Optically active co-ordination compounds. Part XVI. Dimeric complexes in the tartratobisethylenediamine cobalt(III) system

Abstract

The (+)-tartrate ion combines with the DL-carbonatobisethylenediaminecobalt(III) ion to give a mixture of diastereoisomeric dimers, of stoicheiometry [en₂Co{(+)-tartrate}Co en₂]²⁺. The isomer in which both cobalt ions have the L-configuration has been obtained pure as its perchlorate salt, and evidence from analysis, conductivity, and spectroscopy (i.r., n.m.r., electronic, and c.d.) supports the formulation given. The configuration at cobalt has been obtained by chemical correlation, via oxidation to L-(–)-oxalatobisethylenediaminecobalt(III). Another isomer (in which both cobalt atoms have the D-configuration) has been obtained less pure.