Synthesis and characterization of monodisperse oligofluorenes
Synthesis and characterization of monodisperse oligofluorenes
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DOI：
10.1002/chem.200305659
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发表时间：
2004-06-07
影响因子：
4.3
通讯作者：
Yoon, DY
中科院分区：
文献类型：
--
作者：
Jo, JH;Chi, CY;Yoon, DY
报道了一种高效合成9,9-二（2-乙基己基）芴低聚物直至七聚体的方法，在合成中采用了重复铃木和山本偶联反应。制备必需中间体的关键步骤包括钯催化芳基溴转化为芳基硼酯（Miyaura反应），以及在钯催化芳基重氮盐交叉偶联反应中应用芳基硼酯对芳基溴的高反应活性。报道了其紫外/可见吸收和光致发光特性随链长的变化。此外，还描述了低聚物的玻璃化转变和液晶特性，并与聚合物的特性进行了比较。
An efficient synthesis of 9,9-bis(2-ethylhexyl)fluorene oligomers up to the heptamer is reported, with repetitive Suzuki and Yamamoto coupling reactions employed in the synthesis. The key steps for preparation of the essential intermediates include Pd-catalyzed transformation of aryl bromides to aryl boronic esters (Miyaura reaction) and the application of the much higher reactivity of aryl boronic esters over aryl bromides in the Pd-catalyzed cross-coupling reaction with aryl diazonium salts. Variation of the UV/Vis absorption and photoluminescence characteristics with chain length is reported. Moreover, glass transition and liquid-crystal characteristics of the oligomers are described and compared with those of the polymer.