Synthesis and characterization of bis [ n -(4-benzoyloxy) Benzylidene{ n (n -di-/tri-alkoxy)benzoyl}-hydrazinato]nickel(II) complexes displaying liquid crystalline columnar phases

A series of materials based on the aroylhydrazinatonickel (II) complex is synthesized and characterized. The molecule in the materials consist of two 4-benzoyloxy-benzene groups and two benzene rings having two or three alkoxy chains containing 6, 8, 10, and 12 carbon atoms attached at the azomethine moiety. The synthesis, characterization by NMR and the phase sequence observed by DSC and polarized light microscopy are presented. Most of the compounds in the series display columnar phases in the temperature range between 100°C and 200°C. The phases observed and their temperature ranges are discussed in terms of the number and position of attached alkoxy chains.