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首页> 外文期刊>Chemistry: A European journal >Counterion effects on the columnar mesophases of triphenylene substituted [18]crown-6 ethers: Is flatter better?
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Counterion effects on the columnar mesophases of triphenylene substituted [18]crown-6 ethers: Is flatter better?

机译：抗衡离子对三亚苯基取代的[18]皇冠6醚的柱状中间相的影响：更平坦吗？

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摘要

The twisted lateral tetraalkyloxy ortho-terphenyl units in dibenzo[18]crown-6 ethers 1a-f were readily converted into the flat tetraalkyloxytriphenylene systems 2a-f by oxidative cyclization with FeCl _3 in nitromethane. Reactions of the latter with potassium salts gave complexes KX·2, which displayed mesomorphic properties. The aromatization increased both the clearing and melting points; the mesophase stabilities, however, were mainly influenced by the respective anions upon complexation with various potassium salts. In contrast, the alkyl chain lengths played only a secondary role. Among the potassium complexes of triphenylene-substituted crown ethers KX·2, only those with the soft anions I~- and SCN ~- displayed mesophases with expanded phase temperature ranges of 93 °C and 132°C (for KX·2e), respectively, as compared to the corresponding o-terphenyl-substituted crown ether complexes KI·1e (ΔT = 51°C) and KSCN·1e (plastic crystal phase). Anions such as Br~-, Cl~-, and F~- decreased the mesophase stability, and PF_6~- led to complete loss of the mesomorphic properties of KPF_6·2 although not for KPF _6·1. For crown ether complexes KX·2 (X = F, Cl, Br, I, BF_4, and SCN), columnar rectangular mesophases of different symmetries (c2mm, p2mg, and p2gg) were detected. In contrast to findings for the twisted oterphenyl crown ether complexes KX·1, the complexation of the flat triphenylene crown ethers 2 with KX resulted in the formation of organogels. Characterization of the organogel of KI·2e in CH _2Cl_2 revealed a network of fibers.
机译：通过在硝基甲烷中用FeCl 3氧化环化，将二苯并[18]冠-6醚1a-f中的扭曲的横向四烷氧基邻三苯基单元容易地转化为平面四烷氧基三亚苯基系统2a-f。后者与钾盐的反应得到配合物KX·2，其表现出介晶性质。芳构化增加了透明性和熔点。然而，中间相的稳定性主要受与各种钾盐络合的各个阴离子的影响。相反，烷基链长仅起次要作用。在三亚苯基取代的冠醚KX·2的钾络合物中，只有具有软阴离子I〜-和SCN〜-的钾络合物显示中间相，相温范围分别为93°C和132°C（对于KX·2e）与相应的邻-三苯基取代的冠醚配合物KI·1e（ΔT= 51°C）和KSCN·1e（塑性晶体相）相比。阴离子，例如Br​​〜-，Cl〜-和F〜-降低了中间相的稳定性，而PF_6〜-导致KPF_6·2的同构性质完全丧失，尽管KPF _6·1并非如此。对于冠醚配合物KX·2（X = F，Cl，Br，I，BF_4和SCN），检测到不同对称度（c2mm，p2mg和p2gg）的柱状矩形中间相。与对扭曲的邻苯基冠醚配合物KX·1的发现相反，平面三亚苯基冠醚2与KX的配合导致形成有机凝胶。 CH _2Cl_2中KI·2e有机凝胶的表征揭示了纤维网络。

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