Q7(c). Isomers of [CoCl₂(en)₂]⁺; is there a meso form?
Draw labelled structures of all the possible isomers of dichloro-bis(ethylenediamine) cobalt(III) ion. Does a meso-form exist? Give reason to support your answer.
Answer in brief
Three stereoisomers: trans (optically inactive) and a pair of cis enantiomers (Δ and Λ). No meso form: the ion has only one stereocentre (Co); the trans isomer is inactive because it is achiral, not because two halves cancel.
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Coversmirror planesoptically inactivenon-superimposableenantiomersdiastereomer
All parts of Question 7
- 7(a)(i) Metal carbonyls; how they are formed; tetrahedral Ni(CO)₄10 marks
- 7(a)(ii) Structure of Fe₂(CO)₉ and the 18-electron rule10 marks
- 7(b) Ferredoxin: structure and role in photosynthesis10 marks
- 7(c) Isomers of [CoCl₂(en)₂]⁺; is there a meso form?10 marks