Synthesis and mesogenic behavior studies of monosubstituted ferrocene-containing Schiff base liquid crystals

Two series of ferrocene compounds with structure of Fc-C6H4-N=CH-C6H4-OCnH2n+1 (series I) and Fc-C6H4-N=CH-C6H4-O2C-C6H4-OCnH2n+1 (series II) (Fc: ferrocenyl; n = 2, 4, 6, 8, 10, 12, 14, 16) were prepared. Their mesogenic behaviors were studied with DSC and polarized optical microscopy. The results show that series I compounds do not possess liquid crystalline properties, while series 11 compounds have narrow liquid crystal temperature range. These results prove that the length of the rigid core in the molecule has an important effect on the mesogenic properties.