An efficient and simple method for preparing titanium or niobium containing MCM-41 has been developed. The mesoporous materials were synthesized at room temperature using tetraethoxysilane (TEOS), cetyltrimethylammonium bromide (CTMABr) as template and (NH4)(2)TiF6 or NH4[NbO(C2O4)(2)(H2O)(2)].(H2O)(3) as metal source. The materials were characterized by X-ray diffraction (XRD),FT-IR and diffuse reflectance UV-Vis spectroscopies, which showed that most of the metal was incorporated into the framework of MCM-41. Ti and Nb containing MCM-41 were tested in the solvent-free epoxidation of cis-cyclooctene using tert-butyl hydroperoxide as oxidant and a catalyst: cyclooctene molar ratio of 1:1000. After 24h of reaction using Ti-MCM-41 and Nb-MCM-41 as catalyst, we obtained 82 and 65% yields of cyclooctene oxide, respectively, without formation of any by-products. (C) 2004 Elsevier B.V. All rights reserved.2662223227