Importance and Applications of Coordination Compounds
NCERT Reference: Chapter 5 – Coordination Compounds – Page 136
Quick Notes
- Coordination compounds are vital in chemical analysis, industrial extraction, medicinal use, and biological systems.
- They function as analytical reagents, metal extractants, catalysts, and diagnostic agents.
- Several biological molecules (e.g. haemoglobin, chlorophyll, vitamin B12) are coordination compounds.
- Coordination chemistry has applications in fields such as electroplating, water treatment, and cancer therapy.
Full Notes
Coordination compounds play a critical role in many practical and industrial processes, as well as in the functioning of living organisms.
Analytical Chemistry
Examples:
- [Ni(DMG)2] is used to detect Ni2+ ions, forming a red precipitate with dimethylglyoxime (DMG).
- EDTA forms stable complexes with metal ions, enabling complexometric titrations.
- Estimation of hardness of water involves titration with EDTA.
Extraction/Metallurgy of Metals
Example: In cyanide process, gold and silver form soluble complexes like [Ag(CN)2]− which can then be separated.
Medicinal Chemistry
Examples:
- Cisplatin: a platinum-based complex used in chemotherapy for cancer treatment.
- Chelating agents (e.g. EDTA) are used for treating metal poisoning by binding toxic metals and facilitating their removal.
Biological Systems
Examples:
- Haemoglobin: an iron-porphyrin complex that transports oxygen in blood.
- Chlorophyll: a magnesium-porphyrin complex responsible for photosynthesis.
- Vitamin B12: a cobalt-containing coordination compound.
Industrial Catalysis and Applications
Examples:
- Wilkinson’s catalyst [RhCl(PPh3)3]: used in hydrogenation of alkenes.
- Zeise’s salt [PtCl3(C2H4)]−: example of an alkene complex.
- Nickel complexes in hydrogenation reactions.
Colour and Material Properties
Coordination compounds often exhibit vivid colours due to d–d transitions.
- Pigments
- Dyes
- Staining agents in microscopy
Other Uses
- Electroplating, water softening, photography, and chemical sensors all use coordination chemistry principles.
- Complexes also play roles in storage and transport of gases, and separation processes (e.g. solvent extraction using complexes).
Summary
- Coordination compounds are essential in analysis, extraction, catalysis, medicine, and biology.
- EDTA and specific complexes enable selective detection and quantification of metal ions.
- Industrial catalysis with metal complexes increases efficiency and selectivity.
- Key biomolecules such as haemoglobin, chlorophyll, and vitamin B12 are metal complexes.
- Applications include electroplating, water treatment, photography, pigments, and dyes.