Intramolecular Interconversions in Cyclosilazane Chemistry: A Joint Experimental–Theoretical Study

Klingebiel, Uwe; Helmold, Nina; Schmatz, Stefan

doi:10.1016/s0065-3055(05)54001-2

Cited by 8 publications

(7 citation statements)

References 58 publications

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“…During the last years we studied migrations of hydrogen atoms and silyl groups in the chemistry of silyl hydrazines, , silyl hydroxylamines, , cyclosilazanes, and aminosiloxanes both experimentally and by quantum-chemical calculations. It was found that in such isomerization reactions hydrogen atoms can migrate from a silicon to a nitrogen atom, from a carbon to a nitrogen atom, and from one nitrogen to another nitrogen atom …”

Section: Introductionmentioning

confidence: 99%

Intramolecular Rearrangement of Organosilyl Groups in Silylamines: A Combined Experimental−Theoretical Study

et al. 2007

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The lithium salt of Me 3 CSiMe 2 NH 2 reacted with halosilanes to give the bis(silyl)amines 1-3, Me 3 -CSiMe 2 NHSiMe 2 R (1: R ) H, 2: R ) Me, 3: R ) CMe 3 ), which form lithium salts with BuLi. 4, the lithium salt of 1, crystallized as the trimer via the Li-N bond. Halosilanes reacted with lithiated bis-(silyl)amines to give tris(silyl)amines 5-9, RSiMe 2 N(SiMe 2 Hal)SiMe 2 R′ (5: R, R′ ) Me, Hal ) Cl; 6: R, R′ ) Me, Hal ) F; 7: R ) CMe 3 , R ) Me, Hal ) Cl; 8: R ) CMe 3 , R′ ) Me, Hal ) F; 9: R, R′ ) CMe 3 , Hal ) F). The ammonolysis of 5 and 7 led to the formation of the NH 2 -substituted compounds 10 and 11, RSiMe 2 N(SiMe 3 )SiMe 2 NH 2 (10: R ) Me, 11: R ) CMe 3 ). The fluorine-containing compounds (6, 8, 9) reacted with LiNH 2 to give the 1,3,5-trisila-2,4-diazanes 12-14, RSiMe 2 -NH-SiMe 2 -NH-SiMe 2 R′ (12: R, R′ ) Me; 13: R ) Me, R′ ) CMe 3 ; 14: R, R′ ) CMe 3 ). 10 and 12 as well as 11 and 13 are structural isomers. 12 and 13 are the result of a 1,3-silyl group migration in solution at low temperatures. Thermally the 1,3-silyl group migration occurred above 200 °C for 10 and at 130 °C using 11. Quantum-chemical calculations on the thermal isomerization process reveal a two-step mechanism, whereas the anionic isomerization occurs via a single transition state at lower temperatures. 10 and 12 form the same lithium salt (15), (Me 3 SiNH-SiMe 2 -NLi(THF)-SiMe 3 ) 2 . In the reaction of 15 with FSiMe 2 CMe 3 or of the lithiated compounds of 13 with ClSiMe 3 (Me 3 Si) 2 NSiMe 2 NHSiMe 2 CMe 3 (16) was obtained (eq 8). Starting from 15, the reaction again includes a 1,3-silyl group migration from one nitrogen to the other. In the reaction of lithiated 14 with ClSiMe 3 substitution occurred and 17 was obtained. Crystal structures of 4 and 15 are presented, and the mechanisms of the rearrangements are discussed.

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Section: Introductionmentioning

confidence: 99%

Intramolecular Rearrangement of Organosilyl Groups in Silylamines: A Combined Experimental−Theoretical Study

et al. 2007

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“…the reaction of lithium-diisopropyl-fluorosilyl-tertbutylamide and trichloroalane leads quantitatively to the formation of a dimeric adduct of an iminosilene. Hydrolyses give a dicationic cyclodisilazane [10]. The counterion is bis(trichloro)aloxane, (Eq.…”

Section: [8]mentioning

confidence: 99%

From lithiumhalosilylamide to small and large ring compounds, iminosilenes and iminosilanes

Klingebiel

Matthes

2007

Journal of Organometallic Chemistry

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“…In the meantime, silyl group migration has been applied to the synthesis of isomeric compounds, as well as to stabilizing elements in lower coordination numbers [3,6,7]. During the last years we studied migrations of hydrogen atoms and silyl groups in the chemistry of silazanes [8] and silyl hydrazines [6,9] both experimentally and by quantum-chemical calculations [10]. It was found that in such isomerization reactions hydrogen atoms can migrate from a carbon to a nitrogen atom [3,6] and from one nitrogen to another atom [6].…”

Section: Introductionmentioning

confidence: 99%

“…Silyl groups are usually bonded to the more electronegative atom in the rearranged molecule, but migration from a nitrogen to another nitrogen atom was also observed [8], partly via dyotropic transition states or via iminosilenes [9,11]. In addition, silyl groups can become inserted into N-N 0932-0776 / 09 / 0500-0525 $ 06.00 c 2009 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com bonds [6,9] leading to the formation of cyclosilazanes [9].…”

Section: Introductionmentioning

confidence: 99%

Acyclic and Cyclic Silylaminohydrazines

Klingebiel

Matthes²,

Ringe³

et al. 2009

Zeitschrift Für Naturforschung B

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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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Intramolecular Interconversions in Cyclosilazane Chemistry: A Joint Experimental–Theoretical Study

Cited by 8 publications

References 58 publications

Intramolecular Rearrangement of Organosilyl Groups in Silylamines: A Combined Experimental−Theoretical Study

Intramolecular Rearrangement of Organosilyl Groups in Silylamines: A Combined Experimental−Theoretical Study

From lithiumhalosilylamide to small and large ring compounds, iminosilenes and iminosilanes

Acyclic and Cyclic Silylaminohydrazines

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