Surface and bulk characterisation of titanium–oxo clusters and nanosized titania particles through 17O solid state NMR

Scolan, Emmanuel; Magnenet, C.; Massiot, Dominique; Sánchez, Clément

doi:10.1039/a903714d

Cited by 72 publications

(71 citation statements)

References 29 publications

(32 reference statements)

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“…However, for the 17 O resonances from TiO 2 gels initial studies suggested that broadening of the MAS NMR spectra is dominated by chemical shift dispersion. Recently a much more complete study that also included 3Q MAS NMR of 17 O showed, in nanocrystalline TiO 2 for most of the sites with oxygen only coordinated to titanium, that chemical shift dispersion was the dominant broadening mechanism [31]. It has also been shown in other 17 O NMR studies of crystalline materials with ionic M-O bonds that the central transition can show very significant chemical shift anisotropy [32][33][34].…”

Section: Implications For Observation Of Ti-o-si Linkagesmentioning

confidence: 99%

Solid State NMR Interaction Parameters of Oxygens Linking Titanium and Silicon in Crystalline Cyclic Titanodiphenylsiloxanes

Gervais

Babonneau

Hoebbel

et al. 2000

Solid State Nuclear Magnetic Resonance

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Section: Implications For Observation Of Ti-o-si Linkagesmentioning

confidence: 99%

Solid State NMR Interaction Parameters of Oxygens Linking Titanium and Silicon in Crystalline Cyclic Titanodiphenylsiloxanes

Gervais

Babonneau

Hoebbel

et al. 2000

Solid State Nuclear Magnetic Resonance

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“…A collapse of the D2 and D3 components is also expected in the high-temperature phase (O1 sites). The critical point in such an experiment is a risk of 17 O/ 16 O back-exchange in the sample at high temperature.…”

Section: Resultsmentioning

confidence: 99%

“…Following the n nomenclature, 16 the O1 oxygen site (22% in the high-temperature phase) corresponds to a 4 environment whereas O2 (53%) and O3 (25%) correspond to a 3 environment. Based on the known correlation 16 (see Introduction), we therefore ascribe the D1 domain in the spectrum to 3 and the D2 and D3 range to 4 , which is also in agreement with the fact that quadrupolar splitting is weaker in the D2 and D3 [ 4 ] domains than in the D1 [ 3 ] domain. The contribution of the D2 and D3 domains obtained from our results corresponds to 18% of the overall intensity, which is close to the abundance of the O1 sites in the crystal structure.…”

Section: Discussionmentioning

confidence: 99%

“…Based on these measurements, computing the isotope mass balance of gas and sample, the 17 O enrichment of the sample is of 60 š 2%. Weight loss after 16 O back-exchange was in slight excess of the expected amount owing to the presence of a small amount of 18 O isotope in the isotope gas used.…”

Section: Experimental Synthesismentioning

confidence: 97%

“…15 In iono-covalent materials involving heavy ions (Zr, Ti, W), the range of chemical shift is much wider (several hundred ppm) with much lower quadrupolar coupling constants. In these materials, the chemical shift differences allow a clear spectral separation of the different O structural positions n (where n is the number of oxygen ligands), 11,16 the increased coordination number leading to a decreased isotropic chemical shift. The covalent system line positions are found at lower chemical shifts than for the iono-covalent systems.…”

Section: Introductionmentioning

confidence: 99%

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17O NMR in room temperature phase of La2Mo2O9 fast oxide ionic conductor

et al. 2005

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A room temperature (17)O NMR study of La(2)Mo(2)O(9), a fast oxide ionic conductor exhibiting a phase transition at 580 degrees C between a low-temperature alpha-phase and a high-temperature beta-phase, is presented. Four partly overlapping quasi-continuous distributions of oxygen sites are evidenced from 1D magic angle spinning (MAS) and 2D triple quantum MAS NMR experiments. They can be correlated with the three oxygen sites O1, O2 and O3 of the high-temperature crystal structure. The low-temperature phase is characterized by two distributed sites of type O1, which proves that the symmetry is lower than in the cubic high-temperature phase. Two-dimensional experiments show that there is no dynamic exchange process, on the NMR time-scale, between the different oxygen sites at room temperature, which agrees well with conductivity results.

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New Mesotextured Hybrid Materials Made from Assemblies of Dendrimers and Titanium(IV)-Oxo-Organo Clusters

et al. 2000

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The discovery that micellar and lyotropic liquid-crystal phases can direct the assembly of periodic inorganic or hybrid organic ± inorganic materials heralded a new class of materials with hierarchical structures and complex forms. [1] The chemical construction and patterning of such materials remains an important challenge in the science of organized matter chemistry. [1d] A number of imaginative routes to prepare new hybrid materials have been recently reviewed in some excellent articles. [2] The chemistry of silica-based hybrid systems is quite well understood and a large amount of work has been devoted to these materials, which have been formed as mesoscopic powders, films, and fibers. [3] On the contrary, the organic ± inorganic interfaces built from non-silicate precursors (transition metals, Al or Sn) are more difficult to control; fine tuning of the hydrolysis/condensation and the assembly processes is more difficult to achieve. For many transition metals, their higher reactivity towards hydrolysis [4] precludes the reproducible synthesis of ordered hybrid phases. These problems can be overcome by resorting to less reactive, preformed transition metal ± oxo building blocks and controlling their connection into organized nano-or mesostructures. Such strategies, based on the assembly of nano building blocks (ANBB) [5] with well-defined structures, can provide new pathways to design new chemical systems with novel properties or combinations of properties.Herein we report, what is to the best of our knowledge, the first synthesis and characterization of new mesoscopically ordered hybrid materials built through the ANBB. New functional dendrimers [6] (hereafter called G1(COOH) 6 or G1(OH) 6 ; see Scheme 1) and structurally well-defined Tioxo-organo clusters, [Ti 16 O 16 (OEt) 32 ] [7±9] (TS, Scheme 1) were used as nano building blocks. The preparation of both building blocks (BBs) and the hybrids is described in the Experimental Section. Hybrids are named TS-G1(OH) 6 -Z or

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Surface and bulk characterisation of titanium–oxo clusters and nanosized titania particles through 17O solid state NMR

Cited by 72 publications

References 29 publications

Solid State NMR Interaction Parameters of Oxygens Linking Titanium and Silicon in Crystalline Cyclic Titanodiphenylsiloxanes

Solid State NMR Interaction Parameters of Oxygens Linking Titanium and Silicon in Crystalline Cyclic Titanodiphenylsiloxanes

17O NMR in room temperature phase of La2Mo2O9 fast oxide ionic conductor

New Mesotextured Hybrid Materials Made from Assemblies of Dendrimers and Titanium(IV)-Oxo-Organo Clusters

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