Figure 2.

Spontaneous breaking of mirror symmetry and chiral conformational isomerism: a) Cartoon depictions of the local molecular organisation present in the achiral uniaxial nematic phase and the spontaneously chiral twist–bend nematic phase exhibited by rod‐like (calamitic), bent core and dimeric liquid crystals. b) Demonstration of rotation about the first ‐CH₂‐CH₂‐ dihedral in a cyanobiphenyl dimer with a pentamethylene spacer (CB5CB, transitions: Cr 150 N_TB 92 N 97 Iso) leading to −gauche (Figure 2 c −60 °) and +gauche (Figure 2 c +60 °) conformers, which are non‐superimposable. c) Plots of energy (kJ mol⁻¹) versus this torsional angle as obtained for an isolated molecule of CB5CB using relaxed scans (36×10° steps) at the B3LYP/6‐31G(d) level of DFT in the Gaussian 09 suite of programs.20 The solid red line is a fit to guide the eye.