Synthesis and characterization of bis-phenyl heptasilsesquioxane
Heptamertic cyclopentyl siloxane 1 containing three SiOH functions was synthesized by the controlled hydrolysis of cyclopentyltrichloros ilane. Then heptameric cyclopentyl siloxane 2 containing one SiOSiMe_3 functio n and two SiOH functions was prepared by adding chlorotrimethylsilane to the sol ution of 1 in THF by controlling the proper molar ratio. Finally, cage-like he pta(cyclopentyl) silsesquioxane(POSS) 3 containing two SiOSiMe_2Ph functions an d one SiOSiMe_3 function was obtained by adding excessive chlorodimethyl- phenylsilane to the solution of 2 in THF. The prepared compounds were character ized by FTIR,1H NMR,29Si NMR .The results showed that difunctional POSS with clear structure could be prepared by this method with a high yield.A n ew,simple and feasible route to design and synthesize difunctional POSS was prop osed.