Why do enantiomers rotate light?
1 Answer
As a consequence of the way plane polarised light is composed.....
Explanation:
They only rotate plane polarised light. Plane polarised light has properties that are in some ways similar to chirality.
Light that has passed through a polarising filter emerges as a wave form composed of electrical components oscillating as two vectors, one rotating left to right, and one rotating right to left. They are essentially helixes.
Helixes are non-superimposable, so the light is made up of what can be envisaged as a pair of enantiomeric vectors (if you resolve them they show as oscillating in the same plane, however).
So when plane polarised light interacts with chiral centres, one of the two helixes will slow down more than the other, and will therefore go out of synchronisation. Resolving the vectors demonstrates that the light rotates either left or right after passing through the chiral centre..
