Nonaqueous, Molecular Precursor Route to Hybrid Inorganic/Organic Zirconia−Silica Materials Containing Covalently Linked Organic Bridges

Abstract

New hybrid inorganic/organic materials possessing zirconium in the inorganic framework have been synthesized. Co-thermolyses in sealed reactors (toluene, AlCl3 catalyst, 155 °C) of Zr[OSi(OtBu)3]4 in the presence of (EtO)3Si(CH2)nSi(OEt)3 (n = 1, 2) or (EtO)3Si(C6H4)nSi(OEt)3 (n = 1, 2; C6H4 = 1,4-phenylene) monomers rapidly yielded monolithic, transparent gels. The resulting xerogels were amorphous and exhibited high surface areas and high surface coverages of OH functionalities. Solid-state 29Si and 13C CP MAS NMR spectroscopies were used to establish the presence of intact, organic bridging groups and to verify the presence of unreacted ethoxy groups. Energy-dispersive X-ray spectroscopy was used to elucidate the elemental composition and distribution throughout the material, and atomic force microscopy was used to probe surface adhesive properties.