PARAMAGNETIC SMECTIC LIQUID-CRYSTALS - SYNTHESIS AND PROPERTIES OF BIS(N-ARYL-4-[(4'-DECYLOXY)BENZYLOXY]SALICYLALDIMINE)COPPER(II) AND OXOVANADIUM(IV)

The synthesis and characterization (by optical microscopy, differential scanning calorimetry (DSC), X-ray diffraction and electron paramagnetic resonance (EPR)) of two new series of low molecular weight paramagnetic complexes with copper atoms and oxovanadium groups derived from N-aryl-4-[(4'-decyloxy)benzyloxy]salicylaldimine are reported. These complexes form paramagnetic smectic mesophases (S(C) and/or S(A)). The X-ray diffraction patterns taken in the smectic A phase with oriented samples indicate a positive anisotropy of the magnetic susceptibility for both kinds of complex. The EPR spectra recorded at variable temperature indicate that in the smectic phase an exchange interaction remains in the copper(II) complexes and a restricted rotation of molecules takes place in both kinds of complex. The liquid-crystalline properties of the ligands are also discussed.