Acyclic and Cyclic Silylaminohydrazines

The reaction of H2N-NH2 with ClSiMe2N(SiMe3)2 in a molar ratio 1 : 2 gave the bis(silylamino) hydrazine [HNSiMe2-N(SiMe3)2]2 (1). Compound 1 forms a monomeric dilithium salt with BuLi. From n-hexane (Me3Si-NSiMe2-NLiSiMe3)2 (2) crystallizes while from THF [Me3Si-NSiMe2- NLi(THF)SiMe3]2 (3) precipitates. Compounds 2 and 3 are formed from 1 via a silyl group migration. In the rearranged salts, the silyl groups are bonded at the hydrazino nitrogen atoms. Hydrolysis of 2 led to the formation of (Me3Si-N-SiMe2-NHSiMe3)2 (4) which is a structural isomer of 1. Ring closure occurs in reactions of 2 or 3 with F3B ・ OEt2 or SiF4. The seven-membered rings (Me3Si- N-SiMe2-NSiMe3)2BF (5) and (Me3Si-NSiMe2-NSiMe3)2SiF2, (6) were isolated as the products. The crystal structures of 2, 3 and 5 have been determined.

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Cyclisierungsreaktionen lithiierter Fluorsilanole und Aminofluorsiloxane - Kreuzdimerisierung eines Silicenium-Ylids / Cyclisation Reactions of Lithiated Fluorosilanols and Aminofluorosiloxanes - Cross-dimerisation of a Silicenium-Ylid

Zeitschrift für Naturforschung B ◽

10.1515/znb-1982-0407 ◽

1982 ◽

Vol 37 (4) ◽

pp. 423-431 ◽

Cited By ~ 16

Author(s):

William Clegg ◽

Uwe Klingebiel ◽

George M. Sheldrick

Keyword(s):

Crystal Structures ◽

Silyl Group ◽

Group Migration ◽

Silyl Group Migration

KOH reacts with bis(isopropyl-trimethylsilyl)-amino-difluorosilane to give the fluoro-silanol 1. An aminofluorosiloxane 2 is obtained in the reaction of [(Me3Si)2N]2SiF2 with KOH via a 1,3-silyl-group migration. The four-membered SiOSiN ring 5 can be prepared in several steps from 1. Six-membered SiO rings 8-10 are formed in the reaction of 1,3-fluorosilanols 6 and 7 with butyllithium. Lithiated 2 reacts with PCl3 to give a four-membered P2N2 ring 11, and with 2-methyl-2-propenal to give two isomeric (2 + 4) cycloadducts 12 and 13. The silicenium ylid formed initially by thermal elimation of LiF from lithiated 2 in PE/THF cross-dimerises to give a Si2N2 ring 14. If the reaction is carried out in n-heptane, the product after recrystallisation from acetone, 16, is an isomer of 14. The crystal structures of 14 and 16 have been determined.

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Two-coordinate Group 13 Element (Al, Ga) Centered Cations Formed by Silyl Group Migration: Synthesis and Characterization

Chemistry Letters ◽

10.1246/cl.2007.984 ◽

2007 ◽

Vol 36 (8) ◽

pp. 984-985 ◽

Cited By ~ 6

Author(s):

Masaaki Nakamoto ◽

Kousuke Shimizu ◽

Akira Sekiguchi

Keyword(s):

Synthesis And Characterization ◽

Group 13 ◽

Silyl Group ◽

Coordinate Group ◽

Group Migration ◽

Silyl Group Migration

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Aminofluorsilane: 1.3-Silylgruppenwanderung und gehinderte Si-N-Bindungsrotation / Aminofluorosilanes: 1.3-Migration of Silyl Groups and Si-N-Rotational Barrier

Zeitschrift für Naturforschung B ◽

10.1515/znb-1980-0917 ◽

1980 ◽

Vol 35 (9) ◽

pp. 1155-1161 ◽

Cited By ~ 10

Author(s):

Uwe Klingebiel ◽

Jutta Neemann

Keyword(s):

Room Temperature ◽

Electronic Effects ◽

Amino Groups ◽

Structural Isomers ◽

Hindered Rotation ◽

Silyl Groups ◽

Group Migration ◽

Silyl Group Migration ◽

Trimethylsilyl Groups ◽

Coalescence Temperature

Triaminofluorosilanes with bulky amino groups are prepared by the reaction of bis- (organyl-trimethylsilyl)amino-difluorosilanes with lithiated amines. A 1,3-migration of trimethylsilyl groups from bulky alkylamino substituents to arylamino substituents is observed in these reactions. Structural isomers of the new triaminofluorosilanes were isolated. The silyl group migration depends on steric and electronic effects. Further reactions of the triaminofluorosilanes with butyllithium and trifluoroorganylsilanes lead to the formation of difluorosilyl-substituted triaminofluorosilanes and LiF. The symmetric compounds show AB-systems for the fluorine atoms of the difluorosilyl groups in the low temperature 19F NMR Spectra, due to hindered rotation about the Si-N-bond. The coalescence temperature depends on the bulkiness of the substituents and is observed at or about room temperature.

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