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'Cyclodisilazanes' in keywords
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2000 (1)
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1Author    Jan Schneider, Eckhard Popowski, Normen PeuleckeRequires cookie*
 Title    Reaktionen der Lithiumhydridosilylamide Me2(H)Si-N(Li)R (R = CMe3, SiMe3) mit Chlortrimethylstannan und Chlormethylsilanen M e^ SiC l« {n = 1 -3) Reactions of Lithium Hydridosilylamides Me2(H)Si-N(Li)R (R = CMe3, SiMe3) with Chlorotrimethylstannane and Chloromethylsilanes Me4_" SiCl, in = 1 -3)  
 Abstract    The under reflux conditions in /7-octane stable lithium hydridosilylamides Me2(H)Si-N(Li)R (1: R = CM e3, 2: SiMe3) were allowed to react with chlorotrimethylstannane and chlorom e­ thylsilanes Me4_"SiCl" (n = 1 -3) in different molar ratios. 1 reacts with Me3SnCl in n-pentane to give the cyclodisilazane [Me2Si-NCMe3]2 (3) and Me3SnH. The reaction of 2 with Me3SnCl under the same conditions leads to a mixture of Me2 (H)Si-N(SnM e3)SiMe3 (5), [Me2Si-NSiM e3]2 (4), and to Me3SnH. In the reactions of 1 and 2 with chlorotrimethylstannane in tetrahydrofuran the corresponding N-stannylation products Me2(H)Si-N(SnMe3)R 5, 6 and very small amounts of (M e3Sn)2 are formed. The results of the reactions of 1 and 2 with Me2SiCl2 and of 1 with MeSiCl3 in n-hexane show that hydrogen-chlorine-exchange proceeds between the reactants. With Me2SiCl2 the cor­ responding cyclodisilazanes [Me2Si-NR]2 3, 4, N-silylation products Me2(H)Si-N(SiM e2Cl)R 7b, 8b, and Me2(H)Si-N(SiMe2H)R 7c, 8c, and the silanes Me2SiHCl and M e2SiH2 are formed, the cyclodisilazanes being the main products. 1 and M eSiCl3 produce 3, Me2(H)Si-N(R')CM e3 (7d: R' = SiMeCl2, 7e: R' = SiMeCIH, 7f: R' = SiM eH2) and MeSiH3. In comparison with the reaction of 1 with Me2SiCl2 the yield o f cyclodisilazane is smaller and that of N-silylated compounds is higher. The reaction behaviour of 1 towards M e2SiCl2 and M eSiCl3 in THF is comparable to that in n-hexane. No silanimine intermediates are observed in the reactions of 1 or 2 with the chloromethylsi­ lanes Me4_,7SiCl" (n = 1 -3) in the molar ratios 1:5 and 1:10. 
  Reference    Z. Naturforsch. 55b, 924—934 (2000); eingegangen am 25. Mai 2000 
  Published    2000 
  Keywords    Hydridosilylamides, Cyclodisilazanes, Hydrogen-Chlorine-Exchange 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0924.pdf 
 Identifier    ZNB-2000-55b-0924 
 Volume    55 
2Author    William Clegg, Michael Hesse, Uwe Klingebiel, GeorgeM. Sheldrick, Lutz SkodaRequires cookie*
 Title    Ringkontraktion am Cyclotrisilazan -System - Synthese und Molekülstrukturen zweifach silylverknüpfter Cyclodisilazane Ring Contraction in the Cyclotrisilazane System - Synthesis and Molecular Structures of Silyl-Bridged Cyclodisilazanes  
 Abstract    l-(Fluorodiorganylsilyl)-2,2,4,4,6,6-hexamethyl-3-(trimethylsilyl)cyclotrisilazanes react with butyllithium to give the corresponding lithium salts. Ring contraction of the lithium salts with formation of lithiated (fluorodiorganylsilyl)amino-substituted four-membered rings is observed in THF solution. The dimerisation of these cyclodisilazanes with elimina-tion of LiF is demonstrated by crystal structure determinations of three products. Monoclinic and triclinic crystalline modifications of one compound could be isolated. 
  Reference    Z. Naturforsch. 35b, 1359—1365 (1980); eingegangen am 29. Juli 1980 
  Published    1980 
  Keywords    Cyclotrisilazanes, Ring Contraction, Cyclodisilazanes, Crystal Structures 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-1359.pdf 
 Identifier    ZNB-1980-35b-1359 
 Volume    35 
3Author    Kerstin Dippel, Uwe KlingebielRequires cookie*
 Title    Kontraktionsreaktionen lithiierter Cyclotetrasilazane zu Cyclotri-und Cyclodisilazanen C ontraction Reactions of Lithiated Cyclotetrasilazanes Yielding Cyclotri-and Cyclodisilazanes  
 Abstract    The lithium derivate o f the octamethylcyclotetrasilazane 1 reacts with fluorosilanes with substitution (2) or substitution and contraction to give cyclotrisilazanes (3 —6). Lithiated 6 again reacts with substitution (7, 11, 12) or substitution and isomerization to give l,3 -(S i-N -S i) substituted cyclodisilazanes (8 , 13). Starting with the dilithiated eight mem-bered ring (14) the reactions with fluorosilanes lead to the formation o f the unsymmetrically l-(S i)-3 -(S i-N -S i-N -S i)-s u b s titu te d four mem bered rings (9, 10). The isomerization o f the lithium salts depends on thermal, thermodynamic and kinetic effects. 
  Reference    Z. Naturforsch. 45b, 1147—1154 (1990); eingegangen am 26. Januar 1990 
  Published    1990 
  Keywords    Cyclotetrasilazane, Lithium Salts, Isomerization, Cyclodisilazanes, Cyclotrisilazanes 
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 TEI-XML for    default:Reihe_B/45/ZNB-1990-45b-1147.pdf 
 Identifier    ZNB-1990-45b-1147 
 Volume    45