Synthese von Mono‐ und Bis(silyl)hydroxylaminen

Abstract

Durch eine Basenaustauschreaktion von Silylaminen mit Hydroxylaminhydrochlorid entstehen die Mono(silyl)hydroxylamine R2FSiONH2 (R = CMe3 1), R2R′SiONH2 (R = CMe3, R′ = Me 2), R2(NH2)SiONH2 (R = CMe3 3). In Gegenwart von HCl‐Akzeptoren oder bei vorheriger Lithiierung reagiert 1 mit Me3SiCl oder F2Si(CMe3)2 zu den Bis(silyl)hydroxylaminen, (Me3C)2FSiONHSiMe3 4 und (Me3C)2FSiONHSiF(CMe3) 5. Die Lithiumderivate von Me3SiONH2 und 2 reagieren mit Flurorsilanen zu den Bis(silyl)hydroxylaminen: Me3SiONHSiFRR′ (R = R′ = CMe3, 6, R = CMe3, R′ = F 7, R = R′ = NMeSiMe3 8), (Me3C)2MeSiNHOSiFRR′ (R = CMe3, R′ = F 9, R = (Me3C)3C6H2, R′ = F 10, R = R′ = CMe3 11, R = R′ = CHMe2 12). Die Bis(silyl)hydroxylamine 4 und 6 sind Strukturisomere.

Synthesis and Molecular Structures in the Gas Phase of N,N-Dimethylaminoxy-trimethylsilane and -trimethylgermane

“…In this molecule the acceptor ability of the Si atom is reduced by methylation and the donor ability of the nitrogen center is reduced because of the two CF 3 substituents. Nevertheless, the Si−O−N angle is still much less than expected on the basis of Bartell's one-angle radii for Si and N. Only if the N basicity is even more reduced by silylation, as verified MesF 2 SiON(SiMe 3 ) 2 , the Si···N distance (2.692 Å) is consistent with the sum of Bartell's one-angle radii (2.69 Å), indicating the absence of a significant attraction between Si and N atoms.…”

SiONB Unit as Reference for Blocked Si···N Interactions in SiON Compounds

“…However, it remains unclear why the conformation is not such that a Si-O-N-C torsional angle of approximately 180°is realized, and it might be speculated that this is due to a hybridization at oxygen, which leads to two different lone pairs, one p-type and one that is in the SiON plane and causes this conformation by minimizing the repulsion. The Si-O-N angles are rather large if compared to those of nonborylated aminoxysilanes such as MesF 2 SiON(SiMe 3 ) 2 [117.7(1)°in the crystal], 11 Me 3 SiONMe 2 [107.9(6)°in the gas phase], 12 H 2 Si(ONMe 2 ) 2 [95.6°(ave) in the crystal] 13 or ClH 2 -SiONMe 2 [79.1(1)°in the crystal], 14 which shows that an attractive force between silicon and nitrogen atoms is absent in the borane adduct MeHSi[ON(BH 3 )Me 2 ] 2 but definitely operative in the aminoxysilanes. Moreover, a credible argument may be advanced that in the borane adducts the lone pair of electrons at the nitrogen is completely involved in the B-N adduct formation and thus is not accessible for an intramolecular interaction with the silicon center.…”

“…Attractive secondary interactions between donor and acceptor atoms in geminal positions relative to one another have been shown to be structure-determining in certain classes of p-block compounds containing SiON, GeON, SnON, AlON, SiNN, BCN, BNN, AlCN, and AlNN linkages. We have systematically studied SiON compounds (i.e., oximatosilanes and aminoxysilanes) and found a broad range of different strengths for such β-donor interactions, from predictably weak ones in Me 3 SiONMe 2 to medium ones in H 2 SiONMe 2 11 to really strong ones in anti-ClH 2 SiONMe 2 . These interactions are indicated by short Si···N distances leading to a three-membered ring with one weakly bound edge and are advantageously characterized by the contraction of their SiON angles.…”

Stable O,O‘-Bis(hydroxylamino)silanes R2Si(ONH2)2 and Isomeric N,N‘- and O,O‘-Bis(silylhydroxylamino)silanes R2Si(NHOSiR3)2 and R2Si(ONHSiR3)2

“…Whether the second silyl group is again attached to the oxygen atom or to the nitrogen atom depends on the reaction pathway; − for example, the reaction of a O -silyl-hydroxylamine with a chlorotriorganylsilane leadsin the presence of Et 3 Nto the bonding of the second silyl group to the nitrogen. However, starting with the lithium salt of the O -silylhydroxylamine, the new silyl group is bonded to the oxygen atom.…”