Fig. (14) Structure of the minocycline-Zn⁺⁺ complex. (A) 3-D electronic distribution in the minocycline molecule. Pink volumes represent negatively charged zones. (B) Chemical structure of the minocycline-Zn⁺⁺ complex. (C) 3-D structure of the minocycline-Zn⁺⁺ complex with the zinc cation in dark grey.