Do enantiomers always change the color of light?

1 Answer
Dec 3, 2015

Enantiomers, when reasonably pure, change the plane of rotation of plane-polarized light. The amount of rotation must be determined by experiment.

Explanation:

Check this link. So the answer to your question is NO; they don't even always change the plane of rotation of plane-polarized light. A pure enantiomer will change the plane of rotation of plane-polarized light in 1 direction (clockwise or counter clockwise). If quantities of the other enantiomer are available, it will change the plane of rotation in the OTHER direction. But the amount of rotation may be small or insignificant, or even zero.

Biology is replete with examples of handedness and chirality. When you next put sugar on your cornflakes, reflect that the sugar is not only highly chemically pure, it is optically pure, and you could do an experiment to measure its rotation of plane polarized light. Sugar's optical isomer would not be metabolized, because the enzymes that act on sugar are themselves handed, and are not spatially configured to work on the other isomer.