ISSN:
1572-8870
Keywords:
Hexamethylcyclotrisiloxane
;
triphenylphosphine oxide
;
ring-opening reactions
;
siloxane oligomers
;
chlorosilanes
;
Lewis base catalysts
;
molecular complexes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A molecular complex of triphenylphosphine oxide and tetrachlorosilane (II) in a solvent mixture that contains 90% toluene and 10% acetonitrile acts as a catalyst to open the cyclic siloxane oligomer, hexamethylcyclotrisiloxane (I). The primary product is the linear oligomer 1,1,1,7-tetrachlorohexamethyltetrasiloxane (III). III can be converted quantitatively to the structural isomer, 1,3,3,7-tetrachlorohexamethyltetrasiloxane (IV), in the same catalyst–solvent mixture either by stirring at room temperature for 12 h or by heating at 90°C for about 1 h. In both reactions, the disappearance of the reactants and the formation of the products can be followed by glc. Products III and IV are characterized by elemental analysis, molecular mass, infrared spectra, and 1H- and 29Si-NMR spectra. III and IV can be transformed into their fluorinated derivatives, VI and VII, respectively, by stirring for several days in a toluene slurry of KSiF6. The 19F-NMR spectra of VI and VII are consistent with the proposed isomeric structures.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1021433520992
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