Investigation of Liquid Crystalline Behavior of Copper(II) Complexes Derived from Azo-Containing Salicylaldimine Ligands with Lateral Hydroxyl Group

Abstract

The one-step metal promoted reaction between 5-(4-alkoxyphenylazo) salicylaldehyde (alkoxy = decyloxy, dodecyloxy, tetradecyloxy) and 2-propanolamine in the presence of Cu (CH₃COO)·4H₂O yields new azo-containing salicylaldimine based copper(II) bis(chelates) as a result of the [1 + 1] Schiff base condensation. The mesogenic properties of these complexes were studied by differential scanning calorimetry (DSC) and polarizing microscope equipped with a heating and cooling stage. Copper complexes containing dodecyloxy and tetradecyloxy chain gave liquid crystalline character, while decyloxy containing copper complex was non-mesomorphic.

Keywords:

• azo
• copper complexes
• metallomesogen
• salicylaldimine
• schiff bases
• smectic A

ACKNOWLEDGMENT

The authors sincerely appreciate the financial support from Azarbaijan University of Tarbiat Moallem research Vice Chancellor Office and Faculty of Basic Science.

Notes

s: strong, m: medium, br: broad.

^a Cr: Crystal, SmA: Smectic A, I: Isotropic liquid.

^b Data obtained from first heating DSC cycle.

^c Data in parenthesis obtained from first cooling DSC cycle.