CRYSTAL STRUCTURE OF THE Ni (II) AND Zn (II) HETEROMETALLIC COMPLEX WITH ETHYLENEDIAMIN-N, N'-DISUCCINIC ACID

Abstract

By the direct-synthesis of zinc oxide, nickel hydroxocarbonate with ethylenediaminedisuccinic acid was obtained a heterometallic complex of the composition C10H22N2Ni0.30O13Zn1.70. The crystal structure of this compound was characterized by X-ray diffraction analysis, absorption and IR-spectroscopy. The complex crystallizes in a triclinic system (spatial group P-1) with parameters of the elementary cell a=8,6844(3), b=10,4442(3), c=11,2520(3). The final values of the divergence factors R1=0,0581, wR2=0,0828, GOF 0,964 at reflections with I> 2σ (I). The final electronic difference from the Fourier series of the last-minute refinement cycle is 0.348 and -0.485 e/Å3. The heterometallic complex has a polymer structure, formed by structural units (NiEDDS)- and ZnOEDDS(H2O), which are bidentarily bound via atoms of the oxygen of the β-carboxyl group performing the bridge function and the oxygen atoms of the other three carboxyl groups of the ligand with their monodendental coordinates up to zinc atoms. In the ZnNiEDDS complex, the Ni2+ ion is coordinated with 5 donor atoms of the deprotonated anion EDDS4-, forming a distorted octahedral NiN2O4 environment. At the same time, three 5-membered (two glycine (Gly) and one ethylenediamine (En)) and one 6-membered β-alanine (Al) non-flat metallocycles are formed. Gly is simultaneously three 5-membered and one 6-membered non-flat metallocycles. -cycle, one-cycle Two 5-membered (En NiN2C6C5N1, Gly NiO5C8C7N2) 6-membered Al NiN1C4C3C2O3 cycles are located in the equatorial plane of the octahedron. The glitinous cycle of NiN1C4C1O2 is located in the axial plane of the coordination polyhedron and bound by C4N1 bonds with two cycles, En and Al. The molecule of water is in the axial plane, completing the structure of the polyhedron to the octahedral. In the axial position of the octahedron is a nitrogen atom N1, which, due to the stiffness of the ethylene diamine bridge structure, forms an angle N1-Ni-N2 with inequalities of Ni-N2 (2.151(3) Å) and Ni-N1 (2.108(3) Å), which leads to the formation of tetragonal distortion of the octahedron. The Zn2+ ion is bound to oxygen atoms of β-carboxylic groups of three different EDDS molecules, two of which are coordinated monodentally, and one is bidentanic, and with one molecule of water. In this case, one 4-membered cycle of ZnO7iC9iO8i is formed due to the β-carboxyl group of one of the EDDS molecules. The five-coordinated zinc ion forms a trigonal-bipimaramal distorted square pyramid, at the top of which is the atom of oxygen of the water molecule. In the complex there are molecules of crystallization water, which take part in the formation of the hydrogen bonds system. The distance of hydrogen bonds is in the range of 1.85 (4) - 3.378 (5) Å.