Chelating agents and it's application

Chelating agent is a substance whose molecule can form several bond to a single metal ion.

1. Chelating Agents and its Application Presenation By Beena Rollno. 180000701011 M.Sc (P)

2. Contents Introduction Examples of chelating agents Types of chelating agents Property of ideal chelating agents Appplication of chelating agents Drawback of chelating agents Conculsion Referance

3. chelating agents A Chelating agent is a substance whose molecules can form several bond to a single metal ion.In other words A chelating agent is a chemical compound that react with metal ion to form stable ,soluble complexes.for example ethylenediamine (en),oxalato ion,EDTA etc.T he process in which chelating agent coordinated with metal ion is called chelation .and the resulting complex is known as chelates.for example

4. Example of chelating agents

5. Proteins ,polysaccharides and polynucleic acid are excellent polydentate ligand for many metal ion . Amino acid such as glutamic and histidine are typical chelators. Porphyrin rings in hemoglobin and chlorophyll act as Chelating agent.

6. Examples of metal chelates :

7. Types of chelating agents Classfication of chelating agents made on the basis of number of the atoms in molecules which coordinated with metal ion. They are classified as 1.Bidentate ligands e.g ethylenediammime ,oxalato ion 2.Tridentate ligands e.g diethylene triamine, 2,2’,2” Terpyridine (tery). 3.Tetradentate ligands e.g Triethylene tetraamine (trien). 4.Pentadentate ligands e.g Ethylenediamine triacetate anion. 5.Hexadentate ligands e.g EDTA ,

8. Chelating effect :chelating effect is the enhanced affinity of chelating ligands for a metal ion compared to the affinity of non chelating (monodentate) ligand for the same metal.greater the chelating effect greater will be stability of the resulting complex. For example [cu(en)] have higher stability constant than [cu(Me NH 2 )]. Some properties of an ideal chelating agent are Highly soluble in water. Low affinity for calcium . form non toxic complex with toxic metal. They are biologically inert. More affinity for metals than the endogenous ligand.

9. Applications of chelating agent Chelating agents play an important role in many field discuss below: In Agricultural : Metal chelate compound are common compontents of fertilizers to provide micro-nutritents . The micronutritents (Mn,Fe,Zn,Cu) are required for the growth of plants .most fertilizers contain phosphate salts that in the absence of chelating agents typically convert these metal ions into insoluble solids that are of no nutritional value to the plants .EDTA is the common typical chelating agents that keeps these metal ion in a soluble form . Some of chelating agents can be applied directly to the soil for root uptakes ,others via foliar sprays.some are also well suited for use in soilless culture ,as there is no formation of precipitates within the active ph ranges. Most common chelates used in agriculture are EDTA,DTPA

10. EDDHA

11. in extraction of metals : chemical weathering is attributed to chelating agents e.g.peptides,sugars that extract metal ions from minerals and rocks. Chelation solvent extraction an example of pre treatment techique for metal ions from aqueous sample (e.g sea water ) in oils production : in oil field chelating agents are used in stimulation treatment and for cleaning surface facilities . Typical oilfield chelating agent inclued EDTA,HEDTA (hydroxyethylenediamine triacetic acid),NTA (nitriotriacetic acid) and citric acid.

12. 2. In industrial field : used as catalysis : Homogeneous catalysts are often chelated complex. For example BINAP (bidentate Phosphine) in noyori Asymmetric hydrogenation . And used in manufacture of Synthetic (-)- menthol.

13. Noyori asymmetric hydrogenation : it is a chemical reaction for the enantioselective hydrogenation of ketones ,aldehydes and imines.

14. Preparation of synthetic (-)- menthol

15. chelating agents used for heavy metal removal from electroplating effluent. chelating agents used to soften water in soaps and detergents .e.g citric acid .chelation has little effect on the water ‘s mineral content ,other than to make it soluble. citric acid

16. Dental application : detin adhesives system were based on a co-monomer chelating ligand with calcium on the surface of the tooth and generated very weak water resistance chemical bonding. pharmaceuticals application : chelate complexes of gadolinium are often used as contrast agents in MRI scans. Penicillamine which form chelate complexes of copper is used in the treatment of wilson’ s disease. Antibotic drugs of the tetracycline and quinolone families are chelates of Fe 2+ ,Ca 2+ and Mg 2+ ions .

17. in chelation therapy : chelation therapy is a medical procedure that involves the administration of chelating agent to remove heavy metals from the body. There are number of chelating agents which used as drugs against heavy metal poisoning in chelation therapy : Ligand type of poisoning Dimercaprol arsenic ,copper EDTA derivatives lead Succimer lead ,arsenic,mercury Penicillamine gold toxicity ,copper ,lead, mercury Trienrine copper Deferrionamine lead

18. Drawback of chelating agents 1.Redistribution of toxic metal 2.Essential metal loss . 3.No removal of metal from intracellular sites . 4.Poor clinical recovery . 5.Pre –oxidant effect (DTPA). 6.Increased blood pressure ,headche,nausea.

19. Conculsion chelating agents are important in medical ,industry,agricultural,in bio chemistry and in other field. Chelating agents form stable complexes with metals Ion. But in chelation therapy they have some adverse effect like burning on part where injection given,headche ,kidney issuses.Nitrilotriacetic acid (NTA) ,ethylene diamine disuccinic acid (EDDS),iminodisuccinic acid(IDS) are most commnly used biodegrable chelating agents in place of non biodegrable agents EDTA,DTPA.

20. Reference https : // pubchem. ncbi. nlm. Nih.gov https : //en. Chem.station.com https : // en.m.wikipedia org https : // chem. Libertexts .org https : // www.elsevier .com