Enantiomería

Enantiomería is a form of stereoisomerism in which a molecule and its mirror image are non-superimposable. These two forms are called enantiomers. Enantiomers have identical physical properties such as melting point, boiling point, and solubility, except for their interaction with plane-polarized light. They rotate plane-polarized light in equal but opposite directions. One enantiomer rotates the light clockwise (dextrorotatory, denoted by d or +) and the other rotates it counterclockwise (levorotatory, denoted by l or -).

Chirality is the property of a molecule that makes it non-superimposable on its mirror image, and therefore enantiomeric. A molecule that is not chiral is achiral and is superimposable on its mirror image. The most common source of chirality in organic molecules is a stereogenic center, typically a carbon atom bonded to four different atoms or groups.

Enantiomers are chemically identical in achiral environments but can exhibit different biological activities in chiral environments, such as within living organisms. This is because biological systems, such as enzymes and receptors, are themselves chiral. For example, one enantiomer of a drug might be therapeutically effective, while the other might be inactive or even harmful.

A racemic mixture, also known as a racemate, is a mixture of equal amounts of two enantiomers. Racemic mixtures are optically inactive because the rotation of plane-polarized light by one enantiomer is exactly cancelled out by the opposite rotation of the other enantiomer. The synthesis of chiral molecules often produces racemic mixtures, and separation of the enantiomers, known as chiral resolution, can be a crucial step in their purification and application, especially in the pharmaceutical industry.