Specificity in the interaction of asymmetric tris(ethylenediamine)cobalt(III) ions with different polyanions in aqueous solution. A circular dichroism and ultraviolet spectral investigation

Abstract

Circular dichroism and u.v. spectra of tris(ethylenediamine)cobalt(III), [Co en₃]³⁺, ions in aqueous solutions of various polyelectrolytes are reported. The results indicate that the c.d. of the Co^III complex ions is diversely changed upon interaction with polyanions which differ in chemical constitution and also with polyanions different only in chain stereoregularity. In the case of poly(methacrylic acid) it is also shown that the optical activity of [Co en₃]³⁺ ions varies discontinuously with increasing the degree of neutralisation, α, of the polyacid in the interval of α values in which poly(methacrylic acid) chains undergo a conformational transition.