Di(5-substituted-salicylidene)ethylene diaminato-Complexes (Part II). Mesomorphic Properties of Di(5-alkylsalicylidene)ethylene diaminato Nickel(II) and Copper(II) Complexes and an X-Ray Structure Determination of Di(5-hexyloxy salicylidene)ethylenediaminato Nickel(II)

Abstract

Di(5-alkylsalicylidene)ethylenediaminato nickel(II) and copper(II) complexes have been synthesized and investigated. They show similar behaviour to the corresponding alkyloxy-substituted complexes—wide mesophase ranges and calamitic smectic phases. The thermal stability of the nickel(II) complexes is higher than that of the copper(II) complexes.

The title compound crystallizes with one water molecule per formula unit (water—diethyl ether interface) and Z = 4 in space group P2₁/c. X-ray crystal structure analysis shows that the molecular skeleton with the exception of the ethylene bridge is essentially planar and adopts a maximum stretched form. The crystal packing is characterized by a herringbone arrangement of columns of centrosym- metrical pairs of molecules.

Key Words:

• nickel(II) complexes
• copper(II) complexes
• salicylaldiminato complexes
• metallo-mesogens
• smectic A complexes