| 1. |
- Khasanova, Nellie R., et al.
(författare)
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A New Structure Type of the Ternary Sulfide Eu1.3Nb1.9S5
- 2002
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Ingår i: Journal of Solid State Chemistry. - : Elsevier. - 1095-726X .- 0022-4596. ; 164:2, s. 345-353
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Tidskriftsartikel (refereegranskat)abstract
- The structure model for the Eu1.3Nb1.9S5 compound is determined based on high-resolution electron microscopy evidence. This compound crystallizes in a hexagonal unit cell with a=8.8732(8) Å and c=23.45(1) Å. Its structure is built up as an alternating sequence of trigonal-prismatic NbS2 layers of formula [Nb7S14] and [Nb(Eu3S4)2] slabs along the c-direction. In the [Nb(Eu3S4)2] block the stacking of two close-packed (Eu3S4) layers creates octahedral interstices formed by S atoms; these cavities are occupied by Nb cations. The model is compared with structures of other Eu-containing niobium sulfides, such as Eu0.167NbS2 and the misfit compound [(EuS)1.5]1.15NbS2.
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| 2. |
- Grippa, Alexander Yu, et al.
(författare)
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Crystal Structure of BaNb0.9S3
- 2001
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Ingår i: Crystallography Reports. - : American Institute of Physics. - 1063-7745. ; 46:3, s. 373-376
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Tidskriftsartikel (refereegranskat)abstract
- Single crystals of the composition BaNb[sub 0.9]S[sub 3] have been synthesized from the BaS, Nb, and S mixture and the BaCl[sub 2] flux at 900°C. The BaNb[sub 0.9]S[sub 3] structure was refined by X-ray single-crystal and electron diffraction data. The compound is crystallized in the sp. gr P6[sub 3]/mmc (z = 2) with the unit-cell parameters a = 6.839(1) Å and c = 5.745(1) Å. It was established that the cationic vacancies in the niobium positions are statistically distributed over the structure.
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| 3. |
- Grippa, Alexander Yu, et al.
(författare)
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New strontium and rare earth-based mixed niobium misfit sulfides
- 2003
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Ingår i: Solid State Sciences. - : Elsevier. ; 5:3, s. 495-502
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Tidskriftsartikel (refereegranskat)abstract
- New niobium-based misfit sulfides [(Ln1/3Sr2/3S)1.5]1.15NbS2 (Ln=Sm, Tb) have been synthesized from a mixture of SrS, Ln2S3, Nb(m), and S in evacuated and sealed silica tubes by annealing at 1000 °C for 144 h under a sulfur partial pressure of 49.3 kPa. The compounds have been characterized by EDX analysis, X-ray single crystal and powder diffraction, electron diffraction, and magnetic susceptibility measurements. Both sulfides have misfit structures with orthorhombic symmetry for the (Ln1/3Sr2/3S)1.5 (Ln=Sm, Tb) and NbS2 subsystems. The lattice parameters for the different subsystems are: for the Sm-based sulfide [(Sm1/3Sr2/3S)1.5]: a=5.7953(9) Å, b=5.8007(5) Å, c=14.957(2) Å and [NbS2]: a=3.3420(7) Å, b=5.8008(5) Å, c=14.955(2) Å, and for the Tb-based sulfide [(Tb1/3Sr2/3S)1.5]: a=5.769(2) Å, b=5.7766(7) Å, c=14.906(2) Å and [NbS2]: a=3.340(1) Å, b=5.7769(8) Å, c=14.905(2) Å. The [(Sm1/3Sr2/3S)1.5]1.15NbS2 crystal structure has been refined from X-ray single crystal data. It belongs to the 1.5Q/1H homologue type where the (Sm1/3Sr2/3S)1.5 part is a three-atoms-thick slab. Sr-cations are mainly located at the exterior of the slab whereas Sm preferably occupy the positions at its center. Both compounds exhibit paramagnetic temperature dependence down to 2 K.
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| 4. |
- Ivanov, Alexander V., et al.
(författare)
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Adducts of Diethyldithiocarbamate Complexes of Zinc(II) and Copper(II) with Piperidine [M(Pip)(Edtc)2] and Their Solvated Forms [M(Pip)(Edtc)2] · L (L = C6H6, C5H5N, C4H9NO): Synthesis, EPR and Solid-State (13C, 15N) CP/MAS NMR Studies
- 2001
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Ingår i: Russian journal of coordination chemistry. - 1070-3284 .- 1608-3318. ; 27:3, s. 158-166
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Tidskriftsartikel (refereegranskat)abstract
- Crystal adducts of diethyldithiocarbamate complexes of zinc(II) and copper(II) with piperidine (Pip) were synthesized, and their solvated forms with the outer-sphere molecules of benzene, pyridine (Py), and morpholine (Mf) were obtained. Adducts with composition [M(Pip)(Edtc)2] · L (L = Py, Mf) were shown to be able, in principle, to give solvated isomers [M(L)(Edtc)2] · Pip with the Pip molecule arranged in the outer sphere. The composition, structure, and properties of the obtained adducts were studied by EPR, high-resolution solid-state 13C, 15N NMR spectroscopy. Solvation of all three adducts with Pip, Mf, and Py was found to result in a substantial increase in the contribution of the trigonal-bipyramidal component to the geometry of a copper coordination pentahedron. In addition, for adducts with Mf and Py, a structural unification of two isomeric forms was observed at the molecular level to yield a qualitatively new (rather than intermediate) state. It was shown that in all solvated forms of the copper(II) adducts, the metal polyhedron is mainly a trigonal bipyramid, while the square-pyramidal contribution is insignificant. Results of (13C, 15N) NMR studies revealed a structural inequivalence of the Edtc-ligands in the zinc adducts under investigation.
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| 5. |
- Ivanov, Alexander V., et al.
(författare)
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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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Ingår i: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 48:3, s. 415-421
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Ivanov, Alexander V., et al.
(författare)
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Binuclear cadmium dithiophosphate crystals: 13C, 31P, and 113Cd CP/MAS NMR studies
- 2003
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Ingår i: Russian journal of coordination chemistry. - 1070-3284 .- 1608-3318. ; 29:5, s. 301-306
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Tidskriftsartikel (refereegranskat)abstract
- 31P NMR signals for the terminal and bridging ligands of the complexes were differentiated. The experimental NMR spectra show 31P-111,113Cd and 113Cd-31 P spin-spin couplings only for the terminal ligands. The chemical shift anisotropy δ and the asymmetry parameter η were calculated for 31P and 113Cd NMR signals. It was found that the 31P chemical shifts for the terminal and bridging dithiophosphato groups differ in anisotropy character.
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| 7. |
- Ivanov, Alexander V., et al.
(författare)
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Copper(II) and Nickel(II) Alkylxanthate complexes (R = C2H5, i-C3H7, i-C4H9, s-C4H9, and C5H11) : EPR and solid-state 13C CP/MAS NMR Studies
- 2004
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Ingår i: Russian journal of coordination chemistry. - 1070-3284 .- 1608-3318. ; 30:7, s. 480-485
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Tidskriftsartikel (refereegranskat)abstract
- Alkylxanthate complexes of the general formula [M{S(S)COR}2] (M = Ni, 63Cu, and 65Cu; R = C2H5, i-C3H7, i-C4H9, s-C4H9, and C5H11) were synthesized and studied by EPR and high-resolution solid-state 13C CP/MAS NMR. In the copper(II) complexes stabilized in the matrix of nickel(II) compounds, square planar chromophores [CuS4] are characterized by rhombic distortion (EPR data). Experimental EPR spectra were simulated at the second order of perturbation theory. Nickel(II) complexes were characterized by 13C NMR spectra. In all cases, the -OC(S)S- groups were found to exhibit intramolecular structural equivalence.
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| 8. |
- Ivanov, Alexander V., et al.
(författare)
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Isomorphism of bis(diethyldithiocarbamato)zinc(II) adduct with pyridine, [Zn(Py)(EDtc)2]: hysteresis in the reaction of the adduct formation
- 2002
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Ingår i: Polyhedron. - 0277-5387 .- 1873-3719. ; 21:27-28, s. 2727-3731
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Tidskriftsartikel (refereegranskat)abstract
- The structure of the polycrystalline adduct bis(diethyldithiocarbamato)-pyridine zinc(II) depends on the pathway of physico-chemical conditions during the preparation procedure, as was revealed by solid state 15N CP/MAS spectroscopy in good correlation with known single crystal X-ray diffraction structures of this adduct. Two isomorphs of the adduct, namely α-[Zn(Py)(S2CNEt2)2] and β-[Zn(Py)(S2CNEt2)2], are the two molecules in the asymmetric unit of a single crystal (or polycrystalline) sample that can be obtained by recrystallization from toluene of the equimolar solution of the initial diethyldithiocarbamate zinc(II) complex and pyridine. The third isomorph, γ-[Zn(Py)(S2CNEt2)2], can be obtained by recrystallization from pure pyridine of the diethyldithiocarbamate zinc(II) complex, or by its equimolar absorption of pyridine, or by desorption of pyridine from the clathrated adduct, [Zn(Py)(S2CNEt2)2]·Py. Finally, the γ-[Zn(Py)(S2CNEt2)2] isomorph recrystallizes from the melt into α/β-isomorphs of the adduct.
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| 9. |
- Ivanov, Alexander V., et al.
(författare)
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Polycrystalline and surface O,O′-dialkyldithiophosphate zinc(II) complexes : preparation, 31P CP/MAS NMR and single-crystal X-ray diffraction studies
- 2001
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Ingår i: Inorganica Chimica Acta. - 0020-1693 .- 1873-3255. ; 315:1, s. 26-35
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Tidskriftsartikel (refereegranskat)abstract
- Dithiophosphate zinc(II) complexes with eight different O,O′-dialkyldithiophosphate ligands have been prepared in solid/liquid states and as surface complexes on a synthetic sphalerite, and studied by means of 31P NMR spectroscopy. All 31P resonances, corresponding to dithiophosphate ligands with different structural functions (i.e. terminal chelating or bridging between two metal atoms in bi- and tetranuclear complexes), have been assigned on the basis of comparative analyses of chemical shift data for solid complexes, their melts and chloroform solutions at various concentrations. The bridging coordination of O,O′-dialkyldithiophosphate ligands by the two neighbouring zinc(II) atoms was established in the case of zinc(II) complexes formed at the surface of the synthetic sphalerite. In addition, novel molecular and crystal structures of the binuclear O,O′-di-cyclo-hexyldithiophosphate zinc(II) complex have been resolved by single-crystal X-ray diffraction data analysis, and useful correlations with 31P NMR data for this complex were obtained.
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| 10. |
- Ivanov, Alexander V., et al.
(författare)
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Solvation isomers of solvated adducts of copper and zinc diethyldithiocarbamate complexes in the M(II)-EDtc-Py-Mf systems : synthesis, EPR, and solid-state C-13 and N-15 CP/MAS NMR
- 2001
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Ingår i: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 46:12, s. 1832-1838
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Tidskriftsartikel (refereegranskat)abstract
- The crystalline adducts [M(B)(EDtc)(2)] (M = Zn, Cu; B = Py, Mf) quantitatively absorb bases to produce their solvated forms incorporating outer-sphere molecules of N-donor bases: [M(Mf)(EDtc)(2)] . Mf, [M(Mf)(EDtc)(2)] . Py, and [M(Py)(EDtc)(2)] . Mf. The adducts of the last two types ire solvate isomers, which differ in the distribution of different bases between the outer and inner coordination spheres, Computer simulation points to the individual character of the EPR spectra of the isomers [Cu(Mf)(EDtc)(2)] . Py and [Cu(Py)(EDtc)(2)] . Mf and the lack of redistribution of base molecules between two coordination spheres. The copper coordination polyhedra in these compounds are close to a trigonal bipyramid (the TBP contribution is about 80%); the ground state of the unpaired electron is dominated by the 3d(z2) copper(II) AO. Combined analysis of C-13 and N-15 NMR data permitted the identification of the signals that arise from the coordinated and outer-sphere pyridine molecules in the solvate isomers [Zn(Mf)(EDtc)(2)] . Py and [Zn(Py)(EDtc)(2)] . Mf.
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