Enantiomers are non-superimposable mirror images of each other, meaning they have the same molecular formula and connectivity, but a different arrangement of atoms in space. This difference in spatial arrangement can lead to differences in their photochemical properties, reactivity, and reaction outcomes.The photochemical properties of enantiomers can differ due to their chiral nature. When chiral molecules interact with plane-polarized light, they can either rotate the plane of polarization to the left levorotatory or to the right dextrorotatory . This phenomenon is known as optical activity. The extent of rotation is dependent on the specific enantiomer and its concentration in the sample.In terms of reactivity, enantiomers can exhibit different reactivity profiles when they interact with other chiral molecules or chiral environments. This is because the spatial arrangement of the atoms in the enantiomers can lead to different interactions with other chiral molecules, such as steric hindrance or favorable interactions. This can result in different reaction rates and selectivities for each enantiomer.The differences in photochemical properties and reactivity of enantiomers can have significant effects on reaction outcomes. For example, enantioselective reactions can produce one enantiomer preferentially over the other, leading to a higher enantiomeric excess ee of the desired product. This is particularly important in the pharmaceutical industry, where the biological activity of a drug can be highly dependent on its stereochemistry. In some cases, one enantiomer may have the desired therapeutic effect, while the other may be inactive or even harmful.In summary, the photochemical properties of enantiomers can differ due to their chiral nature, which can lead to differences in their reactivity and reaction outcomes. Understanding these differences is crucial for the development of enantioselective reactions and the synthesis of chiral molecules with specific biological activities.