Galaburda M. Properties of iron-containing silica synthesized using iron(III) acetylacetonate.

The singularities of Fe(acac)3 adsorption from different solvents on the surface of fumed silica were investigated. It was established that iron acetylacetonate adsorbed on the silica surface by means of hydrogen bonding of hydrogen atoms of silanol groups with oxygen of carbonyl group and п-electron system of the lіgand. The process is accompanied by the loss of one ligand or two Fe(acac)3 ligands.The thermal transformations of grafted iron acetylacetonate groups were investigated. Heat treatment of the silica modified wit Fe(acac)3 from the isopropanol solution leads to formation of hematite with controlled crystallites size (17-20 nm) whereas in the case of ССІ4 maghemite is formed (crystallites size from 15 to 30 nm). Thermal treatment of samples obtained under gass-phase modification leads to amorphous Fe2O3 formation. It was found out that silica matrix stabilizes the maghemite phase up to 900 °C. The existence of the Fe-O-Si bonds in the nanocomposites has been proved. It was shown that nanoparticles of iron oxides raised the temperature range of thermal degradation of polymethylphenylsiloxane and extended the temperature range of hydrophobic properties of the obtained coatings. Fe2O3-doped xerogels and transparent monolithic quartz sol-gel glasses were synthesized.