Synthesis, structural characterization and properties of a cubic octa-n-propylsilsesquioxane inorganic–organic hybrid material

Synthesis, structural characterization and property studies were carried out on cubic octa-n-propylsilsesquioxanes (n-Pr-POSS) in this paper. n-Pr-POSS was synthesized by an acid-catalyzed hydrolytic condensation of n-propyltriethoxysilane with a 68.9% yield. Common organic solvents, such as benzene, chloroform, tetrahydrofuran, diethyl ether, dichloromethane, toluene, cyclohexane, hexane and pentane can be used to dissolve n-Pr-POSS; however, n-Pr-POSS is insoluble or poorly soluble in acetone, dichloroethane, chlorobenzene, dimethylformamide, xylene, methanol, alcohol and isopropanol. The cubic structure and crystal morphology of n-Pr-POSS have been investigated by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), optical microscope, 1H, 13C and 29Si nuclear magnetic resonance (NMR), X-ray single crystal diffraction and X-ray powder diffraction (XRD) methods. Crystalline n-Pr-POSS is a triclinic system crystal with a P-1 space group. Thermogravimetric analysis (TGA) indicates that n-Pr-POSS begins to sublimate above 200 °C and does not decompose until 524 °C under a nitrogen atmosphere.

► Cubic octa-n-propylsilsesquioxanes was synthesized with a 68.9% yield.
► Soluble in common organic solvents.
► A triclinic system crystal with a P-1 space group.
► Sublimate above 200 °C and not to decompose until 524 °C under a nitrogen atmosphere.