This work has been digitalized and published in 2013 by Verlag Zeitschrift für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namensnennung 4.0 Lizenz. Synthesis, Structure and Characterization of Trisodium Bis[N-(2-oximinopropionyl)glycinato(3-)-0,N,N] Cobaltate(III) Nonahydrate Igor O. Fritsky*, Rostislav D. Lampeka, Victor V. Skopenko Department of Chemistry, T. G. Shevchenko University, 252017 Kiev, Ukraine Yury A. Simonov, Alexander A. Dvorkin, and Tadeusz I. Malinowsky Institute of Applied Physics of the Academy of Sciences of Moldova, 5 Grosul Street, 277028 Kishinev, Moldova Z. Naturforsch. 48b, 270-276 (1993); received February 27/November 6, 1992 Cobalt, Pyruvylglycine Oxime, X-Ray, IR Spectra, NM R Spectra A cobalt(I II) complex with pyruvylglycine oxime (H3G) of composition Na3[CoG2] • 9 H20 is synthesized and investigated by means of X-ray analysis, infrared, electronic and NMR spec troscopy. The crystals are triclinic, space group P I, a = 15.477(5), = 9.931 (4), c = 7.773(4) Ä; a = 75.60(3); ß = 82.86(4); y = 93.54(3)°; Z = 2. The structure was refined to final R = 0.036 for 3347 independent observed reflections. The structure consists of the complex anions, Na+ cations and water molecules. The ligands are coordinated via the deprotonated oxime and amide nitrogen and the carboxyl oxygen atoms in a meridional fashion (Co-O(carboxyl) = 1.971 and 1.947Ä; Co-N(oxime) = 1.891 and 1.909; Co-N(amide) = 1.876 and 1.866Ä). The Co(III) coordination octahedron is slightly distorted; the C o-O and C o-N distances are in agreement with the data for oxime and peptide complexes of Co(III). The unit cell contains 2 enantiomeric complex anions related by a center of symmetry. The electronic, IR and NMR ('H and 13C) spectra of the complex are compared to those of the free ligand and of dipeptidato complexes of Co(III). Coordination compounds of the transition met als with N-substituted amino acids and oligopep tides are of considerable interest as models of met al protein interaction and in connection with their possible practical application. Pyruvylamino acid oximes, the object of present research, are similar as to their structure to dipeptides, but differ from these by oxime-containing fragment -C (= N O H )- instead of the terminal amino group -CH (N H 2)-: CH 3-C ( = N 0H)-C(0)NH-CH(R)-C00H R - amino acid side chain). These compounds are expected to be coordinat ed similarly to peptides upon complexation [ 1, 2]. In our previous paper the preparation of 3d metal complexes containing singly and doubly charged residues of pyruvylamino acid oximes as acido li gands coordinated in dipeptide-like fashion was reported [3]. Unlike dipeptides, the present ligands can act as triply charged anions. Ambidentate be haviour of the deprotonated oximino group gives room for a greater variety of possible coordination modes. * Reprint requests to Dr. I. O. Fritsky. Verlag der Zeitschrift für Naturforschung, D-W-7400 Tübingen 0932 - 0776/93/0300-0270/$ 01.00/0 The X-ray structure studies of pyruvylglycine oxime (H 3G, R = H) [4], pyruvyl-L-alanine oxime (R = CH3) [5] and pyruvyl-L-methionine (R = CH 2CH 2SC H 3) [6] show that in the molecules of all these compounds the orientation of the carboxyl group with reference to the molecule framework is different, the configuration of the amide and ox ime groups being the same. In case of the first compound a planar structure is realized [4], In two others the carboxyl group forms angles of 30-90° with the molecule framework [5, 6]. Such rather small conformational differences are not expected to have significant influence on the properties of these compounds. The present paper deals with the synthesis, X-ray and various spectroscopic investigations of the cobalt(III) complex with H3G of composition Na 3[CoG 2]-9H 20. In this compound the maxi mum possible degree of deprotonation of the li gand is realized, with G3_ acting as a triply charged ligand. Experimental Synthesis and analytical data Freshly precipitated cobalt(II) hydroxide ob tained from 0.73 g (2.5 mmol) Co(N0 3)2-6 H 20