Structures, properties and miscibility behaviour of liquid crystalline polycatenar tetrone derivatives

The tetrones represent an interesting new mesogenic building block. The results of this study show that they can be incorporated into a variety of mesophases. A smectic phase was observed in the polycatenar compound with four terminal chains as expected. The phase exhibits a tilted structure (S_c phase) to prevent void formation. The compound with six pendant chains forms a columnar phase. In spite of their structural similarity, the tetrones studied tended not to be completely miscible. However, complete miscibility with a semi-discoid phenylhydrazone was observed. When this hydrazone, which forms a columnar 'D_ho phase', was mixed with tetrone which forms a columnar 'D_hd phase' a columnar hexagonal phase was produced with enhanced stability. We believe that the stability enhancement derives from a charge transfer interaction between the tetrone and the phenylhydrazone.