Applications of coordination compounds

Govt.

Postgraduate

College

Topic

Islamia

Faisalabad.

Applications of Coordination Compounds

Course title

Inorganic Chemistry-II

Course code

CHM-501

Submitted by

Submitted to

Rashid Hussain

Sir Aqib Amjad

Roll no. 303

Lecturer

BS Chemistry 5th Remarks:________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________


Contents (Hyperlinks to find quickly)

Applications of coordination compounds in in chemistry      

Qualitative analysis Quantitative analysis Detection of ions Chelating ligands Complexometric titrations and masking agents Colour test

Applications of coordination compounds in industry      

Metal extraction Purification of metal DYES and Pigments Coordination compounds in detergents Photography Electroplating

Applications of coordination compounds in living systems (Life)      

Chlorophyll and pigment Haemoglobin and enzymes Coordination compounds in chelation therapy EDTA Cis-platin Lead poisoning treatment

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Coordination compounds play a vital role in chemistry, our daily life and in industry. Today we will discuss some of the applications of coordination compounds. So let’s get started:

Applications of coordination compounds in in chemistry Coordination compounds are used in analytical chemistry for quantitative as well as qualitative analysis of different chemicals.

(1) Qualitative analysis Qualitative methods of analysis are used to identify and separate many inorganic compounds. For example the complex formation of immense is used to identify and separate the inorganic ions. E.g. Detection of cupric ions in the salt: Following reaction is used to detect the presence of cupric ions in the salt CuSO4 (solution) + NH3 → deep blue complex When copper sulphate is mixed with aqueous ammonia, a deep blue colour is produced which shows the presence of cupric ions in the salt.

(2) Quantitative analysis Complexes formed during the quantitative analysis method are used for the detection of ions. For example during quantitative analysis the formation of scarlet red complex with dimethyl glyoxime is used to detect and assessment of Ni+2 ions.

(3) Detection of ions

Ca+2 and Mg+2 ions are stable complexes with EDTA. We can use EDTA for the estimation of Ca+2 and Mg+2 ions in hard water. Hardness of water can be determined by titration method using the sodium salt of EDTA. During titration Calcium EDTA and Magnesium EDTA complexes are formed. These complex ions can be estimated on the basis of their stability constants.

Figure 1: Calcium complex ion (taken from:

Figure 2: Mg complex ion (taken from:

https://www.nextgurukul.in/wiki/concept/cbse/ class-12/chemistry/coordinationcompounds/importance-andapplications/3961754#/)

https://www.nextgurukul.in/wiki/concept/cbse/cl ass-12/chemistry/coordinationcompounds/importance-andapplications/3961754#/)

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(4) Chelating ligands Chelating ligands are often used to form insoluble complexes e.g. Ni(DMG) (Nickeldimethylglyoxime) and Al(oxine)3 (tris(8-hydroxyquinoline) aluminium)

(5) Complexometric titrations and masking agents EDTA is used in the volumetric determination of a wide variety of metal ions in solutions, e.g. Zn +2, Pb+2, Ca+2, Co+2, Ni+2, Cu+2, etc. mixtures of metals can be analysed by the careful adjustment of pH and using suitable indicators. E.g. Bi+3 in the presence of Pb+2. EDTA can also be used as masking agent in order to remove a metal ion.

(6) Colour test Mostly complexes are coloured compounds. It means they can be used as colorimetric reagents. For example formation of red 2, 2-bipyridyl and 1, 10-phenanthroline complexes as a test for Fe+2. Cu+2 can be identified as it makes blue complex with NH3. CuC l+ 4NH → [Cu(NH3)4]Cl Blue complex

Fe+3 can be identified as it makes red complex with KSCN. FeCl3 + KSCN → K3[Fe(SCN)6] Red complex

Applications of coordination compounds in industry (1) Metal extraction Metals are extracted from their ores through a process called solvent extraction. Such as silver and gold can be extracted from their ores by the formation of cyanide complexes. In this method the ore is mixed with cyanide solution under oxidizing conditions. It results in the production of linear complexes which can be separated and reduced with metal like zinc to give a precious metals. Copper is extracted at large scale by solvent extraction process. Copper is extracted from a mixture of metals using a reagent like 5-nonyl-2hydroxybenzaldoxime. It was introduced by ICI. When the reagent solution LH is added to Cu+2 it forms a complex CuL2. It is a neutral compound and is soluble in organic solvent.

Figure 3:Copper extraction (taken from: http://www.mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect8c.html )

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(2) Purification of metal The subsequent decomposition of coordination compounds gives purified metals. For example when nickel is treated with CO it gives tetracarbonyl Nickel (0), which can be decomposed thermally to get pure nickel. Similarly, Bauxite is purified by forming complex with NaOH.

(3) DYES and Pigments Coordination compounds have been used from the earliest times as dyes and pigments, for example madder dye. Its colour is red. It is a complex of hydroxyanthraquinone. A blue pigment Copper phthalocyanine is the more modern example of pigments. Co[(H2O)6]Cl2 can be used as invisible ink. CoCl2.6H2O is invisible solution. But on slightly heating it produces Co[CoCl4] which gives blue colour. 2Co[(H2O)6]Cl2

⇌

Co[CoCl4] + 12H2O

Invisible when written

Blue on heating

(4) Coordination compounds in detergents We know that due to the presence of Ca+2 and Mg+2 ions in water makes it hard water. Removing these ions from hard water is a matter of great importance for industries. It can be done by complexation. The reagents which are used for this purpose are called sequestrating agents and the process is known as sequestration. The most commonly used sequestrating agent is polyphosphates. Polyphosphates make much stronger complex with Ca+2 and Mg+2 ions. In this way hard water is purified. But the much more use of polyphosphates may lead to some serious problems such as eutrophication and uncontrolled growth of algae. Therefore, this reagent has been replaced with tetra sodium salt of EDTA nitrilotriacetate. It is abbreviated to NTA.

Figure4: Phosphate and nta

( Taken from:http://www.mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect8d.html)

(5) Photography In black & white photography, when AgBr forms a complex hypo solutions, a complex [Ag(S2O)2]3 is formed. In this way, a developed film in black and white photography can be fixed.

(6) Electroplating Coordination compounds are also used in electroplating e.g. K[Ag(CN)2] is used for electroplating of silver, and K[Au(CN)2] is used for gold plating.

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Applications of coordination compounds in living systems (Life) Metals are present in biologicals system in a wide range. For example iron in haemoglobin, calcium in bones, sodium and potassium in nerve cells.

(1). Chlorophyll and Pigment Coordination compounds are of great importance in living systems such chlorophyll and pigment which is involved in photosynthesis is a coordination compound of magnesium.

Figure 4: Chlorophyll Taken from: https://www.nextgurukul.in/wiki/concept/cbse/class12/chemistry/coordination-compounds/importance-and-applications/3961754#/

(2). Haemoglobin and enzymes It is a red pigment. I is present in blood cells. It carries oxygen. It is very important coordination compound of iron. There are many enzymes which are metal complexes. They regulate biological processes in our body. For example an enzyme called carboxypeptidase. It is a hydrolytic enzyme which is involved in digestion process. This enzyme consists of zinc ion which surrounded by many amino acids molecules. Another enzyme called catalase. It canalizes the waste H2O2 of cells.

(3). Coordination compounds in chelation therapy Figure 5: Haemoglobin (Taken from: The removal of unwanted and toxic metal ions like lead, https://www.nextgurukul.in/wiki/concept/cbse/classCadmium, Hg can be removed from the human body is called 12/chemistry/coordination-compounds/importance-andchelation therapy. During First World War one of the applications/3961754#/) poisonous gases𝜷-chlorovinyldichloroarsine was used. It is also called Lewisite. This gas reacts with SH group of different essential enzymes. This gas does a lot of damage to the body cells. So an effective treatment was needed. It must be a compound that could react with arsenic more effectively as compared to enzyme. So a British Anti-Lewisite (BAL) was developed for this purpose. Chemically it is known as 2, 3-dimercaptopropanol.

BAL can also be used to remove the metal ions of Hg and lead but not for Cd, because it forms a soluble complex with Cd which can disperse in the whole body. We should choose our reagent very carefully. Because we want to remove only unwanted metal from the body. But the other precious metals which are already present in the body like iron that is present in the haemoglobin and the calcium that is present in the bones, can also be removed. So be very careful while choosing the reagent. For example in the treatment of lead poisoning dicalcium salt of EDTA can be used but it also removed the zinc metal from the body. On

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other hand disodium calcium salt of EDTA remove only the lead metals ions from the body. Hence, it is very useful in lead poisoning treatment. Similarly, D-penicillamine (a product of penicillin) can be used for the treatment of poisoning of metals, including Wilson's disease (build-up of copper in the body). desferrioxamine B is used to remove unwanted iron by the chelation therapy process. desferrioxamine B occurs naturally. Bacteria use it for uptaking of iron.

Figure 6: BAL (taken from: http://www.mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect8e.html )

Figure 7: D-penicillamine and desferrioxamine (taken from: http://www.mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect8e.html )

(4). EDTA

EDTA is used to remove Pb+2 by forming Pb-EDTA Complex. It is eliminated in urine. It is found very useful in lead ion treatment.

(5). Cis-platin Cis-platin can be used as anti-tumour agent for the purpose of cancer treatment. It is found very useful in cancer treatment. Figure 8: Cis-platin:

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(6). Treatment of lead poisoning EDTA is used for the treatment of lead poisoning. Metals are present as free metal ions but not as complex in biological systems. The ligans may be more complicated but the donar atom are ussually Oxygen, Nitrogen, Sulphur, and sometimes Carbon. In biological systems, when a metal is attached to a ligand, it is known as Macrocycles. These cyclic compounds contain many donor atoms for example porphyrin ring and corrin ring.

Figure 9: Lead EDTA Complex (taken from: https://www.nextgurukul.in/wiki/concept/cbse/class12/chemistry/coordination-compounds/importance-andapplications/3961754#/)

Figure 10: Prophyrin and corrinn (taken from: http://www.mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect8f.html 1/)

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References 1. :: Next Gurukul Platform ::. (n.d.). Retrieved November 9, 2017, from https://www.nextgurukul.in/wiki/concept/cbse/class-12/chemistry/coordinationcompounds/importance-and-applications/3961754#/ 2. Coordination complex. (2017, November 5). Retrieved November 9, 2017, from https://en.wikipedia.org/wiki/Coordination_complex#Application_of_coordination_co mpounds 3. coordination compound -- Britannica Online Encyclopedia. (n.d.). Retrieved November 9, 2017, from https://www.britannica.com/print/article/136410 4. Haq, B. N., & Rabia, R. (2017). Advanced Inorganic Chemistry. Lahore: Carvan. 5. Http://www.livewebtutors.com. (n.d.). Coordination Compounds Assignment Help Chemistry. Retrieved November 9, 2017, from https://www.livewebtutors.com/homework-help/chemistry/coordination-compoundsstructure-and-their-applications 6. Lee, J. D. (1991). complexes, Crowns and Crypts. In A new concise inorganic chemistry (4th ed., p. 308). New York, NY: Chapman and Hall. 7. Online Homework - Importance and Applications of Coordination Compounds. (n.d.). Retrieved November 9, 2017, from http://onlinehomework.zohosites.com/Importanceand-Applications-of-Coordination-Compounds.html 8. Sequestration of metal ions. (n.d.). Retrieved November 9, 2017, from http://www.mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect8d.html

Applications of coordination compounds

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