enantiomeerit

Enantiomeerit are a pair of stereoisomers of a chiral molecule that are mirror images of each other and cannot be superimposed. Each member of the pair is called an enantiomeer; together they form the enantiomeeric pair. The concept is central to molecular chirality, which arises when a molecule has one or more stereocenters or other forms of chirality that prevent mirror-image interconversion without breaking bonds.

In achiral environments, enantiomeerit have essentially identical physical properties, including boiling points, melting points, and solubility. Differences appear when they interact with chiral surroundings, such as biological receptors or enzymes, where the two enantiomeerit can exhibit different binding affinities or activities. They also rotate plane-polarized light in opposite directions, a property described by optical activity and specific rotation.

The two members are commonly labeled using R/S configurations by the Cahn–Ingold–Prelog rules, or by the conventional D/L or (+)/(−) descriptors for optical rotation. A mixture containing equal amounts of both enantiomeerit is called a racemate or racemic mixture and is optically inactive because the rotations cancel.

Separation and analysis of enantiomeerit rely on methods that exploit differences in chiral interactions, such as chiral chromatography, crystallization with chiral resolving agents, or formation of diastereomeric salts. The study of enantiomeerit is crucial in fields like pharmacology and agrochemistry, since the two enantiomers of a compound can have markedly different biological effects. A well-known example is thalidomide, where one enantiomer proved therapeutic while the other caused adverse effects, highlighting the importance of enantiomeerit in drug development.