Geminal Bis(hypersilyl) Compounds – The Reaction of Tris(trimethylsilyl)silyllithium with Dialkyl(chloromethylene)ammonium Chlorides
✍ Scribed by Thoralf Gross; Rhett Kempe; Hartmut Oehme
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 171 KB
- Volume
- 1999
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
trimethylsilyl)silanes / (Chloromethylene)ammonium chlorides Tris(trimethylsilyl)silyllithium (1) reacts with dialkyl-5c: 1.99 and 1.97 A ˚) and an extreme widening of the SiϪCϪSi angles at the central sp 3 -carbon atoms (5a: 132.6°; (chloromethylene)ammonium chlorides (molar ratio 2:1) to give the (dialkylamino)bis(hypersilyl)methanes [(Me 3 Si) 3 -5c: 128.7°). By concentrated sulfuric acid, 5a is converted to give, after hydrolysis, the silanol (Me 3 Si) 2 Si(OH)-Si] 2 CHNR 2 (5a؊c; a: R = Me, b: R = Et, c: R 2 = [CH 2 ] 5 ). Due to the extreme bulkiness of the hemispherical (Me 3 Si) 3 Si
CH 2 Si(SiMe 3 ) 3 ( 13). The formation of 13 is discussed as proceeding through the transient silene (Me 3 Si) 2 Si= substituents, the structures of these geminal bis(hypersilyl) derivatives are characterized by tremendous distortions of CHSi(SiMe 3 ) 3 ( 11), generated by a formal (dimethylamino)trimethylsilane elimination from 5a according to an their molecular skeletons. This was confirmed by X-ray structural analyses of 5a and 5c, which revealed considerable acid-induced sila Peterson mechanism. elongations of the central SiϪC bonds (5a: 2.01 and 1.95 A ˚;
Actually, the gap formed by the two (Me 3 Si) 3 Si hemi-