Reactions of sulphur diimides with di- and tri-silanes: 15N and 29Si nuclear magnetic resonance study and the crystal structure of bis[tert-butyl(trichlorosilyl)amino]sulphane

Wrackmeyer, Bernd; Frank, Stefan M.; Herberhold, Max; Simon, Arndt; Borrmann, Horst

doi:10.1039/dt9910002607

Cited by 6 publications

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“…Values for 2 J( 29 Si 15 N) are rarely found in the literature, and one example is a value of 5.0 Hz for (Me 3 Si)(Cl 3 Si)NSN(SiMe 3 )-(SiCl 2 SiCl 3 ). 33 However, the occurring of such a coupling has never been observed before in SiON systems, even not in an ultrahigh-resolution study of N,O-bis-(trimethylsilyl)hydroxylamine. 34 The observation of these couplings in 1 and 2 is therefore indicative of an unusual Si‚‚‚N interaction, and the magnitude of these couplings is consistent with the range of values of 1 J( 29 Si 15 N) for Si•••N donor bonds in silatranes (0.1-3.4 Hz).…”

Section: Resultsmentioning

confidence: 94%

“…Under high resolution conditions, the 15 N NMR resonances of 1 and 2 are flanked by pairs of 29 Si satellites corresponding to J ( 29 Si 15 N) coupling constants of 1.8 and 2.7 Hz, respectively. Values for 2 J ( 29 Si 15 N) are rarely found in the literature, and one example is a value of 5.0 Hz for (Me 3 Si)(Cl 3 Si)NS N (SiMe 3 )(SiCl 2 Si Cl 3 ) .…”

Section: Resultsmentioning

confidence: 99%

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β-Donor Bonds in SiON Units: An Inherent Structure- Determining Property Leading to (4 + 4)-Coordination in Tetrakis-(N,N-dimethylhydroxylamido)silane

1997

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Tetrakis(N,N-dimethylhydroxylamido)silane, Si(ONMe2)4 (1), and the analogous ethyl compound, Si(ONEt2)4 (2), have been prepared by the reaction of silicon tetrachloride with 4 equiv of the corresponding lithium N,N-dialkylhydroxylamide. The compounds have been characterized by elemental analysis, IR spectroscopy, NMR spectroscopy of the nuclei 1H, 13C, 15N [including the determination of 1 J(29Si15N) coupling constants], 17O, and 29Si, and nominal and high-resolution mass spectrometry. A crystal structure determination on 1 showed the molecule to be (4 + 4)-coordinate with short Si···N contacts [2.514(3)−2.555(3) Å] and narrow SiON angles [109.1° on average]. For comparison, the crystal structure of the isoelectronic Si(OCHMe2)4 (in situ grown crystal) was determined, showing the absence of β-donor interactions and an SiOC angle of 124.7(1)°. Ab initio calculations have been performed on the model compounds Si(ONH2)4 and H3SiONMe2 as well as the electronegatively substituted fluoro derivatives FH2SiONMe2 and F3SiONMe2 up to the MP2/6-311G** level of theory. Si(ONH2)4 is predicted to adopt C 2 symmetry and to have an SiON angle of only 109.5°, while the interactions in the other model compounds are predicted to be much stronger, as indicated by their SiON angles: H3SiONMe2 102.5°, FH2SiONMe2 90.0°, and F3SiONMe2 93.8°. The results are discussed with respect to the consequences of enlargement of the coordination sphere at the silicon atom, the unique chemical behavior of O-silylhydroxylamines (in particular their fast nucleophilic substitutions reactions), and the resulting use of this class of compounds in the silicone rubber industry.

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%