Siloxane and hydrocarbon octopus molecules with silsesquioxane cores

Abstract

Hydrogen silsesquioxane, (HSiO)₈, T₈, has been synthesized and isolated in synthetically useful quantities. The T₈ cage-like structure allows eight pendant groups to be placed symmetrically about the surface of a sphere to form an ‘octopus’ molecule. Using T₈ to hydrosilylate compounds with the formula CH₂CH(X)_nY, octopus molecules of the formula (SiO)₈(CH₂CH₂(X)_nY)₈ have been synthesized, including octopus molecules with organic ‘arms’ as well as those with silicone ‘arms’ of various lengths. The regioselectivity of addition in the above two cases was found to differ. The synthesis of these novel octapus molecules and their characterisation by ²⁹Si NMR, FTIR, and gel-permeation chromatography (GPC) is described.