Publisher Summary This chapter focuses on Silicon-29( 29 Si) nuclear magnetic resonance (NMR) spectroscopy One nucleus that has become increasingly important from an NMR point of view is 29 Si Silanes are important to the chemical industry as catalysts or additives in catalyst systems New and better ways to characterize these compounds are urgently needed The Silicon-29 ( 29 Si) isotope is a very difficult nucleus to observe because of its low natural abundance (47 %) and low NMR sensitivity at constant field (784 x 10 -3 ) relative to 1 H This chapter includes compounds of general structure (R 3 - n SiO n ) x , where n > 0, x > 2, and R = alkyl, aryl, or H Silicates and extravalent silicon compounds are described The spectral dispersion for organosilicones may be considerable for certain families of compounds The first, 29 Si NMR results reported on polydimethylsiloxanes showed that individual resonance lines can be found for each different silicon nucleus up to a ten-unit oligomer, surpassing the structural resolution achieved by I3 C and 1 H NMR on the same materials

Silicon-29 NMR Spectroscopy

The first known cyclosilane Si5H10 is yielded by the reaction of Si5Br10 with LiAlH4. The cyclic Si5Br10 results at the reaction of the known Si5
ph
10 with HBr and is the first known representative of the class of cyclic silicon bromides too. Si5H10 and Si5Br10 are characterized and their properties are described. A detailed mass spectroscopic investigation shown an interesting fragmentation into Si
 5
 +
 -particle.

Darstllung und Eigenschaften von Cyclopentasilan

Cyclopentasilan, das erste unsubstituierte cyclische Siliciumhydrid

Zur reaktion der silicium—phenyl-bindung mit HCl

https://link.springer.com/content/pdf/10.1007%2FBFb0111403.pdf

Properties and preparations of Si-Si linkages

Aus dem aus Si5(C6H5)10 mit HJ herstellbaren Pentaphenylpentajodpentacyclosilan Si5(C6H5)5J5 lassen sich eine Reihe von Derivaten Si5(C6H5)5X5 mit X=H,me, bu und Ome synthetisieren. Darstellung und Eigenschaften dieser Cyclosilane werden beschrieben. Aus der KopplungskonstanteJ (29SiH), ν SiH und den chemischen Eigenschaften von Si5(C6H5)5H5 ersieht man eine Schwachung der Si−H-Bindung, die durch eine erhohte Elektronendichte im Si5-Ring erklart werden kann.

E. Hengge

Papers

Pentaphenylcyclopentasilan und Derivate

Pentaphenylcyclopentasilan und derivate