Design and investigation of calamitic liquid crystals with low aspect-ratios: rigid y-shaped 1,2,4-tris(4-alkoxyphenylethynyl)benzenes
摘要:
报告了 1-碘-2,4,5-三(4-烷氧基苯乙炔基)苯 (1) 三炔基苯的合成和表征,并研究了它们的结构-同构关系。通过延长烷氧基链或用较小的原子取代碘基,这些化合物具有带有刚性线性间隔的 Y 形几何形状和稳定的向列相。这些刚性 y 型液晶的低纵横比和确定的钙钛矿性质使它们适合作为液晶显示设备液晶层的潜在候选材料,以改善视角。此外,1 的几何形状也从刚性 y 形逐步修改为刚性矩形,以实现之前报道的板状 1,2,4,5-四(4-十三烷氧基苯乙炔基)苯的不稳定向列行为,这种不稳定向列行为有望显示出双轴向列相。第四侧臂的尺寸以及这些四取代苯的长宽比都归因于较低的液态结晶度。
Nonlinear Polyfused Aromatics with Extended π-Conjugation from Phenanthrotriphenylene, Tetracene, and Pentacene: Syntheses, Crystal Packings, and Properties
摘要:
New classes of nonlinear polyaromatics with extended conjugation at lateral and longitudinal directions from triphenylene, tetracene, and pentacene backbones are reported. These planar and twisted polyfused aromatics are obtained through specific and selective multifold Scholl reactions from predesigned polyaryls. These derivatives displayed shifted or perfect cofacial packing motifs. Single crystals of one derivative, phenanthro[9,10:b]triphenylene, were used as p-channel materials in fabricating transistor devices, which exhibited an average mobility of 0.38 cm(2) s(-1) and a maximum mobility reaching 1.15 cm(2) V-1 s(-1)