Tuning the thermotropic properties of liquid crystalline p-substituted aroylhydrazones

Abstract

Lamellar smectic A to columnar mesophase crossover is observed in p-substituted aroylhydrazones by variation of the alkoxy chain density at peripherals.

Targeted synthesis of cadmium(ii) Schiff base complexes towards corrosion inhibition on mild steel

“…The obtained data were tested for Langmuir adsorption isotherm, which can be represented by the eqn (11),…”

“…In this scenario, Schiff bases are studied extensively due to the presence of >C]Ngroups which allow the corresponding Schiff bases to get adsorbed on the surface of mild steel and to form a monolayer on the surface spontaneously. Therefore, it can act as an effective corrosion inhibitor 8,9 for mild steel, [10][11][12][13] stainless steel, 14,15 iron, nickel, 16 copper, 17 aluminum, 18 and alloy, 19 in various aggressive solutions. The Schiff base ligands form stable complexes closely packed in the coordination sphere of metal ion to generate another class of compounds for corrosion inhibition.…”

“…Most of the complexes show considerable corrosion inhibition property while one polymeric cadmium azide complex has shown the maximum inhibition efficiency, which is quite good in comparison with other metal complex reported earlier. 10,11,13,20,27,31 The corrosion inhibition efficiency was studied by electrochemical methods and protection of metal surface by Cd(II) complexes was shown by FE-SEM images. Nuclearity driven corrosion inhibition trend of Cd(II) complexes was further corroborated by quantum chemical calculations.…”

Molecular approach to phase transitions in a calamitic ester substituted aroylhydrazone liquid crystal

“…At room temperature amide CO stretching vibrations at ~1650 confirms the intermolecular hydrogen bonding between the amide groups . These CO bonds are likely to form intermolecular hydrogen bonds in the LCs containing amide linking group particularly in aryolhydrazones . At Cr I → Cr II transition, the amide band shifts higher to 1656 cm −1 .…”

“…In continuation of earlier studies, we have shown that aroylhydrazone forms a suitable core for the design of liquid crystals capable of undergoing lamellar smectic mesophases in mono alkoxy chain derivatives . Recently, we have shown that presence of nonflexible (imine) substituent at aryolhydrozone core leads to complete breaking of intermolecular hydrogen bonding and formation of SmA phase . To the best of our knowledge, studies on origin of frequently observed tilted lamellar SmC mesophase has not been performed so far.…”