Iron(III) acetylacetonate complex immobilized on silica surface was obtained by the following three steps synthesis: (i) synthesis of organic precursor (acacsil) containing the acetylacetonate (acac) group; (ii) simultaneous polycondensation of the acacsil with the tetraethylorthosilicate (TEOS) by the sol-gel method resulting in the acac/silica xerogel; and (iii) complexation of the Fe(III) on the acac sites of the xerogel surface forming a Fe-acac/silica xerogel. The xerogels, acac/silica and Fe-acac/silica, are hybrid polymers that present a covalent organic/inorganic interface between the acac groups and silica. Xerogels were characterized by using scanning electron microscopy, energy dispersive spectroscopy, infrared spectroscopy, N-2 adsorption desorption isotherms (pore size distribution and surface area) and elemental analysis. The Fe-acac/silica xerogel was tested as heterogeneous catalyst for the cis-cyclooctene epoxidation, employing the same conditions of the homogeneous Mukaiyama system. (c) 2005 Elsevier B.V. All rights reserved.