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Photoluminescent and Liquid‐Crystalline Properties of Donor–Acceptor‐Type 2,5‐Diarylthiazoles
Author(s) -
Shikuma Junichi,
Mori Atsunori,
Masui Kentaro,
Matsuura Ryuichi,
Sekiguchi Akitoshi,
Ikegami Haruka,
Kawamoto Masuki,
Ikeda Tomiki
Publication year - 2007
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200600305
Subject(s) - photoluminescence , acceptor , materials science , type (biology) , crystallography , optoelectronics , chemistry , condensed matter physics , physics , geology , paleontology
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 CH arylation reactions developed by us. The compounds were synthesized by the CH arylation of unsubstituted thiazole at the 2‐position with a palladium/copper catalyst in the presence of tetrabutylammonium fluoride (TBAF) as an activator. Further CH 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.