Controlling liquid and liquid crystalline network formation by core-fluorination of hydrogen bonded supramolecular polycatenars

Photo-switchable materials with liquid crystalline (LC) properties and being capable of showing mirror-symmetry breaking are of special interest from a fundamental scientific point of view as well as for the development of π-conjugated materials with tailored superstructures for optical, emissive and photonic materials. Herein we report two new series of supramolecular photosensitive polycatenar (multi-chained) mesogens formed by hydrogen bonding interaction between a taper shaped triple-chain benzoic acid as the hydrogen bond-donor and fluorinated azopyridines with only a single chain as hydrogen bond-acceptors. The self-assembly of these materials was characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X-ray diffraction (XRD). Depending on the position of the fluorine atom different types of LC phases were observed, including spontaneously chiral isotropic liquid (Iso₁^[*^]) and bicontinous cubic phases (Cub_bi^[⁎]/I23), as well as achiral cubic (Cub_bi/Ia3̄d) and non-cubic 3D phases with tetragonal symmetry. This report provides guidelines for the application of core fluorination at different positions as a powerful tool for controlling spontaneous helical self-assembly in supramolecular liquid and liquid crystalline materials.