Figure 4

Density functional theory calculations.
The optimized structures, HOMOs and LUMOs of the chelate structures of [SCH2N4]2− and heavy metal ions, as well as the selected bond length parameters (Å).
Density functional theory calculations.
The optimized structures, HOMOs and LUMOs of the chelate structures of [SCH2N4]2− and heavy metal ions, as well as the selected bond length parameters (Å).