Final answer:
Stereoisomers with two asymmetric centers that differ in the spatial arrangement of atoms at only one of the centers are known as diastereomers.
Step-by-step explanation:
Stereoisomers with two asymmetric centers are called diastereomers if one of the asymmetric centers has the same configuration in both stereoisomers and the other asymmetric center has the opposite configuration in the two stereoisomers. Diastereomers have the same sequence of bonds but differ in their spatial arrangement of atoms or groups of atoms without being mirror images of each other. This contrasts with enantiomers, which are stereoisomers that are non-superimposable mirror images of each other due to their chirality, such as those found in molecules with a single chiral center.
Diastereomers can exist in molecules such as cis-1,2-dimethylcyclopropane and trans-1,2-dimethylcyclopropane, where switching the configuration of one methyl group while keeping the other the same results in different spatial arrangements of the groups, leading to diastereomerism. The cis form in particular can exhibit a special case called a meso structure, which possesses an internal plane of symmetry, making it achiral despite having stereogenic centers.
Configurational isomers, including diastereomers and enantiomers, are only interconverted by making and breaking bonds. The concept of chirality plays an essential role in the properties of molecules and is a significant factor in biological systems, as demonstrated in the differing activities of enantiomers of biologically important molecules like glucose and amino acids.