Collect. Czech. Chem. Commun. 1990, 55, 1002-1009

Crystal and molecular structure of potassium [Δ,Λ-racemic-(1-phenylethylenediamine-N,N,N',N'-tetraacetato)cobaltate(III)] sesquihydrate

Viktor Kettmann, Marián E. Kalina, Ján Lučanský and Milan Strašák

Department of Analytical Chemistry, Faculty of Pharmacy, Comenius University, 832 32 Bratislava, Czechoslovakia


The crystal and molecular structure of the title compound was determined by X-ray analysis. It crystallizes in the orthorhombic system, space group Ccc2, with cell parameters a = 3.773(3), b = 1.404(11), c = 0.6962(6) nm, V = 3.687 nm3, and Z = 8. The main factors determining stereochemistry of the complex are intramolecular hydrophobic stacking interaction between the methylene hydrogens of the out-of-plane R1 ring and the aromatic ring of the phenyl group, and the nonbonding van der Waals interactions between the methylene hydrogens of the central ethylenediamine (E), in-plane glycinate (G) and R rings as well as of the hydrogens of the phenyl group. The observed stereospecific coordination is due to an energy preference for the equatorially located phenyl group on the E ring.