Application of Coordination Compounds

When comes our interest in coordination compounds? What are the real-world implications of this theory? How significant these coordination molecules are in real life may surprise you. Coordination compounds will be discussed in detail in this chapter. We’ll take a look at how these substances can be put to use in the real world.

Compounds known as coordination compounds fall within this category. In part, this is due to the unique chemistry of the substances involved. Even though we’ve studied their structures and isomers, we need more information. 

Importance And Applications Of Coordination Compounds

Some elements, such as transition metals, have the unusual capacity to establish bonds with charged or neutral molecules or atoms, resulting in the formation of new compounds known as coordination compounds. Coordination compounds or coordination complexes are the complex molecules that result from this process.

The Distinction Between Double Salt And Coordination Compound

Double salts and coordination compounds are the two forms of addition compounds. These are classified below based on how they dissolve in solution.

Werner’s Coordination Compounds Theory: applications of coordination compounds

Alfred Werner, a Swiss chemist, developed the concepts of coordination compounds and their structures in 1898. Based on what he believed, he postulated a primary and secondary valence for the core metal ion. After examining numerous chemicals, Werner proposed the postulates for the theory, known as Werner’s theory of coordination compounds.

Theoretical Postulates: applications of coordination compounds

1. Metals have two types of linkages in coordination compounds: primary and secondary valencies.
2. The oxidation number of the core metal ion is the same as the primary valency. The valency is ionisable and non-directional. Negative ions satisfy a primary valency.
3. The secondary valency of the central metal ion is determined by its coordination number. This valency is non-ionisable and directed. The neutral molecules or negative ions satisfy the secondary valencies. A metal’s secondary valency is fixed.
4. The following are some examples of primary and secondary valency: In a compound, the three Cl– ions in [Co(NH3)6]Cl3 form the primary valency of the metal ion, and the six NH3 neutral molecules produce the secondary valency.
5. Coordination secondary linkages produce polyhedra, a distinctive configuration, surrounding the metal atom. As a result, the coordination complexes have octahedral, tetrahedral, and square planar forms.

Importance and Application of Coordination Compounds

Because of their unique structure and characteristics, coordination compounds are essential in both nature and industry. The following are some major applications of coordination compounds in various aspects:

• In Biological Systems:

1. Haemoglobin, which is found in blood, functions as an oxygen transporter and is a coordination molecule with Fe2+ as the core atom and a porphyrin ring structure.
2. Cobalamin, also referred to as cyanocobalamin or Vitamin–B12 is a coordination molecule containing the metal element Cobalt.
3. Chlorophyll, the pigment responsible for plants’ green colour and photosynthesis, is a coordination molecule containing a Magnesium core atom.

• Metallurgical Use Of Coordination Compounds:

1. Metal extraction from ores involves complicated structures. Silver and gold, for example, create complexes with NaCN when dissolved in them. This method is used to extract them.
2. Mond’s technique, which is used to purify nickel, includes converting impure Ni to [Ni(CO4)] complex, which may then be dissolved to yield free and pure nickel.

• Analytical Chemistry:

1. Metals are detected analytically using complicated formations. Cu2+ ions, for example, can be identified via the creation of their complex.
2. Coordination chemistry can be used to calculate the hardness of the water.
3. Nickel can be detected by treating it with dimethyl glyoxime (DMG); Nickel and DMG produce a red-coloured complex.
4. Ag+ and Hg2+ can be separated by dissolving AgCl in NH3 to create a complex, whereas Hg2Cl2 forms an intractable black material.

• Pharmaceutical Use Of Coordination Compounds:

1. The platinum complex, cis-platin, has the formula cis -[Pt(NH3)2Cl2] and is a frequently used anti-tumour drug in medicine.
2. Lead toxicity is treated with calcium and EDTA combination.
3. Excess copper and iron in animal systems are eliminated by forming complexes with chelating ligands such as D-penicillamine and desferrioxamine B.

• Other Uses Of Coordination Compounds:

1. Metals are electroplated via the production of complex salts as electrolytes.
2. Coordination chemicals can act as homogeneous or heterogeneous catalysts. In the hydrogenation of alkenes, for example, the Wilkinson catalyst [(Ph3P)3RhCl] is used.
3. [(C2H5)4Pb] is a compound that is utilised as an antiknock.
4. When a developed photographic film is washed with hypo solution, a complex Ion, [Ag(S2O3)2]3- is produced. The extra AgBr dissolves to form the complexion.

Some Examples Of Coordination Compounds

Some examples of coordination compounds, along with their formulas, are provided in the following table:

The complexes can be classified as homoleptic or heteroleptic complexes, depending on their composition. Generally speaking, a homoleptic complex is one in which the metal is solely linked to one sort of donor group, such as: [Fe(CN)4]4-is a complex in which the central atom is attached to a variety of distinct donor groups, and the centre atom is the donor group.

Conclusion: 

Coordination complexes are formed by transition metals because of their unique ability to build these structures. The high charge to mass ratio and the availability of d-orbitals are to blame. Many complex compounds have been developed as a result of breakthroughs in coordination chemistry. There are several industries where coordination chemicals are used. Some examples include mining and metallurgy, as well as the medical sciences. Coordination compounds are employed in hydrometallurgical processes for the extraction of metals such as nickel, cobalt, and copper from their ores and in crucial catalytic processes to bring about polymerization of organic compounds such as polyethylene and polypropylene.