Shoji Taku, Ito Shunji, Toyota Kozo, Yasunami Masafumi, Morita Noboru
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
Chemistry. 2008;14(27):8398-408. doi: 10.1002/chem.200701981.
Mono-, bis-, tris-, and tetrakis(1-azulenylethynyl)benzene and mono- and bis(1-azulenylethynyl)thiophene derivatives 5-10 have been prepared by Pd-catalyzed alkynylation of ethynyl arenes with 1-iodoazulene derivative or the 1-ethynylazulene derivative with tetraiodobenzene and iodothiophenes under Sonogashira-Hagihara conditions. Compounds 5-10 reacted with tetracyanoethylene in a [2+2] cycloaddition reaction to afford the corresponding 1,1,4,4,-tetracyano-2-(5-isopropyl-3-methoxycarbonyl-1-azulenyl)-3-butadienyl chromophores 12-16 in excellent yields, except for the reaction of the tetrakis(1-azulenylethynyl)benzene derivative. 1,1,4,4,-Tetracyano-2,3-bis(1-azulenyl)butadiene (17) was also prepared by the similar reaction of bis(1-azulenyl)acetylene (11) with tetracyanoethylene (TCNE). The redox behavior of novel azulene derivatives 12-17 was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed multistep electrochemical reduction properties. Moreover, a significant color change was observed by visible spectroscopy under electrochemical reduction conditions.
通过在Sonogashira-Hagihara条件下，使乙炔基芳烃与1-碘薁衍生物或1-乙炔基薁衍生物与四碘苯和碘噻吩进行钯催化的炔基化反应，制备了单、双、三、四（1-薁基乙炔基）苯以及单和双（1-薁基乙炔基）噻吩衍生物5-10。化合物5-10与四氰基乙烯发生[2+2]环加成反应，以优异的产率得到相应的1,1,4,4-四氰基-2-（5-异丙基-3-甲氧基羰基-1-薁基）-3-丁二烯基发色团12-16，但四（1-薁基乙炔基）苯衍生物的反应除外。1,1,4,4-四氰基-2,3-双（1-薁基）丁二烯（17）也通过双（1-薁基）乙炔（11）与四氰基乙烯（TCNE）的类似反应制备。通过循环伏安法（CV）和差分脉冲伏安法（DPV）研究了新型薁衍生物12-17的氧化还原行为，结果显示出多步电化学还原性质。此外，在电化学还原条件下通过可见光谱观察到显著的颜色变化。
