Details

Autor(en) / Beteiligte

• Al-Karawi, Ahmed Jasim M.
• OmarAli, Al-Ameen Bariz
• Awad, Adil A.
• Doungmo, Giscard
• Terraschke, Huayna

Titel

Liquid crystal and photoluminescent properties of a series of symmetrical 1,2-bis(4-alkoxybenzylidene)hydrazines bearing long-tails of hydrocarbon chain

Ist Teil von

• Liquid crystals, 2021-02, Vol.48 (3), p.412-422

Ort / Verlag

Abingdon: Taylor & Francis

Erscheinungsjahr

2021

Quelle

Taylor & Francis Journals Auto-Holdings Collection

Beschreibungen/Notizen

• In this work, 1,2-bis[4-(n-alkoxy)benzylidene]hydrazine (n-alkoxy: O(CH 2 ) n H, n = 11-18 or 20), a symmetrical series of azines (linear compounds with rod-like shape structure), were synthesised using a very simple two-step procedure as a part of our continuing effort in evaluating hydrophobic 1,2-disubstituted hydrazine compounds as photoluminescent liquid crystalline materials. The first step of the synthesis involved the alkylation of the OH group of 4-hydroxybenzaldehyde in basic medium using the Williamson method to obtain 4-alkoxybenzaldehydes. While the second step included the condensation reaction of hydrazine hydrate and appropriately 4-alkoxybenzaldehydes compounds (mole ratio 1:2, respectively) in acidic medium under ambient conditions. The prepared compounds were characterised and their structures elucidated depending upon infrared (IR), ultraviolet-visible (UV-Vis), nuclear magnetic resonance ( 1 HNMR, 13 CNMR, DEPT NMR, 2D 1 H- 1 H-COSY and 2D 1 H- 13 C- HSQC) and elemental analysis (CHN). Liquid crystalline behaviour and photoluminescent properties were studied using polarised light optical microscopy (POM), fluorescence emissions (FE), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) techniques. The studies showed that all of these compounds are enantiotropic liquid crystalline materials exhibiting smectic (SmA and SmC) and nematic (droplet and thread) mesophases . The study also displayed that all of the prepared compounds are photoluminescent in the crystalline and liquid crystal states.