Characterization of siloxane copolymers by solution 17O NMR spectroscopy

Kählig, Hanspeter; Mayer-Helm, Bernhard X.

doi:10.1016/j.polymer.2005.03.110

Cited by 7 publications

(1 citation statement)

References 28 publications

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“…They afforded the improvement of separation characteristics of columns and service lives. In turn, modern analytical equipment provided better understanding of the structures and properties of the known polymers [38][39][40].…”

Section: Polydimethylsiloxanes With Carboranyl Substituentsmentioning

confidence: 99%

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

Анисимов¹,

Зайцев²,

Ol’shevskaya³

et al. 2018

INEOS OPEN

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Section: Polydimethylsiloxanes With Carboranyl Substituentsmentioning

confidence: 99%

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

Анисимов¹,

Зайцев²,

Ol’shevskaya³

et al. 2018

INEOS OPEN

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¹⁷O NMR and Computational Study of a Tetrasiliconiobate Ion, [H_2+xSi₄Nb₁₆O₅₆]^(14−x)−

Johnson

Villa

Ohlin

et al. 2011

Chemistry A European J

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Rates of oxygen-isotope exchange were measured in the tetrasiliconiobate ion [H(2+x)Si(4)Nb(16)O(56)]((14-x)-) to better understand how large oxide ions interact with water. The molecule has 19 nonequivalent oxygen sites and is sufficiently complex to evaluate hypotheses derived from our previous work on smaller clusters. We want to examine the extent to which individual oxygen atoms react independently with particular attention given to the order of protonation of the various oxygen sites as the pH decreases from 13 to 6. As in our previous work, we find that the set of oxygen sites reacts at rates that vary over approximately 10(4) across the molecule at 6

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Reactivity of the Sterically Demanding Siloxanediol Mes₂Si(OH)(μ‐O)Si(OH)Mes₂ Towards Water and Ether Molecules

Roesch

Warzok

Enke

et al. 2017

Chemistry A European J

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A series of isotopologues of the siloxanediol Mes Si(OH)(μ-O)Si(OH)Mes (3 a) (Mes=2,4,6-trimethylphenyl) were synthesized by reactions of the corresponding disiloxane precursors Mes Si(μ-O) SiMes (2 a), Mes Si(μ- O) SiMes (2 b) or Mes Si(μ- O) SiMes (2 c) with an excess of H O, H O or H O. NMR and IR signal assignments for the siloxanediols in benzene are supported by quantum-chemical calculations, which indicate small energy differences between trans and cis conformers, the latter of which exhibits an intramolecular hydrogen bond. H NMR as well as IR data suggest the presence of a mixture of both conformers in C D . Hydrogen-bonded adducts of Mes Si(OH)(μ-O)Si(OH)Mes with ethers such as diethylether, dimethoxyethane or dioxane were observed in the solid state, where they form polymeric chain-like structures. The latter appear to be stable only in the crystal. O{ H} NMR and IR data in THF solution suggest an interaction of 3 a with at least one THF molecule, whereas diethylether appears not to interact. Water adducts form neither in solution nor in the solid state as indicated by NMR and ATR IR data. O{ H} NMR and ESI-MS experiments illustrate the remarkably high stability of the siloxanediols towards water and show no evidence for intra- or intermolecular oxygen-exchange reactions. In marked contrast, a stepwise exchange of all three oxygen atoms-including the one in the Si-O-Si bridge-occurred in the gas phase, when [Mes Si( OH)(μ- O)Si( O)Mes ] was treated with H O in the hexapole of an ESI FT-ICR mass spectrometer. The scrambling between the bridging and the other oxygen atoms likely proceeds through cyclic Si O intermediates.

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Characterization of siloxane copolymers by solution 17O NMR spectroscopy

Cited by 7 publications

References 28 publications

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

¹⁷O NMR and Computational Study of a Tetrasiliconiobate Ion, [H_2+xSi₄Nb₁₆O₅₆]^(14−x)−

Reactivity of the Sterically Demanding Siloxanediol Mes₂Si(OH)(μ‐O)Si(OH)Mes₂ Towards Water and Ether Molecules

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Characterization of siloxane copolymers by solution 17O NMR spectroscopy

Cited by 7 publications

References 28 publications

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

17O NMR and Computational Study of a Tetrasiliconiobate Ion, [H2+xSi4Nb16O56](14−x)−

Reactivity of the Sterically Demanding Siloxanediol Mes2Si(OH)(μ‐O)Si(OH)Mes2 Towards Water and Ether Molecules

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¹⁷O NMR and Computational Study of a Tetrasiliconiobate Ion, [H_2+xSi₄Nb₁₆O₅₆]^(14−x)−

Reactivity of the Sterically Demanding Siloxanediol Mes₂Si(OH)(μ‐O)Si(OH)Mes₂ Towards Water and Ether Molecules