Collect. Czech. Chem. Commun. 1988, 53, 1725-1734

The stereochemistry of the bis[N-(2-carbamoylethyl)iminodiacetate] cobalt(III) complex

František Pavelčíka, Pavol Novomeskýa, Jiřina Soldánováa and Tamara N. Polynovab

a Department of Analytical Chemistry, Pharmaceutical Faculty, Comenius University, 832 32 Bratislava, Czechoslovakia
b Faculty of Chemistry, Lomonosov Moscow State University, Moscow, U.S.S.R.


A complex with the composition K[Co(ceida)2].2 H2O was isolated from solution after reaction of N-(2-carbamoylethyl)iminodiacetic acid, H2ceida, with CoCl2 in an aqueous solution of CH3COOK after oxidation with H2O2. Its structure was studied in D2O solution using 1H and 13C NMR spectroscopy and by X-ray diffraction of the crystalline substance. Both methods indicate that the complex anion is centrosymmetric in the octahedral complex. The ligand is coordinated by two oxygen atoms of the carboxylic groups and the nitrogen atom of the imino group. The amide group is not coordinated. Of the three possible isomers, only the trans-facial isomer was isolated. The uncoordinated ceida chain can assume two different conformations in the crystal. The K+ cations and molecules of water of crystallization are disordered.