7 Difference Between Enantiomers And Diastereomers

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What Is Enantiomers?

An Enantiomer is one of the two molecules (stereoisomers) that are mirror images of each other and are non-superposable. Enantiomers have identical chemical and physical properties such as boiling point, melting point and spectroscopic features except for their ability to rotate plane-polarized by equal amounts but in opposite directions. Enantiomers interact differently with other chiral molecules i.e biologically active molecules as aminoacids, sugars, steroids etc.

Most of the essential oils contain enantiomeric compounds and these Enantiomers may possess different properties of interest in defining the quality of an essential oil. Enantiomers are preferably separated on capillary columns coated with a chiral stationary phase. There is no universal column for separation of all enantiomeric compounds. The three main types of chiral stationary phases are chiral amino acid derivatives, chiral metal coordination compounds and cyclodextrin derivatives.

To distinguish between a pair of Enantiomers, one must either place them in a chiral environment or use a probe that is inherently chiral in nature (like a polarized beam).

What You Need To Know About Enantiomers

  1. Enantiomers are stereoisomers or chiral molecules that are mirror images of one another and are non-superimposable.
  2. Enantiomers are always in pairs.
  3. Enantiomers have identical physical and chemical properties but differ in optical properties because some rotate polarized light in opposite directions.
  4. Separation of Enantiomers is a tedious process.
  5. Have one or more stereocenter. Stereocenter is the tetrahedral carbon to which the different atoms are attached.
  6. The naming of the structures of Enantiomers unfolds with the R and S naming system assigned based on the atomic mass of the substituents attached on the chiral center. 
  7. The shape of the molecules is similar in Enantiomers.

What Are Diastereomers?

Diastereomers are stereoisomers compounds with molecules that are not mirror images of one another and that are not superimposable. They occur when two or more stereoisomers of a compound have different configurations at one or more of the equivalent stereocenters and are not mirror images of each other.

When two diastereoismers differ from each other at only one stereocenter they are epimers. Each stereocenter give rise to two different configurations and thus typically increases the number of stereoisomers by a factor of two. It is sometimes difficult to determine whether or not two molecules are Diastereomers.

Diastereomers can have different physical properties and reactivity. They also have different melting points and boiling points and different densities. They usually have two or more stereocenters.

What You Need To Know About Diastereomers

  1. Diastereomers are stereoisomers compounds with molecules that are not mirror images of one another and that are not superimposable.
  2. There can be several molecules which are Diastereomers of each other.
  3. Diastereomers differ in all physical properties.
  4. Separation from the other pairs of Enantiomers is easy.
  5. They have two stereocenters.
  6. In Diastereomers, only one structure has the R and S configuration while the other has same configurations.  This is what distinguishes them from Enantiomer mirror images.
  7. Diastereomers have different molecular shapes.

Difference Between Enantiomers And Diastereomers

BASIS OF COMPARISON ENANTIOMERS DIASTEREOMERS
Description Enantiomers are stereoisomers or chiral molecules that are mirror images of one another and are non-superimposable.   Diastereomers are stereoisomers compounds with molecules that are not mirror images of one another and that are not superimposable.  
Molecules Configuration Enantiomers are always in pairs.   There can be several molecules which are Diastereomers of each other.  
Physical And Chemical Properties Enantiomers have identical physical and chemical properties but differ in optical properties because some rotate polarized light in opposite directions.   Diastereomers differ in all physical properties.  
Separation Separation of Enantiomers is a tedious process.   Separation from the other pairs of Enantiomers is easy.  
Stereocenters Have one or more stereocenter. They have two or more stereocenters.  
R and S Configuration The naming of the structures of Enantiomers unfolds with the R and S naming system assigned based on the atomic mass of the substituents attached on the chiral center.    In Diastereomers, only one structure has the R and S configuration while the other has same configurations.  This is what distinguishes them from Enantiomer mirror images.  
Molecular Shapes The shape of the molecules is similar in Enantiomers.   Diastereomers have different molecular shapes.  

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