Thus, achiral synthetic methods were first applied in order to obtain all four possible stereoisomers, while a subsequent resolution, via chiral chromatography, has led to the optically active single derivatives (compounds 76 a-d). (thno.org)
Heeb and his colleagues concluded early on that individual stereoisomers may differ not only in their three - dimensional structure, but also in their toxicity and their environmental behaviour. (sciencedaily.com)
The octahydrophenanthroline ring system includes four distinct stereoisomers. (thno.org)