A spectroscopic study of hydrogen bond formation by silatranes and their analogues

Воронков, М. Г.; Brodskaya, E.I.; Deriglazov, N. M.; Baryshok, V. P.; Belyaeva, V. V.

doi:10.1016/s0022-328x(00)86822-9

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…The Δν OH value increases with increase of the dielectric constant (ε) of the employed solvent. A similar relationship is observed in the case of oxygen-containing isostructural model compounds of tetracoordinated silicon RSi(OEt) 3 [39]. This indicates that the equatorial oxygen atom of the silatranyl group participates in formation of the hydrogen bond.…”

supporting

confidence: 77%

Basicity of silatranes (Review)

Воронков

Belyaeva

Абзаева

2012

Chem Heterocycl Comp

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The silatranes basicity study results are summarized. A large amount of experimental data obtained 25-40 years ago is critically reviewed. It is shown that the reactivity and physicochemical properties of silatranes are determined by their basicity, which depends on the stereoelectronic structure.Silatranes substituted at the silicon atom XSi(OCH 2 CH 2 ) 3 N (XSa) represent a widely studied class of chelate compounds of pentacoordinated silicon. Investigators of silatranes have been attracted primarily by their unique crystal and stereoelectronic structure and also by their high biological activity. The systematic and comprehensive investigations of silatranes started by M. G. Voronkov and co-workers as far back as 1963 continue to this day [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Of particular practical interest here is the specific biological activity of silatranes [11][12][13][14]. Their unique reactivity is due both to the electron density distribution and the spatial structure.During study of the structure and properties of silatranes by numerous physicochemical methods [1-10] greatest attention has been paid to the axial fragment of their molecule and particularly to the length of the transannular N→Si bond. Insufficient attention has been paid to the equatorial fragment of the molecule. Here account was rarely taken of the fact that there is a redistribution of electron density during the transition of the silicon atom from the tetravalent state to the pentacoordinated state; in the silatrane molecule the positive charge of the central silicon atom and the negative charge of the surrounding three oxygen atoms and also of the axial substituent are increased [15][16][17].During studies of the silatranes basicity the attention of investigators was turned first of all to the basicity of the nitrogen atom, which was always considered a stronger nucleophile than the oxygen atom. Nevertheless, the ability of silatranes to form onium complexes with the participation of the nitrogen or oxygen atoms has been the subject of heated discussions in the literature. By this time in a letter to the editor, which initiated the story of silatranes (described at that time by the systematic name 5-aza-2,8,9-trioxa-1-silabicyclo[3.3.3]undecanes), Frye and co-workers unexpectedly announced that silatranes are not neutralized by perchloric acid in anhydrous acetic acid, but are only slowly titrated by it at 100°C. This led said authors to conclusion that the nitrogen atom does not have basic properties due to the presence of the transannular donoracceptor N→Si bond in the silatranes [18].

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supporting

confidence: 77%

Basicity of silatranes (Review)

Воронков

Belyaeva

Абзаева

2012

Chem Heterocycl Comp

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“…The ultraviolet absorption spectra of silatranes display only an edge of the n-Ł band ( max < 190 nm) 216,220,221 . A hypsochromic shift of this band relative to that observed in the spectra of triethylamine (204 nm), triethanolamine and its tris-TMS derivative (195 196 nm) confirms the Si N bonding in silatranes.…”

Section: Ultraviolet Spectramentioning

confidence: 99%

“…Spectroscopic studies of hydrogen bond formation between silatranes and such proton donors as phenol and methanol revealed enhanced basicity of silatranes relative to the corresponding organyltriethoxysilanes 150,216,217,221,234 . Analysis of the solvent effects on the spectroscopic basicity of these compounds showed that the oxygen atoms (equatorial in 1-organylsilatranes and axial in 1-alkoxysilatranes) rather than the nitrogen are the proton acceptor centers 216,217,221,234 .…”

Section: Vibrational Spectramentioning

confidence: 99%

“…Analysis of the solvent effects on the spectroscopic basicity of these compounds showed that the oxygen atoms (equatorial in 1-organylsilatranes and axial in 1-alkoxysilatranes) rather than the nitrogen are the proton acceptor centers 216,217,221,234 . A higher basicity of these atoms in silatranes and also in O-trimethylsilylated 2-aminoalkanols was explained by a peculiarity of throughbond interactions in compounds containing the Si O C C N fragment 216,217 .…”

Section: Vibrational Spectramentioning

confidence: 99%

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Silatranes and Their Tricyclic Analogs

Pestunovich

Kirpichenko

Воронков

1998

PATAI'S Chemistry of Functional Groups

144

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“…3-(Silatranylmethylsulfanyl)butanal and 3-[2-(silatranylethylsulfanyl)butanal] 1,1-dimethylhydrazones (XIII, XIV) in which the sulfur and silicon atoms are intervened by one (XIII) or two (XIV) methylene units were of particular interest in view of the presence in their molecules of a superelectron-donor group Si(OCH 2 CH 2 ) 3 N (s* 33.49 [19]). Previously we found that 1-(organylsulfanylmethyl)silatranes extremely easily react with methyl iodide to form dimethylsilatranylmethylsulfonium iodides [20].…”

Section: (Xii)mentioning

confidence: 99%