The principle of action of chelating agents mainly involves coordination chemistry and complexation reactions. When chelating agents contact metal ions, their coordination sites will form Chemical bond with metal ions, and these bonds are usually strong Coordinate covalent bond. The following are the general steps for the principle of action of chelating agents:
Coordination sites: Chelating agents usually have multiple coordination sites, which can provide electron pairs or isolated electrons to form Coordinate covalent bond with metal ions. These coordination sites can be oxygen atoms, nitrogen atoms, sulfur atoms, etc., depending on the structure and chemical properties of the chelating agent.
Coordinate covalent bond formation: the coordination site in the chelating agent interacts with metal ions to form Coordinate covalent bond. This process involves the formation of Covalent bond, and electrons are transferred from the coordination sites to metal ions to form Coordinate covalent bond. The formation of Coordinate covalent bond makes metal ions surrounded in the coordination sphere formed by chelating agent.
Stabilizing complexes: chelating agents stabilize metal ions through Coordinate covalent bond formed with metal ions. This complexation can reduce adverse reactions between metal ions and other ions in water, such as oxidation, precipitation, or other forms of complex formation. The chelating effect of chelating agents can make metal ions more stable and alter their properties and behavior.
Reaction kinetics: The kinetics of complexation reactions are important factors affecting the action of chelating agents. The reaction rate, reaction equilibrium, and selectivity are all related to the kinetics of the reaction. The structure of chelating agents and the properties of coordination sites can affect the reaction rate and equilibrium, thereby affecting the chelating process and effect of chelating agents with metal ions.
It should be noted that the action principle of chelating agent also involves Coordination number, solvent environment, charge state of metal ions and other factors. Different chelating agents have different affinity and selectivity for different metal ions. Therefore, when using chelating agents, it is necessary to select appropriate chelating agents based on specific application requirements and target metal ions, and control appropriate experimental conditions to achieve the desired effect.