Preparation and characterization of metallacalixarenes anchored to a mesoporous silica SBA-15 LP as potential catalysts

Abstract The calixarene [[4H]-(OH) 3 (H)] was used as a linker between a mesoporous silica SBA-15 LP (large pore) modified with Al( i Bu) 3 ·(Et 2 O) and organometallic complexes Zr( ∗ CH 2 Ph) 4 or W( C t Bu(CH 2 t Bu) 3 ) to avoid steric and electronic interactions of the metallic centers with the oxide surface, and insure a better controlled coordination sphere. Hence, materials M1 , [( SiO) 2 Al i Bu·(Et 2 O), Si- i Bu] SBA-15 LP-(700) and M2 , [( SiO) 2 Al-[O-[4H]-(OH) 2 (H)], Si- i Bu] SBA-15 LP-(700) were successively prepared by reaction of Al(i-Bu) 3 ·(Et 2 O) with the OH groups of SBA-15 LP treated at 700 °C under vacuum, then with the calixarene [[4H]-(OH) 3 (H)] at 25 °C with a yield of 70%. M2 could then react with Zr( ∗ CH 2 Ph) 4 at 25 °C and W( C t Bu(CH 2 t Bu) 3 ) at 65 °C to form the corresponding bipodal surface complexes on materials M3 , [( SiO) 2 Al-[O-[4H]-(H)(O) 2 Zr( ∗ CH 2 Ph) 2 ], Si- i Bu] SBA-15 LP-(700) and M4 , [( SiO) 2 Al-[O-[4H]-(H)(O) 2 W( C t Bu(CH 2 t Bu))], Si- i Bu] SBA-15 LP-(700) respectively. M4 proved to catalyze the propene metathesis with a high initial activity.