Synthesis of functional cubes from octavinylsilsesquioxane (OVS).
Octavinylsilsesquioxane, (CH(2)CH)(8)Si(8)O(12), a cubic molecule with vinyl groups at each vertex, has been elaborated to give a series of potential starting materials for nanohybrid synthesis. Terminal bromophenyl groups were introduced onto the surface of octavinylsilsesquioxane either by cross-metathesis or hydrosilylation to give fully bromide substituted POSS A, POSS B and POSS C; the last two were further capped with trimethylsilylacetylene by Sonogashira coupling to produce POSS D and POSS E, showing interesting potential for more useful end group functionalisation. Heck coupling with iodobenzene was used to make the simple phenyl terminated dendrimer POSS F. Cross-metathesis of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)styrene with octavinylsilsesquioxane afforded POSS G with eight aryl borate groups on its periphery, suitable for use as a starting material in Suzuki coupling. Finally, POSS H has been functionalized with 8 benzyl chloride groups via Grubbs coupling, allowing further substitutions by nucleophiles.
Cheng
Ge
G
EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, KY16 9ST, UK.
Vautravers
Nicolas R
NR
Morris
Russell E
RE
Cole-Hamilton
David J
DJ