Racemic Assembly of Octahedral Metallomesogens via Δ−Λ Chiral Interaction: Detection of Novel VCD Signals in Quasi‐Racemate

Abstract The liquid crystalline columnar assemblies have been developed by using racemic metal complexes with Δ, Λ chirality ( M‐C8 , M = Ru or Ir) as mesogens. A racemic M‐C8 exhibits rectangular columnar (Col _r ) and hexagonal columnar (Col _h ) phases upon cooling from their isotropic phases, which are analyzed by the combination of grazing‐incidence X‐ray diffraction (GI‐XRD) measurements and molecular dynamics (MD) simulation. In the Col _h phase, with lattice parameter a = 3.2 nm, single molecules are proposed to stack and form columns. By contrast, a large lattice with dimensions a = 12.4 nm and b = 2.6 nm is formed in the Col _r phase. MD simulations demonstrated that two columns, each formed by the alternating stacking of Δ and Λ isomers, form a pair that subsequently assembles to construct a rectangular lattice. The paired columns are proposed to separate into individual columns in the Col _h phase at the higher temperature, with each column behaving independently. A quasi‐racemic assembly of Δ‐ Ru‐C8 and Λ‐ Ir‐C8 or vice versa is further prepared via the Δ−Λ interaction. It is found to have the same structure as rac ‐ M‐C8 and exhibit different vibrational circular dichroism (VCD) signals from the individual enantiomers.