Sol-gel incorporation of organometallic compounds into silica: Useful precursors to metallic nanostructured materials

Abstract

Inclusion of the organometallic MLn = [HOC 5H 4N• Cp 2TiCl][PF 6] (1), HOC 5H 4N• W(CO) 5 (2), HOC 5H 4N•Mo(CO) 5 (3), [HOC 6H 4CH 2CN•Cp 2TiCl] [PF 6] (4), HOC 6H 4CH 2CN•W(CO) 5 (5) and HOC 6H 4CH 2CN•Mo(CO) 5 (6) into amorphous silica using the gelator precursor TEOS and N 3P 3{NH[CH 2] 3Si[OEt] 3} 6 afford the gels (MLn)(SiO 2)n. The inorganic-organic hybrid nanocomposites were pyrolyzed under air at 800°C to give nanostructured metal oxides and/or metal pyrophosphates (phosphates) included in the silica matrices. The morphology of the monolithic nanocomposites exhibited a strong dependence on the gel precursor used being mainly laminar for those prepared using N 3P 3{NH[CH 2] 3Si[OEt] 3} as gelator. TEM images show different shape and size such as circular nanoparticles, nanocables and agglomerates in some cases with sizes of 20 nm for the circular nanostructures, and diameter about 25 nm for the nanocables.