The utilization of organometallic complexes of palladium and platinum to form mono and bimetallic catalysts on basic magnesium oxide support was studied and rationalized. Thermoanalytical data in hydrogen flow suggested the uselessness of volatile, fluorinated organometallic precursors for platinum catalysts, because the strong chemical interaction on the surface, occurring during CVD, prevents the subsequent conventional reductive elimination process to take place. Conventional solvent impregnation of acetylacetonate complexes was instead successful. Chemical interaction of the organometallic complex with basic surface sites of the MgO support was occurring already in the deposition step, resulting in an even surface distribution of the metal precursor, and the formation of bimetallic Pt-Pd sites. Alloy formation between platinum and palladium in the bimetallic catalyst was then proposed and studied using methylcyclopentane conversion between 350 and 500degreesC as test reaction. (C) 2003 Elsevier Science B.V. All rights reserved.