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Geminal Bis(hypersilyl) Compounds – The Reaction of Tris(trimethylsilyl)silyllithium with Dialkyl(chloromethylene)ammonium Chlorides
Author(s) -
Gross Thoralf,
Kempe Rhett,
Oehme Hartmut
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199901)1999:1<21::aid-ejic21>3.0.co;2-3
Subject(s) - chemistry , trimethylsilyl , geminal , trimethylsilane , silanol , medicinal chemistry , tris , ammonium , hydrolysis , cyclohexane , carbon fibers , organic chemistry , polymer chemistry , catalysis , biochemistry , materials science , composite number , composite material
Tris(trimethylsilyl)silyllithium ( 1 ) reacts with dialkyl(chloromethylene)ammonium chlorides (molar ratio 2:1) to give the (dialkylamino)bis(hypersilyl)methanes [(Me 3 Si) 3 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 substituents, the structures of these geminal bis(hypersilyl) derivatives are characterized by tremendous distortions of their molecular skeletons. This was confirmed by X‐ray structural analyses of 5a and 5c , which revealed considerable elongations of the central Si–C bonds ( 5a : 2.01 and 1.95 Å; 5c : 1.99 and 1.97 Å) and an extreme widening of the Si–C–Si angles at the central sp 3 ‐carbon atoms ( 5a : 132.6 ° ; 5c : 128.7°). By concentrated sulfuric acid, 5a is converted to give, after hydrolysis, the silanol (Me 3 Si) 2 Si(OH)‐CH 2 Si(SiMe 3 ) 3 ( 13 ). The formation of 13 is discussed as proceeding through the transient silene (Me 3 Si) 2 Si=CHSi(SiMe 3 ) 3 ( 11 ), generated by a formal (dimethylamino)trimethylsilane elimination from 5a according to an acid‐induced sila Peterson mechanism.