New 6,6'-disubstituted-binaphthol derivatives as chiral dopants: Synthesis and temperature dependence of molecular conformations
New 6,6'-disubstituted-binaphthol derivatives as chiral dopants: Synthesis and temperature dependence of molecular conformations
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DOI：
10.1080/02678299608032841
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发表时间：
1996-09-01
期刊：
影响因子：
2.2
通讯作者：
Shibaev, VP
中科院分区：
文献类型：
--
作者：
Deussen, HJ;Shibaev, PV;Shibaev, VP
本文合成了一些新的手性双萘酚（BN）衍生物，它们在开放（BN-二乙醚）和桥接形式（BN-缩醛）的6,6‘位置具有不同的取代基R，R’。本文首次报道了手性6,6′-二取代-2,2′-二氧基-1,1′-二萘基(R,R′= -CH = CHCHO, -CH = CH-(p-BrPh), -CH = CH-(p-CHOPh))和手性9,14-二取代-二萘基[2,1-d: 1′，2′-f][1,3]与R，R′= -CH = CH-(p-BrPh), -CH = CH-(p-CHOPh)的合成。研究了BN衍生物在三种不同向列液晶（lc）中可能的液晶性质和摩尔扭功率（β (M)）。在6,6'位置上具有空间扩展取代基的衍生物（如苯乙烯基或乙烯基）表现出异常高的摩尔扭功率（高达124.5 μ M(-1)）。发现β (M)的大小与取代基的长度有直接的关系。桥式结构中，萘基基团之间的二面角约为54度，比相应的开式结构显示出更高的扭转力，开式结构允许θ变化约90度，从而在横切面和顺切面结构之间达到平衡。从开放和桥接bn的β (M)的不同温度依赖性出发，建立了分子构象和扭转力的分子模型。虽然在合成的任何化合物中都没有发现中间相，但它们可以被认为是合成潜在的手性含bn LCs的重要前体。
A number of new chiral binaphthol (BN) derivatives with different substituents R,R' in the 6,6'-positions in open (BN-diethylethers) and bridged forms (BN-acetals) have been synthesized. The syntheses of the chiral 6,6'-disubstituted-2,2'-diethoxy-1,1'-binaphthyls (R,R' = -CH = CHCHO, -CH = CH-(p-BrPh), -CH = CH-(p-CHOPh)) and the chiral 9,14-disubstituted-dinaphtho [2,1-d : 1',2'-f][1,3] dioxepins with R,R' = -CH = CH-(p-BrPh), -CH = CH-(p-CHOPh) are reported for the first time. The possible liquid crystalline properties and molar twisting powers (beta(M)) in three different nematic liquid crystals (LCs) of the BN derivatives were investigated Derivatives with spatially extended substituents in the 6,6'-positions (e.g. styryl or vinyl) show unusually high molar twisting power (up to 124.5 mu m(-1)). A direct correlation between the magnitude of beta(M) and the length of the substituents was found. Bridged forms, in which the dihedral angle theta between the naphthyl moieties is approximate to 54 degrees, show higher twisting power than the corresponding open forms, where theta is allowed to vary around 90 degrees resulting in an equilibrium between transoid and cisoid forms. From the different temperature dependencies of beta(M) of the open and bridged BNs, a molecular model was developed relating the molecular conformation and twisting power. Although no mesophase was found in any of the compounds synthesized, they can be considered as important precursors for the synthesis of potential chiral BN-containing LCs.