Liquid crystalline conjugated oligomers: synthesis and mesomorphic properties of laterally and terminally alkyl-substituted oligo(1,4-phenyleneethynylene)s
Liquid crystalline conjugated oligomers: synthesis and mesomorphic properties of laterally and terminally alkyl-substituted oligo(1,4-phenyleneethynylene)s
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液晶共轭低聚物：侧面和末端烷基取代的低聚（1,4-亚苯基乙炔基）的合成和介晶性质
DOI：
10.1039/b808036d
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发表时间：
2008
影响因子：
--
通讯作者：
Y. Kawanishi
中科院分区：
文献类型：
--
作者：
Tetsuo Yatabe;Yasuzou Suzuki;Y. Kawanishi
合成了一系列新的共轭液晶低聚物，即侧链和末端烷基取代的低聚（1，4-亚苯基乙炔基）衍生物，并研究了其分子结构与液晶性能的关系。通过差示扫描量热法和偏光显微镜研究了低聚物衍生物的介晶性质。在具有不同核长的烷基取代的低聚物C_8H_17C_6H_4CC [C_6H_2（C_2H_5）_2CC]_nC_6H_4C_8H_17（n = 2-5）中，三聚体（n = 2）呈现单致性的双晶相，而其它三聚体呈现各向异性的双晶相。在烷基取代的四聚体R1 C6 H4 CC [C6 H2（R2）2CC][C6 H2（R3）2CC][C6 H2（R2）2CC] C6 H4 R1（其中R1、R2和R3 =不同长度的烷基链和H）中，大多数四聚体衍生物表现出双晶相，而其他四聚体衍生物没有表现出任何中间相。结果发现，中间相的形成和结晶-结晶和向列-各向同性转变温度强烈地受低聚物分子的结构特征的影响：（i）低聚物核的长度，（ii）侧链的长度、数目和位置，以及（iii）末端链的长度。
A new series of liquid crystalline conjugated oligomers, namely laterally and terminally alkyl-substituted derivatives of oligo(1,4-phenyleneethynylene)s, were synthesized, and the relationships between the molecular structures and the mesomorphic properties were investigated. The mesomorphic properties of the oligomer derivatives were examined by differential scanning calorimetry and polarizing microscopy. In the alkyl-substituted oligomers with varying core lengths, C8H17C6H4CC[C6H2(C2H5)2CC]nC6H4C8H17 where n = 2–5, the trimer (n = 2) exhibited a monotropic nematic phase, and the others showed enantiotropic nematic phases. In the alkyl-substituted tetramers, R1C6H4CC[C6H2(R2)2CC][C6H2(R3)2CC][C6H2(R2)2CC]C6H4R1 where R1, R2, and R3 = alkyl chains of varying lengths and H, most of the tetramer derivatives exhibited nematic phases, whereas the others did not show any mesophases. It was found that the formation of the mesophase and the crystalline–nematic and nematic–isotropic transition temperatures are strongly affected by the structural features of the oligomer molecules: (i) the length of the oligomer core, (ii) the length, number, and position of the lateral chains, and (iii) the length of the terminal chains.
低聚噻吩衍生物的手性向列相中的电子传导。
影响因子：
2.9
作者：
M. Funahashi;N. Tamaoki
通讯作者：
N. Tamaoki
影响因子：
4.3
作者：
Tour, JM;Rawlett, AM;Campbell, I
通讯作者：
Campbell, I