G. Cerveau et al., SYNTHESIS OF MONOPHASIC HYBRID ORGANIC-INORGANIC SOLIDS CONTAINING [ETA(6)-(ORGANOSILYL)ARENE]CHROMIUM TRICARBONYL MOIETIES, Chemistry of materials, 9(11), 1997, pp. 2561-2566
Silica gel containing benzenechromium tricarbonyl units have been obta
ined from molecular organosilicon precursors. The hydrolytic sol-gel p
olymerization of [eta(6)-C6H5Si(OMe)(3)]Cr(CO)(3) (1), [eta(6)-1,4-C6H
4RR']Cr(CO)(3) [R = R' = Si(OMe)(3) (2), R = R' = CH2Si(OMe)(3) (3), R
= R' = CH2CH2Si(OMe)(3) (4)], {eta(6)-1,3,5-C6H3[Si(OMe)(3)](3)}Cr(CO
)(3) (5), under nucleophilic catalysis by fluoride ion (NH4F), have le
d quantitatively to new monophasic hybrid organic-inoroanic silica gel
s. The derived xerogels X were characterized by FT IR, C-13 and Si-29
solid state CP MAS NMR spectroscopies. The silicon-carbon bond and the
tricarbonylchromium ligand were retained within the gel. The major en
vironment of the Si atoms corresponded to a T-2:CSi(OR)(OSi)(2) substr
ucture for X2-X4, a T-3:CSi(OSi)3 one for X1 and a Ts:CSi(OR)(2)(OSi)
in the case of X5. In most cases, these were amorphous materials that
exhibited low specific surface areas (similar to 10 m(2) g(-1)). Upon
heating the xerogels X1, X2, and X4 at 400 degrees C under an argon fl
ow, weight losses corresponding to complete carbon monoxide eliminatio
n were obtained, leading to chromium in a low oxidation state within t
he solid.