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3,5‐Dimethylpyrazolyl‐Substituted Di‐ and Trisiloxanes
Author(s) -
Bitto Florian,
Brendler Erica,
Böhme Uwe,
Wagler Jörg,
Kroke Edwin
Publication year - 2016
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/ejic.201600591
Subject(s) - chemistry , disiloxane , quantum chemical , silylation , molecule , nuclear magnetic resonance spectroscopy , silicon , stereochemistry , crystallography , crystal structure , tetra , polymer chemistry , medicinal chemistry , organic chemistry , catalysis
The synthesis and characterization of di‐ and trisiloxanes with 3,5‐dimethylpyrazolyl (pz*) moieties are presented. Disiloxanes of the type O(SiMe 3– n pz* n ) 2 ( n = 1, 2, and 3 in 2 , 3 , and 4 , respectively) are easily accessible through a trans ‐silylation approach. Crystal structure analyses of compound 4 and the two side products 5 and 6 illustrate different coordination motifs of pz* (terminal vs. bridging) in the disiloxane system. The reaction of O 2 Si 3 Cl 8 with Me 3 Sipz* led to the unsymmetrically substituted trisiloxane pz* 3 SiO‐Sipz* 2 O‐SiCl 2 pz* ( 7 ) with bridging pz* units and tetra‐ and pentacoordinate silicon atoms and the fully pyrazolyl‐substituted trisiloxane O 2 Si 3 pz* 8 ( 8 ), depending on the choice of the reaction conditions. The 29 Si NMR properties of 7 were investigated by 29 Si CP/MAS NMR spectroscopy and supporting quantum chemical calculations analyzing the principal components of the chemical‐shift tensor for all three silicon atoms in this molecule.