The vinyl cubic polyhedral silsesquioxanes (vinylSiO(1.5))(8) and [(vi
nylMe(2)SiO)SiO1.5](8) were epoxidized using ten equivalents of m-chlo
roperoxybenzoic acid (m-CPBA) per cube. The [(vinylMe(2)SiO)SiO1.5](8)
compound converts, quantitatively, to the octaepoxide, [(epoxyMe(2)Si
O)SiO1.5](8) as demonstrated by H-1, C-13, and Si-29 solution NMR, che
mical and mass spectral analysis. The (vinylSiO(1.5))(8) cube was like
wise fully epoxidized as determined by NMR; however, efforts to isolat
e it always led to intractable gels. Partial epoxidation was achieved
using only three equivalents of m-CPBA. The partially epoxidized compo
und, when characterized by CI mass spectra, chemical analysis and NMR,
was shown to have an average of two epoxy groups per cube. Both polye
poxides readily polymerized in the presence of Lewis acid catalysts or
on reaction with simple amines, which suggests their potential as cou
pling agents in the synthesis of novel inorganic-organic hybrids.