For searching the chemical spaces, SpaceMACS V.0.9.2 was used with the following settings: a maximum of 100,000 printed results per query, and 1,000 possible alternatives for an unmatched linker extension during result building. Further, for SpaceMACS the identified metal-chelating groups were used as input SMARTS with some modifications because SpaceMACS does not allow explicit hydrogen atoms. Therefore, the explicit hydrogen atoms ("[H]") were changed to implicit ones ("h") or represented as explicit number of connections ("D"). For example, "[H]O" was changed to "[OD1]", "[H]N" to "[ND2]", and "[H][n+]" into "[nh1+]". All obtained SMARTS were inspected before the search to ensure that they were compatible with SpaceMACS. The same SMARTS were used for substructure searches in the libraries using RDKit.