JO URNAL O F zyxwvutsrq MO LEC ULA R C A TA LYSIS Journal of Molecular Catalysis 89 ( 1994) 77-92 Reactivity of ruthenium carbonyl carboxylates hydroformylation conditions under Antonella Salvini, Piero Frediani, Donella Rovai, Mario Bianchi, Franc0 Piacenti” Dipartimento di Chimica Organicu, Universitci di Firenze. Via Gino Capponi 9, 50121 Firenze, Italy (Received August 14, 1993; accepted November 16, 1993) zyxwvutsrqponmlkjihgfedcbaZYX Abstract Ru(CO),(MeC00)2(PBu,)2, Ru,(CO),(MeCOO),(PBu,)2, Ru,(CO),(MeCOO),(PBu,)2, and [Ru,(CO),(MeC00)2] n react, in the presence of CO, with molecular hydrogen, losing the carboxylato ligand while the metal is reduced to Ru( 0). Evidence is given of the involvement of ruthenium hydrides in this reaction. The role of the above precursors in the catalytic cycle of the hydroformylation of olefins is discussed. Key words: carbonyl complexes; carboxylates; hydroformylation; olefins; ruthenium 1. Introduction Several ruthenium carbonyl complexes have been described as catalytic precursors in the hydroformylation of olefins [ l-61. The reaction rate provided by them is usually low, up to 150°C; the trialkylphosphine substituted derivatives show an even lower activity and regioselectivity [ 71. Recently Jenck et al. [ 8,9] reported an easy hydroformylation of act- 1-ene under mild conditions in the presence of phosphine substituted ruthenium carbonyl carboxylates, a base (KOH or NEt,) and water and suggested a novel reaction mechanism. We have been studying for some time the reactivity of Ru(CO),( MeCOO),( PBu3)Z (I), Ru,(CO),(MeCOO),(PBu,), (II), Ru,(CO),(MeCOO),(PBu,), (III), and [ RuZ( CO),( MeCOO),] n (IV) [ 10-141, and their activity as catalysts in the hydrogenation and carbonylation reactions [ 15-191. *Corresponding author; fax. ( + 39-55)2757660. 0304-5102/94/$07.00 0 1994 Elsevier Science B.V. All rights reserved .SSDZ0304-5102(93)E0316-9