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Diastereomers are distinct molecular configurations that are a broader category. [3] They usually differ in physical characteristics as well as chemical properties. If two molecules with more than one chiral centre differ in one or more (but not all) centres, they are diastereomers. All stereoisomers that are not enantiomers are diastereomers.
Diastereomers differ from enantiomers in that the latter are pairs of stereoisomers that differ in all stereocenters and are therefore mirror images of one another. [3] Enantiomers of a compound with more than one stereocenter are also diastereomers of the other stereoisomers of that compound that are not their mirror image (that is, excluding ...
There are three common naming conventions for specifying one of the two enantiomers (the absolute configuration) of a given chiral molecule: the R/S system is based on the geometry of the molecule; the (+)- and (−)- system (also written using the obsolete equivalents d- and l-) is based on its optical rotation properties; and the D/L system is based on the molecule's relationship to ...
Enantiotopic groups are identical and indistinguishable except in chiral environments. For instance, the CH 2 hydrogens in ethanol (CH 3 CH 2 OH) are normally enantiotopic, but can be made different (diastereotopic) if combined with a chiral center, for instance by conversion to an ester of a chiral carboxylic acid such as lactic acid, or if coordinated to a chiral metal center, or if ...
Stereoisomers have the same atoms or isotopes connected by bonds of the same type, but differ in the relative positions of those atoms in space. Two broad types of stereoisomers exist, enantiomers and diastereomers. Enantiomers have identical physical properties but diastereomers do not. [7]
When a mixture of enantiomers is introduced into the chromatographic system, the individual enantiomers form transient diastereomeric complexes with the chiral mobile phase additive. In the chiral mobile phase additive technique, two possible mechanisms may operate: one possibility is that CMPA and the enantiomers may form diastereomers in the ...
Diastereomers are stereoisomers not related through a reflection operation. [4] They are not mirror images of each other. These include meso compounds , cis – trans isomers , E-Z isomers , and non-enantiomeric optical isomers .
More generally, for any pair of enantiomers, all of the descriptors are opposite: (R,R) and (S,S) are enantiomers, as are (R,S) and (S,R). Diastereomers have at least one descriptor in common; for example (R,S) and (R,R) are diastereomers, as are (S,R) and (S,S). This holds true also for compounds having more than two stereocenters: if two ...