Unusual mesomorphic behaviour of silyloxy-linked chiral bimesogens

In this article, we report on the synthesis of chiral bimesogens that possess silyloxy central linking groups. On first examination of the mesomorphic properties of the materials by X-ray diffraction and electrical field studies we came to the conclusion that the materials exhibit ferroelectric and antiferroelectric smectic C* phase behaviour. However, detailed investigations of the bimesogens indicated that the phases were not conventional smectics, but in addition strange phases that exhibited natural helical filaments on cooling from the isotropic liquid were formed. Indications are that these phases are possibly related to twist-bend structures or in-plane, modulated bent-core phases.