Mixed nonhydrolytic/hydrolytic sol-gel routes to novel metal oxide/phosphonate hybrids

Titanium oxide/phenylphosphonate hybrids were prepared by a two-step sol-ge l processing, involving first the nonhydrolytic condensation between titani um isopropoxide and phenylphosphonic acid (or the parent bis(trimethylsilyl )ester), followed by the hydrolysis-condensation of the remaining alkoxide groups. Partial hydrolysis led to the formation of Ti-4(mu(3)-O)(mu(2)-(OPr )-Pr-i)(3)((OPr)-Pr-i)(5)(PhPO3)(3); the potential use of this intermediate compound as a single-source precursor was explored. The composition, therm al stability, and structure of the hybrid xerogels were investigated using EDX, TGA, XRD, FTIR, and P-31,C-13, and Si-29 MAS NMR. The compositional an d structural stability of the hybrids was investigated over a nide pH domai n.