The Absorption Spectra of Cobalt(III) Complexes. IV. The Preparation and the Absorption Spectra of Monohalogenomonoamine-bis (ethylenediamine)-cobalt(III) Complexes

The four iodo-amine complexes and some chloro- and bromo-amine complexes belonging to [CoX(NH2-R)en2]X2 type have been newly synthesized to complete the series. From the measurements of the near-infrared, visible and ultraviolet absorption spectra, the geometrical structures of the complexes have been determined. The ammine complexes, [CoX(NH3)en2]X2, exist in both the cis- and the trans-forms, but the organic amine complexes, [CoX(NH2-R)en2]X2, exist only in the cis-form. The weak splitting of the A band has been observed for the first time in the bromo-amine complexes.