TRANSITION-METALS COMPLEXED TO ORDERED MESOPHASES .13. SYNTHESIS AND MESOMORPHIC PROPERTIES OF POTENTIALLY FERROELECTRIC SCHIFFS BASE PALLADIUM(II) COMPLEXES

A series of N-[4'-(dodecyloxy)resorcylidene]-4-(RO)-anilines (HL(n) n = 1, RO = (-)-cis-myrtanyl; n = 2, R*O = (-)-menthyl; n = 3, R*O = S (-)-beta-citronellyl; n = 4, RO = R-(-)-2-octyl) has been synthesized and the mesomorphic properties investigated. These ligands are able t o chelate a metal atom; accordingly three different series of palladiu m complexes, [(Ln)Pd(Ln)], [(Ln)Pd(Azoxy-6)] and [(L3)Pd(Ph-Py(n))] (w here Azoxy-6 and PhPy(n) are cyclopalladated 4,4'-dihexyloxyazoxybenze ne and 5-substituted-244-substituted-phenyl)pyrimidine, respectively) have been prepared. The mesogenic HL3 and HL4 ligands exhibit a S(C) phase, retained in [(L3)Pd(L3)], which changes to a cholesteric phase in [(L4)Pd(L4)] and becomes the more ordered S(H) phase in the [(Ln)P d(Azoxy-6)] (n = 3,4) derivatives. In contrast, in the [(L3)Pd(Ph-Py(n ))] compounds the mesomorphic phase is a S(A) phase.