diastereoomeeriühendite

Diastereoomeeriühendid are stereoisomers that are not mirror images of each other. Stereoisomers are molecules with the same molecular formula and the same connectivity of atoms but a different spatial arrangement of atoms. Diastereomers are a specific type of stereoisomer. Unlike enantiomers, which are non-superimposable mirror images, diastereomers are stereoisomers that cannot be superimposed on their mirror images. This distinction arises when a molecule contains more than one stereocenter.

In molecules with multiple stereocenters, the configurations at each stereocenter can vary. If two stereoisomers have different configurations at one or more, but not all, stereocenters, they are diastereomers. For example, a molecule with two stereocenters can have four possible stereoisomers. Two of these will be enantiomers (mirror images), and the other two will be diastereomers to each other and to the first pair.

A key characteristic of diastereomers is that they generally have different physical and chemical properties. For instance, their melting points, boiling points, solubilities, and spectroscopic data (like NMR spectra) can differ. This makes it possible to separate diastereomers using standard laboratory techniques such as chromatography or fractional crystallization. In contrast, enantiomers have identical physical properties and can only be separated by specialized methods like chiral chromatography or by forming temporary diastereomeric derivatives. The presence of diastereomers is common in organic chemistry, particularly in compounds with multiple chiral centers like carbohydrates and some cyclic molecules.