2. Articole
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Item EFFECT OF THE NATURE OF THE ANION ON THE COMPOSITION AND STRUCTURE OF COBALT COMPLEX WITH MONOETHANOLAMINE(2013) Cotovaia, Aliona; Șova, Sergiu; Melnic, Elena; Simonov, Iurie; Gulea, Aurelian; Pahonțu, ElenaA number of products formed in reactions of cobalt(II) salts with monoethanolamine (HEtm) in a neutral medium were synthesized and studied. X-Ray diffraction study showed that the nitrate and acetate form the dimers [Co(HEtm)3][Co(Etm)3](NO3)3 and [Co(HEtm)3][Co(Etm)3](CH3COO)3 · 8H2O, respectively. In chloride solutions, cobalt is partially oxidized to give the trinuclear complex [CoII{Co III(Etm)3}2]Cl3 · H 2Etm · 2H2O. The reaction of the chelate [Co(Etm)3] · 3H2O with nitric acid is accompanied by complete protonation of the coordinated aminoethanolate ions, and the reaction with formic acid involves complete replacement of the coordinated ligand by acid residue anions and water molecules to give the coordination polymer {Co2(μ-HCOO)4(H2O)4} n .Item HETEROMETALLIC COMPOUNDS WITH THE BINUCLEAR COMPLEX ANION [CR2 (OH)(AC)(NTA)2 ]2– : SYNTHESIS AND STRUCTURE(2009) Ciornea, Victor; Șova, Sergiu; Novițchi, Ghenadie; Ganju, Dumitru; Cajeva, Olga; Gulea, Aurelian; Simonov, IurieHeterometallic compounds BaCr2(OH)(Ac)(Nta)2 • 4H2O (I) and [Fe(L)3][Cr2(OH)(Ac)(Nta) 2] • nH2O (L is Bipy (II) and Phen (III); Bipy is, αα′-bipyridine, Phen is o,o′-phenanthroline, Ac - is acetate ion, Nta is nitrilotriacetate ion; n = 8 (II) and 6.25 (III)) are synthesized. According to the X-ray diffraction data, compounds II and III have ionic structures built of the isolated complex cations [Fe(L) 3]2+, binuclear complex anions [Cr2(OH)(Ac) (Nta)2]2-, and crystallization water molecules. The magnetic properties of compounds II and III in the interval from 2 to 300 K confirm assumptions on the diamagnetic character of [Fe(L)3] 2+ and indicate the antiferromagnetic interaction between the chromium atoms in the dimeric fragment [Cr2(OH)(Ac)(Nta) 2]2-.Item NEW COMPLEXES OF TRIS(2-AMINOETHANOLATO-O,N)COBALT(III) SULFATES: SYNTHESIS AND STRUCTURE(2009) Cotovaia, Aliona; Șova, Sergiu; Simonov, Iurie; Gulea, AurelianThe reaction of [Co(Etm)3] • 3H2O (I) with sulfuric acid affords [Co(HEtm)3]2(SO4) 3 • 4H2O (II). The change in the synthesis procedure (the direction interaction of cobalt(II) sulfate with β-aminoethanol (HEtm)) makes it possible to isolate [Co(HEtm)3](SO 4)(HSO4) • H2O (III) and {[Co(HEtm) 3][Co(Etm)3]}2(SO4)3 • 7.75H2O (IV). The X-ray diffraction analyses of compounds II-IV show that all of them are of the ionic type. In compounds II and III, the ionic structure consists of the [Co(HEtm)3]3+ cations and sulfate anions in a ratio of 2: 3 and 1: 2, respectively. The basic difference in compounds II and III is the different degrees of deprotonation of the acid residues. In complex II, two anions SO 4 2- are doubly deprotonated. In complex III, of the four anions found in the independent part of the unit cell of the sulfate anion two anions are monodeprotonated. In structure IV, two crystallographically independent complexes [Co(HEtm) 3]3+ and [Co(Etm)3] are joined into a dimer through the O-H⋯O hydrogen bonding.Item SYNTHESIS AND STRUCTURE OF HETEROMETALLIC CHROMIUM(III) COMPLEXES WITH ETHYLENEDIAMINETETRAACETIC ACID(2005) Ciornea, Victor; Filippova, Irina; Gulea, Aurelian; Șova, Sergiu; Borta, A.; Simonov, IurieThe complexes [M(Tsc)2][Cr(Edta)]2, where M is Ni, Cu; Tsc is thiosemicarbazide; Edta4- is the ethylenediaminetetraacetate anion, were synthesized and characterized by X-ray diffraction. The ionic structures are composed of the [M(Tsc)2] 2+ cations and [Cr(Edta)]- anions with a component ratio of 1 : 2. The cation has a distorted trans-square coordination. The carboxyl groups of the H4Edta molecule are deprotonated and the ligand is attached to the Cr atom in the hexadentate chelating mode. The cations and anions are linked by a system of hydrogen bonds.