Figure 4. Calculated average relative hydrogen bond energies E and configurations of different complexes.

Dashed arrows indicate the energy change of different complexes with adding DMSO to NMF (grey color) or NMA (black color). In the configurations, only −N−H···O = C− units are drawn in the ball-stick model, and N, H, O, C atoms are shown in blue, white, red, and grey balls, respectively. The numbers labeled in the models are the hydrogen bond lengths, and the unit is Å. All the NMF are trans-conformers without specific notification.