Hydrogen Activation by Benzene-Ruthenium Complexes in Aqueous Solution: Synthesis, Molecular Structure, and Intercalation of the Cluster Cation [{C6H6)4Ru4H4]2+

Abstract

The hydrogenation of the aqua complex [(C6H6)Ru(H20)3?+, prepared in situ by hydrolysis of (C6H6)2Ru2CI4 in water, was found to lead to the tetranuclear cluster dication [(C6H6)4Ru4H4]2+ (1) which crystallizes as the dichloride from the aqueous solution. In the presence of acetate ions, however, the reaction yields the dinuc1ear cations [(C6H6)2Ru2H(OOCCH3)X]+ (X=OH: 2, X=Cl: 3) which crystallize as the hexafluorophosphate salts. The X-ray crystal-structure analysis of [(C6H6)4Ru4H4]CI2 reveals the cluster dication 1 to consist of a tetrahedral ruthenium framework; the four hydrido ligands are presumably coordinated to three faces and to one edge of the RU4 tetrahedron. The cationic complexes 1 and 2 have been found to intercalate in sodium hectorite.