SMECTOGENIC COPPER(II) COMPLEXES OF N-SALICYLIDENEANILINE DERIVATIVES- A COMPARATIVE-STUDY OF HOMOLOGOUS SERIES CARRYING ALKOXY AND OR ALKANOYLOXY SUBSTITUENTS/

A series of oxy-N-(4-ethoxyphenyl)salicylaldiminato]copper(II) complex es have been prepared and shown to possess smectic A phases with isotr opization temperatures ranging from 157 to 182 degrees C over butoxy t o octadecyloxy homologues. Corresponding series of the ligands have al so been isolated and characterized for their mostly nematogenic proper ties. Analogous series of xy-N-(4-acerosyphenyl)salicyladiminato]-copp er(II) complexes and their ligands have also proved to be mesomorphic; both of the phase type and the thermal stability are similar to those of the N-(4-ethoxyphenyl) counterparts. On the other hand, a series o f oxy-N-(4-ethoxyphenyl)salicylaldiminato]copper(II) complexes, in whi ch terminal alkyl soups are attached to the 4-oxysalicylidene groups v ia carbonyl groups, have been shown to melt at high temperatures (184- 228 degrees C) and not mesogenic at all, while the phase behavior of t he ligand series is very similar to that of the above 4-alkoxy series. An X-ray powder diffraction study of the two series of metallosmectic phases has led to a common structural model, in which layers of bis [ N-phenylsalicylaldiminato]copper(II) cores are intervened by fully int erdigitated alkyl chains. The thermodynamic parameters for the first s eries have been analyzed for their dependence on the terminal alkyl ch ain length and partial ordering of short chains is suggested.