Studies on the Cobalt(III) Complexes Containing Only One Chelate Ring. III. Rotatory Dispersion of Tetrammine-I-leucinato-cobalt(III) Perchlorate, [Co (NH3)4(I-leuc)](ClO4)2

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Abstract
A new complex compound, [CoIII(NH3)4(l-leuc)](ClO4)2, has been prepared, in which the asymmetric center is only on a carbon atom of the ligand leucinate ion. From the measurements of the visible and the ultraviolet rotatory dispersion of this compound, it has been concluded that the so-called “vicinal effect” exists between the cobalt atom and the asymmetric carbon atom. The rotatory dispersion measurements have also been made for d-[Co en2 (l-leuc)]Cl2, d-[Co en2 (NH3)Cl(2)(1)]Br2 and d-[Co en3]Br3·2H2O. On the basis of these data the relation of the splitting of the first absorption band with the so-called anomalous rotatory dispersion has been discussed. Thus it has been shown that the anomalous rotatory dispersion of [Co(NH3)4(l-leuc)]2+ or of [Co en2 (NH3) Cl]2+ is explicable by assuming the overlap of the two inversive dispersions, Ia and Ib, which correspond to the component bands, Ia and Ib, of the split first absorption band. In agreement with the observations by several previous authors, it has been shown that all the complexes studied scarecely show the anomalous rotatory dispersion in the vicinity of their second absorption bands.