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 Rx 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 CrIII complexes elute more slowly and with less discrimination than their CoIII analogues. (ii) There is a generally regular correlation between the elutions of analogous CrIII and CoIII complexes, so that deductions of geometric configurations of new CrIII complexes from chromatographic comparisons should be possible. Two small reversals of elution order of complexes with different eluents are observed.