| 1. |
- Bechta, Sevostian, et al.
(author)
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Phase Relations in the ZrO2–FeO System
- 2006
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 51:2, s. 325-331
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Journal article (peer-reviewed)abstract
- We present the results of the investigation of the ZrO2-FeO system under an inert atmosphere. We have refined the position of the eutectic point, which lies at 1332 +/- 5 degrees C and 10.3 +/- 0.6 mol % ZrO2. The iron oxide solubility boundaries in zirconium dioxide have been determined over a wide temperature range taking into account the polymorphism in ZrO2. A phase diagram for the system has been designed.
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| 2. |
- Bredyuk, O. A., et al.
(author)
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Structural organization of cadmium(II) and copper(II) dithiocarbamate complexes with dialkyl-substituted and cyclic ligands: Synthesis, single-crystal X-ray diffraction, EPR, and CP/MAS13C, 15N, and 113Cd NMR
- 2005
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 50:11, s. 1710-1726
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Journal article (peer-reviewed)abstract
- A comparative study of polynuclear thallium complexes with dialkyldithiocarbamates [Tl2{S2CNR2} 2]n (R = CH3, i-C3H7, C4H9, and i-C4H9; R2 = (CH2)6) was performed by solid-state 13C and 15N CP/MAS NMR spectroscopy. The dithiocarbamate groups were found to be structurally equivalent in the complexes studied. An increase in the positive inductive effect of alkyl substituents at the N atom increased 15N chemical shifts as a result of a combination of positive inductive effect of the alkyl substituents and the mesomeric effect of =NC(S)S-groups. The first representative of thallium(I) complexes with a cyclic dithiocarbamate ligand [Tl2{S2CN(CH2) 6}2]n was obtained. Its molecular structure was determined from X-ray diffraction data. The β-form of the isotope-substituted complex [63/65CuTl2{S 2CN(CH2)6}4] was obtained and examined by EPR spectroscopy. The EPR spectra were modeled at the second order of the perturbation theory. The spin density at the thallium atoms was calculated and its distribution over the AOs of thallium was determined.
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| 3. |
- Durmus, Z., et al.
(author)
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The effect of neutralizing agent on the synthesis and characterization of Mn3O4 nanoparticles
- 2010
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 55:12, s. 1947-1952
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Journal article (peer-reviewed)abstract
- We report on the synthesis of Mn3O4 nanoparticles via a two-step hydrothermal route by using Mn(CH3COO)(2) as the only starting material and TMAOH and NaOH as hydrolysing agents. XRD and FT-IR analyses confirmed the composition and structure of Mn3O4. TEM images showed that spheroid Mn3O4 nanostructures obtained by this method have average particle size of 6 and 14 nm for NaOH and TMAOH hydrolyzed samples respectively. Particle size analysis indicated a strong aggregation of nanoparticles and exhibited bi-modal distribution with average size of aggregates as similar to 250 nm and 1.1 mu m for both samples. Zeta potential analysis revealed adsorbed TMAOH species on the surface of Mn3O4 nanoparticles hydrolyzed using TMAOH. ESR analyses resulted in broader lines and smaller g values than bulk Mn3O4 nanoparticles, probably due to the exchange-coupled system with unlike spins such as canted spin at surface of high-surface-disordered nanoparticles.
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| 4. |
- Haiduk, Y. S., et al.
(author)
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WO3—Co3O4 Compositions Prepared by the Sol—Gel Process : Structure and Gas-Sensing Properties
- 2019
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In: Russian Journal of Inorganic Chemistry. - : Pleiades Publishing. - 0036-0236 .- 1531-8613. ; 64:6, s. 717-724
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Journal article (peer-reviewed)abstract
- The structure and phase features of the WO3−Co3O4 compositions prepared by the sol-gel process are studied by X-ray powder diffraction, IR spectroscopy, scanning electron microscopy, thermogravimetry, and by specific surface determination from low-temperature nitrogen adsorption in the temperature range 200–800°C. An appreciable rise is observed in the gas sensitivity of the compositions compared to the constituent oxides. The dependence of the CO and NO2 sensitivity on the two-phase composition is elucidated, and an explanation is given to the discovered trend. Low-power semiconductor sensors are manufactured, providing the determination of low nitrogen dioxide concentrations (<1 ppm) with good response and recovery times.
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| 5. |
- Ivanov, Alexander V., et al.
(author)
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A comparative study of the structural organization of nickel(II) and copper(II) complexes with dialkyl-substituted and cyclic dithiocarbamate ligands by X-ray single-crystal diffraction, EPR, and CP/MAS C-13 and N-15 NMR
- 2002
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 47:3, s. 410-422
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Journal article (peer-reviewed)abstract
- X-ray single-crystal diffraction, EPR, and CP/MAS C-13 and N-15 NMR were used for studying the structures and spectral properties of nickel(II) and copper(II) dithiocarbamate complexes [M(S2CNR2)(2)] (R = CH3, C2H5, C3H7, i-C3H7 or R-2 = (CH2)(5), (CH2)(6), (CH2)(4)O). The [CUS4] chromophores in the lattice of nickel(II) complexes have, predominantly, a square-planar structure. The chromophore geometry is somewhat distorted only in bis(morpholinedithiocarbamato)copper(II). Differences in the N-15 NMR isotropic chemical shifts of dialkyldithiocarbamate ligands were interpreted in terms of a unified conceptual approach based on the concept of joint manifestation of the mesomeric effect of dithiocarbamate groups and the inductive effect of alkyl substituents. Experimental NMR (C-13, N-15) signals were assigned to the structural positions of atoms in allowed molecular structures. Refined structural data on [Ni{S2CN(C3H7)(2)}(2)] point to the occurrence of two types of structurally nonequivalent complex molecules; the [Ni(S2CN(CH2)6)2] complex is characterized by the intramolecular nonequivalence of dithiocarbamate ligands.
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| 6. |
- Ivanov, Alexander V., et al.
(author)
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A comparative study of the structural organization of zinc complexes with dialkyl-substituted and cyclic dithiocarbamate ligands : synthesis, single-crystal X-ray diffraction, and CP/MAS C-13 and N-15 NMR
- 2003
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 48:1, s. 45-54
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Journal article (peer-reviewed)abstract
- The structures and spectral properties of eight zinc(II) dithiocarbamate complexes [Zn-2(S2CNR2)(4)] (R = CH3, C2H5, C3H7, C3H7, C4H9; or R-2 = (CH2)(5), (CH2)(6), (CH2)(4)O) have been studied by single-crystal X-ray diffraction and CP/MAS C-13 and N-15 NMR. The experimental C-13 and N-15 NMR signals have been assigned to the positions of the corresponding atoms in the ligands with different structural functions (terminal or bridging). Differences in the N-15 NMR isotropic chemical shifts of dialkyldithiocarbamate ligands have been interpreted based on the concept of joint manifestation of the mesometic effect of dithiocarbamate groups and the inductive effect of alkyl substituents. The zinc dibutyl-, pentamethylene-, and morpholinedithiocarbamate complexes have been prepared and comprehensively characterized. The binuclear complex [Zn-2{S2CN(C4H9)(2)}(4)] appears to be the second example of a noncentrosymmetiic molecule of zinc dithiocarbamate. Another structural feature of the dimer is the fact that the eight-membered [Zn2S4C2] metallacycle is stabilized in the boat rather than in the chair conformation.
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| 7. |
- Ivanov, Alexander V., et al.
(author)
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Adduct formation of the zinc morpholinedithiocarbamate complex with morpholine as studied by CP/MAS 15N NMR and single-crystal X-ray diffraction
- 2004
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 49:12, s. 1863-1870
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Journal article (peer-reviewed)abstract
- The adduct of the zinc morpholineditiohcarbamate complex with morpholine [Zn(Mf)(MfDtc)2] and its solvated form [Zn(Mf)(MfDtc) 2]·Mf were studied by CP/MAS 15N NMR and single-crystal X-ray diffraction. These complexes are molecular, and the dithiocarbamate ligands therein are structurally nonequivalent. Solvation of the adduct aggravates this nonequivalence. The molecular and crystal structure of [Zn(Mf)(MfDtc)2]·Mf was determined by X-ray crystallography. The crystal structure of this compound has a system of ordered channels accommodating the outer-sphere morpholine molecules of solvation, which points to the formation of clathrate structures. The zinc coordination polyhedron [ZnS4N] is a somewhat distorted square pyramid with the four sulfur atoms at the base and the nitrogen atom at the apex. The square-pyramidal (SP) (97%) and trigonal-bipyramidal (TBP) (3%) contributions to the geometry of the zinc polyhedron were calculated. The 15N NMR signals were assigned to the structural positions of the nitrogen atoms in the molecular structure determined
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| 8. |
- Ivanov, Alexander V., et al.
(author)
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Adducts of zinc and copper(II) dialkyldithiocarbamate complexes with dialkylamines: Synthesis, EPR, and 13C and 15N CP/MAS NMR
- 2007
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 52:5, s. 691-697
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Journal article (peer-reviewed)abstract
- Crystalline adducts of zinc and copper(II) dithiocarbamate (Dtc) complexes with dialkylamines [M(NHR′2)(S2CNR2)2] (M = Zn, 63Cu, 65Cu; R = CH3, C2H5, or R2 = (CH2)4O; R′ = C2H5, C3H7) have been preparatively isolated. The structures and spectral properties of the adducts have been studied by EPR and 13C and 15N MAS NMR. Chemisorption of bases on powders of dinuclear dithiocarbamates leads to their dissociation into monomeric adducts. Computer simulation demonstrates that the experimental EPR spectra of isotope-substituted copper(II) adducts have an individual character. The geometry of the copper polyhedra is intermediate between a trigonal bipyramid (TBP) and a tetragonal pyramid (TP). The TBP and TP contributions have been quantified based on EPR data. 13C and 15N MAS NMR data show that the Dtc ligands incorporated into the zinc adduct molecule are structurally nonequivalent. The dependence of the isotropic 15N chemical shifts of the Dtc groups on the alkyl substituents at the nitrogen atom is interpreted based on the concept of joint manifestation of the (+)inductive effect of the alkyl substituents and the mesomeric effect of the Dtc groups.
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| 9. |
- Ivanov, Alexander V., et al.
(author)
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Adducts of zinc and copper(II) dialkyldithiocarbamate complexes with hexamethyleneimine: Synthesis, EPR, and CP/MAS 13C and 15N NMR
- 2004
-
In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 49:1, s. 95-101
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Journal article (peer-reviewed)abstract
- Powders of the zinc and copper(II) dimethyl- (MDtc), diethyl- (EDtc), and morpholinedilhiocarbamate (MfDtc) complexes quantitatively absorb hexamethyleneimine (Hmi) to produce the adducts [M{NH(CH2) 6}(S2CNR2)2] (M = Zn, Cu; R = CH3, C2H5; R2 = (CH 2)4O). The heterogeneous reaction of adduct formation is accompanied by dissociation of the binuclear molecules [M2(DtC) 4] of the initial dithiocarbamate complexes. Computer-aided simulation of EPR spectra for the copper(II) adducts shows that they are individual. The coordination polyhedron of copper in these compounds is intermediate between a trigonal bipyramid (TBP) and a square pyramid (SP). Based on EPR data, the TBP contribution is quantitatively estimated. 13C and 15N NMR shows that the MDtc and EDtc ligands in the adducts are structurally nonequivalent, whereas the MfDtc ligands are structurally equivalent. The 15N isotropic chemical shifts of the dithiocarbamate groups depend on alkyl substituents at the nitrogen atom.
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| 10. |
- Ivanov, Alexander V., et al.
(author)
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Adducts of zinc and copper(II) morpholinedithiocarbamate complexes with morpholine of the composition [M(Mf)(MfDtC)(2)] and [M(Mf)(MfDtC)(2)]center dot Mf: Synthesis, thermal analysis, EPR, and CP/MAS C-13 NMR
- 2003
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In: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 48:3, s. 415-421
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Journal article (peer-reviewed)abstract
- The zinc and copper(II) morpholineditiohcarbamate complexes [M-2(MfDtc)(4)] and their adducts with morpholine [M(Mf)(MfDtc)(2)], including the solvated forms [M(Mf)(MfDtc)(2)] . Mf (M = Zn, Cu-63, Cu-65), have been synthesized and characterized by thermal analysis, EPR, and CP/MAS C-13 NMR data. Upon thermal destruction, the initial complexes, their adducts, and solvated forms lose weight in one, two, and three steps, respectively. The ultimate products of the thermal destruction of these complexes are zinc and copper sulfides. The range of the thermal destruction of the "dithiocarbamate part" is progressively shifted to lower temperatures in going from the initial binuclear complexes to their adducts and solvated forms. EPR shows that the geometry of the [CuS4N] chromophore in the [Cu(Mf)(MfDtc)(2)] adduct is close to square-pyramidal, the unpaired electron being predominantly localized in the metal 3d(x2-y2) AO. The outer-sphere solvation of the adduct is accompanied by structural reorganization at the molecular level. This reorganization involves a distortion of the [CuS4] base of the square-pyramidal polyhedron [CuS4N] toward a trigonal bipyramid. C-13 NMR shows that all of the zinc complexes under consideration are characterized by intramolecular nonequivalence of dithiocarbamate ligands. The N-15 NMR spectra adequately reflect the difference in the structural functions of pairs of dithiocarbamate ligands in [Zn-2(MfDtc)(4)].
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