Fig. 3

PM3-optimized structures of (A) Erythrosin B, (B) berberine, and (C) their 1:1 ion-pair complex showing three stabilizing interactions: hydrogen bond (1.7 Å), electrostatic interaction (3.2 Å), and halogen bond (3.9 Å).

PM3-optimized structures of (A) Erythrosin B, (B) berberine, and (C) their 1:1 ion-pair complex showing three stabilizing interactions: hydrogen bond (1.7 Å), electrostatic interaction (3.2 Å), and halogen bond (3.9 Å).