124980-17-2Relevant academic research and scientific papers
Intramolecular rearrangement of organosilyl groups between oxygen and nitrogen in aminosiloxanes: A joint experimental-theoretical study
Kliem, Susanne,Klingebiel, Uwe,Schmatz, Stefan
, p. 16 - 23 (2007/10/03)
Lithium amino-di- tert -butysilanolate reacts with halosilanes to give 1-silylamino-1,3-siloxanes (1-4). The tetrakis(1-silylamino)siloxane 4 thermally condenses yielding a spiocyclic six-membered ring (5) and NH3. Lithium salts of animo-disiloxanes form silylamino-silanolates or amido-disiloxanes. The first includes a 1,3-silyl group migration from the oxygen to the nitrogen atonm. The energies of the isomeric lithium salts of model compunds are calculated. Exemplary crystal structures are presented.(SiOSiN)-four- or eight-membered rings (6,7) are thermally obtaines by LiF-elimination from fluoro containing salts. In further reactions of lithiated animo-disiloxanes with halosilanes isomeric 1-silylamino-1,3-disiloxanes can be obtaines (15,16). The 1,3-silyl group migration can sterically (9) or electronically (10-14) be prevented.The most stable lithium salts of 1-silylamino-1,3-disiloxanesform amides. This explains that in further reactions with halosilanes, the new ligand is bonded wo the nitrogen atom (23-25). In results of crystal structure determinations new lithium-1-fluorosilylamio-1,3-disiloxanes (19-21) are presented. 19 crystallizes as tricyclic, 20 as an unknown pentacyclic, and 21 as monomeric compound. In 21, the shortest Si-N bond length (157.9 pm) with four coordinate silicon is found.
Synthesis of (SiNSiO) four-membered rings; crystal structure of (Me3C)2SiOSi(CMe3)2NSiMe3
Schmidt-Baese, Dieter,Klingebiel, Uwe
, p. 313 - 322 (2007/10/02)
Siloxanes (1-3), of the type H2NSi-O-Si are formed in the reaction of halogenosilanes with a lithiated aminosilanol.Lithium salts of 1-3 (4-6) react with halogenosilanes to yield 7-9 (-Si-NH-Si-O-Si-); 8 and 9 are structural isomers.The silyl group introduced normally becomes bonded to the oxygen atom.The silyl group migration can be kinetically controlled, as shown by the formation of 7.Compounds 7 and 8 from the thermally stable lithium compounds 10, 11 (-Si-NLi-Si-O-Si-F), which are direct precursors of four-membered 1-oxa-3-aza-2,4-disiletanes (12, 13).The intramolecular cyclization is catalyzed by fluorosilanes present.The crystal structure of the four-membered (SiNSiO) ring species 12, has been determined, and its features are compared with those of (-Si-O-)2 ring species.
