Synthesis, optical properties, crystal structures and phase behaviour of symmetric, conjugated ethynylarene-based rigid rods with terminal carboxylate groups
作者:Tolulope M. Fasina、Jonathan C. Collings、Jacqueline M. Burke、Andrei S. Batsanov、Richard M. Ward、David Albesa-Jové、Laurent Porrès、Andrew Beeby、Judith A. K. Howard、Andrew J. Scott、William Clegg、Stephen W. Watt、Christopher Viney、Todd B. Marder
DOI:10.1039/b413514h
日期:——
Sonogashira cross-coupling reactions of 4-ethynylmethylbenzoate (1) with aryl halides gave 1,2-bis(4-carbomethoxyphenyl)ethyne (2), 1,4-bis(4-carbomethoxyphenylethynyl)benzene (3), 1,4-bis(4-carbomethoxyphenylethynyl)tetrafluorobenzene (4) and 9,10-bis(4-carbomethoxyphenylethynyl)anthracene (5), protected precursors to conjugated rigid rod bis(carboxylato) ligands. The compound 1,4-bis(4-carbomethoxyphenyl)butadiyne (6) was prepared by the oxidative homo-coupling of 1. The hydrolysis of 2 and 3 by NaOH in methanol gave the sodium salts of the respective carboxylate anions and subsequent treatment with HCl gave the corresponding free carboxylic acids. Compounds 2–6 were characterised by absorption, emission, IR, NMR and mass spectrometry and examined for liquid crystal phase behaviour by differential thermal analysis (DTA) and transmitted polarised light microscopy (TPLM). Compound 4 exhibited a nematic phase stable from 233.6 °C until decomposition at 320 °C. The single-crystal structures of 2, 5 and 6 were determined by X-ray diffraction at 110–160 K.
4-ynylmethylbenzoate (1) 与芳基卤化物的 Sonogashira 交叉偶联反应生成了 1,2-双(4-羰基甲氧基苯基)乙炔 (2)、1,4-双(4-羰基甲氧基苯乙炔基)苯 (3)、1、4-双(4-甲氧基苯乙炔基)四氟苯 (4) 和 9,10-双(4-甲氧基苯乙炔基)蒽 (5),它们是共轭硬棒双(羧基)配体的受保护前体。2 和 3 在甲醇中用 NaOH 进行水解,得到各自羧酸阴离子的钠盐,随后用 HCl 处理,得到相应的游离羧酸。化合物 2-6 通过吸收、发射、红外、核磁共振和质谱进行表征,并通过差热分析(DTA)和透射偏振光显微镜(TPLM)检查液晶相行为。化合物 4 在 233.6 ℃ 至 320 ℃ 分解期间表现出稳定的向列相。在 110-160 K 的温度下,通过 X 射线衍射测定了 2、5 和 6 的单晶结构。