Estereoisomería

Estereoisomería is a type of isomerism where molecules have the same molecular formula and the same connectivity of atoms, but differ in the three-dimensional arrangement of their atoms in space. These isomers are called stereoisomers. The key distinction lies in their spatial orientation, not in how the atoms are linked together.

There are two main categories of stereoisomerism: diastereomers and enantiomers. Enantiomers are stereoisomers that are non-superimposable mirror images of each other. They have the same physical properties but can differ in their interaction with other chiral molecules, such as enzymes, and in their effect on plane-polarized light. Diastereomers, on the other hand, are stereoisomers that are not mirror images of each other. They can arise in molecules with multiple chiral centers or in molecules with double bonds that have different groups attached to each carbon of the double bond (cis-trans isomerism). Diastereomers generally have different physical and chemical properties.

Chirality is a fundamental concept related to stereoisomerism. A chiral molecule is one that is not superimposable on its mirror image, analogous to how a left hand is not superimposable on a right hand. Molecules with a chiral center, typically a carbon atom bonded to four different groups, are often chiral. The presence of chirality is a prerequisite for the existence of enantiomers. Understanding stereoisomerism is crucial in fields such as organic chemistry, biochemistry, and pharmacology, as the biological activity of many molecules is highly dependent on their three-dimensional structure.