Adsorption Complexes of Cr(Acac)<sub>3</sub> on Fumed SiO<sub>2</sub> Surface upon Vapour-Phase Modification
Keywords:
Cr(acac)3, fumed silica, vapour-phase modification, adsorption complexAbstract
The modifying mechanism fumed SiO2 particles of 12 nm size with Cr(acac)3 vapour at 463 K in argon flow has been studied. Adsorption of Cr(acac)3 on SiO2 surface has been found out to occur due to hydrogen bonding of oxygen atoms of acetylacetonate ligands of Сr(acac)3 with hydrogen atoms of hydroxyl groups of SiO2 surface that preceded ligand substitution above 500 K and SiО–Cr bond formation. Hydrogen bonding has been proved with 2–8 nm high-wavelength shift of ???, d?? and d?d transition bands in UV-vis spectrum and 4 cm-1 low-wavenumber shift of ?s (C- C- O) vibration band in IR spectrum of Cr(acac)3 resulted from its adsorption at SiO2surface.References
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