Chiral Complexes of the and Types

Douglas et al. took up bis dicarboxylato)ethylenediamine complexes such as [Co(ox)2(en)] and [Co(mal)2(en)] as crystal field models of the ethylenediamine-tetraacetatocobaltate(III) ion and compared the absorption and CD spectra the 

These results show that in the [Co(0,0)2(diamine)] -type complex the variation of 0,0-donor bidentates causes a change in the CD pattern observed. Thus, it seems worthwhile to examine the CD spectra for a series of c (N)-[Co(0,0)2(N)2] -type complexes, where (N)2 represents a diamine or two unidentate N-donor ligands. Shibata et al. prepared such complexes. based on m-substitution of the ligating 

As an example, the preparation of Na[Co(ox)(mal)(en)] H2O is briefly de ribed. An aqueous solution of K[Co(C03)(ox)(en)] H2O (0.1 mol) was mixed with a solution of malonic acid (0.15 mol) and then stirred at 40 °C for 2 h. The filtrate was chromatographed on a column of anion-exchange resin (Dowex 1-X8, Cl form). By elution with 0.1 mol/dm NaCl, three bands descended. From the second fraction, the desired complex was obtained. The products from the first and third were Na[Co(mal)2(en)] and Na[Co(ox)2(en)], respectively. 

Two kinds of resolving agents, (—)s89[Co(ox)(en)2] (C2H3O2) and (—)5g9[Co-(NOjlifenlj] (C2H3O2), were successfully used for the optical resolution of the complexes except [Co(C03)2(NH3)2l . However, an optically active lithium salt of this 

In so far documented asymmetric syntheses of metal complexes, optical lability 

---