A natural abundance 77Se solid-state NMR study of inorganic compounds

Kemp, Thomas F.; Wong, Alan; Smith, Mark E.; Bishop, P J; Carthey, Nicholas

doi:10.1016/j.ssnmr.2008.10.003

Cited by 15 publications

(21 citation statements)

References 40 publications

(27 reference statements)

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“…13a) or other semiconducting and insulating metal selenides 28 . The 77 Se SSNMR spectrum of commercial NbSe 2 matches that previously reported 29 . Borsa et al 30 attributed the large positive 77 Se isotropic shift of NbSe 2 to a Knight shift, while Smith and co-workers 29 attributed the positive 77 Se isotropic shift to the hyperfine coupling between Se and unpaired d electrons residing on Nb(IV) atom 29 .…”

Section: Resultssupporting

confidence: 87%

Unprecedented generation of 3D heterostructures by mechanochemical disassembly and re-ordering of incommensurate metal chalcogenides

et al. 2020

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Three-dimensional heterostructures are usually created either by assembling twodimensional building blocks into hierarchical architectures or using stepwise chemical processes that sequentially deposit individual monolayers. Both approaches suffer from a number of issues, including lack of suitable precursors, limited reproducibility, and poor scalability of the preparation protocols. Therefore, development of alternative methods that enable preparation of heterostructured materials is desired. We create heterostructures with incommensurate arrangements of well-defined building blocks using a synthetic approach that comprises mechanical disassembly and simultaneous reordering of layered transitionmetal dichalcogenides, MX 2 , and non-layered monochalcogenides, REX, where M = Ta, Nb, RE = Sm, La, and X = S, Se. We show that the discovered solid-state processes are rooted in stochastic mechanochemical transformations directed by electronic interaction between chemically and structurally dissimilar solids toward atomic-scale ordering, and offer an alternative to conventional heterostructuring. Details of composition-structure-properties relationships in the studied materials are also highlighted.

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Section: Resultssupporting

confidence: 87%

Unprecedented generation of 3D heterostructures by mechanochemical disassembly and re-ordering of incommensurate metal chalcogenides

et al. 2020

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“…1045 and 1325 ppm, respectively. According to the literature, 77 Se δ iso for inorganic selenates and selenites are generally found in the 1024–1050 ppm and 1257–1300 ppm ranges, respectively [33,34]. Thus, we can assume that in the HA 300 - 1.2SeO 4 spectrum both signals originate from selenates and that in the HA 300 - 1.2SeO 3 spectrum the lines come from selenite ions.…”

Section: Resultsmentioning

confidence: 93%

A Solid-State NMR Study of Selenium Substitution into Nanocrystalline Hydroxyapatite

Kolmas¹,

Kuras²,

Olędzka³

et al. 2015

IJMS

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The substitution of selenium oxyanions in the hydroxyapatite structure was examined using multinuclear solid-state resonance spectroscopy (ssNMR). The study was supported by powder X-ray diffractometry (PXRD) and wavelength dispersion X-ray fluorescence (WD-XRF). Samples of pure hydroxyapatite (HA300) and selenate (HA300-1.2SeO4) or selenite (HA300-1.2SeO3) substituted hydroxyapatites were synthesized using the standard wet method and heated at 300 °C to remove loosely bonded water. PXRD data showed that all samples are single-phase, nanocrystalline hydroxyapatite. The incorporation of selenite and selenate ions affected the lattice constants. In selenium-containing samples the concentration of Se was very similar and amounted to 9.55% and 9.64%, for HA300-1.2SeO4 and HA300-1.2SeO3, respectively. PXRD and ssNMR data showed that the selenite doping significantly decreases the crystallite size and crystallinity degree. 31P and 1H NMR experiments demonstrated the developed surface hydrated layer in all samples, especially in HA300-1.2SeO3. 1H NMR studies showed the dehydroxylation of HA during the selenium oxyanions substitution and the existence of hydrogen bonding in structural hydroxyl group channels. 1H→77Se cross polarization NMR experiments indicated that selenites and selenates are located in the crystal lattice and on the crystal surface.

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“…The chemical shifts of the cationic Se species in solution are generally observed in the region between δ = +1000 and +2000 ppm. A survey of the 77 Se resonances in the solid‐state NMR spectra of several inorganic compounds showed that selenides containing Se 2– ions appear at δ ≈ –500 ppm, elemental selenium appears at δ = +800 ppm, and formally positive Se atoms such as the Se IV in SeO 3 2– appear at δ ≈ +1300 ppm 27. Thus, NMR spectroscopy is a sensitive probe for the valence state of Se in molecules and solids.…”

Section: Resultsmentioning

confidence: 99%

Double‐Cube‐Shaped Mixed Chalcogen/Pentele Clusters from GaCl₃ Melts

et al. 2014

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Benzopyrylium ylides generated in situ from 1‐acetoxyisochroman‐4‐ones reacted with α,β‐unsaturated aldehydes in the presence of a bifunctional secondary‐amine/squaramide catalyst to furnish [5+2] cycloaddition products in good yield with high diastereo‐ and enantioselectivity. The reaction proceeds by dienamine activation and involves β,γ‐functionalization of the enal. The dienamine intermediates showed exclusive β,γ‐reactivity and provided direct access to compounds with the 8‐oxabicyclo[3.2.1]octane framework. The ability of the bifunctional secondary‐amine/squaramide catalyst to engage in hydrogen‐bonding interactions with the ylide made it particularly effective in terms of both the yield and the stereoselectivity of the transformation.

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A natural abundance 77Se solid-state NMR study of inorganic compounds

Cited by 15 publications

References 40 publications

Unprecedented generation of 3D heterostructures by mechanochemical disassembly and re-ordering of incommensurate metal chalcogenides

Unprecedented generation of 3D heterostructures by mechanochemical disassembly and re-ordering of incommensurate metal chalcogenides

A Solid-State NMR Study of Selenium Substitution into Nanocrystalline Hydroxyapatite

Double‐Cube‐Shaped Mixed Chalcogen/Pentele Clusters from GaCl₃ Melts

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A natural abundance 77Se solid-state NMR study of inorganic compounds

Cited by 15 publications

References 40 publications

Unprecedented generation of 3D heterostructures by mechanochemical disassembly and re-ordering of incommensurate metal chalcogenides

Unprecedented generation of 3D heterostructures by mechanochemical disassembly and re-ordering of incommensurate metal chalcogenides

A Solid-State NMR Study of Selenium Substitution into Nanocrystalline Hydroxyapatite

Double‐Cube‐Shaped Mixed Chalcogen/Pentele Clusters from GaCl3 Melts

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Double‐Cube‐Shaped Mixed Chalcogen/Pentele Clusters from GaCl₃ Melts