Adsorption of activated ketones on platinum and their reactivity to hydrogenation:: a DFT study

The adsorption of several ketones interesting for the enantioselective hydrogenation on cinchona-modified platinum has been modeled using relativistically corrected density functional theory. Two metal clusters, containing 19 and 31 Pt atoms, respectively, have been used to model a Pt(111) surface. The two adsorption modes eta(1) and eta(2) have been described, and their importance for the mechanism of hydrogenation has been pointed out. The effect of an ester group in alpha position and of alpha-fluorination of a ketone on its adsorption has been studied, and an explanation for the reactivity enhancement due to the ketone substitution has been proposed. (C) 2004 Elsevier Inc. All rights reserved.