Discuss briefly giving an example in each case the role of coordination compounds in: (i) biological systems (iii) analytical chemistry (ii) medicinal chemistry and (iv) extraction/metallurgy of metals

Explanation

### Step-by-Step Solution:

#### (i) Role of Coordination Compounds in Biological Systems
Coordination compounds play a crucial role in biological systems. A prominent example is **hemoglobin**, which is a red pigment found in blood. Hemoglobin is a complex formed between **Fe²⁺ (iron ion)** and a **porphyrin** ligand. The primary function of hemoglobin is to transport oxygen from the lungs to various tissues throughout the body. The iron in hemoglobin can bind to oxygen molecules, allowing for efficient oxygen transport.

#### (ii) Role of Coordination Compounds in Medicinal Chemistry
In medicinal chemistry, coordination compounds are vital for the development of therapeutic agents. A notable example is **cisplatin**, a platinum-based coordination compound used in cancer treatment. The chemical formula for cisplatin is **[Pt(NH₃)₂Cl₂]**. Cisplatin works by binding to DNA in cancer cells, disrupting their replication and ultimately leading to cell death. This makes it an essential drug in chemotherapy regimens.

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