| Abstract: The tris(trimethylsilyl)silanol (H-SST) ligand can be reacted with a
Group 4 or 5 metal alkoxides in a solvent to form an SST-modified metal
alkoxide precursor. Exemplary Group 4 precursors include
[Ti(SST).sub.2(OR).sub.2] (OR=OPr.sup.i, OBu.sup.t, ONep);
[Ti(SST).sub.3(OBu.sup.n)]; [Zr(SST).sub.2(OBu.sup.t).sub.2(py)];
[Zr(SST).sub.3(OR)] (OR=OBu.sup.t, ONep);
[Hf(SST).sub.2(OBu.sup.t).sub.2]; and
[Hf(SST).sub.2(ONep).sub.2(py).sub.n] (n=1, 2), where
OPr.sup.i=OCH(CH.sub.3).sub.2, OBu.sup.t=OC(CH.sub.3).sub.3,
OBu.sup.n=O(CH.sub.2).sub.3CH.sub.3, ONep=OCH.sub.2C(CH.sub.3).sub.3, and
py=pyridine. Exemplary Group 5 precursors include
[V(SST).sub.3(py).sub.2]; [Nb(SST).sub.3(OEt).sub.2];
[Nb(O)(SST).sub.3(py)];
2[H][(Nb(.mu.-O).sub.2(SST)).sub.6(.mu..sub.6-O)];
[Nb.sub.8O.sub.10(OEt).sub.18(SST).sub.2.1/5Na.sub.2O];
[Ta(SST)(.mu.-OEt)(OEt).sub.3].sub.2; and [Ta(SST).sub.3(OEt).sub.2];
where OEt=OCH.sub.2CH.sub.3. When thermally processed, the precursors can
form unusual core-shell nanoparticles. For example, HfO.sub.2/SiO.sub.2
core/shell nanoparticles have demonstrated resistance to damage in
extreme irradiation and thermal environments. |