Siloxane Network Formation from the Si8O20 8ÿ Silicate Species and Dimethyldichlorosilane

Organic-silica hybrids were synthesized from the Si8O20 8ÿ silicate anion by the reaction with an excess of dimethyldichlorosilane. The structure of the hybrids has been found to comprise the Si8O20 8ÿ structure as a building block, linked by the (CH3)2Si unit. Si NMR signals from terminal groups in the hybrids have been assigned. When the amount of dimethyldichlorosilane present for the reaction is increased, the number of terminal groups decreases, indicating that cross-linking of Si8O20 8ÿ with dimethyldichlorosilane proceeds to form three-dimensional siloxane networks in the hybrids. Copyright # 1999 John Wiley & Sons, Ltd.