形成准分子,其时间常数为几皮秒至几百皮秒。聚(取代的亚甲基)中受激准分子的形成要比掺入ene的聚丙烯酸酯(具有相同侧链结构的乙烯基聚合物对应物)的时间常数短得多,这表明poly(取代的)中的rings环之间存在更强的电子相互作用亚甲基)。当每个pyr环通过单亚甲基连接基连接到聚合物骨架上时,每个亚甲基取代的效果均保持不变,而仅在使用四亚甲基连接基时才能观察到该效果。结果证明了每个亚甲基取代在直接或直接与单亚甲基连接基连接到聚合物主链的of的准分子形成中的有效性。
更新日期:2018-07-13
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