Spectroscopic Assignment of d—d Transitions of Achiral Metal Complexes Using Circular Dichroism: DICD of Co(III) Complexes in Sugar Solutions

Circular dichroism may be used to probe the d—d transitions of an achiral metal complex by simply adding a sugar to the aqueous solution of the complex. The interaction between the sugar and the complex is postulated to be dispersive and orientationally unspecific, leading to the possibility of interpreting the induced circular dichroism in terms of the DICD (dispersion-induced circular dichroism) model. The experimental investigation of a range of Co(III) complexes of varying symmetry and in various sugar solutions supports the relevance of the DICD model and furthermore confirms that it constitutes a general method of assigning magnetic dipole allowed transitions in achiral transition-metal complexes.