Transformation from a rod-like to a hockey-stick-like and bent-shaped molecule in 3,4′-disubstituted azobenzene-based mesogens

New 3,4'-disubstituted azobenzene-based mesogens with an azo group joined directly to the central benzene core have been synthesised and their liquid crystalline properties studied. Both molecular arms are gradually elongated by the insertion of a number of benzoate units between the central core and a terminal dodecyloxy chain. Then the lengths of the molecular arms and the overall shape are varied from a rod-like to a hockey-stick-like and bent-shape. Typical bent-shaped mesophases and electro-optical switching can be observed upon reaching a sufficient length of the molecular arms. We demonstrated how the mesoscale organization strictly depends on the molecular shape.