What you should know about isomers definition types and examples
Isomers definition :
An isomer is a chemical species having the same number and type of atoms as another chemical species, but having distinct properties because the atoms are arranged in different chemical structures. When atoms can take different configurations, the phenomenon is called isomerism . There are several classes of isomers, including structural isomers, geometric isomers , optical isomers and stereoisomers.
Isomerization can occur spontaneously or not, depending on whether the binding energy of the configurations is comparable.
Types of isomers
The two main categories of isomers are structural isomers (also called constitutional isomers) and stereoisomers (also called spatial isomers).
Structural isomers : In this type of isomerism, atoms and functional groups are linked differently. Structural isomers have different names IUPAC. An example is the change in position observed in 1-fluoropropane and 2-fluoropropane.
Types of structural isomerism include chain isomerism, where hydrocarbon chains have different degrees of gill, functional group isomerism, where a functional group can be divided into different groups, and skeletal isomerism, where the main carbon chain varies.
Tonomers are structural isomers that can spontaneously convert between forms. An example is the keto / enol tautomerism in which a proton moves between a carbon atom and an oxygen atom.
Stereoisomers : The bonding structure between atoms and functional groups is the same in stereoisomerism, but the geometric positioning can change.
This class of isomers includes enantiomers (or optical isomers), which are mirror images that do not overlap each other, such as the left and right hands. The enantiomers always contain chiral centers.
Enantiomers often exhibit similar physical properties and chemical reactivities, although molecules can be distinguished by how they polarize light. In biochemical reactions, enzymes usually react with one enantiomer over the other. An example of a pair of enantiomers is (S) – (+) – lactic acid and (R) – (-) – lactic acid.
Alternatively, the stereoisomers can be diastereoisomers , which are not mirror images of each other. Diastereoisomers may contain chiral centers, but there are isomers without chiral centers and those that are not even chiral. An example of a pair of diastereoisomers is D-threose and D-erythrose. Diastereoisomers typically have different physical properties and reactivities from each other.
Conformational isomers (conformers): The conformation can be used to classify isomers. The conformers can be enantiomers, diastereoisomers or rotamers.
There are different systems used to identify stereoisomers, including cis-trans and E / Z.
Examples of isomers
Pentane, 2-methylbutane and 2,2-dimethylpropane are structural isomers of each other.
Importance of isomerism
Isomers are particularly important in nutrition and medicine because enzymes tend to work on one isomer rather than another. Substituted xanthines are a good example of an isomer found in food and drugs.
Theobromine, caffeine and theophylline are isomers which differ in the position of the methyl groups. Another example of isomerism occurs in phenethylamine-based drugs. Phentermine is a non-chiral compound that can be used as an appetite suppressant, but does not act as a stimulant. Rearranging the same atoms gives dextromethamphetamine, a stimulant that is stronger than amphetamine.
You may also look at
You may also like that