The GAFF Force Field 53 for organic molecules, was used to construct interaction potentials for the DFO and 4HMS molecules through the Antechamber package. The charges are calculated using the AM1-BCC charge model. The chelator molecules are solvated with 3667 and 3410 water molecules for the DFO and 4HMS molecules respectively, using the single point charge (SPC/E) water model. This water model is rigid-body and non-dissociable and therefore speciation events for example between Zirconium and waters ionic products coming from hydrolysis are not taken into account. In recent years, Mertz and co-workers have shown that in order to obtain both accurate structural and thermodynamic properties associated with the binding of transition metal ions to proteins, classical force fields can be corrected via the inclusion of an extra attractive term 58 (∝ 1 r 4 ) which leads to the following non-bonded interaction potential shown below.