Known Descriptors of Paired Ligands

Further, in the case of molecules vi and vii, nuclei a are homotopic in viii, they are enantiotopic and in ix and x, they are diastereotopic. And yet, the same pro-E/pro-Z notation is used to designate enantiotopic ligands a in viii, and diastereotopic ligands a in ix and x. Here, the designations utilize prostereotopicity descriptors. Finally, there is no descriptor for homotopic ligands in vi and vii. 

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