Crystal structure of cobalt(III) compound with ethylenediamine-N,N '-di-3-propionic acid, [Co(H(2)Eddp)(HEddp)]Br-2 center dot 4H(2)O

The crystal structure of [Co(H(2)Eddp)(HEddp)]Br-2 . 4H(2)O is determined [ R1 = 0.0551 and wR2 = 0.1298 for 2580 reflections with I > 2 sigma(I)]. The structure consists of the [Co(H(2)Eddp)(HEddp)](2+) cationic complexes, Br - anions, and molecules of crystallization water. Two tridentate ligands, w hich differ in the degree of protonation, coordinate the Co atom by two N a toms and one O atom, each forming a meridional isomer. In the complex, the configurations of the N(2) and N(4) atoms, which are included in two chelat e rings each, differ from those of the N(1) and N(3) atoms, which are inclu ded only in the five-membered rings and hear uncoordinated propionate group s. The Co-N(1) and Co-N(3) bonds are longer than the Co-N(2) and Co-N(4) bo nds (mean 1.987 and 1.957 Angstrom, respectively). The Co-O(5) bond with th e neutral ligand is longer than the Co-O(1) bond with the negatively charge d carboxyl group (1.927 and 1.901 Angstrom, respectively). The C(13)-O(5) c arbonyl bond in the coordinated COOH group is elongated to 1.266 Angstrom. The system of hydrogen bonds interlinks the cationic complexes, Br- anions, and water molecules into a three-dimensional framework. (C) 2000 MAIK "Nau ka/Interperiodica".