Systematics and the properties of the lanthanides. : Edited by S. P. Sinha. D. Reidel,Dordrecht/Boston/Lancaster, 1983, 648 pp, 195 D fl.

The Δ-α-and Λ-β- forms of [Co(edda)CO₃]^? have been isolated as crystalline diastereoisomeric salts of the cation Δ-[Co(en)₂(ox)]⁺. When each salt is dissolved in 1.0 F aqueous Na₂CO₃ at 25°C an isomeric equilibration process occurs between these species in which the Δ-α form predominates before the eventual racemisation of both anionic species. On proceeding to equilibrium the Λ-β-[Co(edda) CO₃]^? isomer is observed to invert its absolute configuration at the central metal ion in converting to the Δ-α stereoisomer. This is the first reported example of inversion-isomerisation involving the β → α transformation in a chiral complex containing a linear tetradentate.