Implementing Liquid‐Crystalline Properties in Single‐Stranded Dinuclear Lanthanide Helicates

The connection of flexible protodendritic wedges to the bis‐tridentate rigid polyaromatic ligand L1 provides amphiphilic receptors L5 and L6 ; their reduced affinities for complexing trivalent lanthanides (Ln = La, Y, Lu) in organic solvent (by fifteen orders of magnitude!) prevent the formation of the expected dinuclear triple‐stranded helicates [Ln 2 ( L k ) 3 ] 6+ . This limitation could be turned into an advantage because L1 or L6 can be treated with [Ln(hfac) 3 ] (Hhfac = 1,1,1,5,5,5‐hexafluoro‐2,4‐pentanedione) to give neutral single‐stranded [Ln 2 ( L k )(hfac) 6 ] complexes with no trace of higher‐order helicates. Whereas ligands L1 and L5 are not liquid crystals, L6 can be melted above room temperature (41 °C) to give a nematic mesophase, and its associated dinuclear helical complex [Y 2 ( L6 )(hfac) 6 ] self‐organises at the same temperature into a fluidic smectic mesophase.