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.