Elution Order in the -Type Complexes

This technique was widely used in the separation of isomeric complexes of nonelectrolyte type 33.34,35) pqj jjjg L-aspartatoethylenediamineoxalatocomplex[Co(ox)-(L-asp)(en)] , four isomers, ner-A, mer-A,fac-A. and fac-A, are possible (see Fig. 4.3). With an anion-exchange resin (Dowex 1-X8, Cl form) an extremely long column was necessary since washing gave a diffuse band on the column and successive elution with an electrolyte made each band spread considerably. In contrast, complete 

A cation-exchange column (Dowex 50W-X4, Na form) separates the fac and mer isomers of the neutral [Co(L-ala)(edda)] complex by elution with water. 

For the mixed ligand complex with l- or D-aspartic acid and L-2,4-diaminobutyric acid, [Co(l- or D-asp) (L-2,4-dba)], the possible isomers are shown in Fig. 3.11. Both of L- and D-series are composed of two meridional forms and one facial form about the [Co(N)3(0)3] chromophore. The two L-mer isomers are denoted by L-tranjOs-cisNs (with respect to oxygen) and L-cisOstronjNs. To investigate the H NMR spectra of those isomers, Watabeetal. prepared the complexes with Na3[Co(C03)3] 3 H2O 

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