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Diradicaloid or Zwitterionic Character: The Non‐Tetrahedral Unsaturated Compound [Si 4 {N(SiMe 3 )Dipp} 4 ] with a Butterfly‐type Si 4 Substructure
Author(s) -
Keuter Jan,
Schwedtmann Kevin,
Hepp Alexander,
Bergander Klaus,
Janka Oliver,
Doerenkamp Carsten,
Eckert Hellmut,
MückLichtenfeld Christian,
Lips Felicitas
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201705787
Subject(s) - chemistry , crystallography , electron paramagnetic resonance , ligand (biochemistry) , silicon , nuclear magnetic resonance spectroscopy , stereochemistry , nuclear magnetic resonance , organic chemistry , physics , biochemistry , receptor
Abstract The reduction of the tribromoamidosilane {N(SiMe 3 )Dipp}SiBr 3 (Dipp=2,6‐ i Pr 2 C 6 H 3 ) with potassium graphite or magnesium resulted in the formation of [Si 4 {N(SiMe 3 )Dipp} 4 ] ( 1 ), a bicyclo[1.1.0]tetrasilatetraamide. The Si 4 motif in 1 does not adopt a tetrahedral substructure and exhibits two three‐coordinate and two four‐coordinate silicon atoms. The electronic situation on the three‐coordinate silicon atoms is rationalized with positive and negative polarization based on EPR analysis, magnetization measurements, and DFT calculations as well as 29 Si CP MAS NMR and multinuclear NMR spectroscopy in solution. Reactivity studies with 1 and radical scavengers confirmed the partial charge separation. Compound 1 reacts with sulfur to give a novel type of silicon sulfur cage compound substituted with an amido ligand, [Si 4 S 3 {N(SiMe 3 )Dipp} 4 ] ( 2 ).