Abstract
Polysilacage compounds, 1-alkyl-4-phenyl-2,3,5,6,7,8-hexasilabicyclo[2.2.2]octanes, exhibit hexagonal columnar and rectangular columnar phases in spite of the rod-like molecular structures. To stabilize the mesophases, we introduced a cyano group at the para-position of the phenyl group. Optical measurement disclosed that hexagonal columnar and rectangular columnar phases appeared with alkyl groups ranging from methyl to hexyl, while lamellar columnar phase was observed with a heptyl substituent. Comparison of the mesogenic behavior with parent non-cyanated compounds indicates that the cyano group remarkably enhances the structural order of the mesophase.
