RELATIONSHIP BETWEEN THE MAGNETIC-FIELD-INDUCED ORIENTATION IN THE MESOPHASES OF METALLOMESOGENS DERIVED FROM SCHIFFS BASES AND THEIR MESOPHASE STRUCTURE

In this paper the orientation of the mesophase domains of metallomesog ens derived from Schiff's bases by the effect of applied magnetic fiel ds is analysed. Particular emphasis is put on the copper compounds; in this case, the orientation depends on the number of aromatic rings in the molecule (four or six) and, when four rings are present, it also depends on the type of molecular structure (2,4-versus 2,5-substitutio n). These differences are related to the order of the mesophase and ca n be explained by considering the additional ordering of the short axe s. A strong indication of the existence of biaxial order in the mesoph ase is thus derived. This order is associated with the shape of the mo lecule which imposes geometrical constraints on the molecular packing.