Optically active co-ordination compounds. Part X. Kinetic stereoselectivity and absolute configuration in some complexes of cobalt(III)

Abstract

(+)-Tartaric acid reacts more quickly with L-bisaquobisethylenediaminecobalt(III) ion than with the D-bisaquo-complex. The unchanged D-bisaquo-complex can be converted into D-[Co en₂(NO₂)₂]ⁿ⁺. By exhaustive reactions with (+)-tartrate it can be converted into D-[Co en₂{(+)-tartrate}]⁺. Similarly, L-glutamic acid reacts with D-[Co en₂(H₂O)₂]³⁺ more quickly than with L-[Co en₂(H₂O)₂]³⁺, and the product, D-[Co en₂(L-glutamate)](CIO₄) crystallises optically pure. Absolute configurations of the complexes mentioned are presented, with some comments on the three-point attachments underlying the present effects.