Incorporation of a tungsten Fischer-type metal carbene covalently bound to functionalized SBA-15 Marı ´a Luisa Ojeda a , Antonio Campero b, * , Jose ´ Guadalupe Lo ´ pez-Corte ´s a , Marı ´a Carmen Ortega-Alfaro c , Celso Vela ´squez b,d , Cecilio Alvarez a a Instituto de Quı ´mica, UNAM, Circuito Exterior, Ciudad Universitaria, C.P. 04510, Me ´ xico, D.F, Mexico b Departamento de Quı ´mica, Universidad Auto ´ noma Metropolitana-Iztapalapa, P.O. Box 55-534, C.P. 09340, Me ´ xico, D.F, Mexico c Departamento Q. Orga ´ nica, L-4D, Edif. A Facultad de Quı ´mica-UNAM, Circuito Exterior, Ciudad Universitaria, 04510 Me ´xico, D.F, Mexico d Instituto Nacional de Astrofı ´sica O ´ ptica y Electro ´ nica, Calle Luı ´s Enrique Erro No. 1, Sta Marı ´a Tonantzintla, C.P. 728400 Apdo Postal 51 y 216 72000 Puebla, Pue., Mexico Received 4 June 2007; received in revised form 6 July 2007; accepted 9 July 2007 Available online 19 July 2007 Abstract A metal Fischer carbene [(CO) 5 W@C(u)OCH 2 CH 3 ] 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 meso- porous silica walls functionalized by aminopropyltriethoxysilane (APTES) with a tungsten carbene Wu, while in the second approach a precursor synthesized by reacting APTES with the carbene Wu is then anchored via a direct bond to the silanol groups in the interior pore channels of SBA-15. This tethering is helpful to prevent the decomposition of the metallic complex. XRD, N 2 adsorption–desorption, and TEM analysis provide strong evidence that the mesoporous support structure retains its long-range ordering after the grafting process, despite a sig- nificant 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. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Mesoporous SBA-15; Fischer carbene; Functionalized silica; APTES; T-type NMR sites 1. Introduction The first tungsten(0)–carbene complex was prepared by Fischer and Maasbo ¨ l in 1964 [1]. Almost 40 years after this seminal discovery, these reagents have a widespread use in organic synthesis [2,3]. The metal–carbene complexes of group 6 are especially well suited for structural and mech- anistic studies because of the easiness of their preparation and the amazing variety of their chemical behavior. Now- adays, Fischer carbene complexes are reagents of general use in organic and organometallic chemistry and are pow- erful tools for the selective synthesis of an array of carbo- cycles and heterocycles as well as open chain molecules [4– 7]. The electrophilic character of the carbenic carbon in Fischer complexes facilitates the attack by nucleophiles [8]. As a consequence, metal carbene anions are easily gen- erated upon treatment of alkyl carbene complexes with bases [9]. Such a property has been widely utilised to build elaborated carbene side chains of interest in organic syn- thesis via (i) formation of carbene anion and (ii) reaction with electrophilic organic [2,10] or organometallic [11] reagents. Since the discovery in 1992 of ordered mesoporous silica-based solids [12], a good deal of research work has been devoted to the synthesis of these materials. These 1387-1811/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.micromeso.2007.07.026 * Corresponding author. Tel.: +52 55 5804 4677; fax: +52 55 5804 4666. E-mail address: acc35@xanum.uam.mx (A. Campero). www.elsevier.com/locate/micromeso Available online at www.sciencedirect.com Microporous and Mesoporous Materials 111 (2008) 178–187