C. Pakjamsai, Y. Kawakami
Jan 1, 2005
Citations
0
Influential Citations
20
Citations
Journal
Designed Monomers and Polymers
Abstract
ortho-Methyl- and ethyl-substituted phenyl octasilsesquioxanes, (o-MePh, or o-EtPh)8-T8, with cubic structure were synthesized in good yield (>70%) under mild basic conditions. The position of the alkyl substituent on the phenyl group (ortho-, meta-, para-) in the starting phenyltrimethoxysilane had a big effect on the yield of the product. (Meta- and para-methyl and -ethyl)phenyltrimethoxysilane did not give the desired products under basic conditions; instead, the methyl derivatives gave products in low yield under acidic conditions (<10%). (MePh)8-T8 showed different thermal properties and solubility, depending on the position of the methyl substituent on the phenyl group. (o-EtPh)8-T8, the only obtainable isomer from ethyl-substituted starting materials, showed lower melting point and higher solubility in ordinary solvent than (o-MePh)8-T8.