Problem 17 - A Complete Resource Book in Chemistry for JEE Main

Question

The complex used as an anti-cancer agent is (a) mer-[Co(NH \(\left.\left._{3}\right)_{3} \mathrm{Cl}_{3}\right]\) (b) \(\operatorname{cis}-\left[\mathrm{PtCl}_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]\) (c) \(\mathrm{cis}-\mathrm{K}_{2}\left[\mathrm{PtCl}_{2} \mathrm{Br}_{2}\right]\) (d) \(\mathrm{Na}_{2} \mathrm{CoCl}_{4}\)

Step-by-Step Solution

Answer

The correct complex is (b) \(\text{cis-}\left[\text{PtCl}_2\left(\text{NH}_3\right)_2\right]\), known as cisplatin.

Step 1: Identify Common Anti-Cancer Complexes

First, recall the common complexes known for their use in cancer therapy. Cisplatin, which is widely used as an anti-cancer drug, is a platinum-based compound with the formula \(\text{cis-} \left[ \text{Pt}(\text{NH}_3)_2\text{Cl}_2 \right]\). This complex is known for its ability to bind to DNA and disrupt cell division in cancer cells.

Step 2: Analyze the Options Given

Review each option provided:(a) \(\text{mer-}\left[\text{Co}(\text{NH}_3)_3\text{Cl}_3\right]\): A cobalt complex, not commonly associated with anti-cancer treatments.(b) \(\text{cis-}\left[\text{PtCl}_2\left(\text{NH}_3\right)_2\right]\): Known as cisplatin, a recognized anti-cancer agent.(c) \(\text{cis-}\text{K}_2\left[\text{PtCl}_2\text{Br}_2\right]\): A platinum compound but not the commonly used form for cancer therapy.(d) \(\text{Na}_2 \text{CoCl}_4\): Contains cobalt, similar to option (a), and not typically used in cancer treatment.

Step 3: Determine the Active Complex

Based on scientific knowledge, \(\text{cis-}\left[\text{PtCl}_2\left(\text{NH}_3\right)_2\right]\), or cisplatin, is well-known and widely used in chemotherapy to treat various types of cancers, making option (b) the correct choice.

Key Concepts

Anti-cancer agents

Anti-cancer agents are substances used to prevent, inhibit, or treat cancer. They can include a wide range of compounds and drugs that work through different mechanisms to combat cancer cells. All anti-cancer agents aim to target cancer cells while causing minimal damage to normal, healthy cells. Some agents work by interfering with the DNA within cancer cells, inhibiting their ability to multiply and spread. Others may target specific proteins or pathways involved in cancer cell growth. Cisplatin is one classic example of an anti-cancer agent. By damaging the DNA of cancer cells, cisplatin triggers cancer cell death while also disrupting their division. Although very effective, the choice of anti-cancer agent depends on cancer type, stage, and individual patient needs. For students exploring these compounds, it's essential to recognize that developing effective anti-cancer agents involves understanding the specific biological and chemical interactions within body systems.

Complex compounds in chemotherapy

Complex compounds are at the heart of many chemotherapy treatments, including cisplatin, which is a platinum-based complex. These compounds often consist of metals such as platinum that are coordinated with different ligands. In chemotherapy, complex compounds work by interacting with biological molecules in the body, mainly targeting and affecting cancerous cells. By binding tightly to certain cell components, these compounds can disrupt normal cell processes like replication. Several factors influence the effectiveness of complex compounds:

• The ability of the compound to specifically target cancer cells
• Stability in the body to avoid degradation before reaching the target
• Low toxicity to normal cells compared to cancer cells

Understanding the function of complex compounds in chemotherapy requires knowledge of coordination chemistry, molecular biology, and pharmacology. Future developments continue to focus on designing complex compounds that maximize cancer cell targeting with minimal side effects.

Binding to DNA in cancer treatment

One critical strategy employed by drugs like cisplatin involves binding to DNA in cancer treatment. This approach targets the DNA of cancer cells, preventing them from replicating and leading to cell death. Upon entering the cell, cisplatin undergoes a transformation where chloride ions are replaced with water molecules, activating the molecule for binding. It then forms cross-links with DNA strands by binding to specific nucleotides, disrupting the cell's genetic code. This DNA damage activates cellular mechanisms that lead to programmed cell death (apoptosis), effectively reducing the proliferation of cancer cells. This strategy is particularly effective for certain solid tumors but comes with potential side effects due to interactions with the DNA of healthy cells as well. This mechanism highlights the complex relationship between drug design and biological systems, showcasing the importance of precise targeting in cancer treatment. As research advances, understanding DNA interactions will remain pivotal in developing effective and safe anti-cancer therapies.