Final answer:
Compounds with chiral centers can exist as optical isomers or enantiomers, which are important in organic chemistry and biochemistry. The coordination compound [Co(en)2Cl₂]* can form optical isomers in its cis configuration, and complexes like [M(en)3]+ form enantiomers with distinct biological interactions.
Step-by-step explanation:
Compounds can exist as optical isomers if they have chiral centers, which are carbon atoms attached to four different atoms or groups. Optical isomers, also known as enantiomers, are nonsuperimposable mirror images of each other and have the property of rotating the plane of polarized light. These isomers are significant in both organic chemistry and biochemistry due to their unique interactions with biological systems, leading to different physiological effects.
For instance, the compound [Co(en)2Cl₂]* can exhibit geometric isomerism and its cis form can exist as a pair of optical isomers. In the world of coordination compounds, isomers such as [M(en)3]+, where M⁻⁺ is a central metal ion, can form enantiomers which interact differently with other optical isomers, such as DNA helices which are themselves optical isomers.