Rotatory Dispersion of Metallic Co-ordination Compounds. III. Absorption Spectra and Rotatory Dispersion of Cobalt(III) Complexes of the [CoN2O4]− Type

Three new complexes, cis(N)-K[Co(ada)2]·2.5H2O, tans(N)-K[Co(ada)2]·2H2O and cis(N)-K[Co(ata)gly]·H2O, have been synthesized. The visible and the ultraviolet absorption spectra of these complexes have been measured and discussed in relation to the geometrical structures of the complex ions compared with other complexes of the [CoN2O4]− type. Rotatory dispersion measurements have also been made for d-Na[Co en ox2] and d-K[Co en malo2]. It has been shown that the so-called anomalous rotatory dispersions of these complexes are explicable by assuming the overlap of the two inversive dispersions in their first absorption bands. The slight inversive dispersions are also observed in their second absorption band.