New chiral discotics with helical organization of the mesophase鈥攍iquid crystalline derivatives of dibenzotetraaza[14]annulene

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• 作者：Jaros艂aw Grolik^a ; 艁ukasz Dudek^a ; Julita Eilmes^a ; ^{jeilmes@chemia.uj.edu.pl} ; Andrzej Eilmes^a ; Marcin Gó ; recki^b ; Jadwiga Frelek^b ; Benoî ; t Heinrich^c ; Bertrand Donnio^c
• 关键词：Dibenzotetraaza[14]annulene ; Liquid crystals ; SA-XRD ; Supramolecular chirality ; ECD spectroscopy ; Molecular Dynamics
• 刊名：Tetrahedron
• 出版年：2012
• 期刊代码：107_00404020
• 类别：ch
• 出版时间：20 May, 2012
• 卷：68
• 期：20
• 页码：3875-3884
• 文件大小：2773 K

摘要

Two optically pure derivatives of dibenzotetraaza[14]annulene, bearing four (S)- or (R)- 3,7-dimethyloctoxy peripheral chiral tails, respectively, and two hydroxybenzoyl meso substituents were synthesized using a convergent multi-step route. The structure of the products was determined by ¹H and ¹³C NMR spectroscopy, ESI-MS, and elemental analysis. The mesomorphic behavior of the two chiral compounds, deciphered by differential scanning calorimetry (DSC), small-angle X-ray diffractometry (SA-XRD), and polarizing optical microscopy (POM) investigations, revealed the induction of two lamello-columnar phases, i.e., columnar stacks confined in smectic layers, whose columns may be arranged either according to the pg rectangular planar symmetry (for the low-temperature phase) or without registry between vicinal layers (for the high-temperature mesophase). Evidence of a helical organization of the molecules in the mesophases was obtained using a combination of electronic circular dichroism (ECD) and SA-XRD results, Molecular Dynamics simulations and quantum-chemical calculations.