Chirality is a property of molecules that have non-superimposable mirror images, also known as enantiomers. These enantiomers often have different chemical and physical properties, including their photochemical properties. The interaction of chiral molecules with light can lead to different outcomes depending on the type of light and the specific enantiomer involved. This phenomenon is known as the chiroptical effect.The photochemical properties of chiral molecules can be influenced by the polarization of light. For example, circularly polarized light CPL can selectively interact with one enantiomer over the other, leading to different photochemical reactions or products. This selective interaction is due to the fact that the electric field vector of CPL rotates in a direction that matches the handedness right or left of the chiral molecule.One example of a chiral molecule that exhibits different photochemical properties under different types of light is limonene. Limonene is a chiral molecule found in citrus fruits, and its enantiomers, + -limonene and - -limonene, have distinct smells. When exposed to ultraviolet UV light, the enantiomers can undergo different photochemical reactions, such as the formation of different oxidation products. These differences in photochemical behavior can have significant implications in the fragrance and flavor industries.Another example is the photoisomerization of chiral azobenzene derivatives. Azobenzene is a molecule that can undergo reversible photoisomerization between its cis and trans isomers upon exposure to UV light. Chiral azobenzene derivatives can exhibit different photoisomerization rates and quantum yields for their enantiomers, which can be useful in designing photoresponsive materials and molecular switches.In the field of asymmetric photocatalysis, chirality plays a crucial role in achieving enantioselective reactions. For instance, chiral metal complexes can act as photocatalysts to selectively promote the formation of one enantiomer over the other in a photochemical reaction. This enantioselectivity can be influenced by the type of light used, such as CPL or linearly polarized light.In conclusion, chirality has a significant impact on the photochemical properties of molecules. The interaction of chiral molecules with different types of light can lead to distinct photochemical reactions, products, and enantioselectivities. Understanding these effects is essential for the development of new chiral materials, molecular switches, and asymmetric photocatalysts.