Optically active co-ordination compounds. Part XXIII. Inversion at an octahedral centre

Abstract

One optically pure isomer of the carbonato-bis-L-valinatocobaltate(III) ion, isolated as its potassium salt, has been shown by electronic, circular dichroism, and n.m.r. spectra to be D(+)-cis(N)-cis(O)[Co(L-val)₂CO₃]^–, and this has been confirmed by an X-ray study. The complex reacts rapidly and initially reversibly with acid to give what the circular dichroism spectrum suggests is an inverted product. From the reaction mixture crystals of (–)[Co(L-val)₂(H₂O)₂]⁺ have been isolated as the perchlorate salt.