The detection of chiral perturbations in ferroelectric liquid crystals induced by dopants with axially chiral 2,2′-spirobiindan-1,1′-dione cores
作者:Qian Cui、Christa M. Huntley、Robert P. Lemieux
DOI:10.1039/b900594c
日期:——
Chiral perturbations exerted by the dopants 6,6â²-diheptyloxy-2,2â²-spirobiindan-1,1â²-dione (2) and 6,6â²-diheptoyloxy-2,2â²-spirobiindan-1,1â²-dione (4) in the SmC phase of the liquid crystal host 4-(4â²-heptyl[1,1â²-biphen]-4-yl)-1-hexylcyclohexanecarbonitrile (NCB76) are investigated via (i) probe experiments using the structural analogue 5,5â²-diheptyloxy-2,2â²-spirobiindan-1,1â²-dione (1) as chiral probe, and (ii) 2H NMR experiments using deuterated forms of 2 and NCB76. The results suggest that a probe experiment is more effective than 2H NMR in detecting chiral perturbations provided that the structure of the probe is similar to that of the chiral dopant, and that the chiral perturbations exerted by the dopant may be modeled as a âchiral fieldâ which is conceptually similar to the electric field exerted by a point charge that decays with increasing distance from the latter.
通过以下方法研究了掺杂剂 6,6â²-二庚基氧基-2,2â²-螺茚满-1,1â²-二酮 (2) 和 6,6â²-二庚氧基-2,2â²-螺茚满-1,1â²-二酮 (4) 在液晶宿主 4-(4â²-庚基[1、1â²-联苯]-4-基)-1-己基环己烷甲腈(NCB76)进行了研究,方法是:(i) 使用结构类似物 5,5â²-diheptyloxy-2,2â²-spirobiindan-1,1â²-dione (1) 作为手性探针进行探针实验;(ii) 使用 2 和 NCB76 的氚化形式进行 2H NMR 实验。结果表明,在探测手性扰动方面,探针实验比 2H NMR 更有效,前提是探针的结构与手性掺杂剂的结构相似,而且掺杂剂产生的手性扰动可被模拟为 "手性场",而 "手性场 "在概念上与点电荷产生的电场相似,随着与点电荷距离的增加而衰减。