Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

SawyerRyan,; Wayne, NesbittH.; Michael, BancroftG.; ThibaultYves,; SeccoRichard, A

doi:10.1139/cjc-2014-0248

Cited by 41 publications

(48 citation statements)

References 87 publications

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“…The literature indications for the presence of multiple Q 3 species cited by Sawyer et al 1 do not, in any way, support the reassignment of the 29 Si NMR data because the proposed multiple Q 3 sites are present in sodium silicate glasses, for which the additional NMR peak is absent (Figs. 1a and 1b).…”

Section: Si Nmr Band Assignmentmentioning

confidence: 83%

“…Also, the cited Raman features near 1150 and 1060 cm −1 may have been tentatively assigned to multiple Q 3 environments by some authors, 9,10 but more recent work assigns these features to vibrational modes related to Q 4 and Q 2 /all Q n (n = 1-4), respectively. [11][12][13] In contrast with the lack of evidence for the Sawyer reassignment, the conventional assignment of the 29 Si NMR peaks, based on the presence Q 2= in three-membered rings in the spectra of potassium, rubidium, and cesium silicate glasses, is supported by a wide variety of evidence, 5 despite claims to the contrary by Sawyer et al 1 Among others, the spectral properties, most notably linewidth, peak position, and relative weakness of the J-coupling, are fully consistent with a Q 2 species with narrow Si-O-Si angles typical for three-membered rings. 5 Two-dimensional homonuclear correlation 29 Si NMR data also confirm this interpretation.…”

Section: Si Nmr Band Assignmentmentioning

confidence: 97%

“…To bring the 29 Si NMR data in line with their O1s data, Sawyer et al 1 proposed an alternative assignment for the Q n peaks in the 29 Si NMR spectra. The assignment of the 29 Si NMR spectra of potassium, rubidium, and cesium silicate glasses is complicated by the presence of an additional peak that is absent in the spectra of sodium and lithium silicate glasses (Figs.…”

Section: Si Nmr Band Assignmentmentioning

confidence: 99%

“…1a and 1b). The original assignment 4,5 considers the additional peak to be due to a special type of Q 2 (labeled Q 2= ); the reassignment by Sawyer et al 1 considers an additional peak to be due to a second type of Q 3 (labeled Q 3 *).…”

Section: Si Nmr Band Assignmentmentioning

confidence: 99%

“…Sawyer et al 1,2 concluded from O1s XPS data that significant amounts of free oxygen are present in potassium silicate glasses. This observation is at odds with the strongly basic nature of K 2 O, which should lead to a high reactivity with acidic SiO 2 and the very high enthalpy of mixing in the K 2 O/SiO 2 system.…”

Section: Introductionmentioning

confidence: 99%

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Comment on “Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts”

Malfait

2015

Can. J. Chem.

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Recent O1s XPS studies suggest that significant free oxide (O 2-or K-O-K) is present in potassium silicate glasses, in contrast with what was concluded from 29 Si and 17 O solid-state NMR data. An alternative peak assignment of the Q n peaks in the 29 Si NMR spectra was proposed to bring the 29 Si NMR data in line with the O1s data, but this reassignment (i) is not supported by any evidence other than the resulting agreement between the NMR and XPS data, (ii) is at odds with the spectral properties of the bands (peak position and width), (iii) ignores the strong evidence for the original peak assignment, and (iv) results in highly implausible equilibrium constants for the Q n speciation reactions. More likely causes for the apparent discrepancy between the XPS and NMR data are the incorrect estimation of the precision of the bridging oxygen content from the O1s XPS data, the systematic overestimation of the bridging oxygen content from the O1s XPS data, and (or) the incorrect estimation of the accuracy of the compositional analysis, which was based on the precision rather than the accuracy of the electron microprobe analysis. Thus, the available evidence strongly suggests that the original assignment of the 29 Si NMR spectra is correct. Neither the 29 Si NMR nor the O1s XPS data support the presence of significant amounts of free oxide in potassium silicate glasses with K 2 O/SiO 2 Ͻ Ͻ 2.Key words: potassium silicate glasses, free oxygen, O1s XPS, 29 Si NMR, peak assignment. Résumé :De récentes études en XPS de l'oxygène O1s semblent indiquer la présence importante d'oxyde libre (O 2-ou K-O-K) dans les verres de silicate de potassium, contrairement aux conclusions issues des données RMN 29 Si et 17 O à l'état solide. On y a proposé une attribution différente des pics des espèces Q n dans les spectres RMN 29 Si afin de mettre les données RMN du silicium 29 Si en conformité avec les données XPS de l'oxygène O1s. Toutefois, cette réattribution (i) n'est appuyée par aucune preuve autre que la correspondance résultante entre les données RMN et XPS, (ii) est en désaccord avec les propriétés spectrales des bandes (position et largeur des pics), (iii) fait abstraction des fortes indications appuyant l'attribution originale des pics et (iv) génère des constantes d'équilibre hautement improbables relativement aux réactions de spéciation Q n . Il apparaît plus probable que les incohérences apparentes entre les données XPS et RMN soient dues à une estimation erronée de la précision de la proportion d'atomes d'oxygène pontants à partir des données XPS O1s, à la surestimation systématique de la proportion d'atomes d'oxygène pontants à partir des données XPS O1s et (ou) à l'estimation erronée de l'exactitude de l'analyse élémentaire, laquelle était fondée sur la précision plutôt que sur l'exactitude de l'analyse par microsonde électronique. Par conséquent, l'ensemble des éléments probants dont on dispose laisse fortement supposer que l'attribution originale des spectres RMN 29 Si était correcte. Ni les données RMN ...

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Section: Si Nmr Band Assignmentmentioning

confidence: 83%

Section: Si Nmr Band Assignmentmentioning

confidence: 97%

Section: Si Nmr Band Assignmentmentioning

confidence: 99%

Section: Si Nmr Band Assignmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comment on “Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts”

Malfait

2015

Can. J. Chem.

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Characterization and thermal studies of nano‐synthesized Mn(II), Co(II), Ni(II) and Cu(II) complexes with adipohydrazone ligand as new promising antimicrobial and antitumor agents

Gaber

Khedr

Elsharkawy

2017

Applied Organom Chemis

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New seven complexes of N 1 ,N 6 -bis((2-hydroxynaphthalin-1-yl)methinyl)) adipohydrazone (H 2 L) with MnCl 2 •4H 2 O, CoCl 2 •6H 2 O, NiCl 2 •6H 2 O, CuCl 2 •2H 2 O, Cu(NO 3 ) 2 •3H 2 O, CuSO 4 •5H 2 O, and Cu(OAc) 2 •2H 2 O have beenprepared and characterized by the aid of elemental and thermal analyses, spectra (FT-IR, 1 H NMR, MS, UV-Vis, ESR, X-ray powder diffraction), molar conductance and magnetic moment measurements. The XRD results unambiguously confirmed the nano-sized particles of the complexes. The results showed that H 2 L behaves as dibasic tetra-dentate ligand towards the metal ions of interest. The low molar conductance values revealed the non-electrolytic nature for the chelates. The magnetic moment data, UV-Vis and ESR spectra denoted the formation of octahedral geometries for Mn(II) and Ni(II) complexes, whereas Co(II), Cu(II) complexes exhibited tetrahedral arrangement. The activation parameters for the thermal decomposition stages were calculated from TGA curves using Coats-Redfern and Horowitz-Metzger methods. The obtained data were confirmed by 3-D molecular modeling of the ligand and some complexes. The investigated compounds were screened for their antimicrobial activities against different types of organisms and antitumor activities towards human liver Carcinoma (HEPG2) cell to access their potential chemotherapeutic use. The free ligand (H 2 L) exhibited a weak inhibition of cell viability with IC 50 of 11.80 μg/ml, complexes 4, 6 and 7 showed a moderate activity with IC 50 of 5.56, 7.71 and 5.67 μg/ml, whereas complexes 1, 2, 3, and 5 displayed a strong anticancer activity with IC 50 of 4.65, 3.97, 3.30 and 4.84 μg/ml, compared with IC 50 value of 4.73 μg/ml for the doxorubicin (standard cytotoxin drug).

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Atomic and Electronic Structure of Zircon According to High-Resolution X-Ray Photoelectron Spectroscopy: Methodological Aspects

Shchapova

Zamyatin

Votyakov

et al. 2020

Springer Proceedings in Earth and Environmental Sciences

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Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

Cited by 41 publications

References 87 publications

Comment on “Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts”

Comment on “Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts”

Characterization and thermal studies of nano‐synthesized Mn(II), Co(II), Ni(II) and Cu(II) complexes with adipohydrazone ligand as new promising antimicrobial and antitumor agents

Atomic and Electronic Structure of Zircon According to High-Resolution X-Ray Photoelectron Spectroscopy: Methodological Aspects

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