Atrane precursors in the one-pot surfactant-assisted synthesis of high zirconium content porous silicas

A diversity of zirconium-containing porous silicas of the MCM-41 type (Zr-MCM-41, infinity greater than or equal to Si/Zr greater than or equal to 0.33) has been synthesized from aqueous solution using a cationic surfactant (CTABr = cetyltrimethylammonium bromide) as the structural directing agent, and starting from molecular atrane complexes of Zr and Si as precursors. Atrane inertness toward hydrolysis allows harmonization of the reactivity of the Zr and Si species, which in turn avoids subsequent phase segregation and results in chemically very homogeneous materials. Materials characterization by XRD, TEM, and N-2 adsorption-desorption isotherms shows that all the prepared Zr-MCM-41 solids have high surface area and uniniodal narrow pore size distribution, whereas their pore packing motives range from ordered hexagonal to wormhole-like arrays depending on the Zr content. The study of the local environment of the Zr atoms in these solids has been approached by means of spectroscopic techniques (IR, UV-vis, and NMR).