Enantiomerieverhältnis

Enantiomerieverhältnis refers to the relative abundance of two enantiomers in a sample. Enantiomers are stereoisomers that are non-superimposable mirror images of each other, meaning they have the same chemical formula and connectivity but differ in their three-dimensional arrangement of atoms.

In a racemic mixture, also known as a racemate, the two enantiomers are present in equal amounts. This results in an enantiomeric ratio of 1:1. Such mixtures are often optically inactive because the rotation of plane-polarized light by one enantiomer is exactly canceled out by the equal and opposite rotation caused by the other enantiomer.

When the ratio is not 1:1, the sample is considered enantiomerically enriched or enantiomerically pure. The enantiomeric excess (ee) is a common way to quantify this enrichment. It is defined as the absolute difference between the percentages of the two enantiomers. For example, a sample with 70% of one enantiomer and 30% of the other has an ee of 40%. An ee of 100% indicates a pure enantiomer.

The enantiomeric ratio is a crucial parameter in various fields, including organic chemistry, medicinal chemistry, and pharmacology. Many biologically active molecules, such as drugs and natural products, exhibit stereospecificity, meaning that different enantiomers can have vastly different biological effects, ranging from therapeutic benefits to severe toxicity. Therefore, controlling and determining the enantiomeric ratio is essential for synthesis, analysis, and application.