Columnar mesomorphism of bent-rod mesogens containing 1,2,4-oxadiazole rings

Polycatenar unsymmetrical β-diketonate ligands as a useful tool to induce columnar mesomorphism on highly luminescent boron difluoride complexes

“…4b-d), in agreement with a hexagonal columnar structure. 33,36,[41][42][43] In order to conrm the mesophase identication, compound 17 was selected as a representative example to be subjected to temperature dependent low-angle powder X-ray diffraction measurements. The diffractogram at 50 C on cooling shows a strong maximum from the (100) reection followed by two weaker sharp peaks with a d-spacing ratio of d/O3 and d/O4, from the (110) and ( 200) reections, respectively (Fig.…”

“…This value is consistent with the p-p stacking between neighbouring mesogens within the columns and indicates that the mesophase is highly ordered as a longrange order along the columns can be suggested. 41,44 In addition, a broad band in the wide-angle region is related to the molten alkyl chains. Table 5 displays the results of this study.…”

“…The lattice parameter (a) was calculated by following methods reported in the literature. 5,7,41 The calculated d-spacing values were obtained from the rst maximum (100) assuming a hexagonal structure.…”

1,2,4-oxadiazole: A Brief Review from the Literature About the Synthesis and Pharmacological Applications

“…These medications are designated as "orphans" because in normal market conditions, the pharmaceutical industry has little interest in the development and commercialization of products targeted for the small number of patients affected by rare d i s e a s e s , s u c h a s D u c h e n n e m u s c u l a r d y s t r o p h y, b e c a u s e t h e There are still other useful applications of this group that were not cited in this work, including plant protection (ROHR, 1989;JESCHKE et al, 1995), use as crystalline liquid mesophases (GALLARDO et al, 2011;SHANKER;TSCHIERSKE, 2011), OLED's (WU et al, 2005, tracers for Positron Emission Tomography (PET) (BARROW et al, 2011), polymers (ROSSER et al, 1981 and optical brighteners, among others (PROSSEL et al, 1978), which demonstrates the great versatility of this family of compounds.…”

New liquid crystals derived from thiophene connected to the 1,2,4-oxadiazole heterocycle

“…However, these heterocycles generally have heteroatoms (N, O, S) in their structure, giving the molecules a longitudinal dipole moment, which can induce interesting liquid crystal properties [10,16]. There are many reports in the literatures on 1,2,4-oxadiazole heterocycle derivatives with good thermal stability and emission in the blue region of the visible electromagnetic spectrum [17][18][19][20]. Liquid crystalline compounds can present interesting optical and mesomorphic properties influenced by the curvature [21][22][23][24][25][26].…”