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Willms, Stefan; Grybat, Andreas; Saak, Wolfgang; Weidenbruch, Manfred; Marsmann, H.C.

doi:10.1002/(sici)1521-3749(200005)626:5<1148::aid-zaac1148>3.3.co;2-0

Cited by 8 publications

(13 citation statements)

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“…Good evidence was provided, though, that the addition of water to tetrasilabutadiene 37 yields 1,2-addition product 87 in the first step which cyclises to afford oxatetrasilolane 88 unless a second equivalent of water is available to add to the remaining Si=Si double bond (Scheme 24). [69] Scheme 24. Spiropentasiladiene 86 and 1,2-addition of water to tetrasilabutadiene 37 to yield disilene 87 and cyclization of 87 to afford oxatetrasilolane 88; a: + H2O; R = t Bu2MeSi, Tip = 2,4,6-i Pr3C6H2.…”

Section: E=e-tt Tetrel Functionalities (Tt = Group 14 Element)mentioning

confidence: 99%

Reactivity in the periphery of functionalised multiple bonds of heavier group 14 elements

2016

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Heavier group 14 multiple bonds have intrigued chemists since more than a century. The synthesis of stable compounds with double and triple bonds with silicon, germanium, tin and lead had considerable impact on modern ideas of chemical bonding. These developments were made possible by the use of bulky substituents that provide kinetic and thermodynamic protection. Since about a decade the compatibility of heavier multiple bonds with various functional groups has moved into focus. This review covers multiply bonded group 14 species with at least one additional reactive site. The vinylic functionalities of groups 1 and 17, resulting in nucleophilic and electrophilic disila vinyl groups, respectively, are the most prevalent and well-studied. They have been employed repeatedly for the transfer of heavier multiple bonds to yield low-valent group 14 compounds with novel structural motifs. Vinylic functionalities of groups 2 to 16 and a few σ-bonded transition metal complexes are experimentally known, but their reactivity has been studied to a lesser extent. Donor-coordinated multiple bonds are a relatively new field of research, but the large degree of unsaturation as isomers of alkynes (as well as residual functionality in some cases) offers considerable possibility for further manipulation, e.g. for the incorporation into more extended systems. Heavier allyl halides constitute the major part of heavier multiple bonds with a functional group in allylic position and some examples of successful transformations are given. At present, remote functionalities are basically limited to para-phenylene functionalised disilenes. The reported use of the latter for further derivatisation might encourage investigations in this direction. In summary, the study of peripherally functionalised multiple bonds with heavier group 14 elements is already well beyond its infancy and may be an instrumental factor in awakening the potential of group 14 chemistry for applications in polymers and other materials.

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Section: E=e-tt Tetrel Functionalities (Tt = Group 14 Element)mentioning

confidence: 99%

Reactivity in the periphery of functionalised multiple bonds of heavier group 14 elements

2016

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“…Except for Si 3 C3a and Si 4 O,5g there are no precedents for structural studies on the ring systems Si 4 C, Si n N ( n = 3, 4), and Si n O ( n = 3, 4). The molecular structures of 1b , 2a , 3a−d , 4a−c , 5b , 6a , and 6b were determined by X‐ray crystal analysis; structural data for 1a and 5a could not be obtained by X‐ray analysis.…”

Section: Resultsmentioning

confidence: 99%

Peralkylated Four- and Five-Membered Cyclosilanes Containing a Heteroatom: Synthesis, Structure, and Properties

Watanabe

Suzuki

Takahashi

et al. 2002

Eur. J. Inorg. Chem.

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Seventeen peralkylated four-and five-membered heteroatom-containing silacycles [R 1 R 2 Si] n X [R 1 = iPr and/or R 2 = tBuCH 2 ; n = 3; X = CH 2 (1a, 1b), NR 3 (R 3 = C 6 H 11 ) (3a−d), O (5a−c), and n = 4; X = CH 2 (2a, 2b), NR 3 (R 3 = C 6 H 11 or Pr) (4a−d), and O (6a, 6b)] have been synthesized and characterized. The structural features of twelve compounds − 1b, 3a−d, and 5b (Si 3 X) and 2a, 4a−c, 6a, and 6b (Si 4 X) − determined by X-ray analysis have been investigated and geometrical differences between the silacycles bearing neopentyl groups and those with isopropyl groups as bulky substituents on silicon atoms have been identified. The ring strain energies for the compounds [R 2 Si] n X [n = 3, 4; R = Me, iPr; X = CH 2 , N(iPr), NMe, O, SiH 2 ], estimated by theoretical calculations at the PM3 level, are discussed in relation to experimentally ascertained structural features of the silacycles [R 2 Si] n X (n = 3, 4; R = iPr; X = CH 2 , NC 6 H 11 , O, SiR 2 ). 29 Si NMR spectra for 1−6 showed that the resonances for the α-silicon atoms attached to the heteroatoms X in the two ring-size series were shifted downfield by a deshielding effect due to an electronegative atom X; larger electronegativity (En) of X caused this effect at lower field. The chemical shifts of the Si α atoms showed a good linear correlation with the electronegativities of the heteroatoms X in the [R 2 Si] n X cycles. In the UV spectra for 1−6, little difference in [a] the longest-wavelength absorption (LWA) maxima was observed for [(iPr) 2 Si] n X and [(tBuCH 2 ) 2 Si] n X of the same ring size. The LWA bands for 1−6 and related compounds could be roughly classified into four groups: (a) [R 2 Si] 3 X (X = SiR 2 , GeRЈ 2 ) λ = 286−300 nm; (b) [R 2 Si] 3 X (X = CH 2 , NR 3 , O) (1, 3, 5), λ = 230−250 nm; (c) [R 2 Si] 4 X (X = SiR 2 , GeRЈ 2 ) λ = 274−280 nm; (d) [R 2 Si] 4 X (X = CH 2 , NR 3 , O) (2, 4, 6), λ = 250−260 nm. With the aid of the ionization potentials and the transition energies (E T ), the HOMO and LUMO levels for the series of compounds and the related ones were experimentally evaluated. The HOMO and LUMO levels thus obtained for [R 2 Si] 3 X and [R 2 Si] 4 X (R = iPr and tBuCH 2 ; X = SiR 2 , GeRЈ 2 , CH 2 , NC 6 H 11 , O) are discussed in terms of the calculated values and frontier orbitals on the basis of PM3 levels. The theoretical prediction for bond scission in the silacycles [(iPr) 2 Si] n X (n = 3, 4; X = CH 2 , NMe, O) in which the HOMOs and LUMOs have Si−Si bonding and antibonding character, respectively, was corroborated by the good agreement with experimental results from photolysis of the silacycles [R 2 Si] n X (n = 3, 4; R = iPr and tBuCH 2 ; X = CH 2 , NC 6 H 11 , O), with bond scission occurring only at the Si−Si bonds, and not at the Si−X bonds.

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“…The closest precedent to these reactions involves the action of small amount of water on 1 which is presumably initiated by a 1,2-addition and subsequent 1,3-hydrogen shift to form the saturated oxatetrasilacyclopentane analogue of tetrahydrofuran. In contrast, the action of an excess of water leads to a tetrasilanediol [7]. In analogy, the reaction sequence in the present case should be initiated by a 1,2-addition of the hydrogen halide to one of the double bonds of 1, followed by a 1,3-hydrogen shift to furnish the product isolated.…”

Section: Introductionmentioning

confidence: 88%

“…In analogy, the reaction sequence in the present case should be initiated by a 1,2-addition of the hydrogen halide to one of the double bonds of 1, followed by a 1,3-hydrogen shift to furnish the product isolated. The decisive factor is apparently the slow liberation of the respective hydrogen halide so that the 1,3hydrogen shift presumably proceeds faster than the compet- (8) 92.253(5) β/°98.935 (7) 99.784(4) γ/°103.517 (6) 105.651 (5…”

Section: Introductionmentioning

confidence: 99%

1, 4-Additions of HCl and HBr to a Tetrasilabutadiene: Formation of Unsymmetrically Substituted Disilenes [1]Dedicated to Professor Dieter Naumann on the Occasion of his 60th Birthday

Boomgaarden

Saak

Marsmann

et al. 2002

Z. anorg. allg. Chem.

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The reactions of hexakis(2,4,6-triisopropylphenyl)tetrasilabuta-1,3-diene R 2 SiϭSiRϪSiRϭSiR 2 (1) with HCl and HBr, slowly generated from HSiCl 3 or LiBr and CF 3 COOH, respectively, furnish the unsymmetrically substituted disilenes R 2 XSiϪSiRϭ SiRϪSiHR 2 , X ϭ Cl (2), Br (3), by formal 1,4-addition of the hydrogen halides to 1. However, passing gaseous hydrogen halides 1,4-Addition von HCl und HBr an ein Tetrasilabutadien: Bildung unsymmetrisch substituierter DisileneInhaltsübersicht. Die Reaktionen von Hexakis(2,4,6-triisopropylphenyl)tetrasilabuta-1,3-dien R 2 SiϭSiRϪSiRϭSiR 2 (1) mit HCl und HBr, die langsam aus HSiCl 3 oder LiBr und CF 3 COOH erzeugt wurden, lieferten durch formale 1,4-Addition der Halogenwasserstoffe an 1 die unsymmetrisch substituierten Disilene

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Cited by 8 publications

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Reactivity in the periphery of functionalised multiple bonds of heavier group 14 elements

Reactivity in the periphery of functionalised multiple bonds of heavier group 14 elements

Peralkylated Four- and Five-Membered Cyclosilanes Containing a Heteroatom: Synthesis, Structure, and Properties

1, 4-Additions of HCl and HBr to a Tetrasilabutadiene: Formation of Unsymmetrically Substituted Disilenes [1]Dedicated to Professor Dieter Naumann on the Occasion of his 60th Birthday

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