Photoluminescent and liquid-crystalline properties of donor-acceptor-type 2,5-diarylthiazoles.
Photoluminescent and liquid-crystalline properties of donor-acceptor-type 2,5-diarylthiazoles.
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DOI：
10.1002/asia.200600305
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发表时间：
2007-02
期刊：
影响因子：
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通讯作者：
Junichi Shikuma;A. Mori;K. Masui;R. Matsuura;A. Sekiguchi;H. Ikegami;Masuki Kawamoto;T. Ikeda
中科院分区：
文献类型：
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作者：
Junichi Shikuma;A. Mori;K. Masui;R. Matsuura;A. Sekiguchi;H. Ikegami;Masuki Kawamoto;T. Ikeda
采用我们开发的过渡金属催化C-H芳基化反应合成了2,5-位分别带有给电子N,N-二烷基胺和吸电子氰基的供体-受体型2,5-二芳基噻唑。该化合物是在四丁基氟化铵（TBAF）作为活化剂的存在下，通过钯/铜催化剂对2位未取代的噻唑进行C-H芳基化合成的。在氟化银(I)存在下，通过钯催化反应，将2-芳基化噻唑在5位进一步进行C-H芳基化，得到具有不同链长的N,N-二烷基胺基团的供体-受体型2,5-二芳基噻唑。无论链长如何，紫外/可见光吸收、光致发光和电化学行为都是相似的，而液晶行为和热特性被发现取决于烷基链长度。具有N,N-二乙胺或N-丁基-N-甲基基团的化合物在较宽的温度范围内表现出稳定的液晶相以及较高的热分解稳定性。
The synthesis of donor-acceptor-type 2,5-diarylthiazoles that bear electron-donating N,N-dialkylamine and electron-withdrawing cyano groups at the 2- and 5-position, respectively, were carried out with transition-metal-catalyzed C-H arylation reactions developed by us. The compounds were synthesized by the C-H arylation of unsubstituted thiazole at the 2-position with a palladium/copper catalyst in the presence of tetrabutylammonium fluoride (TBAF) as an activator. Further C-H arylation of the 2-arylated thiazole at the 5-position was carried out by the palladium-catalyzed reaction in the presence of silver(I) fluoride to afford the donor-acceptor-type 2,5-diarylthiazoles with N,N-dialkylamine groups of different chain lengths. The UV/Vis absorption, photoluminescence, and electrochemical behavior were similar regardless of chain length, whereas liquid-crystalline behavior and thermal characteristics were found to be dependent on the alkyl-chain length. The compounds with N,N-diethylamine or N-butyl-N-methyl groups showed a stable liquid-crystalline phase over a wide temperature range as well as higher stability to thermal decomposition.