Structures of Two Cyclotetrasiloxanes with Intra and Intercyclic –CH₂CH₂‐Bridges

Abstract

Molecular structures of two cyclotetrasiloxanes with intra and intercyclic ethylene bridges were determined by an X‐ray structure analysis. The presence of the intracyclic bridge results in a saddle conformation, unusual for tetrasiloxane cycles, and in a significant strain of the cycle. The tetrasiloxane cycles linked by this bridge have a highly symmetric chair conformation which is likely to persist in the corresponding polymer.

1,3,3,5,5,7,9,9,11,11-Decamethyl-2,4,6,8,10,12-hexaoxa-1,3,5,7,9,11-hexasilabicyclo[5.5.2]tetradecane

“…0108-2701/89/010071-03503.00 Struchkov, Astapova & Zhdanov, 1986). In this work the molecular and crystal structure of the cyclohexasiloxane analogue (II) is reported.…”