The reactivity of trinuclear metal cluster compounds with protic acid

Includes bibliographical references (pages 93-95)The reactions of the ruthenium complexes HRu 3(CO)9L (L = MeC==CH==CMe, HC==CMe==CMe, EtC==CH==CMe) with protic acids (CF3SO3H, H2S04, CF3COOH)\ud were studied. Possible structures of the species present in solution\ud have been suggested on the basis of 1H NMR data. The titrations\ud of CD 2Cl2 solutions of the Cs complexes, and their monophosphine\ud derivatives, with CFgSOgH have indicated that initial protonation\ud occurs at the metal core. An excess of strong acid 'l_eQ. to decomposition\ud of the complexes, however it was not possible to determine whether\ud subsequent proton attack took place at the metal cluster or\ud directly at the hydrocarbon ligand. In neat CF3COOH these complexes\ud were found to undergo decomposition with reduction of the hydrocarbon\ud ligand. In the case of the symmetrical complex HRu3 (CO) 3(Mec==CH==-\ud CMe) the cleaved hydrocarbon was identified as 2-pentyl trifluoroacetate\ud by 1HNMR and mass spectroscopy. The use of acid containing potassium trifluoroacetate gave the same organic product, in addition\ud to the new mononuclear complex fac-K[Ru(OCOCF3) 3(CO) 3] which was\ud characterized by spectroscopic (IR, mass) and analytical techniques.\ud This same complex was also obtained using Ru3(CO)l2 as reactant. (See more in text.