Heteroligand Palladium Complexes with One or Two Chiral Centres

A series of chiral mononuclear palladium(II) complexes, [(Az(n))Pd(L-m)], I-VIII, have been synthesized. Herein the Az(n)Pd fragments represent the cyclopalladated 4-tetradecyloxy-4'-alkoxyazobenzene bearing an optically active carbon atom in a terminal alkoxy chain while HLm is the anion arising from the achiral N-[4'(dodecyloxy)resorcylidene]-4-(alkyl)anilines or the N-[4'-(dodecyloxy) resorcylidene]-4-(alkoxy)anilines containing a stereogenic center in a lateral chain. The optically active alkoxy tails are derived by S-(-)-beta-citronellol and R-(-)-2-octanol. Thermotropic mesomorphism, namely nematic and smectic phases, has been observed for almost all the complexes, with higher thermal stability and clearing temperatures of the same order or lower than those of the corresponding organic ligands.