"Henri Kagan and Kenso Soai Win 2026 Chemistry Nobel"
Chirality
property of a molecule whose mirror image cannot be superimposed on itself
Enantiomer
one of a pair of mirror-image forms of the same chiral molecule
Many molecules exist in two forms that are mirror images of each other. They are like a person's left and right hand. Chirality means a molecule and its mirror image cannot be superimposed on one another. Both forms have the same atoms joined in the same order, but they cannot be placed on top of each other. Such mirror-image pairs are called enantiomers. A carbon atom joined to four different groups creates this mirror-image asymmetry. This carbon atom is called a stereocentre. Dutch chemist Van't Hoff and French chemist Le Bel explained in 1874 that this asymmetry comes from the tetrahedral (four-sided) arrangement of bonds around such a carbon atom.
In living things, this mirror-image choice is not random. Homochirality means living organisms use only one mirror-image form of key molecules. These key molecules include amino acids and sugars. Nearly all natural amino acids occur as the L-form. Most natural sugars occur as the D-form. The opposite mirror-image forms exist chemically. However, life rarely uses them. Why biology prefers one form over the other has puzzled scientists for a long time.
In the early 1900s, German chemist Willy Marckwald used a chiral catalyst. A chiral catalyst is a substance that speeds up a reaction without being used up. This substance itself has a mirror-image structure. Marckwald found that it produced slightly more of one enantiomer than the other. For decades after this, chemists could not explain how a catalyst's own chirality controlled the chirality of its product. They also could not make this effect any stronger.
The 2026 Nobel Prize in Chemistry was awarded to Henri Kagan and Kenso Soai for solving this puzzle in the laboratory. Kagan worked in the 1980s. He studied reactions using chiral catalysts. He found that catalyst chirality and product purity have a non-linear relationship. Until then, chemists believed that a catalyst's own mirror-image purity would directly decide the product's purity. They thought this would happen in a straight-line, proportional manner. Kagan proved something different. Even a catalyst containing only a small excess of one mirror-image form could still produce a product that was almost entirely one enantiomer. This came to be called the non-linear effect. …
Consider the following statements regarding chirality in chemistry:
1.Enantiomers have the same chemical formula and the same connectivity of atoms, but differ in three-dimensional spatial arrangement.
2.Chiral molecules found in living organisms typically occur as near-equal mixtures of both mirror-image forms.
Which of the statements given above is/are correct?
Match List I (Scientist) with List II (Contribution) and select the correct answer using the codes given below:
List I
A.Henri Kagan
B.Kenso Soai
C.Willy Marckwald
D.Van't Hoff and Le Bel
List II
1.Demonstrated a non-linear relationship between catalyst chirality and product chirality
2.Designed the first autocatalytic reaction producing a single enantiomer
3.First obtained a slightly asymmetric enantiomer yield using a chiral catalyst
4.Proposed the tetrahedral arrangement of carbon bonds explaining molecular asymmetry
With reference to homochirality in biological systems, consider the following statements:
1.Almost all naturally occurring amino acids in proteins exist as L-isomers.
2.Most naturally occurring sugars in biological systems exist as D-isomers.
Which of the statements given above is/are correct?
An 'autocatalytic reaction', as used in the context of the Soai reaction, refers to a reaction in which:
Assertion (A): A chiral catalyst containing only a small excess of one mirror-image form can still yield a product with very high enantiomeric purity.
Reason (R): There is a strict, proportional (linear) relationship between a catalyst's enantiomeric purity and the enantiomeric purity of its product.
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