Cluster build-up in aqueous solution: synthesis, structure, protonation and catalytic properties of the trinuclear cation [(eta(6)-C6H6)(eta(6)-C6Me6)(2)Ru-3(mu(2)-H)(3)(mu(3)-O)](+)

The trinuclear ore-capped cluster cation [(eta(6)-C6H6)(eta(6)-C6Me6)(2)Ru- 3(mu(2)-H)(3)(mu(3)-O)](+) (2) was synthesised by reacting [(eta(6)- C6Me6) Ru(H2O)(3)](2+) with [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(3)](+) in aqueous solu tion. The single-crystal X-ray structure analysis of the tetrafluoroborate salt shows the cation to contain a H2O molecule hydrogen-bonded to the mu(3 )-oxo ligand. Acidification experiments show two protonation steps occuring at this H2O molecule and the oxo cap of the triruthenium cluster. The clus ter cation 2 catalyses the hydrogenation of aromatic compounds in aqueous s olution under biphasic conditions. (C) 1999 Elsevier Science Ltd. All right s reserved.