metalchelating

Metalchelating, or metal chelation, is the binding of metal ions by multidentate ligands to form chelate complexes. Chelating agents attach to a metal through several donor atoms that belong to the same molecule, often wrapping around the metal to create stable ring structures. The chelate effect generally makes polydentate ligands more effective at stabilizing metal ions than equivalent combinations of monodentate ligands.

In coordination chemistry, the stability and selectivity of metal chelates depend on ligand denticity, ring size, and electronic properties. Common chelating agents include EDTA, which binds many divalent and trivalent metals; DTPA and deferoxamine for specific metals; and dimercaprol and DMSA (succimer) used in clinical settings. Natural chelators, such as siderophores produced by microorganisms, tightly bind iron to support uptake under limiting conditions.

Applications span science and industry, medicine, and environmental management. Chelation is used to solubilize and recover metals in hydrometallurgy, to sequester metals in contaminated environments, and to influence metal bioavailability in agriculture. In medicine, chelation therapy treats heavy metal poisoning (for example lead, mercury, arsenic) and iron overload, using agents such as EDTA, deferoxamine, deferasirox, deferiprone, DMSA, or dimercaprol. Chelators can also serve diagnostic and imaging roles when bound to radiometals or tracked by spectroscopy.

Safety and limitations include risks of depleting essential trace metals, potential nephrotoxicity, and adverse drug interactions. Chelation requires appropriate indication and clinical supervision to balance therapeutic benefit with safety.