| 1. |
- Rusanova, Daniela, et al.
(author)
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Copper(I) O,O '-dialkyldithiophosphate clusters : EXAFS, NMR and X-ray diffraction studies
- 2007
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In: Journal of coordination chemistry (Print). - : Informa UK Limited. - 0095-8972 .- 1029-0389. ; 60:5, s. 517-525
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Journal article (peer-reviewed)abstract
- Copper K- edge EXAFS data for six polycrystalline cubic cluster compounds, {Cu-8[ S2P(OR)(2)](6)(mu(8)- S)} with R= Et, Pr-n, Pr-i, Bu-n, Bu-i and Am-i, show that the architecture of their Cu-8(S2P)(2)S cores is fairly rigid and independent of both length and branching of the alkyl chain, and that the structure of the cluster is maintained in acetone solution. Solid- state P-31 CP-MAS and static Cu-65 NMR data for {Cu-8[S2P(O-n Pr)(2)] 6(mu(8)- S)} and {Cu-8[S2P(OEt)(2)](6) mu(8)- S)} show similarities in the icosahedral O,O'- dialkyldithiophosphate shells and in the `cubic' copper cores in these cluster compounds. The crystal structure of {Cu-8[S2P(O-n Pr)(2)](6) (mu(8)- S)} was resolved using single- crystal X- ray diffraction.
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| 2. |
- Maslova, Marina, et al.
(author)
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Aluminum adsorption on titanium phosphate and silica-modified titanium phosphates
- 2009
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In: The Natural History of Aluminium : From Non-Selection to Natural Selection. ; , s. 41-
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Conference paper (other academic/artistic)abstract
- Synthesis, characterization and sorption affinities of titanium phosphate (TiP) and titanium phosphate silicates (TiPSi) in relation to various metal ions were recently reported by our group. In this work, we explored further adsorption properties of these materials with respect to aluminium ions in aqueous solutions. Sorption of Al3+(aq) increases with pH and reaches ca. 13 mg/g at pH close to neutral conditions and it can be described by an ion-exchange mechanism. Surface speciation of aluminium was studied by 27Al and 31P solid state NMR. These and other spectroscopic data were correlated with adsorption macroscopic measurements. Purification of process and drinking waters is one of the potential applications of these cheap adsorbents manufactured by decomposition of mineral sphene, CaTiOSiO4, which is abundant up to 5 % in tailings of apatite ores in Kola peninsula.
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| 3. |
- Maslova, Marina, et al.
(author)
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Formation of titanium phosphate composites during phosphoric acid decomposition of natural sphene
- 2008
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In: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 181:12, s. 3357-3365
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Journal article (peer-reviewed)abstract
- Decomposition of mineral sphene, CaTiOSiO4, by H3PO4 is investigated in detail. During the dissolution process, simultaneous calcium leaching and formation of titanium phosphate (TiP) take place. The main product of decomposition is a solid titanium phosphate-silica composite. The XRD, solid-sate NMR, IR, TGA, SEM and BET data were used to identify and characterize the composite as a mixture of crystalline Ti(HPO4)2H2O and silica. When 80% phosphoric acid is used the decomposition degree is higher than 98% and calcium is completely transferred into the liquid phase. Formation of Ti(HPO4)2H2O proceeds via formation of meta-stable titanium phosphate phases, Ti(H2PO4)(PO4)2H2O and Ti(H2PO4)(PO4).The sorption affinities of TiP composites were examined in relation to caesium and strontium ions. A decrease of H3PO4 concentration leads to formation of composites with greater sorption properties. The maximum sorption capacity of TiP is observed when 60% H3PO4 is used in sphene decomposition.The work demonstrates a valuable option within the Ti(HPO4)2H2O-SiO2 composite synthesis scheme, to use phosphoric acid flows for isolation of CaHPO42H2O fertilizer.
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| 4. |
- Maslova, Marina, et al.
(author)
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Synthesis, characterization, and sorption properties of amorphous titanium phosphate and silica-modified titanium phosphates
- 2008
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In: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 47:23, s. 11351-11360
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Journal article (peer-reviewed)abstract
- Amorphous titanium hydroxyphosphate with formula Ti(OH)1.36(HPO4)1.322.3H2O and a new silica-modified titanium hydroxyphosphate with a general formula Ti(OH)2x(HPO4)2-xySiO2nH2O are synthesized and characterized using IR, TG, XRD, SEM, solid-state NMR, and BET techniques. It is concluded that SiO2 is evenly distributed within the titanium phosphate (TiP) agglomerates and that neither the separate silica phase nor the titanium silicates are formed during the synthesis of silica-modified titanium hydroxyphosphate. Correlations between the texture, ion-exchange properties of the amorphous titanium hydroxyphosphate, and the amount of SiO2 present within the TiP matrix are established. Sorption properties of silica-modified titanium hydroxyphosphate toward Cs+ and Sr2+ are studied in a series of samples with an increasing amount of silica, at different pH, and in NaCl solutions with a varying ionic strength. It is found that sorption of Cs+ does not depend practically on the amount of SiO2 present, whereas the Sr2+ uptake drastically decreases with an increase of silica amount. The effects of pH and of the electrolyte concentration on the sorption behavior of titanium phosphate are discussed in terms of ionic hydration shell and titanium phosphate structural specificity. The kinetics of sorption processes is also investigated, and the diffusion coefficients for cesium and strontium are obtained.
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| 5. |
- Maslova, Marina V., et al.
(author)
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Extended study on the synthesis of amorphous titanium phosphates with tailored sorption properties
- 2012
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In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 358:22, s. 2943-2950
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Journal article (peer-reviewed)abstract
- The influence of concentrations of both TiO2 and H2SO4 in the syntheses of amorphous titanium phosphates (TiP) is reported. IR, XRD, TGA, BET and NMR techniques were used to characterise the isolated TiP products. The concentration of sulphuric acid in the initial synthesis plays a major role in the structural diversity and sorption properties of the final ionites. In the primary solutions, Ti(IV) is in monomeric, polymeric and colloidal forms. Upon addition of H3PO4 the presence of monomeric titanium ensures formation of the Ti(HPO4)2 phase. The polymeric Ti(IV) is responsible for formation of the titanium hydroxo-phosphate phase, Ti(OH)2(HPO4), whilst the colloidal form of Ti(IV) appears to have a role in coagulation of a minor Ti(OH)4 phase in an amorphous TiP. It is found that TiP ion-exchange capacities gradually increase with an increase of both TiO2 and H2SO4 concentrations and reach a maximum value of 3.8 mg-eq g− 1 when TiO2 is 70–100 g L− 1 and H2SO4 is 480–560 g L− 1. Analyses of compositional, structural and sorption data allowed 3D correlation diagrams to be built that can facilitate fabrication of TiP with tailored sorption properties.
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| 6. |
- Rusanova, Daniela, et al.
(author)
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Formation of {Cu6[S2P(OC2H5)2]6} on Cu2S Surfaces from Aqueous Solutions of the KS2P(OC2H5)2 Collector: Scanning Electron Microscopy and Solid-State 31P Cross-Polarization/Magic Angle Spinning and Static 65Cu NMR Studies
- 2005
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 21:10, s. 4420-4424
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Journal article (peer-reviewed)abstract
- The interactions of synthetic chalcocite surfaces with diethyldithiophosphate, potassium salt, K[S2P(OC2H5)2], were studied by means of 31P cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy and scanning electron microscopy (SEM). To identify the species formed on the Cu2S surfaces, a polycrystalline {CuI6[S2P(OC2H5)2]6} cluster was synthesized and analyzed by SEM, powder X-ray diffraction techniques and solid-state 31P CP/MAS NMR and static 65Cu NMR spectroscopy. 31P chemical shift anisotropy (CSA) parameters, CS and CS, were estimated and used for assigning the bridging type of diethyldithiophosphate ligands in the {CuI6[S2P(OC2H5)2]6} cluster. The latter data were compared to 31P CSA parameters estimated from the spinning sideband patterns in 31P NMR spectra of the collector-treated mineral surfaces: formation of polycrystalline {CuI6[S2P(OC2H5)2]6} on the Cu2S surfaces is suggested. The second-order quadrupolar line shape of 65Cu was simulated, and the NMR interaction parameters, CQ and Q, for the copper(I) diethyldithiophosphate cluster were obtained.
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| 7. |
- Rusanova, Daniela, et al.
(author)
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Formation of Ο,Ο’-di-alkyl-dithiophosphate copper (I) complexes on the surface of synthetic chalcocite : NMR and SEM studies
- 2005
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In: Centenary of Flotation Symposium Proceedings. - : The Australian Institute of Mining and Metallurgy. - 9781920806316 ; , s. 581-590
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Conference paper (peer-reviewed)abstract
- The adsorption mechanism of three different 0,0'-di-alkyl-dithiophosphate (dtp) collectors, K[S22P(OR)2] with R = Et, i-Bu and i'-Amyl, on the surface of synthetic chalcocite (Cu2S)Was studied by means of solid-state 31P CP/MAS NMR spectroscopy. The morphology changes on the conditioned (Cu2S) surfaces, in the collector concentration range 0.1 - 10 mM, were also monitored with scanning electron microscope (SEM). In order to assign Cu(I)-dtp species on the surface of CU 2S, the corresponding bulk Cu(I)-dtp compounds, which are clusters of the monovalent copper containing either Cu6(antiprismatic) or Cu8(cubic) cores, were synthesised, and characterised by means of solid-state 31P CP/MAS and static 65Cu NMR. Further investigations on the crystal habits of the bulk systems were carried out by powder x-ray diffraction and SEM. A comparative analysis of the 31P chemical shift and chemical shift anisotropy (CSA) data estimated from the experimental NMR spectra of the polycrystalline bulk Cu(l) dialkyldithiophosphate complexes was used for assigning the 31P resonance lines in the NMR spectra of the collector treated CU2S powder samples. The species formed on the synthetic Cu2S surfaces were assigned to polycrystalline phases of: Cu6L6 with L = Et2dtp̄μ, Cu6L6, and Cu 8L6(S) with L = i'-Bu2dtp̄, and 3. Cu 8L6S) with L = i-Amyl2dtp̄. A heterophase autocatalytic step process of both formation and growth of solid Cu xLy (L = R2dtp, x = 6 or 8 and y = 6) complexes on the collector treated CU2S surface is proposed. A possible role of the oxidised form of dithiophosphate collectors, bis[di-alkyl-thiophosphoryl] -disulfane (disulfide), is discussed in terms of a specific self-redox reaction. The second order quadrupolar lineshapes in 65Cu NMR spectra were simulated and the interaction parameters, CQ and nQ, for the bulk dialkyldithiophosphato-copper(I) complexes were obtained
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| 8. |
- Rusanova, Daniela, et al.
(author)
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Solid-state 31P CP/MAS and static 65Cu NMR characterization of polycrystalline copper(I) dialkyldithiophosphate clusters
- 2006
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In: Journal of magnetic resonance. - : Elsevier BV. - 1090-7807 .- 1096-0856. ; 179:1, s. 140-145
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Journal article (peer-reviewed)abstract
- Polycrystalline tetra-nuclear Cu4[S2P(O-i-C3H7)2]4, hexa-nuclear Cu6[S2P(OC2H5)2]6, and octa-nuclear Cu8[S2P(O-i-C4H9)2]6(S) complexes were synthesized and analyzed by means of solid-state 31P CP/MAS and 65Cu static NMR spectroscopy. The symmetries of the electronic environments around each P-site were estimated from the 31P chemical shift anisotropy (CSA) parameters, Δaniso and η. The 65Cu chemical shift and quadrupolar splitting parameters obtained from the experimental 65Cu NMR spectra of the polycrystalline CuI-complexes are presented. A solid-state NMR approach for the elucidation of the stereochemistry of poly-nuclear Cu(I) dithiophosphate complexes, when the structural analysis of the systems by single-crystal X-ray diffraction is not readily available, is proposed.
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| 9. |
- Rusanova, Daniela, et al.
(author)
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Solid-state NMR and EXAFS spectroscopic characterization of infoPolycrystalline copper(I) O,O prime -Dialkvldithiophosphate cluster compounds : Formation of copper(I) O,O prime -diisobutyklithiophosphate compounds on the surface of synthetic chalcocite
- 2006
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In: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 12:20, s. 5282-5292
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Journal article (peer-reviewed)abstract
- A number of polycrystalline copper(I) O,O-dialkyldithiophosphate cluster compounds with Cu4, Cu6, and Cu8 cores were synthesized and characterized by using extended X-ray absorption fine-structure (EXAFS) spectroscopy. The structural relationship of these compounds is discussed. The polycrystalline copper(I) O,O-diisobutyldithiophosphate cluster compounds, [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6], were also characterized by using 31P CP/MAS NMR (CP = cross polarization, MAS = magic-angle spinning) and static 65Cu NMR spectroscopies (at different magnetic fields) and powder X-ray diffraction (XRD) analysis. Comparative analyses of the 31P chemical-shift tensor, and the 65Cu chemical shift and quadrupolar-splitting parameters, estimated from the experimental NMR spectra of the polycrystalline copper(I) cluster compounds, are presented. The adsorption mechanism of the potassium O,O-diisobutyldithiophosphate collector, K[S2P(OiBu)2], at the surface of synthetic chalcocite (Cu2S) was studied by means of solid-state 31P CP/MAS NMR spectroscopy and scanning electron microscopy (SEM). 31P NMR resonance lines from collector-treated chalcocite surfaces were assigned to a mixture of [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6] compounds.
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| 10. |
- Rusanova, Daniela, et al.
(author)
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Solid-state static 65Cu and 31P CP/MAS NMR, and liquid-state EXAFS studies on copper(I) O,O′-dialkyldithiophosphate cluster compounds : formation of the copper(I) O,O′-di-iso-amyldithiophosphate cluster compound on the surface of synthetic chalcocite
- 2006
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In: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 25:18, s. 3569-3580
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Journal article (peer-reviewed)abstract
- Polycrystalline octa-nuclear copper(I) O,O′-di-i-propyl- and O,O′-di-i-amyldithiophosphate cluster compounds, {Cu8[S2P(OR)2]6(μ8-S)} where R = iPr and iAm, were synthesized and characterized by 31P CP/MAS NMR at 8.46 T and static 65Cu NMR at multiple magnetic field strengths (7.05, 9.4 and 14.1 T). The symmetries of the electronic environments around the P sites were estimated from the 31P chemical shift anisotropy (CSA) parameters, δaniso and η. Analyses of the 65Cu chemical shift and quadrupolar splitting parameters for these compounds are presented with the data being compared to those for the analogous octa-nuclear cluster compounds with R = nBu and iBu. The 65Cu transverse relaxation for the copper sites in {Cu8[S2P(OiPr)2]6(μ8-S)} and {Cu8[S2P(OiAm)2]6(μ8-S)} was found to be very different, with a relaxation time, T2, of 590 μs (Gaussian) and 90 μs (exponential), respectively. The structures of {Cu4[S2P(OiPr)2]4} and {Cu8[S2P(OiPr)2]6(μ8-S)} cluster compounds in the liquid- and the solid-state were studied by Cu K-edge EXAFS. The disulfide, [S2P(OiAm)2]2, was obtained and characterized by 31P{1H} NMR. The interactions of the disulfide and of the potassium O,O′-di-i-amyldithiophosphate salt with the surfaces of synthetic chalcocite (Cu2S) were probed using solid-state 31P NMR spectroscopy and only the presence of copper(I) dithiophosphate species with the {Cu8[S2P(OiAm)2]6(μ8-S)} structure was observed.
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