Polar Order and Symmetry Breaking at the Boundary between Bent-Core and Rodlike Molecular Forms: When 4-Cyanoresorcinol Meets the Carbosilane End Group
作者:Eduard Westphal、Hugo Gallardo、Giovanni Finoto Caramori、Nerea Sebastián、Maria-Gabriela Tamba、Alexey Eremin、Susumu Kawauchi、Marko Prehm、Carsten Tschierske
DOI:10.1002/chem.201503901
日期:2016.6.6
Two isomeric achiral bent‐core liquid crystals involving a 4‐cyanoresorcinol core and containing a carbosilane unit as nanosegregating segment were synthesized and were shown to form ferroelectric liquid‐crystalline phases. Inversion of the direction of one of the COO groups in these molecules leads to a distinct distribution of the electrostatic potential along the surface of the molecule and to a
合成了两个包含4-氰基间苯二酚核并包含碳硅烷单元作为纳米分离链段的非手性非手性弯曲核液晶,并显示形成铁电液晶相。这些分子中一个COO基团的方向反转会导致静电势沿分子表面的明显分布,并导致分子偶极矩的强烈变化。因此,产生了碳硅烷单元的明显的偏析程度,并因此改变了相结构和极性顺序的相干长度。对于具有更大偶极矩的化合物(CN1)碳硅烷单元的偏析得到抑制,该化合物形成顺电SmA和SmC相;极性顺序只有在过渡到新的LC相(即具有倾斜方向和极性方向一致的独特特征的铁电倾斜相(SmCL s P S))后才能实现。偶极矩较小的异构体化合物CN2形成碳硅烷基团的独立层,并显示出随机的极性SmA相(SmAP AR)和铁电多畴SmC s P S具有倾斜和极性方向的正交组合的相位以及更高得多的极化。因此,令人惊讶的是,具有较小分子偶极矩的化合物在LC相中显示出增加的极性顺序。除了铁电,在CN1的一个SmC相中还观