Cobalt(III) and chromium(III) complexes with ethylenediaminemonoacetic acid (EDMA), [Co(edma)2]Cl·2H2O and [Cr(edma)2Cl·3H2]O, (edma: H2NCH2CH2NHCH2COO−), were prepared. The former complex was isolated as two geometrical isomers. From the electronic absorption spectra, the two isomers were assigned to trans and cis forms with respect to the carboxylate oxygen atoms coordinated. Chromium(III) complex was concluded to have the trans form by comparing the IR spectrum with those of the above two isomers of cobalt (III) complexes.

Thermal reactions of the complexes [Ni(H2O)2(NN-deen)2]X2·nH2O (NN-deen is N,N-diethylethylene-diamine and X is Cl or Br) were investigated. It was found by derivatography and spectral and magnetic measurements that the bromide undergoes transformation from octahedral to square planar structure by “deaquation” upon heating, whereas the chloride turned to the dichloro complex by thermal “deaquation-anation” losing the coordinated water and drawing chloride ion into the coordination sphere with retention of octahedral structure around the central metal. No such transformation could be found in the corresponding iodide and nitrate, since only diamagnetic complexes, [Ni(NN-deen)2]X2 (X is I or NO3), and no paramagentic complexes were obtained.

The formation constants of chromium(III) complexes with the oxalate ion, which is the simplest bidentate ligand coordinating by two oxygen atoms, have been determined by the pH method. It has been shown that the formation constants of oxalato chromium(III) complexes are larger than those of the corresponding titanium-(III) complexes, but smaller than those of the corresponding manganese(III), iron(III) and cobalt(III) complexes in the first transition series. The formation constants of oxalato chromium(III) complexes have been found to be remarkably smaller than those of the ethylenediamine chromium(III) complexes. This result suggests that two nitrogen atoms form a more stable complex with chromium than do the two oxygen atoms serving as donors in the bidentate chelate.

Atropisomeric chiral bisphosphine, (S)-6,6′-dimethyl-2,2′-bis(diphenylphosphinamino)biphenyl (MABP) was newly prepared, and the Rh(I) complex thereof was found to be highly effective for the asymmetric hydrogenation of 2-acetamidoacrylic acid even under 1 atm of hydrogen pressure at a temperature below 0°C.

Durch Reaktion der [Hexammin‐ bzw. Aquopentammin‐metall(III)]‐nitrate oder ‐chloride mit K‐hexacyanocobaltat(III) bzw. ‐chromat(III) wurden die neun Titelkomplexe dargestellt.