Cation-Exchange Chromatography of Hexaminechromium(III)-Type Complexes on SP-Sephadex

Abstract

The chromatographic elutions (with the eluents Na₃PO₄, Na₂-(+)-tart, Na₂SO₄) of the following pairs of analogous hexamine-type complexes of chromium(III) and cobalt(III) on SP-Sephadex have been measured quantitatively (as R_x values relative to [Co(en)₃]³⁺) and compared: [M(NH₃)₆]³⁺,M(en)₃]³⁺, [M( tn )₃]³⁺, s- fac and mer [M( dien )₂]³⁺, and mer -[M( dpt )₂]³⁺. Conclusions are: ( i ) The Cr^III complexes elute more slowly and with less discrimination than their Co^III analogues. (ii) There is a generally regular correlation between the elutions of analogous Cr^III and Co^III complexes, so that deductions of geometric configurations of new Cr^III complexes from chromatographic comparisons should be possible. Two small reversals of elution order of complexes with different eluents are observed.