Fig. 5: DFT-calculated energy landscape for the interconversion of syn-rotamer (B-phase) and anti-rotamer (G-phase).

a 2D contour map indicates the Gibbs free energy (kJ/mol) over a range of inner (θᵢ) and outer (θₒ) torsional angles, whereas (b and c) portray 3D perspectives of this same surface, highlighting the key saddle point and the distinct minima corresponding to each rotamer. Blue marker denotes the syn-rotamer, while green marker denotes the anti-rotamer.