Synthesis and liquid crystal behaviour of tetrathiafulvalenes containing cyanobiphenylyloxy groups

The synthesis and characterization of a series of tetrathiafulvalenes (1–3) bearing a different number of 4′-cyanobiphenyl-4-yloxy side groups is reported. Compound 3 exhibits a nematic and a smectic A mesophase. In the smectic A phase a peculiar local biaxial order due to the unconventional molecular structure is proposed. A charge-transfer salt derived from 3, namely 3·I5 , also shows mesogenic behaviour.