Animated Solution for Chemistry - Coordination Compounds: Match the List-I with List-II. $\begin{array}{ll}\text{List-I}& \text{List-II}\\ \text{(A) Chlorophyll}& \text{(i) Ruthenium}\\ {\text{(B) Vitamin-B}}_{12}& \text{(ii) Platinum}\\ \text{(C) Anticancer drug}& \text{(iii) Cobalt}\\ \text{(D) Grubbs catalyst}& \text{(iv) Magnesium}\end{array}$ Choose the most appropriate answer from the options given below:

The Hidden Metals of Life and Medicine: A Journey Through Coordination Chemistry

Have you ever looked at a green leaf and wondered what makes it green? Or thought about how a tiny pill can fight something as formidable as cancer? The answer to both of these questions lies in the fascinating world of coordination compounds.

In this problem, we are tasked with matching four incredibly important chemical complexes with their central metal atoms. This isn't just a memory exercise; it's a tour through biology, medicine, and advanced organic chemistry. Let's break down each of these marvels one by one.

Chlorophyll

Our first complex is Chlorophyll. We all know it as the green pigment in plants that captures sunlight to drive photosynthesis. But structurally, chlorophyll is a masterpiece of nature. It consists of a large, complex organic ring called a porphyrin ring (specifically, a chlorin ring).

Right at the center of this massive organic structure sits a single, crucial metal ion: Magnesium ($M{g}^{2+}$).

Why Magnesium? Magnesium is a relatively light metal that holds onto its electrons tightly enough to avoid unwanted redox reactions, but it perfectly tunes the electronic properties of the ring to absorb red and blue light, reflecting the green light we see. Without this central Magnesium atom, life on Earth as we know it wouldn't exist! Therefore, Chlorophyll matches with Magnesium.

Vitamin $B_{12}$

Next on our list is Vitamin $B_{12}$. This vitamin is absolutely essential for the proper functioning of our nervous system and the production of red blood cells. A deficiency in $B_{12}$ can lead to severe anemia and neurological issues.

The chemical name for Vitamin $B_{12}$ is cyanocobalamin. If you look closely at the word "cobalamin," it gives away its secret: Cobalt ($Co$).

Vitamin $B_{12}$ features a corrin ring, which is similar to the porphyrin ring in chlorophyll but slightly smaller and less symmetric. At the heart of this corrin ring is a Cobalt ion. This is one of the rare instances where a heavy transition metal is biologically essential in the human body. The Cobalt atom is responsible for catalyzing complex radical reactions and methyl transfers. Thus, Vitamin $B_{12}$ matches with Cobalt.

Cis-platin

Moving from biology to medicine, we encounter our third item: an anticancer drug. The most famous and widely used coordination compound in chemotherapy is Cis-platin.

Its chemical formula is $[Pt(N{H}_3{)}_{2}C{l}_2]$. As the formula and the name suggest, the central metal atom here is Platinum ($Pt$).

Cis-platin has a square planar geometry. When it enters a cancer cell, the chloride ligands are displaced by water, and the Platinum atom binds strongly to the nitrogen atoms of the DNA bases (specifically guanine). Because it is the cis isomer (the two leaving groups are next to each other), it forms a cross-link on the same DNA strand. This kink in the DNA prevents the cancer cell from replicating, ultimately triggering cell death. It's a beautiful, albeit aggressive, application of coordination chemistry. So, the anticancer drug matches with Platinum.

Grubbs Catalyst

Finally, we have the Grubbs catalyst. While the first three compounds are famous in biology and medicine, Grubbs catalyst is a superstar in the chemistry lab.

It is used for a reaction called olefin metathesis, which is essentially a way to break and make carbon-carbon double bonds to build complex organic molecules. This reaction is so important that it won the Nobel Prize in Chemistry in 2005.

The magic behind Grubbs catalyst is the transition metal Ruthenium ($Ru$). Before Grubbs catalyst, chemists used other metals like Molybdenum or Tungsten, but those catalysts were highly sensitive to air and moisture. The Ruthenium-based Grubbs catalyst is incredibly robust and tolerates a wide variety of functional groups, making it a practical tool for synthesizing everything from pharmaceuticals to advanced polymers. Therefore, Grubbs catalyst matches with Ruthenium.

Now that we've explored the science behind each complex, let's finalize our matches: - (A) Chlorophyll $\to$ (iv) Magnesium - (B) Vitamin $B_{12}$ $\to$ (iii) Cobalt - (C) Anticancer drug $\to$ (ii) Platinum - (D) Grubbs catalyst $\to$ (i) Ruthenium

This sequence perfectly aligns with option (b). While this question might seem like a simple test of memory, understanding the why behind these facts makes them impossible to forget. Coordination chemistry isn't just abstract formulas; it's the chemistry that powers life, heals diseases, and builds the future!