1374786-99-8Relevant academic research and scientific papers
New chiral discotics with helical organization of the mesophase - Liquid crystalline derivatives of dibenzotetraaza[14]annulene
Grolik, Jaros?aw,Dudek, ?ukasz,Eilmes, Julita,Eilmes, Andrzej,Górecki, Marcin,Frelek, Jadwiga,Heinrich, Beno?t,Donnio, Bertrand
, p. 3875 - 3884 (2012)
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.
