Refine
Has Fulltext
- yes (3) (remove)
Is part of the Bibliography
- yes (3)
Year of publication
- 1993 (3)
Document Type
- Journal article (3)
Language
- German (3) (remove)
Keywords
- Anorganische Chemie (3)
- 29Si and 15N (1)
- Bond cleavage (1)
- Lambda5-organofluorosilicate (1)
- Si-C I Solid-state NMR (1)
- Silicon (1)
- Spirosilicates (1)
- Zwitterionic (1)
- crystal structure (1)
- pentacoordinate (1)
Institute
No abstract available
The zwitterionic spirocyclic \(\lambda_5\) -Silicates bis(3,4,5,6-tetrabromo- 1,2-benzenediolato(2- ))[2-(pyrrolidinio)ethyl]silicate (5; and its monohydrate 5 · H\(_2\)O) and bis[1,2-benzenediolato(2- )][( dimethylammonio)methyl]silicate (6) were synthesized by various methods including Si-C bond cleavage reactions. The crystal structures of 5, 5 · H\(_2\)O, and 6 were investigated by Xray düfraction. Furthermore, 5, 5 · H\(_2\)O, 6, and the related zwitterionic \(\lambda_5\)-spirosilicates 1 · 1/4 CH\(_3\)CN, 2 · CH\(_3\)CN, 3 · CH\(_3\)CN, and 4 were characterized by solid-state NMR spectroscopy (\(^{29}\)Si and \(^{15}\)N CP/MAS). The pentacoordinate silicon atoms of 5, 5 · H\(_2\)O (two crystallographically independent ZWitterions and two crystallographically independent water molecules), and 6 (two crystallographically independent zwitterions) are surrounded by four oxygen atoms and one carbon atom. The coordination polyhedrons around the silicon atoms of 5 and 6 can be described as distorted (5) or nearly ideal (6) trigonal bipyramids, the carbon atoms being in equatorial positions. 5 forms intramolecular and 6 intermolecular (--+ formation of dimeric units) N- H···O hydrogen bonds. The coordination polyhedrons around the two crystallographically independent silicon atoms of 5 · H\(_2\)O can be described as a nearly ideal and slightly distorted square pyramid, respectively, the carbon atoms being in the apical positions. In the crystal lattice of 5 · H\(_2\)O, intermolecular N-H···O and 0-H···O hydrogen bonds between the zwitterions and water molecules are observed. The results obtained by X-ray diffraction and solid-state NMR spectroscopy are consistent for each compound studied.
Das zwitterionische Tctratluoro[2-(pyrrolidinio) ethyl]silicat (4) wurde durch Reaktion von Trimethoxy( 2-pyrrolidinoethyl)silan (5) mit Fluorwasserstoff in einem Ethanol/Flußsäure-Gemisch bei 0 °C synthetisiert. Die Kristall- und Molekülstruktur von 4 wurde bei - 100 °C mittels einer Einkristall-Röntgenstrukturanalyse untersucht. Außerdem wurde 4 durch NMR-Untersuchungen in Lösung charakterisiert (CD\(_3\)CN: \(^1\)H, \(^{13}\)C).