Friedel–Crafts alkylation of octaphenyloctasilsesquioxane (OPS) introduces a hydrocarbon layer around the rigid OPS core (see figure). Although periodic order is maintained even in the melt, as determined from X-ray diffraction measurements, this layer provides access to low-melting solids for butyl, hexyl, octyl, and decyl substituents. Because the alkyl groups interdigitate, the butyl and hexyl melts are stable to temperatures of ca. 400 °C, which is ca. 100 °C higher than the octyl and decyl compounds.
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