A Novel Approach for Preparation of Acetylacetonate Complex Anchored to High Order Nanoporous Silica (LUS-1)

Tris(3-bromo-acetylacetonato) chromium(III) as an inert and very stable complex with a good leaving group was synthesized using as-prepared Cr(acetylacetonate)3. Highly ordered nanoporous silica (LUS-1), with some great features, was functionalized with 3-aminopropyltriethoxysilane. Then the as-prepared product was modified with tris(3-bromo-acetylacetonato) chromium(III) under mild reaction condition. Results obtained from N2 adsorption desorption, and X-ray powder diffraction proved the successful anchoring of the Cr(III) complex inside the pores of LUS-1 without any distortion in the structure. The morphology and configuration of LUS-1 with Scanning electron microscope and Transmission electron microscopy  and Energy-dispersive X-ray spectrum of the product were prepared. Mid and Far Infrared spectroscopy confirmed that the product was possibly an amine, formed by substitution addition of NH2 group on LUS-1, to C-Br in acac ligands and not a weak and non-stable Schiff base. Thermal stability of the species was assessed by thermogravimetric analysis. This novel method resulted in the formation of a stable covalently bonded acetylacetonate to the support that it can be used in acidic media or even in polar solvents without altering the structure.