Browsing by Author "Simonov, Yurii A."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    CRYSTAL STRUCTURE OF [Co(thios) 3 ] 2 [Bidtpa] 2 (NCS)(OH)⋅8H2O
    (Academia de Ştiinţe a Moldovei, 2006) Petrenko, Peter A.; Bulimestru, Ion; Simonov, Yurii A.; Gdaniec, Maria; Gulea, Aurelian
    Bismuth-based mixed-oxides have been studied extensively for a number of potentially useful physical properties like oxygen ion conductivity, ferroelectricity, superconductivity and catalysts in different oxidation processes. The use of bismuth complexes as precursors for new heterometallic oxide systems turned out to be a more effective route compared to traditional ceramic synthesis. Thus, controlled pyrolysis of alkoxide, carboxylate or polyaminopolycarboxylate precursors has frequently been used to synthesize highly dispersed bismuth containing mixed-oxides and solid solutions. Diethylenetriaminepentaacetic acid (H5Dtpa) gives numerous stable complexes with d, f, and p elements, including Bi. Most frequently, complexes with H5Dtpa are more stable than those with its analogues. Recently, we have characterized two heterometallic coordination compounds, [Co(thios)3]2[Bi(Dtpa)]2SO4·6H2O (I) and [Co(thios)3]4[BiDtpa]4⋅(SO4)2⋅20H2O (II) containing complex cations and anions (thios=thiosemicarbazide). In this work we present synthesis and crystal structure of a new heterometallic compound [Co(thios)3]2[BiDtpa]2⋅(NCS)(OH)⋅8H2O (III) (see fig.). The crystal structure of III is built of complex cations [Co(thios)3]3+, three types of anions [Bi(Dtpa)]2-, [NCS]2-, (OH)- and water molecules. The Bi atom coordination polyhedron is a nanohedron and its coordination number is nine. The coordination of Dtpa residues to the bismuth atom gives rise to five glycine and two ethylenediamine metallocycles which are essentially non-planar. The complex cation [Co(thios)3]3+ is a typical Co(III) tristhiosemicarbazide fac-isomer.
  • Thumbnail Image
    Item
    STRUCTURE OF PALLADIUM COMPLEXES WITH 8-QUINOLINEALDEHYDE THIOSEMICARBAZONE
    (Academia de Ştiinţe a Moldovei, 2006) Bourosh, Pavlina; Bulmaga, Petru; Revenco, Mihail; Jora, Elena; Gdaniec, Maria; Simonov, Yurii A.
    The coordination compounds of palladium(II) with 8-quinolinaldehyde thiosemicarbazone (HQATSC) have not been described yet. When a solution of K2[PdCl4] is treated with an equimolar amount of HQATSC in warm ethanol or dimethylformamide a yellow crystalline precipitate of Pd(QATSC)Cl is formed. The solubility of the resulted compound in DMF is increased when thiourea (Thio) is added. During 3 days yellow well defined crystals were formed and selected for X-ray investigation. The composition of the separated crystals can be described with a conventional formula Pd(QATSC)Cl⋅1,5Thio⋅H2O. A detailed X-ray investigation showed that the product is a new type of palladium complexes with HQATSC, formed by the cation [Pd(QATSC)(Thio)]+, Cl- anion, water and thiourea uncoordinated molecules. This result suggests that increasing of the ion solubility in the presence of Thio is due to the substitution of the chloride-ion from the inner sphere by thiourea molecule, resulting in formation of a cation-anion type of the complex. The structure of the complex cation is presented in the figure. The square-planar coordination of Pd(II) is provided by two nitrogen atoms and sulfur atom of the monodeprotonated residue of 8-quinolinealdehyde thiosemicarbazone. The bond distances in the palladium coordination polyhedron are: Pd(1)N(1) 2.116(4), Pd(1)-N(2) 2.013(4), Pd(1)-S(1) 2.44(1), PdS(1A) 2.336(1) Å. The real composition of the complex is [Pd(Q ATSC)(Thio)]Cl.0,5Thio.0.5H2O. The non-coordinated Thio and H2O molecules are randomly disordered over two positions with occupancy factors equal to 0.5. The components are involved into system of hydrogen bonds, and the composition should be formally described by the dimeric formula [Pd(QATSC)(Thio)]2Cl2 .Thio.H2O.