Incorporation of a tungsten Fischer- type metal carbene eovalently bound to functionalized SBA-15

摘要

A metal Fischer carbene [(CO)5W=C((φ)OCH2CH3] was covalently linked for the first time to the silanol groups of the mesoporous channels of SBA15 by following two different synthetic anchoring routes. The first one goes through the reaction of the SBA15 mesoporous silica walls functionalized by aminopropyltriethoxysilane (APTES) with a tungsten carbene Wφ, while in the second approach a precursor synthesized by reacting APTES with the carbene Wφ is then anchored via a direct bond to the silanol groups in the interior pore channels of SBA-15. This tetheringis helpful to prevent the decomposition of the metallic complex. XRD, N2 adsorption-desorption, and TEM analysis provide strong evidence that the mesoporous support structure retains its long-range ordering after the grafting process, despite a significant reduction of its specific surface area, pore-volume and pore-size. The chemical bonding of the tungsten carbene to the silanol groups of SBA-15 materials was studied with solid-state NMR spectroscopy. Both ~(13)C MAS NMR and ~(29)Si CP MAS NMR spectra confirm the covalent linking of the carbene to the silica-pore system.