Two homologous series of carborane-containing dioxanes 1[n] and 2[n] (n = 1–10) were prepared and their mesogenic properties investigated. All compounds exhibit nematic behavior and three members of series 2[n] show an E phase. Numerical analysis of the clearing temperatures gave a limiting value TNI(∞) of 89 °C for series 2[n] and indicated conformational flexibility of the dioxane ring. Investigations of three-ring derivative 1[4] gave Δn = 0.17, S = 0.53, and Δε = +0.4 ± 0.1 at 85 °C. Extrapolation of dielectric data for dilute solutions of 1[4] in 6-CHBT gave Δε = +0.4 ± 0.25 at 24 °C. Modelling of dielectric results with the Maier–Meier equation demonstrated that conformers with a higher β angle are preferred, which is consistent with conformational selection for the most elongated conformers.
准备了两个含有
碳硼烷的
二噁烷同系物系列1[n]和2[n](n = 1–10),并对它们的介晶性质进行了研究。所有化合物均表现出向列行为,而系列2[n]中的三个成员显示出E相。清晰温度的数值分析给出了系列2[n]的极限值TNI(∞)为89°C,并表明
二噁烷环的构象灵活性。对
三环衍
生物1[4]的研究得到了Δn = 0.17,S = 0.53,以及在85°C时Δε = +0.4 ± 0.1。对1[4]在6-
CHBT稀溶液中的介电数据进行外推时,在24°C得到了Δε = +0.4 ± 0.25。利用Maier–Meier方程对介电结果的建模表明,具有更高β角的构象更为偏好,这与对于最细长构象的构象选择一致。